Liver resection represents the cornerstone treatment for Colo-Rectal Liver Metastases (CRLM), but it is still followed by a high recurrence rate. The identification of a valid and reproducible predictor of recurrence can play a key role in correct and timely management of the disease. In this scenario, liquid biopsy may represent an integrative, less invasive, and easily manageable tool to clinically stratify colorectal cancer patients.We aimed to investigate the prognostic role of persistent circulating tumor DNA (ctDNA) signature on CRLM recurrence after liver resection.

A series of 51 consecutive patients undergoing liver resection for CRLM were prospectively enrolled between January 2020 and March 2023. Patients underwent liquid biopsy from peripheral blood samples before and after surgery. Other risk factors for disease recurrence were also investigated.

Twenty-nine patients were found to be positive for one of the clinically relevant molecular alterations detected by NGS, at preoperative (T0) ctDNA analysis. At univariate analysis, total tumor size bigger than 60 mm (p = 0.046, HR 2.486) and postoperative persistence of ctDNA molecular signature (p = 0.024, HR 2.831) were significantly associated with recurrence. Multivariable Cox Regression analysis showed that only postoperative persistence of ctDNA molecular signature was associated with recurrence (p = 0.027, HR 2.766). Similarly, 1-3 yr DFS was significantly lower in the subgroup with persistence of molecular signature at liquid biopsy (100-49.5 % vs 57.1-21.4 %, p = 0.018).

Postoperative persistence of ctDNA molecular signature could represent a useful tool to predict recurrence after liver resection for CRLM patients.

The current AJCC staging for colorectal cancer liver metastasis (CRLM) classifies stages IVA, IVB, and IVC based on organ metastasis, disregarding lymph node metastasis (LNM). We evaluated the prognostic impact of LNM in CRLM and proposed incorporating LNM into staging criteria.

Data were extracted from the SEER database (2010-2017) and a Chinese cohort (2009-2018), including 11,266 CRLM patients (9648 SEER; 1618 Chinese cohort). Kaplan-Meier and Cox regression analyses assessed cancer-specific survival (CSS) between LNM and non-LNM groups. Inverse probability treatment weighting (IPTW) was used for primary analysis, with subgroup analyses exploring LNM's prognostic impact.

In both the SEER and Chinese cohorts, patients with LNM were significantly associated with worse CSS than patients without LNM before and after IPTW/sIPTW (all p < 0.001). Furthermore, LNM in the M1a subgroup still led to poorer prognosis (all log-rank p < 0.001). In contrast, in the M1b subgroup, the prognostic difference between those with and without LNM was not significant (log-rank p = 0.031 and 0.037, respectively, in the SEER and Chinese cohorts) because the PFDR was set at 0.025. Additionally, in both cohorts, the 5-year CSS rates of M1a stage CRLM patients decreased with advancing N staging, regardless of the resectability of liver metastasis (all log-rank P < 0.001).

LNM has significant association with worse survival outcomes in CRLM patients, although this prognostic impact exhibits progressive attenuation with increasing liver metastatic burden. For patients with M1a stage CRLM, we suggest that incorporating N staging into their prognostic evaluation can further refine the AJCC TNM staging system.

IntroductionDiagnosis and monitoring of metastatic colorectal cancer (mCRC) depend on diagnostic imaging. Circulating carcinoembryonic antigen (CEA) can be analyzed but no optimal, non-invasive biomarker exists. Circulating collagen IV (COL IV) is a promising biomarker in patients with colorectal liver metastases (CLM). This study aimed to evaluate COL IV and other cancer-related and stroma-derived proteins as biomarkers for mCRC.Materials & methodsPlasma COL IV and 10 other proteins were analyzed with ELISA and Luminex multiplex assays.ResultsmCRC patients have elevated levels of circulating COL IV, CEA, interleukin-8 (IL-8), hepatocyte growth factor (HGF), cytokeratin-19 fragments (CYFRA 21-1), osteopontin (OPN), and migration inhibitory factor (MIF) compared to primary CRC (pCRC) patients. COL IV is elevated in mCRC patients compared to healthy individuals. Levels of COL IV, CEA, OPN, CYFRA 21-1, IL-8, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were dependent on the metastatic site. OPN, CEA, and HGF are very good at discriminating between mCRC patients and pCRC controls. COL IV is very good at distinguishing between mCRC patients and healthy controls. The combination of OPN + CEA is superior at detecting mCRC than CEA alone. High HGF and COL IV levels correlate to poor prognosis.ConclusionOPN, CEA, and HGF are potential biomarkers for mCRC. COL IV is a potential biomarker for CLM. The combination of OPN with CEA is superior to CEA alone in detecting mCRC. Levels of circulating proteins depend on metastatic localization, implying that a combination of markers is better than single markers in detecting mCRC disease. High levels of COL IV and HGF have potential prognostic value.

This study aimed to investigate the prognostic impact of lymph node metastasis (LNM) on patients with colorectal cancer liver metastasis (CRLM) and elucidate the underlying immune mechanisms using multiomics profiling.

We enrolled patients with CRLM from the US Surveillance, Epidemiology, and End Results (SEER) cohort and a multicenter Chinese cohort, integrating bulk RNA sequencing, single-cell RNA sequencing and proteomics data. The cancer-specific survival (CSS) and immune profiles of the tumor-draining lymph nodes (TDLNs), primary tumors and liver metastasis were compared between patients with and without LNM. Pathological evaluations were used to assess immune cell infiltration and histological features.

The CRLM patients with LNM had significantly shorter CSS than patients without LNM in two large cohorts. Our results showed that nonmetastatic TDLNs exhibited a greater abundance of immune cells, including CD4+ T cells, CD8+ T cells, and CD19+ B cells, whereas metastatic TDLNs were enriched with fibroblasts, endothelial cells, and macrophages. Immunohistochemical analysis confirmed elevated levels of CD3+ T cells, CD8+ T cells, and CD19+ B cells in nonmetastatic TDLNs. The presence of nonmetastatic TDLNs was associated with enhanced antitumor immune responses in primary tumors, characterized by a higher Klintrup-Makinen (KM) grade and the presence of tertiary lymphoid structures. Furthermore, liver metastasis in patients with nonmetastatic TDLNs were predominantly of the desmoplastic growth pattern (dHGP), while those with metastatic TDLNs were predominantly of the replacement growth pattern (rHGP).

This research highlights the adverse prognostic impact of LNM on patients with CRLM and reveals potential related mechanisms through multiomics analysis. Our research paves the way for further refinement of the AJCC TNM staging system for CRLM in clinical practice.

The benefit of neoadjuvant chemotherapy (NAC) in patients with resectable colorectal liver metastasis (CRLM) is debatable. This study aimed to establish a definition of biologically borderline resectable CRLM based on early surgical failure.

