To investigate the influence of a micro-enema on diagnostic performance, submucosal width, reader confidence, and tumor conspicuity using MRI to stage early rectal cancers (ERC).

In this single-center study, we consecutively included 50 participants with assumed ERC who all completed MRI with (MRin) and without (MRex) a micro-enema. The diagnostic performance was recorded for two experienced radiologists using histopathology as the gold standard. In addition, the width of the submucosa in the tumor-bearing wall, reader confidence for T-staging, and tumor conspicuity were assessed. Significance levels were calculated using McNemar's test (diagnostic performance) and Wilcoxon's signed-rank test (reader confidence, submucosal width, and conspicuity). Interreader agreement was assessed using kappa statistics.

Sensitivity/specificity were for Reader1 91%/87% for both MRex and MRin and for Reader2 74%/87% and 89%/87%, both readers p > 0.05. The micro-enema induced a significant widening of the submucosa, p < 0.001, with a mean increase of 2.2/2.8 mm measured by Reader1/Reader2. Reader confidence in T-staging and tumor conspicuity increased for both readers, p < 0.005. The proportion of tumors with both correct staging and high reader confidence increased from 58% (29/50) to 80% (40/50) (p = 0.04) for Reader1 and from 42% (21/50) to 72% (36/50) (p = 0.002) for Reader2. Interreader agreement increased from moderate (kappa 0.58) to good (kappa 0.68).

The micro-enema significantly increased the submucosal width in the tumor-bearing wall, reader confidence, and tumor conspicuity and improved interreader agreement from moderate to good. Sensitivity and specificity in T-staging did not improve, but there was a significant increase in the proportion of tumors staged with both high confidence and correct T-stage.

Today, endoscopy plays a crucial role not only in the detection of precancerous and malignant colorectal lesions, but also in the treatment of even widespread adenomas and T1 early cancers. In addition to classic polypectomy and endoscopic mucosal resection (EMR) using a snare, in recent years, endoscopic submucosal dissection (ESD) has become increasingly important. Marking, submucosal injection, circumferential incision of the mucosa around the lesion, tunneling, and submucosal dissection using a short diathermic knife facilitate the 'en bloc' resection of lesions larger than 3 cm, difficult to resect in one piece using a snare. Lesions with high-grade dysplasia or mucosal carcinoma are other good candidates aside from widespread adenomata with a high risk of recurrence after piecemeal resection. ESD allows R0 resection rates of more than 90% in specialized centers. Lesions of 20 cm have been removed 'en bloc' by expert endoscopists. ESD provides an optimal histopathologic yield and has a risk of recurrence as low as 3%. Endoscopic full-thickness resection using a special device (eFTRD) is another addition to the resection armamentarium. It is especially suitable for circumscribed lesions up to 2 cm in the middle and upper rectum. Endoscopic intermuscular dissection (EID) is a recent modification of ESD primarily in the rectum, including the inner, circular muscular layer into the resection specimen. In this way, it allows a histopathologic analysis of the entire submucosa beyond the mucosal and upper submucosal layer such as in ESD. This is especially important for T1 cancers invading the submucosa without any other risk factors of invasion.

Similar to T1 colon cancer (CC), risk stratification may guide T2 CC treatment and reduce unnecessary major surgery. In this study, prediction models were developed that could identify T2 CC patients with a lower risk of lymph node metastasis (LNM) for whom (intensive) follow-up after local treatment could be considered.

A nationwide cohort study was performed involving pT2 CC patients who underwent surgery between 2012 and 2020, using data from the Dutch ColoRectal Audit, which were linked to the Nationwide Pathology Databank. Four machine learning models were evaluated to predict LNM.

LNMs were found in 1877/9803 patients (19.1%). Independent risk factors included (younger) age (odds ratio [OR] 0.98, 95% confidence interval [CI] 0.979-0.990), left-sided CC (OR 1.5, 95% CI 1.4-1.7), poor differentiation (OR 1.7, 95% CI 1.4-2.2), and lymphovascular invasion (LVI; OR 4.1, 95% CI 3.6-4.7). A deficient mismatch repair (MMR) status significantly lowered the risk of LNM (OR 0.3, 95% CI 0.2-0.5). The general linear model demonstrated the highest prediction accuracy, achieving area under the receiver operating characteristic curves of 0.67 and 0.68, with good calibration. In the absence of risk factors, elderly patients (≥74 years of age) had a predicted risk of LNM of 10.7%, yet up to 30% experienced postoperative complications, with mortality rates reaching up to 3.5%. Patients with a deficient MMR status had a predicted risk of LNM of 6.1% if LVI was absent and the tumor was well-differentiated.

The risk of LNM should be weighed against surgical risks. The findings of this study will enable clinicians to make more deliberate considerations about these competing risks before making a shared decision.

Local excision is gaining acceptance as standard treatment for T1 colon cancer (CC); however, not all patients are eligible for endoscopic resection. Colonoscopy-assisted laparoscopic wedge resection (CAL-WR) is a relatively new technique that could fill the gap between endoscopic resection and major surgery. The aim of this study was to analyze the oncological safety of CAL-WR for CC.