One hundred forty-two patients who underwent upfront surgery for resectable CRLM were examined. Potential predictors of early surgical failure were investigated to establish a definition of biologically borderline resectable CRLM. The impact of NAC on overall survival (OS) in patients with borderline resectable CRLM was examined, as were predictors of OS.

Extrahepatic lesions (p < 0.01) and tumor ≥ 30 mm with carcinoembryonic antigen (CEA) concentration ≥ 20 ng/mL (p = 0.02) were independent predictors of early surgical failure. Borderline resectable CRLM was defined as extrahepatic lesions or tumor size ≥ 30 mm with CEA concentration ≥ 20 ng/mL. Fifty-eight patients had borderline resectable CRLM. Three-year OS was significantly higher in borderline resectable CRLM patients who received NAC than in those who did not (71.8% vs. 52.7%) and 5-year survival was also significantly higher in this group (62.8% vs. 25.5%).

We have proposed a simple definition of biologically borderline resectable CRLM based on early surgical failure. NAC could be a good indication for patients who met the definition.

Colorectal cancer most commonly metastasizes to the liver. While various treatment strategies have been developed, surgical management of these patients has vital implications on the prognosis and survival of this group of patients. There remains a need for a consensus guideline regarding the surgical evaluation and management of patients with colorectal liver metastases (CRLM).

This review article is a consensus guideline established by the members of the AHPBA Professional Standards Committee, as an amalgamation of existent literature and a guide to surgeons managing this complex disease.

These guidelines reports the benefits and shortcomings of various diagnostic modalities including imaging and next-generation sequencing in the management of patients with CRLM. While surgery has established survival benefits in patients with resectable disease, this report notes the importance of treatment sequencing with non-surgical modalities as well as between colon and liver resection. Finally, the guidelines address the various treatment modalities for patients with unresectable disease, that may have significant impact on survival.

CRLM is a complex diagnosis which warrants multidisciplinary approach with early surgical involvement in both assessment and management of the disease, to optimize patient outcomes and survival.

Kirsten rat sarcoma mutation was reported to adversely affect local tumor control after percutaneous ablation of colorectal liver metastasis. Nevertheless, the effect of Kirsten rat sarcoma mutation on surgical ablation has not been investigated in the literature. The aim of this study is to analyze the impact of Kirsten rat sarcoma mutation on local recurrence after surgical ablation of colorectal liver metastasis.

This was an institutional review board-approved study of patients who underwent surgical ablation of colorectal liver metastasis between 2005 and 2023 at a single center and underwent Kirsten rat sarcoma testing with ≥1 year follow-up. Local recurrence was analyzed using univariate Kaplan-Meier and multivariate Cox hazard models.

A total of 163 patients with 424 lesions fulfilled inclusion criteria. Fifty (30.7%) patients received radiofrequency ablation and 113 (69.3%) patients received microwave ablation. Fifty-seven patients (32.2%) with 177 lesions were found to have a Kirsten rat sarcoma mutation. Patients with Kirsten rat sarcoma mutation had a larger number of tumors, percentage of posteriorly located tumors, and tumor burden score compared with those with wild-type Kirsten rat sarcoma. Nevertheless, there was no difference between the groups regarding local recurrence per lesion (15% vs 17%, respectively, P = not significant). Independent predictors of local recurrence included tumor size, ablation margin, and blood vessel proximity for radiofrequency ablation compared with tumor size and ablation margin for microwave ablation.

There was no effect of Kirsten rat sarcoma mutations on local recurrence after surgical radiofrequency ablation or microwave ablation of colorectal liver metastasis in this study. Tumor size and ablation margin remained as independent predictors.

Liver transplant (LT) for colorectal cancer liver metastases (CRLM) is increasingly popular, yet the ideal selection criteria remain unknown. Pretransplant positron emission tomography (PET) metabolic tumor volume (MTV) has been described as predicting recurrence, with a proposed cutoff of MTV ≥70 cm 3 . This approach has not been validated. Patients undergoing LT for CRLM at 2 academic transplant centers (January 1, 2017, to December 1, 2023) were included. PET-MTV was calculated by a staff radiologist from the most recent PET-scan before LT using the published protocol. Twenty-six patients were included. Median follow-up was 609 days (IQR 320-1069) and from PET to LT was 1.9 months (1.3-2.6). Nearly all (n=24, 92.3%) received living donor transplantation. Absolute recurrence rate was 30.8% (n=8). Actuarial unadjusted 1- and 2-year recurrence-free survival (RFS) were 83% (n=15/18) and 62% (n=8/13); 1- and 2-year overall survival were 100% (n=18/18) and 85% (n=11/13). The incidence of recurrence-per-year follow-up was 0.35 when MTV ≥70 cm 3 versus 0.10 if MTV <70 cm 3 ( P <0.001). Median RFS using Kaplan-Meier product-estimate was 0.83 years (95% CI: 0.43-1.23) in MTV≥70 cm 3 versus 4.1 years (95% CI: 2.90-5.22) when MTV<70 cm 3 ( p <0.001); this was also associated with improved overall survival ( p =0.003). MTV>70 cm 3 demonstrated HR=2.42 (95% CI: 2.2-62.2, p =0.006) for association with RFS on univariate Cox-proportional hazards analysis, and an AUC=0.771 (95% CI: 0.560-0.981) for predicting recurrence ( p =0.030). Nineteen patients (69.2%) had histologically viable tumors, which were associated with recurrence (43% vs. 0%, p =0.039) and reduced RFS (log-rank p =0.019). PET-MTV was associated with the presence of histologically viable tumor (AUC=0.763, 95% CI: 0.583-0.944). PET-MTV ≥70 cm 3 was associated with reduced RFS and overall survival after LT for CRLM, confirming findings from the Norway group. This is likely due to its ability to identify residual viable tumors, which are independently associated with recurrence. PET-MTV should be a key selection criterion prior to LT for CRLM.

Laparoscopic parenchyma-sparing hepatectomy (PSH) is an effective treatment for colorectal liver metastases (CRLMs), but ensuring the safety and radicality of the procedure, particularly for deep-seated tumors, remains challenging. Surgical navigation technologies such as augmented reality navigation (ARN) and indocyanine green fluorescence imaging (ICG-FI) are increasingly utilized to guide surgery, yet their efficacy for CRLMs is unclear. This study aims to evaluate the short-term and long-term outcomes of ARN combined with ICG-FI-guided (ARN-FI) laparoscopic PSH for CRLMs.