A retrospective cohort study was performed, including patients that underwent CAL-WR for CC. Exclusion criteria were double tumors, <1 year follow-up, previous other colorectal malignancy, inflammatory bowel disease or synchronous metastases. The primary outcome was disease recurrence and the secondary outcome was overall survival.

Fifty-three patients were included; 35 patients were diagnosed with T1 CC. CAL-WR was radical (R0) for all T1 CC in 94.3% and 94.7% for tumors with deep submucosal invasion (sm2-3 Kikuchi). The mean follow-up was 3.3 years (Q1: 2.0; Q3: 4.3) for disease recurrence and 4.2 years (Q1: 2.8; Q3: 5.2) for overall survival. None of the patients with T1 CC had disease recurrence or died due to their malignancy. There were 14 patients with a T2 and 4 patients with a T3 CC, 17/18 patients underwent completion surgery. Three patients with T2 and one with T3 CC developed a locoregional recurrence (peritoneal). One patient with T3 CC developed lung metastases. Two patients with T3 and one with T2 CC died due to their malignancy.

This study suggests that CAL-WR is oncologically safe as treatment for T1 CC. The safety of incidental CAL-WR for >T1 CC, followed by completion surgery, remains unclear. Prospective studies are needed to evaluate these results.

Local full-thickness resection techniques for rectal cancer are limited by lesion size, location, or poor margin delineation. We aimed to evaluate the feasibility of endoscopic knife-assisted full-thickness resection (kFTR) guided by the pocket-detection method (PDM) for deeply invasive rectal cancer. Consecutive posterior-lateral rectal lesions suspected of deep submucosal invasion treated at a tertiary care center from February to October 2024 were retrospectively included. kFTR guided by PDM involved creating a submucosal pocket to detect and isolate the suspected invasive component (muscle-retracting sign), followed by muscularis propria incision and full-thickness resection. Technical success, accuracy of detecting deep submucosal invasion, and en-bloc resection rates were 100%. The median procedure time was 141.5 [IQR 123.7-179.5] minutes and the median hospitalization was 1 [IQR 1-7] day. No adverse events occurred. Histopathology showed R1-vertical margin in patient 1 (pT2 adenocarcinoma) and R0 resection in patients 2, 3, and 4 (pT1bsm3) after refinement of the procedure to include a ≥3 mm muscularis propria margin around the suspected invasive component. There was no recurrence at the first endoscopic follow-up of patients 1, 2, and 4. Patient 3 was sent to surgical low anterior resection due to multiple high-risk histological features. The previous kFTR did not impair surgery (no residual rectal carcinoma and 1/17 positive lymph nodes). Endoscopic kFTR guided by the PDM may be a feasible organ-preserving treatment for the detection and resection of deeply invasive posterior rectal cancer. Future studies are needed to ascertain whether rectal kFTR could represent a viable alternative to conventional surgical local excision techniques.

Local resection (LR) in rectal cancer is indicated in stage T1N0M0 without unfavorable pathological factors, achieving oncologically satisfactory outcomes through transanal endoscopic surgery techniques. However, the initial step involves accurate staging and selection of these tumors through specific tests conducted in specialized colorectal units. For T2N0M0 tumors and T1 tumors with poor prognostic factors, the standard treatment is total mesorectal excision (TME), a procedure associated with high postoperative morbidity and mortality, functional impairments, and reduced quality of life. Therefore, new organ-preservation strategies are being explored as alternatives to TME. These include neoadjuvant therapy combined with LR, which has shown promising results, and neoadjuvant therapy followed by a "Watch and Wait" approach -where patients with complete clinical response are selected for strict surveillance- as an ideal future treatment, although there are still current challenges to be addressed.

Endoscopic submucosal dissection (ESD) is increasingly being adopted for the treatment of early-stage colorectal cancer (CRC) lesions.

We retrospectively analyzed patients with early-stage CRC treated between 2015 and 2023, using ESD and colectomy databases, categorizing them into three groups: ESD only (n ​= ​24), oncological colorectal resection (OCR) only (n ​= ​90), and OCR after ESD (n ​= ​59). We compared pathological and oncological outcomes among these groups.

The OCR after ESD group demonstrated higher non-granular lesions, and deeper submucosal invasion compared to ESD only group. The primary OCR group showed higher 2-year overall survival compared to ESD-only group (98.9 ​% vs 85.6 ​%, p ​= ​0.01), with no colorectal cancer-related mortality in any of the groups. Notably, 2-year disease-free survival rates were comparable across all groups (93.8 ​% ESD only, 88.0 ​% primary OCR only, and 97.8 ​% for OCR after ESD, p ​= ​0.27).

The current study highlights feasibility the promising potential and oncologic safety of ESD in carefully selected patients with early malignant lesions.

Endoscopic submucosal dissection is increasingly promoted for the treatment of all large nonpedunculated colorectal polyps (LNPCPs) to cure potential low-risk cancers (superficial submucosal invasion without additional high-risk histopathologic features). The effect of a universal en bloc strategy on oncologic outcomes for the treatment of LNPCPs in the right colon is unknown. We evaluated this in a large Western population.

A prospective cohort of patients referred for endoscopic resection (ER) of LNPCPs was analyzed. Patients found to have cancer after ER and those referred directly to surgery were included. The primary outcome was to determine the proportion of right colon LNPCPs with low-risk cancer.

Over 180 months until June 2023, 3294 sporadic right colon LNPCPs in 2956 patients were referred for ER at 7 sites (median size 30 [interquartile range 22.5-37.5] mm). A total of 63 (2.1%) patients were referred directly to surgery, and cancer was proven in 56 (88.9%). A total of 2851 (96.4%) of 2956 LNPCPs underwent ER (median size 35 [interquartile range 25-45] mm), of which 75 (2.6%) were cancers. The overall prevalence of cancer in the right colon was 4.4% (n = 131 of 2956). Detailed histopathologic analysis was possible in 115 (88%) of 131 cancers (71 after ER, 44 direct to surgery). After excluding missing histopathologic data, 23 (0.78%) of 2940 sporadic right colon LNPCPs were low-risk cancers.

The proportion of right colon LNPCPs referred for ER containing low-risk cancer amenable to endoscopic cure was <1%, in a large, multicenter Western cohort. A universal endoscopic submucosal dissection strategy for the management of right colon LNPCPs is unlikely to yield improved patient outcomes given the minimal impact on oncologic outcomes.

gov, Numbers: NCT01368289, NCT02000141.

Linear-array endoscopic ultrasound (EUS) and narrow-band imaging (NBI) are both used to estimate the invasion depth of nonpedunculated rectal lesions (NPRLs). However, it is unclear which procedure is more accurate. This randomized controlled trial aimed to compare the diagnostic accuracy of linear EUS and NBI for estimating the invasion depth of NPRLs.

This study is a single-center, randomized, tandem trial. Eligible patients with NPRLs were randomly assigned to A group (assessment with EUS followed by NBI) or B group (assessment with NBI followed by EUS). The invasion depth of each lesion was independently measured by each procedure and categorized as mucosal to slight submucosal (M-SM s , invasion depth <1,000 μm) or deep submucosal (SM d , invasion depth ≥1,000 μm) invasion, with postoperative pathology as the standard of measurement. The primary outcome was diagnostic accuracy, and secondary outcomes included sensitivity, specificity, and procedure time.

Eighty-six patients with NPRLs were enrolled, and 79 patients were finally analyzed, including 39 cases in the A group and 40 cases in the B group. Comparable diagnostic accuracies were observed between EUS and NBI (96.2% vs 93.7%, P = 0.625). EUS identified lesions with deep submucosal invasion with 81.8% sensitivity while that of NBI was 63.6% ( P = 0.500). The specificity of both EUS and NBI was 98.5%. The procedure time was also similar between EUS and NBI (5.90 ± 3.44 vs 6.4 ± 3.94 minutes, P = 0.450). Furthermore, the combined use of EUS and NBI did not improve diagnostic accuracy compared with EUS or NBI alone (94.9% vs 96.2% vs 93.7%, P = 0.333).

Linear EUS and NBI measure the invasion depth of NPRLs with comparable accuracy. The combination of the 2 methods does not improve the diagnostic accuracy. Single NBI should be preferred, considering its simplicity and convenience in clinical practice.

Endoscopic submucosal dissection is increasingly used to treat early-stage colorectal cancer. This study evaluated the feasibility of endoscopic submucosal dissection in this setting and the determinants of lymph node metastasis.

We reviewed patients who underwent colorectal endoscopic submucosal dissection for early-stage colorectal cancer at a tertiary center between 2011 and 2023. The primary outcome was the identification of high-risk pathologic features predictive of lymph node metastasis in patients undergoing oncologic colon resection following endoscopic submucosal dissection.

We reviewed 1,398 patients who underwent endoscopic submucosal dissection, and 83 (6%) had colorectal cancer. Twenty-four patients (29%) were closely monitored after endoscopic submucosal dissection, and 59 (71%) underwent oncologic colon resection because of high-risk pathologies of the endoscopic submucosal dissection specimen. In the oncologic colon resection group, the mean age was 62.7 years (±10.2), with 56% male predominance, and 14% showed positive lymph nodes in the final pathology. Analysis comparing patients with and without lymph node metastasis showed significant differences in sex, lesion size, submucosal invasion depth, and budding scores. Multivariate analysis showed that lesions with a submucosal invasion depth ≥2.00 mm of the endoscopic submucosal dissection resection specimen had higher odds of lymph node metastasis (odds ratio 18.7, P = .028), whereas lesions with a diameter >20 mm were associated with a lower likelihood of lymph node metastasis (odds ratio 0.07, P = .036).

The study highlights the oncologic safety of early-stage endoscopic submucosal dissection as a viable treatment option for carefully selected patients with colorectal cancer. After tissue resection with endoscopic submucosal dissection, if the lesion size is less than 20 mm, depth of invasion up to 2 mm may be considered safe in the absence of other high-risk pathologic factors.

Colorectal cancer (CRC) is a common malignancy worldwide, and the stage of the tumour is closely related to clinical outcome. Bowel cancer screening programmes have resulted in the identification of colorectal cancer at earlier stages. Approximately 10% of patients with the earliest stage of CRC (i.e. pT1) will possess regional lymph node metastases (LNM). Therefore, if these patients have initially been treated by local resection (e.g. polypectomy), this subgroup will require surgical resection. Identification of pathological risk factors for LNM within locally resected pT1 CRC is a very important process during the histological assessment of these lesions. This paper describes the most commonly encountered and clinically significant difficulties in the histological assessment of these cases. These pitfalls are illustrated using four examples of locally resected pT1 CRC that were received by our department during routine diagnostic practice.