Between January 2020 and December 2022, 89 consecutive patients who underwent laparoscopic PSH for CRLMs were included in the study. Patients were divided into an ARN-FI group ( n = 38) and a non-ARN-FI group ( n = 51) based on the use of ARN-FI. Inverse probability treatment weighting (IPTW) was used to balance baseline characteristics and minimize potential selection bias. Short-term and long-term outcomes were compared between the two groups. Cox regression analysis was conducted to identify risk factors associated with recurrence-free survival (RFS) and hepatic RFS.

After IPTW, there were 87 patients in the ARN-FI group and 89 patients in the non-ARN-FI group. Shorter parenchymal transection time, postoperative hospital stays, and wider margins were observed in the ARN-FI group. There was no significant difference in RFS or hepatic RFS between the groups. Mutant KRAS status was an independent risk factor for both RFS and hepatic RFS, while tumor diameter ≥ 5 cm and deep-seated location were risk factors for hepatic RFS. In the subgroup analysis of deep-seated tumors, the ARN-FI group also showed less intraoperative blood loss, a lower rate of strategy change, shorter postoperative recovery times, a higher R0 resection rate, and improved RFS and hepatic RFS.

In laparoscopic PSH for CRLMs, ARN-FI may improve surgical efficiency and accuracy. Especially for deep-seated tumors, it has the potential to reduce blood loss and attain higher R0 resection rates.

Colorectal cancer (CRC) is one of the leading cancers globally in terms of both incidence and cancer-related mortality. Liver metastatic disease is the main prognostic driver for patients with CRC. The management options for liver metastatic CRC continue to evolve, particularly with the incorporation of locoregional therapies into the treatment paradigm. Hepatic arterial infusion (HAI) chemotherapy is one such liver directed approach used with the goal of converting patients to liver resection, reducing the risk of recurrence, treating recurrent disease, and most importantly improving overall survival. This article summarizes the role of HAI chemotherapy in the treatment of liver metastatic CRC.

Perioperative chemotherapy has emerged as a critical component in managing resectable colorectal liver metastases (CRLM), aiming to improve long-term survival, although data supporting its use remains controversial. This narrative review explores the current state of perioperative chemotherapy in patients with resectable CRLM, focusing on its role in different oncological risk categories. The review highlights ongoing controversies, such as optimal patient selection and the role of post- versus preoperative treatment in specific scenarios.

Primary tumor resection and metastasectomy are curative for metastatic colorectal cancer. However, there is still a paucity of data regarding the clinical outcomes and risk factors after disease recurrence and second metastasectomy.

We retrospectively evaluated the clinical outcomes of patients who underwent the second metastasectomy. In addition, risk factors for the outcomes were analyzed.

A total of 94 patients (39 females and 55 males) received a second metastasectomy after the recurrence. Recurrent sites included the lung (47 patients), liver (36 patients), both lung and liver (four patients), and non-lung/non-liver (seven patients). Among them, 89 (94.7 %) patients achieved R0 resection, while three (3.2 %) and two (2.1 %) patients achieved R1 and R2 resections, respectively. The 5-year disease-free survival (DFS) and overall survival (OS) were 42.8±5.3 % and 67.2±4.9 %, respectively. Multivariable analysis for DFS identified that primary rectal cancer (hazard ratio [HR] 0.45, P=0.033) and disease-free interval after the first metastasectomy of ≥12 months (HR 0.39, P=0.002) were good predictive factors; in contrast, non-lung/non-liver metastasis (HR 3.32, P=0.020) was a poor predictive factor. Multivariable analysis for OS showed that age ≥70 years (HR 3.27, P=0.011), non-lung/non-liver metastasis (HR 4.04, P=0.024), and lesion number ≥2 (HR 2.25, P=0.023) were poor prognostic factors.

Patients who underwent a second metastasectomy had a long-term disease-free state and good OS. Our data suggest that a second metastasectomy should be considered if a patient has a limited number of metastases confined to the liver and/or lung and long DFS after the first metastasectomy.

We describe a novel pre-liver transplant (LT) approach in colorectal liver metastasis, allowing for improved monitoring of tumor biology and reduction of disease burden before committing a patient to transplantation. Patients undergoing LT for colorectal liver metastasis at Cleveland Clinic were included. The described protocol involves intensive locoregional therapy with systemic chemotherapy, aiming to reach minimal disease burden revealed by positron emission tomography scan and carcinoembryonic Ag. Patients with no detectable disease or irreversible treatment-induced liver injury undergo transplant. Nine patients received liver transplant out of 27 who were evaluated (33.3%). The median follow-up was 700 days. Seven patients (77.8%) received a living donor LT. Five had no detectable disease, and 4 had treatment-induced cirrhosis. Pretransplant management included chemotherapy (n = 9) +/- bevacizumab (n = 6) and/or anti-EGFR (n = 6). The median number of pre-LT cycles of chemotherapy was 16 (range 10-40). Liver-directed therapy included Yttrium-90 (n = 5), ablation (n = 4), resection (n = 4), and hepatic artery infusion pump (n = 3). Three patients recurred after LT. Actuarial 1- and 2-year recurrence-free survival were 75% (n = 6/8) and 60% (n = 3/5). Recurrence occurred in the lungs (n = 1), liver graft (n = 1), and lungs+para-aortic nodes (n = 1). Patients with pre-LT detectable disease had reduced RFS ( p = 0.04). All patients with recurrence had histologically viable tumors in the liver explant. Patients treated in our protocol (n = 16) demonstrated improved survival versus those who were not candidates (n = 11) regardless of transplant status ( p = 0.01). A protocol defined by aggressive pretransplant liver-directed treatment and transplant for patients with the undetectable disease or treatment-induced liver injury may help prevent tumor recurrence.

Laparoscopic hepatectomy for colorectal liver metastases (CRLM) is performed worldwide. However, owing to a lack of palpatory information and difficulties associated with accurate intraoperative ultrasonographic diagnosis, the tumor may be exposed at the hepatic transection margin. This study aimed to investigate the pathological significance of near-infrared (NIR) fluorescence imaging with indocyanine green (ICG)-guided laparoscopic hepatectomy and determine its usefulness in securing the resection margin for CRLMs.

Fifty-nine patients who underwent laparoscopic hepatectomy for CRLM using NIR fluorescence imaging between February 2017 and June 2021 at Sapporo Medical University Hospital were included. Generally, all patients received intravenous ICG (2.5 mg/body) as a fluorescence agent 1 to 2 days before surgery. During the surgical procedure, real-time NIR fluorescence imaging was repeatedly performed to assess the surgical margins.