Due to the greater risks of adverse events (AEs) and the lower rate of submucosal invasive cancer (SMIC), large proximal colonic polyps are frequently treated by piecemeal endoscopic mucosal resection (EMR) in the West. However, this implies the risk of surgery to radicalize non-curative endoscopic resection in case of early colorectal cancer (CRC). We evaluated procedure outcomes in patients undergoing ESD for proximal colonic lesions at risk of SMIC.

All consecutive patients with lesions at risk of SMIC proximal to splenic flexure referred for ESD at a tertiary center were prospectively included from 2019 to 2021. En bloc, R0, and curative resection rates were primary outcomes, while length of hospitalization, AEs, need for surgery due to AEs, and recurrence rates were secondary outcomes.

A total of 116 patients (mean age: 68.4±10.91 years; men: 69.8%) were included. En bloc, R0, and curative resection rates were 84.5%, 78.4%, and 72.4%, respectively. T1 adenocarcinoma was reported in 25% of lesions (29/116). Eleven patients (9.5%) underwent secondary surgery due to non-curative resections; residual disease was found in one patient. Most frequent AE was intra-procedural perforation (9.9%); no AE required surgery. Median follow-up was 36 months; three of 97 recurrences (3.1%) at 6 months and one of 85 recurrence (1.2%) at 36 months were reported, which were all endoscopically treated.

In expert hands, ESD is effective and safe for proximal colonic lesions at risk of SMIC for the favorable balance between risk of AEs and benefit of avoiding unnecessary surgery, even for early CRC.

We investigated the clinical practice patterns of Korean endoscopists for the endoscopic resection of colorectal polyps.

From September to November 2021, an online survey was conducted regarding the preferred resection methods for colorectal polyps, and responses were compared with the international guidelines.

Among 246 respondents, those with <4 years, 4-9 years, and ≥10 years of experience in colonoscopy practices accounted for 25.6%, 34.1%, and 40.2% of endoscopists, respectively. The most preferred resection methods for non-pedunculated lesions were cold forceps polypectomy for ≤3 mm lesions (81.7%), cold snare polypectomy for 4-5 mm (61.0%) and 6-9 mm (43.5%) lesions, hot endoscopic mucosal resection (EMR) for 10-19 mm lesions (72.0%), precut EMR for 20-25 mm lesions (22.0%), and endoscopic submucosal dissection (ESD) for ≥26 mm lesions (29.3%). Hot EMR was favored for pedunculated lesions with a head size <20 mm and stalk size <10 mm (75.6%) and for those with a head size ≥20 mm or stalk size ≥10 mm (58.5%). For suspected superficial and deep submucosal lesions measuring 10-19 mm and ≥20 mm, ESD (26.0% and 38.6%) and surgery (36.6% and 46.3%) were preferred, respectively. The adherence rate to the guidelines ranged from 11.2% to 96.9%, depending on the size, shape, and histology of the lesions.

Adherence to the guidelines for endoscopic resection techniques varied depending on the characteristics of colorectal polyps. Thus, an individualized approach is required to increase adherence to the guidelines.

Robust evidence regarding the management after endoscopic resection of malignant colorectal polyps (MCP) is lacking. Inconsistencies in reporting on potential prognostic factors hinder the decision process. To address these issues, the Scottish Screen-detected Polyp Cancer Study (SSPoCS) introduced an algorithm based in two easily obtainable variables: resection margin and lymphovascular invasion. This study aims to assess the applicability of the SSPoCS algorithm in a Portuguese multicentric cohort.

Endoscopically resected MCP in five centers were included. The main outcome was residual/recurrent malignancy (RRM), defined as any of the following: (1) residual intramural or lymph node malignancy in the surgical specimen after completion surgery; (2) local or systemic recurrent disease in conservatively managed patients.

Two-hundred and eleven patients were included (mean age: 68.6 ± 10.4 years; male participants: 65.4%); 121 underwent completion surgery while 90 remained in surveillance. Thirty-two patients (15.2%) experienced RRM: 27 displayed residual malignancy in the surgical specimen and five developed recurrent disease. According to the SSPoCS algorithm: 120 patients were classified as having low-risk of residual disease, six of whom displayed RRM (5.0%); 10 as medium-risk, with one having RRM (10.0%); and 81 as high-risk, 25 of whom experienced RRM (30.9%). Lesions classified as low risk showed a negative predictive value (NPV) of 95.0% to exclude RRM. The algorithm demonstrated good accuracy in predicting RRM in a Receiver Operating Characteristic curve analysis (AUC: 0.74; 95% CI: 0.65-0.83; p < 0.001).

The SSPoCS algorithm revealed good accuracy in predicting residual/recurrent malignancy with a NPV of 95.0% to exclude RRM in low-risk lesions.

Endoscopic submucosal dissection (ESD) is a standardized procedure for intramucosal and slightly invasive submucosal colorectal cancers (CRC). However, the role of ESD for T1b (depth of submucosal invasion: ≥1,000 μm) CRC remains unclear. This study aimed to investigate the long-term efficacy and safety of ESD for T1b CRC.