Of the 94 tumors in 59 patients, laparoscopic NIR fluorescence imaging identified 56 tumors (59.6%) on the liver surface. Pathological analysis indicated clear margins in 96.6% (57/59) of patients. Examination of paraffin-embedded sections, which were successful in only 20 of 94 cases (21.3%), revealed that there were no tumor cells positive for NIR fluorescence, and the median distance of the continuous fluorescent signal from the tumor margin was 1.074 mm.

We demonstrated a high R0 rate using NIR fluorescence-guided hepatectomy. This technique has the potential to improve intraoperative tumor identification and tumor margin assurance and reduce the rate of positive resection margins in patients with CRLMs.

Colorectal cancer cells containing mobile lipids are said to be an early indicator of chemotherapy effects. The objective of the study was to examine the frequency and clinical relevance of intratumoral fat deposition in colorectal liver metastases (CRLM) post-chemotherapy using dual-echo chemical shift gradient-echo magnetic resonance imaging (MRI).

A retrospective analysis of 98 patients with CRLM diagnosed between 2017 and 2022 (69 M, mean age 62.87 ± 10.73 years old) who had an MRI after chemotherapy was performed. On dual-echo chemical shift gradient-echo MRI, intratumoral fat deposition of CRLM was evaluated. A signal intensity drop of ≥ 12% in opposed-phase images vs. in-phase images indicated intratumoral fat. After chemotherapy, the presence of fat deposition was correlated with patients' overall survival.

Before and after chemotherapy, 0 (0%) and 29 (29.59%) patients exhibited intratumoral fat. The number of CRLM ranged from 1 to 25 with a median of 3 and a mean size of 32.58 ± 22.95 mm. The groups had statistically different survival times. Overall survival was shorter for patients with intratumoral fat deposition in CRLM (32 months (24-60, 95% CI)) than for patients without fat deposition in CRLM (48 months (36-NA, 95% CI)).

In our group, nearly 30% of CRLM patients exhibited intratumoral fat after chemotherapy. Patients with intratumoral fat deposition in CRLM have a shorter overall survival time. The presence of fat in CRLM correlates with a poor long-term prognosis.

Colorectal cancer (CRC) is a common malignancy with a low survival rate as well as a low response rate to immunotherapy. This study aims to develop a risk model based on tertiary lymphoid structure (TLS)-associated gene signatures to enhance predictions of prognosis and immunotherapy response.

TLS-associated gene data were obtained from TCGA-CRC and GEO cohorts. A comprehensive analysis using univariate Cox regression identified TLS-associated genes with significant prognostic implications. Subsequently, multiple algorithms were employed to select the most influential genes, and a stepwise Cox regression model was constructed. The model's predictive performance was validated using independent datasets (GSE39582, GSE17536, and GSE38832). To further investigate the immune microenvironment, immune cell infiltration in high-risk (HRG) and low-risk (LRG) groups was assessed using the CIBERSORT and ssGSEA algorithms. Additionally, we evaluated the model's potential to predict immune checkpoint blockade therapy response using data from The Cancer Imaging Archive, the TIDE algorithm, and external immunotherapy cohorts (GSE35640, GSE78200, and PRJEB23709). Immunohistochemistry (IHC) was employed to characterize TLS presence and CCL2 gene expression.

A three-gene (CCL2, PDCD1, and ICOS) TLS-associated model was identified as strongly associated with prognosis and demonstrated predictive power for CRC patient outcomes and immunotherapy efficacy. Notably, patients in the low-risk group (LRG) had a higher overall survival rate as well as a higher re-response rate to immunotherapy compared to the high-risk group (HRG). Finally, IHC results confirmed significantly elevated CCL2 expression in the TLS regions.

The multi-algorithm-integrated model demonstrated robust performance in predicting patient prognosis and immunotherapy response, offering a novel perspective for assessing immunotherapy efficacy. CCL2 may function as a TLS modulator and holds potential as a therapeutic target in CRC.

Lymphatic node metastatic disease encompasses a distinct oncological entity which has been associated with poor prognosis. Image-guided thermal ablation has recently been proposed as a safe and alternative treatment for these lesions. The aim of this systematic review is to evaluate the pooled safety and efficacy of thermal ablation techniques for the treatment of oligometastatic non-cervical lymph nodal disease.

A systematic search of the three major databases (MEDLINE, EMBASE, and CENTRAL) from inception to 30 December 2023 was conducted according to the PRISMA Guidelines. Observational studies reporting technical success, complications and oncologic outcomes were included. Meta- analysis was performed by estimating the pooled incidence rates and risk ratios by fitting random-effect models. Overall, 8 studies were included, comprising of 225 patients and 305 ablated LNMs and a median follow-up of 12 months. The combined data analysis showed that technical success after thermal ablation was 98% (CI: 95%-99%), major complication rate was 1% (CI: 95%-99%), pooled overall response rate was 72% (CI: 54%-87%), local tumor progression rate was 18% (CI: 8%-33%) and disease-free survival rate was 68% (CI: 51%-81%). No difference between radiofrequency ablation and cryoablation was found for every outcome during subgroup analysis. Image-guided percutaneous thermal ablation (with either radiofrequency ablation or cryoablation) is safe and effective for the treatment of oligometastatic LMN disease, however further studies to confirm these findings are still needed.

Two-stage hepatectomy (TSH) enables patients to undergo surgery for colorectal liver metastasis (CRLM), which one-stage hepatectomy cannot remove. Although the outcome of TSH has been reported, there is no original report from Japan. The aim of this retrospective study was to evaluate the outcome of TSH in Japanese patients with CRLM.

The authors conducted a retrospective cohort study using the nationwide database that included clinical information of 12 519 patients treated with CRLM between 2005 and 2017 in Japan. The primary outcome measure was overall survival. The second outcome measure was progression-free survival. Fisher's exact test, χ 2 test and Mann-Whitney U test were conducted to examine an intergroup difference. Univariate and multivariate analyses were performed using Cox regression model. Survival analysis was performed by Kaplan-Meier method and log-rank test.

Of the database, 53 patients undergoing TSH using portal vein embolization (PVE) were identified and analyzed. Their morbidity and in-hospital mortality rates at the second hepatectomy were 26.4% and 0.0%. The mean observation period was 21.8 months. The estimated 1-, 3- and 5-year overall survival rate were 92.5%, 70.8% and 34.7%. Multivariate analyses showed that more than 10 liver nodules significantly increased the mortality risk by 4.2-fold (95% CI 1.224-14.99, P = 0.023). Survival analysis revealed that repeat hepatectomy for disease progression after TSH was superior to chemotherapy in overall survival (mean: 49.6 vs. 18.7, months, P = 0.004).

In the Japanese cohort, TSH was confirmed to be a safety procedure with an acceptable survival outcome. More than 10 liver nodules may be a predictor for unfavorable outcomes of patients with CRLM undergoing TSH. Furthermore, repeat hepatectomy can be a salvage treatment for resectable intrahepatic recurrence after TSH.