This study involved 50 patients with T1b CRC who underwent ESD, including 31 who received subsequent surgery (ESD + surgery group) and 19 who reported comorbidities or refused subsequent surgery (ESD-alone group). The clinical outcomes, lymph node metastasis (LNM) rate, and recurrence and survival rates were determined.

All the patients achieved en-bloc resection, and 41 patients achieved R0 resection. The mean tumor diameter was 31.2 ± 11.9 mm. LNM was detected in 3 (6%) cases, demonstrating high-grade tumor budding (Bd 2/3) and invasion depth of >1,500 um. LNM was significantly correlated with tumor budding (P = 0.030). The overall median follow-up period was 41.00 ± 27.69 months and 33.16 ± 19.05 months in the ESD-alone and ESD + surgery groups, respectively (P = 0.241). Two patients in the ESD group had local recurrence and two patients died. Patients in the ESD + surgery group reported no local recurrence, distant metastasis, or disease-related death. Recurrence (P = 0.074) and survival rates (P = 0.072) were not significantly different between the two groups.

The LNM rate was exceedingly low in patients with T1b. ESD is an effective and safe method for these patients. The necessity of additional surgical treatment after ESD should be comprehensively determined following the patient's characteristics.

Endoscopic resection (ER) is widely performed to treat early colorectal cancer. However, additional surgery for pathological T1 colorectal cancer (pT1CRC) after ER is controversial because of the imprecise prediction of lymph node metastasis (LNM). Recently, several patients of pT1CRC with lymphoid follicular replacement (LFR) without LNM have been reported. This study aimed to investigate the clinicopathological features and risk of LNM in patients with pT1CRC with LFR.

We retrospectively analyzed patients who underwent ER or surgical resection and were diagnosed with pT1CRC between January 2010 and December 2020. We defined pT1CRC with LFR as the replacement of a part of the lymphoid follicular component within the submucosal area by adenocarcinoma, with no invasion into other submucosal areas.

Among the 600 eligible patients, the incidence rate of pT1CRC with LFR was 6.7% (40/600). Patients with pT1CRC with LFR represented 14.3% (37/258) of the endoscopically treated patients and 0.9% (3/342) of the surgically treated patients. For patients with pT1CRC with LFR, 80.0% (32/40) had flat and depressed lesions, and 35.0% (14/40) had submucosal invasion depth ≥1000 μm. Patients with pT1CRC with LFR had negative lymphovascular invasion, differentiated type, and budding grade 1. In the median follow-up of 61 months, patients with pT1CRC with LFR had no LNM.

The presence of LFR in pT1CRC may be associated with a low risk of LNM. In patients with pT1CRC with LFR, follow-up without additional surgery is possible even if the submucosal invasion depth is ≥1000 μm.

This study investigated the incidence of lymph node metastasis and long-term outcomes in patients with T1 colorectal cancer where endoscopic submucosal dissection (ESD) resulted in noncurative treatment. It is focused on those with deep submucosal invasion, a factor considered a weak predictor of lymph node metastasis in the absence of other risk factors.

This nationwide, multicenter, prospective study conducted a post-hoc analysis of 141 patients with T1 colorectal cancer ≥20 mm where ESD of the lesion resulted in noncurative outcomes, characterized by poor differentiation, deep submucosal invasion (≥1000 μm), lymphovascular invasion, high-grade tumor budding, or positive vertical margins. Clinicopathologic features and patient prognoses focusing on lesion sites and additional surgery requirements were evaluated. Lymph node metastasis incidence in the low-risk T1 group, identified by deep submucosal invasion as the sole high-risk histological feature, was assessed.

Lymph node metastasis occurred in 14% of patients undergoing additional surgery post-noncurative endoscopic submucosal dissection for T1 colorectal cancer. In the low-risk T1 group, in the absence of other risk factors, the frequency was 9.7%. The lymph node metastasis rates in patients with T1 colon and rectal cancers did not differ significantly (14% vs. 16%). Distant recurrence was observed in one patient (2.3%) in the ESD only group and in one (1.0%) in the additional surgery group, both of whom had had rectal cancer removed.

The risk of lymph node metastasis or distant occurrence was not negligible, even in the low-risk T1 group. The findings suggest the need for considering additional surgery, particularly for rectal lesions (Clinical Trial Registration: UMIN000010136).

Endoscopic procedures and surgery are common treatments for early colorectal cancer (CRC). However, only approximately 10% of patients who undergo surgery have lymph node metastases (LNM) detected on postoperative pathology, which often leads to overtreatment. This study aims to comprehensively analyze the risk factors for LNM in early CRC patients, establishing a predictive model to aid in treatment decisions.

This study reviewed the clinicopathologic data of patients with early CRC who underwent surgery from January 2015 to June 2023. Univariate and multivariate logistic regression analyses were employed to identify LNM risk factors. The receiver operating characteristic (ROC) analysis and calibration curves were also constructed to verify the model's discrimination and calibration. A simplified scale was calculated to promote the risk stratification for LNM.

The study analyzed medical records of 375 patients. Of these, 37 (9.9%) cases had LNM. Univariate analysis identified age, nerve invasion, depth of submucosal invasion, histologic grade, LVI, and tumor budding as risk factors. The multivariate analysis confirmed histologic grade (OR, 13.403; 95% CI, 1.415-126.979; P = 0.024), LVI (OR, 6.703; 95% CI, 2.600-17.284; P < 0.001), and tumor budding (OR, 3.090; 95% CI, 1.082-8.820; P = 0.035) as independent predictors. The optimal nomogram, incorporating six risk factors, demonstrated strong predictability with an area under the ROC curve (AUC) of 0.837 (95% CI, 0.762-0.912). A simplified risk assessment scale with a total score of 19 points was developed.

The study developed a nomogram and a simplified risk assessment scale to predict LNM risk, potentially optimizing the management of early CRC patients.

Rectal cancer is one of the most prevalent malignancies worldwide, and the introduction of an endoscopic submucosal dissection (ESD) has offered minimally invasive management for early colorectal cancers. On the other hand, a post-ESD pathological examination showed that the risk of lymph node metastasis increases with deep submucosal (SM) invasion, positive lymphovascular invasion, grade 2/3 tumor budding, and certain histological types. An intestinal resection with a lymph node dissection is recommended in these cases, and chemoradiotherapy (CRT) is also effective adjuvant therapy. This paper reports a case series of patients who underwent ESD for rectal cancer and received concurrent CRT because of pathologically confirmed deep SM invasion.

Assessing a locally excised colorectal adenoma for malignancy is a common but often challenging scenario. This article outlines a simple, stepwise approach to this diagnostic assessment. The first steps are to assess for high-grade dysplasia and, if present, to determine whether any neoplastic glands lie within the submucosa. If so, a distinction must then be made between epithelial misplacement and adenocarcinoma; this process is aided by certain clinical and endoscopic data together with assessment of six key histological features. If adenocarcinoma is diagnosed, a final step is to report the presence/absence of high-risk features of polyp cancers because this will then determine if further surgical resection is required for that malignancy. Caveats, uncertainties and newly introduced concepts exist at several steps of the assessment pathway presented and are therefore discussed in detail throughout the article.

Background: Resected rectal polyps with deep invasion into the submucosa (pT1b-sm2,3) or the muscle layer (pT2) are currently confronted with surgery due to non-curative resection. Aims: We evaluated the efficacy, safety, and locoregional control of adjuvant radiotherapy (RT) and/or chemotherapy (CT) following endoscopic KAR (knife-assisted resection) in patients with invasive early rectal cancers who are unwilling or unsuitable for additional surgical resection. Methods: Fifty-one patients with early rectal cancers, pT1b or pT2, underwent post-resection adjuvant RT and/or CT in 15 centers worldwide. "En bloc" macroscopic resection, R0 resection, recurrence rate, and adverse events following resection and adjuvant therapy were recorded in a multicenter retrospective cohort study. Results: Diagnostic staging (38/51, 75%) was the main reason for ELE. Macroscopic "en bloc" resection was demonstrated in 50/51 (98%), with an average follow-up of 20.6 months. Endoscopic recurrence occurred in 7/51 (13.7%) of patients, with mean time for diagnosis of recurrence at 8.9 months. Adjuvant therapy consisted of RT in 49.0% (25/51), CT in 11.8% (6/51), and combined CRT in 39.2% (20/51) of the cases. Perforation, severe post-procedural bleeding, and incontinence were the most frequent complications. The absence of superficial ulceration was associated with macroscopic complete resection, while the lesions with lower budding stage, clear lateral margins, lesion size < 40 mm, and needle-type knife used were associated with less endoscopic recurrencies. Conclusions: Our data investigated adjuvant RT and/or CT after endoscopic KAR of infiltrative rectal cancers (pT1bsm2,3-pT2) as being safe and effective for locoregional control and providing a non-surgical treatment option for patients with a non-curative resection.

There have been significant advances in the management of large (≥20 mm) laterally spreading tumors (LSTs) or nonpedunculated colorectal polyps; however, there is a lack of clear consensus on the management of these lesions with significant geographic variability especially between Eastern and Western paradigms. We aimed to provide an international consensus to better guide management and attempt to homogenize practices.

Two experts in interventional endoscopy spearheaded an evidence-based Delphi study on behalf of the World Endoscopy Organization Colorectal Cancer Screening Committee. A steering committee comprising six members devised 51 statements, and 43 experts from 18 countries on six continents participated in a three-round voting process. The Grading of Recommendations, Assessment, Development and Evaluations tool was used to assess evidence quality and recommendation strength. Consensus was defined as ≥80% agreement (strongly agree or agree) on a 5-point Likert scale.

Forty-two statements reached consensus after three rounds of voting. Recommendations included: three statements on training and competency; 10 statements on preresection evaluation, including optical diagnosis, classification, and staging of LSTs; 14 statements on endoscopic resection indications and technique, including statements on en bloc and piecemeal resection decision-making; seven statements on postresection evaluation; and eight statements on postresection care.

An international expert consensus based on the current available evidence has been developed to guide the evaluation, resection, and follow-up of LSTs. This may provide guiding principles for the global management of these lesions and standardize current practices.