Colorectal cancer (CRC) is the third most common cause of cancer mortality worldwide. Of these, approximately 25% will have liver metastasis. We performed 394 microwave ablations (MWAs) and analyzed outcomes for survival and ablation failure.

We conducted a retrospective review of patients who underwent a surgical MWA at a single-center high-volume institution from October 2006 to September 2022 using a prospectively maintained database. The primary outcome was overall survival.

A total of 394 operations were performed on 328 patients with 842 tumors undergoing MWA. Median tumor size was 1.5 cm (range 0.4 to 7.0 cm), with the median number of tumors ablated per operation being 1 (range 1 to 11). A laparoscopic approach was used 77.9% of the time. Concomitant procedures were performed 63% of the time, most commonly hepatectomy (22.3%), cholecystectomy (17.5%), and colectomy (6.6%). Clavien-Dindo grade III or IV complication occurred in 12 patients (3.6%), and all of these patients had undergone concomitant procedures. Mortality within 30 days occurred in 4 patients (1.2%). The rate of incomplete ablation was 1.5% per tumor. Local recurrence occurred at a rate of 6.3% per tumor. Black patients were found to have a higher incidence of incomplete ablation and local recurrence. One-year survival probability was 91% (95% CI 87.9 to 94.3), with a mean overall survival of 57.6 months (95% CI 49.9 to 65.4 months).

Surgical MWA offers a low-morbidity approach to treatment of colorectal liver metastasis, with low rate of failure. This large series reviews the outcomes of MWA as definitive treatment for colorectal liver metastasis.

Mucinous adenocarcinoma (MAC) is a distinct subtype of colorectal cancer. Previous studies have confirmed the poor prognosis of rectal or left-sided colon MAC, while the prognosis and response to chemotherapy in proximal colon MAC remains controversial. The aim of this study was to investigate the clinicopathological characteristics, prognosis, response to chemotherapy, and risk prediction factors of proximal colon MAC. Patients with proximal colon MAC and non-mucinous adenocarcinoma (NMAC) were retrospectively analyzed in this study. The analyzed variables included gender, age, smoking, drinking, chemotherapy, metastasis, pathological stage, and tumor size. Overall survival (OS) was the primary outcome. Kaplan-Meier analysis was used to assess the impact of mucinous subtype and chemotherapy on OS. We conducted univariate and multivariate Cox regression analyses to determine prognosis factors for proximal colon MAC and NMAC. A total of 284 cases of proximal colon MAC and 1384 cases of NMAC were included in the study. Compared to NMAC, proximal colon MAC was diagnosed at a younger age. The proportion of synchronous and metachronous metastasis was also higher, as well as the pathological stage and tumor size. Proximal colon MAC had a worse prognosis than NMAC, especially in stage 3. Moreover, the prognosis of proximal colon NMAC improved after chemotherapy, while MAC showed no improvement in prognosis after chemotherapy. Advanced age, N1 and N2 stage were independent prognostic factors for adverse outcomes in MAC. For proximal colon adenocarcinoma, the independent predictors of adverse outcomes included mucinous subtype, order age, N1 and N2 stages, and pathological stage 4. Proximal colon MAC had a worse prognosis compared to NMAC. Chemotherapy did not improve the prognosis of proximal colon mucinous adenocarcinoma.

This study aimed to assess the prognostic value of total tumor volume (TTV) for early recurrence (within 6 months) and overall survival (OS) in patients with colorectal liver metastases (CRLM), treated with induction systemic therapy followed by complete local treatment.

Patients with initially unresectable CRLM from the multicenter randomized phase 3 CAIRO5 trial (NCT02162563) who received induction systemic therapy followed by local treatment were included. Baseline TTV and change in TTV as response to systemic therapy were calculated using the CT scan before and the first after systemic treatment, and were assessed for their added prognostic value. The findings were validated in an external cohort of patients treated at a tertiary center.

In total, 215 CAIRO5 patients were included. Baseline TTV and absolute change in TTV were significantly associated with early recurrence (P = 0.005 and P = 0.040, respectively) and OS in multivariable analyses (P = 0.024 and P = 0.006, respectively), whereas RECIST1.1 was not prognostic for early recurrence (P = 0.88) and OS (P = 0.35). In the validation cohort (n = 85), baseline TTV and absolute change in TTV remained prognostic for early recurrence (P = 0.041 and P = 0.021, respectively) and OS in multivariable analyses (P < 0.0001 and P = 0.012, respectively), and showed added prognostic value over conventional clinicopathological variables (increase C-statistic, 0.06; 95 % CI, 0.02 to 0.14; P = 0.008).

Total tumor volume is strongly prognostic for early recurrence and OS in patients who underwent complete local treatment of initially unresectable CRLM, both in the CAIRO5 trial and the validation cohort. In contrast, RECIST1.1 did not show prognostic value for neither early recurrence nor OS.

Metastatic colorectal cancer (mCRC) is a major cause of cancer-related death, with a 5-year relative overall survival of up to 20%. The liver is the most common site of distant metastasis in colorectal cancer (CRC), with about 50% of CRC patients metastasizing to their liver over the course of their disease. Complete liver resection is the primary modality of treatment for resectable colorectal cancer liver metastasis (CRLM), with an overall 5-year survival rate of up to 58%. However, only 15% to 20% of patients with CRLM are deemed suitable for resection at presentation. For unresectable diseases, the median survival of patients remains low even with the best chemotherapy. In recent decades, the management of CRLM has continued to evolve with the expansion of resection criteria, novel targeted systemic therapies, and improved locoregional therapies. However, due to the heterogeneity of the CRC patient population, the optimal evaluation of treatment options for CRLM remains complex. Therefore, effective management requires a multidisciplinary team to help define resectability and devise a personalized treatment approach, from the initial diagnosis to the final treatment.