Additional surgery with lymph node (LN) dissection is recommended for pT1 colorectal carcinoma (CRC) resected by endoscopy, based on pathological risk factors for LN metastasis (LNM), according to guidelines by the Japanese Society for Cancer of the Colon and Rectum (JSCCR), National Comprehensive Cancer Network (NCCN), and European Society for Medical Oncology (ESMO).

We retrospectively analyzed 560 consecutive patients with T1 CRC who underwent endoscopic resection alone (n=190) or initial or additional surgery with LN dissection (n=370) between 1992 and 2017 at Hiroshima University Hospital. Patients were classified into LNM low- and high-risk groups according to guidelines by the JSCCR, NCCN, and ESMO as follows. Patients without any specified pathological LNM risk factor were included in the LNM low-risk group, while the high-risk group comprised all other patients. We analyzed the LNM predictive ability of each guideline.

The LNM high-risk rate, sensitivity, specificity, positive and negative predictive values, accuracy of LNM risk, and AUC for LNM predictive ability were 82%, 100%, 19%, 9%, 100%, 26% and 0.596 in the JSCCR guidelines; 52%, 98%, 52%, 15%, 99%, 56%, and 0.749 in the NCCN; and 54%, 98%, 50%, 15%, 99%, 54%, and 0.743 in the ESMO, respectively.

The JSCCR guidelines could diagnose LNM in all cases but had the highest false-positive rate. It is important to reduce unnecessary additional surgeries for pT1 CRCs after ER.

After endoscopic resection of colorectal cancer with submucosal invasion (pT1 CRC), additional surgical treatment is recommended if deep submucosal invasion (DSI) is present. This study aimed to further elucidate the risk factors for lymph node metastasis (LNM) in patients with pT1 CRC, especially the effect of DSI on LNM.

Patients with pT1 CRC who underwent lymph node dissection were selected. The Chi-square test and multivariate logistic regression were used to analyze the relationship between clinicopathological characteristics and LNM. The submucosal invasion depth (SID) was measured via 4 methods and analyzed with 3 cut-off values.

Twenty-eight of the 239 patients presented with LNM (11.7%), and the independent risk factors for LNM included high histological grade (P=0.003), lymphovascular invasion (LVI) (P=0.004), intermediate to high budding (Bd 2/3) (P=0.008), and cancer gland rupture (CGR) (P=0.008). Moreover, the SID, width of submucosal invasion (WSI), and area of submucosal invasion (ASI) were not significantly different. When one, two, three or more risk factors were identified, the LNM rates were 1.1% (1/95), 12.5% (7/56), and 48.8% (20/41), respectively.

Indicators such as the SID, WSI, and ASI are not risk factors for LNM and are subjective in their measurement, which renders them relatively inconvenient to apply in clinical practice. In contrast, histological grade, LVI, tumor budding and CGR are relatively straightforward to identify and have been demonstrated to be statistically significant. It would be prudent to focus on these histological factors rather than subjective measurements.

 Recognition of submucosal invasive colorectal cancer (T1 CRC) is difficult, with sensitivities of 35 %-60 % in Western countries. We evaluated the real-life effects of training in the OPTICAL model, a recently developed structured and validated prediction model, in Dutch community hospitals.

 In this prospective multicenter study (OPTICAL II), 383 endoscopists from 40 hospitals were invited to follow an e-learning program on the OPTICAL model, to increase sensitivity in detecting T1 CRC in nonpedunculated polyps. Real-life recognition of T1 CRC was then evaluated in 25 hospitals. Endoscopic and pathologic reports of T1 CRCs detected during the next year were collected retrospectively, with endoscopists unaware of this evaluation. Sensitivity for T1 CRC recognition, R0 resection rate, and treatment modality were compared for trained vs. untrained endoscopists.

 1 year after e-learning, 528 nonpedunculated T1 CRCs were recorded for endoscopies performed by 251 endoscopists (118 [47 %] trained). Median T1 CRC size was 20 mm. Lesions were mainly located in the distal colorectum (66 %). Trained endoscopists recognized T1 CRCs more frequently than untrained endoscopists (sensitivity 74 % vs. 62 %; mixed model analysis odds ratio [OR] 2.90, 95 %CI 1.54-5.45). R0 resection rate was higher for T1 CRCs detected by trained endoscopists (69 % vs. 56 %; OR 1.73, 95 %CI 1.03-2.91).

 Training in optical recognition of T1 CRCs in community hospitals was associated with increased recognition of T1 CRCs, leading to higher en bloc and R0 resection rates. This may be an important step toward more organ-preserving strategies.

The effect of tumor budding (TB) on the prognosis of patients with esophageal squamous cell carcinoma (ESCC) after endoscopic submucosal dissection (ESD) remains unclear. We evaluated the long-term outcomes of patients with superficial ESCC after ESD and the risk factors of TB for the long-term prognosis.

We conducted a retrospective study in a Chinese hospital. All patients with ESCC treated by ESD and reported TB were included consecutively. Comparative analyses were conducted in three parts: specimen analysis, follow-up analyses of unmatched patients, and propensity score-matched (PSM) patients. Cox proportional hazard regression models were constructed to identify risk factors for overall survival and recurrence-free survival (RFS).