Early diagnosis and accurate prognosis of colorectal cancer is critical for determining optimal treatment plans and maximizing patient outcomes, especially as the disease progresses into liver metastases. Computed tomography (CT) is a frontline tool for this task; however, the preservation of predictive radiomic features is highly dependent on the scanning protocol and reconstruction algorithm. We hypothesized that image reconstruction with a high-frequency kernel could result in a better characterization of liver metastases features via deep neural networks. This kernel produces images that appear noisier but preserve more sinogram information. A simulation pipeline was developed to study the effects of imaging parameters on the ability to characterize the features of liver metastases. This pipeline utilizes a fractal approach to generate a diverse population of shapes representing virtual metastases, and then it superimposes them on a realistic CT liver region to perform a virtual CT scan using CatSim. Datasets of 10,000 liver metastases were generated, scanned, and reconstructed using either standard or high-frequency kernels. These data were used to train and validate deep neural networks to recover crafted metastases characteristics, such as internal heterogeneity, edge sharpness, and edge fractal dimension. In the absence of noise, models scored, on average, 12.2% ( α = 0.012 ) and 7.5% ( α = 0.049 ) lower squared error for characterizing edge sharpness and fractal dimension, respectively, when using high-frequency reconstructions compared to standard. However, the differences in performance were statistically insignificant when a typical level of CT noise was simulated in the clinical scan. Our results suggest that high-frequency reconstruction kernels can better preserve information for downstream artificial intelligence-based radiomic characterization, provided that noise is limited. Future work should investigate the information-preserving kernels in datasets with clinical labels.

Colorectal liver metastasis (CRLM) is a disease entity that warrants special attention due to its high frequency and potential curability. Identification of "high-risk" patients is increasingly popular for risk stratification and personalization of the management pathway. Traditional regression-based methods have been used to derive prediction models for these patients, and lately, focus has shifted to artificial intelligence-based models, with employment of variable supervised and unsupervised techniques. Multiple endpoints, like overall survival (OS), disease-free survival (DFS) and development or recurrence of postoperative complications have all been used as outcomes in these studies. This review provides an extensive overview of available clinical prediction models focusing on the prognosis of CRLM and highlights the different predictor types incorporated in each model. An overview of the modelling strategies and the outcomes chosen is provided. Specific patient and treatment characteristics included in the models are discussed in detail. Model development and validation methods are presented and critically appraised, and model performance is assessed within a proposed framework.

Colorectal cancer is the second most common cause of cancer death in the United States, and up to half of patients develop colorectal liver metastases (CRLMs). Notably, somatic genetic mutations, such as mutations in RAS, BRAF, mismatch repair (MMR) genes, TP53, and SMAD4, have been shown to play a prognostic role in patients with CRLM. This review summarizes and appraises the current literature regarding the most relevant somatic mutations in surgically treated CRLM by not only reviewing representative studies, but also providing recommendations for areas of future research. In addition, advancements in genetic testing and an increasing emphasis on precision medicine have led to a more nuanced understanding of these mutations; thus, more granular data for each mutation are reviewed when available. Importantly, such knowledge can pave the way for precision medicine with the ultimate goal of improving patient outcomes.

Colorectal cancer (CRC) is the 3rd most common malignancy with the liver being the most common site of metastases. The recurrence rate of colorectal liver metastases (CRLM) after liver resection (LR) is notably high, with an estimated 40% of patients experiencing recurrence within 6 months. In this context, we conducted a meta-analysis to synthesize and evaluate the reliability of evidence pertaining to prognostic factors associated with early recurrence (ER) in CRLM following LR.

Systematic searches were conducted from the inception of databases to July 14, 2023, to identify studies reporting prognostic factors associated with ER. The Quality in Prognostic Factor Studies (QUIPS) tool was employed to assess risk-of-bias for included studies. Meta-analysis was then performed on these prognostic factors, summarized by forest plots. The grading of evidence was based on sample size, heterogeneity, and Egger's P value.

The study included 24 investigations, comprising 12705 individuals, during an accrual period that extended from 2007 to 2023. In the evaluation of risk-of-bias, 22 studies were rated as low/moderate risk, while two studies were excluded because of high risk. Most of the studies used a postoperative interval of 6 months to define ER, with 30.2% (95% confidence interval [CI], 24.1-36.4%) of the patients experiencing ER following LR. 21 studies were pooled for meta-analysis. High-quality evidence showed that poor differentiation of CRC, larger and bilobar-distributed liver metastases, major hepatectomy, positive surgical margins, and postoperative complications were associated with an elevated risk of ER. Additionally, moderate-quality evidence suggested that elevated levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA199), lymph node metastases (LNM) of CRC, and a higher number of liver metastases were risk factors for ER.

This review has the potential to enhance the efficacy of surveillance strategies, refine prognostic assessments, and guide judicious treatment decisions for CRLM patients with high risk of ER. Additionally, it is essential to undertake well-designed prospective investigations to examine additional prognostic factors and develop salvage therapeutic approaches for ER of CRLM.

Colorectal cancer (CRC) liver metastasis, albeit a stage-IV disease, is completely curable by surgical resection in selected patients. In addressing the molecular basics of this phenomenon, differentially expressed genes at primary and liver metastatic sites were screened by RNA sequencing with the use of paraffin-embedded surgical specimens. Chemokine C-C motif ligand 1 (CCL1), a chemotactic factor for a ligand of the chemokine C-C motif receptor 8 (CCR8), was isolated as one of the differentially expressed genes. Histological analysis revealed that the number of CCL1-positive cells, mainly tumour associated macrophages (TAMs) located in the stroma of CRC, decreased significantly at liver metastatic sites, while the expression level of CCR8 on CRC remained unchanged. To explore the biological significance of the CCL1-CCR8 axis in CRC, CCR8-positive CRC cell line Colo320DM was used to assess the effect of the CCL1-CCR8 axis on major signalling pathways, epithelial mesenchymal transition induction and cell motility. Upon stimulation of recombinant CCL1 (rCCL1), phosphorylation of AKT was observed in Colo320DM cells; on the other hand, the corresponding significant increase in MMP-2 levels demonstrated by RT-qPCR was nullified by siRNA (siCCR8). In the scratch test, rCCL1 treatment significantly increased the motility of Colo320DM cells, which was similarly nullified by siCCR8. Thus, the activation of the CCL1-CCR8 axis is a positive regulator of CRC tumour progression. Reduced CCL1 expression of TAMs at liver metastatic sites may partly explain the unique slow tumour progression of CRC, thus providing for a grace period for radical resection of metastatic lesions.

Advancement in systemic and regional radiation therapy, surgical technique, and anesthesia has provided a path for increased long-term survival and potential cure for more patients with stage IV rectal cancer in recent years. When patients have resectable disease, the sequence for surgical resection is classified in three strategies: classic, simultaneous, or combined, and reversed. The classic approach consists of rectal cancer resection followed by metastatic disease at a subsequent operation. Simultaneous resection addresses both rectal and metastatic disease in a single surgery. The reversed approach treats metastatic disease first, followed by the primary tumor in several months. Simultaneous resection is appropriate for selected patients to avoid delay of definitive surgery, and reduce number of surgeries, hospital stay, and cost to the health care system. It may also improve patients' psychological effect. Multidisciplinary discussions including colorectal and liver surgeons to review patients' baseline medical conditions, tumor biology and behavior, and disease burden and distribution is imperative to guide proper patient selection for simultaneous resection and perioperative treatments.