A total of 437 patients were enrolled [154 TB and 283 no tumor budding (NTB)], and 258 patients (52 TB and 206 NTB) were included in the follow-up analysis. Results showed that the invasion depth, differentiation type, and positive vascular invasion (all p < 0.001) of the TB group were significantly different from the NTB group. The all-cause mortality and the median RFS time between the two groups were comparable. RFS rate at 5 years were 84.6% and 80.6%, respectively (p = 0.43). Cox analyses identified that having other cancers but not TB, as a risk factor independently associated with overall survival and RFS after ESD.

TB tends to be associated with invasion depth, differentiation type, and positive vascular invasion. However, it might not affect the long-term outcomes of patients with superficial ESCC after ESD when other high-risk factors are negative.

We review and analyze research on the application of machine learning (ML) and deep learning (DL) models to lymph node metastasis (LNM) prediction in patients with T1 colorectal cancer (CRC). Predicting LNM before radical surgery is important in patients with T1 CRC. However, current surgical treatment guidelines are limited. LNM prediction using ML or DL may improve predictive accuracy. The diagnostic accuracy of LNM prediction using ML- and DL-based models for patients with CRC was assessed.

We performed a comprehensive search of the PubMed, Embase, and Cochrane databases (inception to April 30th of 2022) for studies that applied ML or DL to LNM prediction in T1 CRC patients specifically to compare with histopathological findings and not related to radiological aspects.

33,199 T1 CRC patients enrolled across seven studies with a retrospective design were included. LNM was observed in 3,173 (9.6%) patients. Overall, the ML- and DL-based model exhibited a sensitivity of 0.944 and specificity of 0.877 for the prediction of LNM in patients with T1 CRC. Six different types of ML and DL models were used across the studies included in this meta-analysis. Therefore, a high degree of heterogeneity was observed.

The ML and DL models provided high sensitivity and specificity for predicting LNM in patients with T1 CRC, and the heterogeneity between studies was significant. These results suggest the potential of ML or DL as diagnostic tools. However, more reliable algorithms should be developed for predicting LNM before surgery in patients with T1 CRC.

Approximately 7% of the polyps resected endoscopically have an adenocarcinoma focus, with no previous endoscopic evidence of malignancy. This raises the question of whether endoscopic resection has been curative. Furthermore, there is no consensus on what the endoscopic and histological criteria for good prognosis are, the appropriate follow-up strategy and what are the long-term results. The aim of the retrospective study by Fábián et al was to evaluate the occurrence of local relapse or distant metastasis in those tumors that were resected endoscopically compared to those that underwent oncologic surgery. They concluded that, regardless of the treatment strategy chosen, there was a higher recurrence rate than described in the literature and that adherence to follow-up was poor. The management approach for an endoscopically benign polyp histologically confirmed as adenocarcinoma depends on the presence of any of the previously described poor prognostic histological factors. If none of these factors are present and the polyp has been completely resected en bloc (R0), active surveillance is considered appropriate as endoscopic resection is deemed curative. These results highlight, once again, the need for further multicentric clinical practice studies to obtain more evidence for the purpose of establishing appropriate treatment and follow-up strategies.

Submucosal invasive (T1) colorectal cancer is a significant clinical management challenge, with an estimated 10% of patients developing extraintestinal lymph node metastasis. This condition necessitates surgical resection along with lymph node dissection to achieve a curative outcome. Thus, the precise preoperative assessment of lymph node metastasis risk is crucial to guide treatment decisions after endoscopic resection. Contemporary clinical guidelines strive to identify a low-risk cohort for whom endoscopic resection will suffice, applying stringent criteria to maximize patient safety. Those failing to meet these criteria are often recommended for surgical resection, with its associated mortality risks although it may still include patients with a low risk of metastasis. In the quest to enhance the precision of preoperative lymph node metastasis risk prediction, innovative models leveraging artificial intelligence or nomograms are being developed. Nevertheless, the debate over the ideal sensitivity and specificity for such models persists, with no consensus on target metrics. This review puts forth postoperative mortality rates as a practical benchmark for the sensitivity of predictive models. We underscore the importance of this method and advocate for research to amass data on surgical mortality in T1 colorectal cancer. Establishing specific benchmarks for predictive accuracy in lymph node metastasis risk assessment will hopefully optimize the treatment of T1 colorectal cancer.

Local resection (LR) is an alternative to total mesorectal excision (TME) that avoids its associated morbidity to the detriment of oncological radicality in early stages of rectal cancer. There are several conditioning factors for the success of this strategy, such as poor prognosis histological factors (PPHF), involvement of resection margins, clinical under staging, or complications that may lead to the indication for radical surgery with TME.

An international multicenter prospective observational open-label study has been designed. Consecutive patients diagnosed with early rectal cancer (cT1N0 on MRI +/- endorectal ultrasound) whose lower limit is a maximum of 2 cm proximal to the ano-rectal junction will be included. The primary objective of the study is to determine the overall prevalence of PPHF after LR and requiring TME or postoperative radio-chemotherapy.

The prevalence of PPHF conditioning the success of LR in early distal rectal cancer has been scarcely studied in the literature, and there are very few prospective data. Considering the increasing interest in the watch and wait strategy in rectal cancer and its possible application in early-stage tumors, it seems necessary to know this information. The results of this study will help guide clinical practice in patients with early distal rectal cancer. It will also provide quality information for the design of future comparative studies to improve organ preservation success in these patients.

NCT05927584.