Colorectal cancer is a common malignancy in men and women. Historically, stage IV colorectal cancer has 10 to 15% five-year survival. Developments in the management of colorectal metastatic disease have helped improve the overall survival of stage IV colorectal cancers from 12 to 30 months with some patients achieving disease-free survival.

Colorectal cancer liver metastasis (CRLM) occurs in upto 50% of cases and drives patient outcomes. Up-front liver resection is the treatment of choice in resectable cases. There is no consensus yet established as to the safety of intraoperative autotransfusion in liver resection for CRLM.

Patients undergoing curative-intent hepatectomy for CRLM at a single quaternary-care institution from 1999 to 2016 were included. Demographics, surgical variables, Fong Clinical Risk Score (FCRS), use of intraoperative auto and/or allotransfusion, and survival data were analyzed. Propensity score matching (PSM) was performed accounting for allotransfusion, extent of hepatectomy, FCRS, and systemic treatment regimens.

Three-hundred sixteen patients were included. The median follow-up was 10.4 years (7.8-14.1 years). The median recurrence-free survival (RFS) and overall survival (OS) in all patients were 1.6 years (interquartile range: 0.63-6.6 years) and 4.4 years (2.1-8.7), respectively.  Before PSM, there was a significantly reduced RFS in the autotransfusion group (0.96 vs. 1.73 years, p = 0.20). There was no difference in OS (4.11 vs. 4.44 years, p = 0.118). Patients in groups of FCRS 0-2 and 3-5 both had reduced RFS when autotransfusion was used (p = 0.005). This reduction in RFS was further found when comparing autotransfusion versus no autotransfusion within the FCRS 0-2 group and within the FCRS 3-5 group (p = 0.027). On Cox-regression analysis, autotransfusion (hazard ratio = 1.423, 1.028-2.182, p = 0.015) remained predictive of RFS. After PSM, there were no differences in FCRS (p = 0.601), preoperative hemoglobin (p = 0.880), allotransfusion (p = 0.130), adjuvant chemotherapy (p = 1.000), immunotherapy (p = 0.172), tumor grade (p = 1.000), use of platinum-based chemotherapy (p = 0.548), or type of hepatic resection (p = 0.967). After matching, there was a higher rate of recurrence with autotransfusion (69.0% vs. 47.6%, p = 0.046). There was also a reduced time to recurrence in the autotransfusion group compared with the group without (p = 0.006). There was no difference in OS after PSM (p = 0.262).

Autotransfusion may adversely affect recurrence in liver resection for CRLM. Until further studies clarify this risk profile, the use of intraoperative autotransfusion should be critically assessed on a case-by-case basis only when other resuscitation options are not available.

Proper preclinical models for the research of colorectal cancer (CRC) and CRC liver metastases (CLM) are a clear and unmet need. Patient-derived organoids have recently emerged as a robust preclinical model, but are not available to all scientific researchers. Here, we present paired 3D organoid cell lines of CWH22 (CRC-derived) and CLM22 (CLM-derived) with sound background information and the short tandem repeats are identical to those of the normal tissue. Morphological and immunohistochemical staining, along with whole-exome sequencing (WES), confirmed that the organoids exhibited the same differentiation, molecular expression, and mutation status as the corresponding tumor tissue. Both organoids possessed mutated APC/KRAS/SMAD4/CDKN1B/KMT2C genes and wild-type TP53 and PIK3CA; stably secreted the tumor markers CEA and CA19-9, and possessed sound proliferation rates in vitro, as well as subcutaneous tumorigenicity and liver metastatic abilities in vivo. IC50 assays confirmed that both cell lines were sensitive to 5-fluorouracil, oxaliplatin, SN-38, and sotorasib. WES and karyotype analyses revealed the genomic instability status as chromosome instability. The corresponding adherent cultured CWH22-2D/CLM22-2D cells were established and compared with commonly used CRC cell lines from the ATCC. Both organoids are publicly available to all researchers and will be useful tools for specific human CRC/CLM studies both in vitro and in vivo.

This paper presents a deep learning (DL) approach for predicting survival probabilities of renal cancer patients based solely on preoperative CT imaging. The proposed approach consists of two networks: a classifier- and a survival- network. The classifier attempts to extract features from 3D CT scans to predict the ISUP grade of Renal cell carcinoma (RCC) tumors, as defined by the International Society of Urological Pathology (ISUP). Our classifier is a 3D convolutional neural network to avoid losing crucial information on the interconnection of slides in 3D images. We employ multiple procedures, including image augmentation, preprocessing, and concatenation, to improve the performance of the classifier. Given the strong correlation between ISUP grading and renal cancer prognosis in the clinical context, we use the ISUP grading features extracted by the classifier as the input to the survival network. By leveraging this clinical association and the classifier network, we are able to model our survival analysis using a simple DL-based network. We adopt a discrete LogisticHazard-based loss to extract intrinsic survival characteristics of RCC tumors from CT images. This allows us to build a completely parametric survival model that varies with patients' tumor characteristics and predicts non-proportional survival probability curves for different patients. Our results demonstrated that the proposed method could predict the future course of renal cancer with reasonable accuracy from the CT scans. The proposed method obtained an average concordance index of 0.72, an integrated Brier score of 0.15, and an area under the curve value of 0.71 on the test cohorts.

CRC with liver metastases is a major contributor to cancer-related mortality. Despite advancements in liver resection techniques, patient survival remains a concern due to high recurrence rates. This study seeks to uncover prognostic biomarkers that predict overall survival in patients undergoing curative hepatic resection for CRC liver metastases.

Prospectively collected serum samples from a cohort of 49 patients who received curative hepatic resection for CRC liver metastases were studied. The patients are part of a cohort, previously analyzed for perioperative complications (see methods). Various preoperative serum markers, clinical characteristics, and factors were analyzed. Univariate and multivariate Cox regression analyses were conducted to determine associations between these variables and disease-free survival as well as overall survival.

For disease-free survival, univariate analysis highlighted the correlation between poor outcomes and advanced primary tumor stage, high ASA score, and synchronous liver metastases. Multivariate analysis identified nodal-positive primary tumors and synchronous metastases as independent risk factors for disease-free survival. Regarding overall survival, univariate analysis demonstrated significant links between poor survival and high preoperative IL-8 levels, elevated neutrophil-lymphocyte ratio (NLR), and presence of metastases in other organs. Multivariate analysis confirmed preoperative IL-8 and having three or more liver metastases as independent risk factors for overall survival. The impact of IL-8 on survival was particularly noteworthy, surpassing the influence of established clinical factors.

This study establishes preoperative IL-8 levels as a potential prognostic biomarker for overall survival in patients undergoing curative liver resection for CRC liver metastases. This study underscores the importance of incorporating IL-8 and other biomarkers into clinical decision-making, facilitating improved patient stratification and tailored treatment approaches. Further research and validation studies are needed to solidify the clinical utility of IL-8 as a prognostic marker.

Despite the increasing trend in liver resections for non-colorectal non-neuroendocrine liver metastases (NCNNLM), the role of surgery for these liver malignancies is still debated. Registries are an essential, reliable tool for assessing epidemiology, diagnosis, and therapeutic approach in a single hub, especially when data are dispersive and inconclusive, as in our case. The dissemination of this preliminary survey would allow us to understand if the creation of an International Registry is a viable option, while still offering a snapshot on this issue, investigating clinical practices worldwide. The steering committee designed an online questionnaire with Google Forms, which consisted of 37 questions, and was open from October 5th, 2022, to November 30th, 2022. It was disseminated using social media and mailing lists of the Italian Society of Endoscopic Surgery and New Technologies (SICE), the Association of Italian Surgeons in Europe (ACIE), and the Spanish Chapter of the American College of Surgeons (ACS). Overall, 141 surgeons (approximately 18% of the total invitations sent) from 27 countries on four continents participated in the survey. Most respondents worked in general surgery units (62%), performing less than 50 liver resections/year (57%). A multidisciplinary discussion was currently performed to validate surgical indications for NCNNLM in 96% of respondents. The most commonly adopted selection criteria were liver resectability, RECIST criteria, and absence of extrahepatic disease. Primary tumors were generally of gastrointestinal (42%), breast (31%), and pancreaticobiliary origin (13%). The most common interventions were parenchymal-sparing resections (51% of respondents) of metachronous metastases with an open approach. Major post-operative complications (Clavien-Dindo > 2) occurred in up to 20% of the procedures, according to 44% of respondents. A subset analysis of data from high-volume centers (> 100 cases/year) showed lower post-operative complications and better survival. The present survey shows that NCNNLM patients are frequently treated by surgeons in low-volume hospitals for liver surgery. Selection criteria are usually based on common sense. Liver resections are performed mainly with an open approach, possibly carrying a high burden of major post-operative complications. International guidelines and a specific consensus on this field are desirable, as well as strategies for collaboration between high-volume and low-volume centers. The present study can guide the elaboration of a multi-institutional document on the optimal pathway in the management of patients with NCNNLM.

Small retrospective series suggest that local consolidative treatment (LCT) may improve survival in oligometastatic pancreatic ductal adenocarcinoma (PDAC). However, no uniform definition of oligometastatic disease (OMD) in PDAC exists; this impedes meaningful conclusions.

A systematic literature search using PubMed, Web of Science, and Cochrane CENTRAL registries for studies and protocols reporting on definitions and/or LCT of OMD in PDAC was performed. The primary endpoint was the definition of OMD. Levels of agreement were categorized as consensus (≥75% agreement between studies), fair agreement (50%-74%), and absent/poor agreement (<50%).

After screening of 5374 abstracts, the full text of 218 studies was assessed, of which 76 were included in the qualitative synthesis. The majority of studies were retrospective (n = 66, 87%), two were prospective studies and eight were study protocols. Studies investigated mostly liver (n = 38, 51%) and lung metastases (n = 15, 20%). Across studies, less than one-half (n = 32, 42%) reported a definition of OMD, while 44 (58%) did not. Involvement was limited to a single organ (consensus). Additional criteria for defining OMD were the number of lesions (consensus), metastatic site (poor agreement), metastatic size (poor agreement), treatment possibilities (poor agreement), and biomarker response (poor agreement). Liver OMD could involve three or fewer lesions (consensus) and synchronous disease (fair agreement), while lung metastases could involve two or fewer lesions and metachronous disease (consensus). The large majority of studies were at a high risk of bias or did not include any control groups.

Definitions of OMD were not used or varied widely between studies hampering across-study comparability and highlighting an unmet need for a consensus. The present study is part of a multistep process that aims to develop an interdisciplinary consensus on OMD in pancreatic cancer.

Recurrence post hepatectomy for colorectal liver metastases (CRLM) occurs in 70 % of patients within two years. No established guidance on the method or intensity of follow-up currently exists. The aim of this systematic review was to summarise literature and determine whether it is possible to identify an optimal follow up regime. To this date there are no randomised prospective studies investigating this.

A systematic review was performed according to PRISMA guidelines. Outcomes included general demographics, method, frequency and duration of follow up, survival and recurrence data. Quality assessment of the papers was performed.

Twenty-five articles published between 1994 and 2022 were included, including 9945 patients. CT was the most common imaging modality (n = 14) and CEA most common blood test (n = 11). Intensity of follow up was higher in the first two years post resection and only two papers continued follow up post 5 years resection. There was wide variation in outcome measures - Overall survival (OS) was most commonly reported. Nine papers reported OS ranging between 39 and 78.1 %.

There is wide variation in follow up methods and outcome reporting. There is no strong evidence to support intensive follow up, and the benefits of long term follow up are also unknown due to the lack of patient centred data. High quality, prospective studies should be the focus of future research as further retrospective data is unlikely to resolve uncertainties around optimal follow up.

Background and Objectives: The issue of a missing variable precludes the external validation of many prognostic models. For example, the Liverpool score predicts the survival of patients undergoing surgical therapy for colorectal liver metastases, but it includes the neutrophil-lymphocyte ratio, which cannot be measured retrospectively. Materials and Methods: We aimed to find the most appropriate replacement for the neutrophil-lymphocyte ratio. Survival analysis was performed on data representing 632 liver resections for colorectal liver metastases from 2000 to 2020. Variables associated with the Liverpool score, C-reactive protein, albumins, and fibrinogen were ranked. The rankings were performed in four ways: The first two were based on the Kaplan-Meier method (log-rank statistics and the definite integral IS between two survival curves). The next method of ranking was based on univariate and multivariate Cox regression analyses. Results: The ranks were as follows: the radicality of liver resection (rank 1), lymph node infiltration of primary colorectal cancer (rank 2), elevated C-reactive protein (rank 3), the American Society of Anesthesiologists Classification grade (rank 4), the right-sidedness of primary colorectal cancer (rank 5), the multiplicity of colorectal liver metastases (rank 6), the size of colorectal liver metastases (rank 7), albumins (rank 8), and fibrinogen (rank 9). Conclusions: The ranking methodologies resulted in almost the same ranking order of the variables. Elevated C-reactive protein was ranked highly and can be considered a relevant replacement for the neutrophil-lymphocyte ratio in the Liverpool score. These methods are suitable for ranking variables in similar models for medical research.