Transanal endoscopic surgery is a recommended full-thickness resection technique for the treatment of rectal neuroendocrine tumors. We aimed to compare the efficacy, safety and follow-up of patients with rectal neuroendocrine tumors treated with transanal endoscopic microsurgery in the primary setting and as salvage therapy after non-radical endoscopic polypectomy.

A retrospective analysis of a 10-year database of patients treated with transanal endoscopic microsurgery was performed. The procedure-related measures, including duration of the procedure, adverse events, and patient-related measures, including age, gender, tumor size, grading, and length of follow-up, were obtained. We compared the primary TEM group with the salvage group.

In total, 30 patients with rectal neuroendocrine tumors were included in the study; 13 of them received primary treatment and 17 salvage therapy of the scar. Patients receiving primary treatment were significantly older (60.5 vs. 51.7 years). There were no significant differences in patient gender, tumor size and grading, length of follow-up, hospital stay or procedure time. The R0 resection rate was 92.3% in the primary treatment group. Adverse events were mild or managed with endoscopic treatment. Follow-up was slightly but not significantly longer in the primary treatment group and showed no recurrences in both groups of patients.

Transanal endoscopic microsurgery is safe and effective for both primary and salvage treatment of rectal neuroendocrine tumors.

Available platforms for local excision (LE) of early rectal cancer are rigid or flexible [trans‑anal minimally invasive surgery (TAMIS)]. We systematically searched the literature to compare outcomes between platforms.

PRISMA-compliant search of PubMed and Scopus databases until September 2022 was undertaken in this random-effect meta-analysis. Statistical heterogeneity was assessed using I2 statistic. Studies comparing TAMIS versus rigid platforms for LE for early rectal cancer were included. Main outcome measures were intraoperative and short-term postoperative outcomes and specimen quality.

7 studies were published between 2015 and 2022, including 931 patients (423 females); 402 underwent TAMIS and 529 underwent LE with rigid platforms. Techniques were similar for operative time (WMD 11.1, 95%CI - 2.6 to 25, p = 0.11), percentage of defect closure (OR 0.7, 95%CI 0.06-8.22, p = 0.78), and peritoneal violation (OR 0.41, 95%CI 0.12-1.43, p = 0.16). Rigid platforms had higher rates of short-term complications (19.1% vs 14.2, OR 1.6, 95%CI 1.07-2.4, p = 0.02), although no significant differences were seen for major complications (OR 1.41, 95%CI 0.61-3.23, p = 0.41). Patients in the rigid platforms group were 3-times more likely to be re-admitted within 30 days compared to the TAMIS group (OR 3.1, 95%CI 1.07-9.4, p = 0.03). Rates of positive resection margins (rigid platforms: 7.6% vs TAMIS: 9.34%, OR 0.81, 95%CI 0.42-1.55, p = 0.53) and specimen fragmentation (rigid platforms: 3.3% vs TAMIS: 4.4%, OR 0.74, 95%CI 0.33-1.64, p = 0.46) were similar between the groups. Salvage surgery was required in 5.5% of rigid platform patients and 6.2% of TAMIS patients (OR 0.8, 95%CI 0.4-1.8, p = 0.7).

TAMIS or rigid platforms for LE seem to have similar operative outcomes and specimen quality. The TAMIS group demonstrated lower readmission and overall complication rates but did not significantly differ for major complications. The choice of platform should be based on availability, cost, and surgeon's preference.

The treatment of rectal cancer has evolved with the advancement of surgical techniques. Less invasive approaches are becoming more accepted as the primary treatment method.

Such methods as transanal excision, transanal endoscopic microsurgery, and transanal minimally invasive surgery can reduce morbidity and mortality rates. However, not all patients are suitable candidates for these procedures, and proper diagnostics are necessary to establish indications. Compared to total mesorectal excision, transanal excision techniques have been shown to have fewer complications and comorbidities while still being able to remove cancerous tissue entirely. Transanal excision is the simplest method, where the operator removes visible rectal lesions. The basic principle of transanal endoscopic microsurgery is to dilate the rectum mechanically and by air insufflation and then use special surgical instruments to remove suspicious lesions under the vision of a telescope. Transanal minimally invasive surgery combines transanal endoscopic microsurgery and single-incision laparoscopic surgery, making the hard-to-reach proximal rectum accessible to classic laparoscopic instruments.

Local excision techniques, when used as a monotherapy for treating patients with rectal cancer, have established themselves as a curative and less radical treatment for strictly selected patients with early rectal carcinoma, leading to improved quality of life. When combined with other modalities such as neoadjuvant chemoradiotherapy, total neoadjuvant therapy, and immunotherapy, transanal surgery can be offered to patients with locally advanced rectal cancer as part of the organ preservation strategy. This review will discuss the patient selection and technical aspects of transanal surgery, showcasing its current role in treating rectal carcinoma.

Transanal endoscopic surgery encompasses the minimally invasive surgical techniques used to operate in the rectum under magnification while maintaining pneumorectum via a resectoscope or port. The view, magnification, and surgical precision afforded by these advanced transanal techniques have resulted in excellent specimen quality and low recurrence rates, especially compared with traditional transanal surgery. For rigid platforms, the surgeon operates through a rigid 4-cm diameter steel proctoscope of varying lengths that is clamped to the operating table with an articulating arm. Transanal minimally invasive surgery (TAMIS) is a newer flexible platform using a disposable port which "hooks" into the anorectal ring to remain in place. The cost-effectiveness and versatility of the TAMIS platform have resulted in its popularity and use in more advanced applications such as transanal total mesorectal excision. Ultimately, the choice of operating platform should be based on surgeon preference, patient characteristics, availability, and cost. The pros and cons of each platform will be discussed in this article.

Transanal minimally invasive surgery (TAMIS) was first described in 2010 as an alternative to transanal endoscopic microsurgery (TEM). The TAMIS technique can be access to the proximal and mid-rectum for resection of benign and early-stage malignant rectal lesions and also used for noncurative intent surgery of more advanced lesions in patients who are not candidates for radical surgery. TAMIS has a shorter learning curve, reduced device setup time, flexibility in instrument use, and versatility in application than TEM. Also, TAMIS shows similar results in a view of the operation time, conversion rate, reoperation rate, and complication to TEM. For these reasons, TAMIS is an easily accessible, technically feasible, and cost-effective alternative to TEM. Overall, TAMIS has enabled the performance of high-quality local excision of rectal lesions by many colorectal surgeons. As TAMIS becomes more broadly utilized such as pelvic abscess drainage, rectal stenosis, and treatment of anastomotic dehiscence, the acquisition of appropriate training must be ensured, and the continued assessment and assurance of outcome must be maintained.

Since its introduction, transanal endoscopic microsurgery (TEM) has become the treatment of choice for rectal benign lesions not amenable to flexible endoscopic excision and for early rectal cancer. Disposable soft devices as the Trans-anal Minimally Invasive Surgery (TAMIS) are a valid alternative to non-disposable rigid trans-anal endoscopic microsurgery (TEM) platforms. The aim of the present study is to compare TEM and TAMIS in terms of incidence of R1 resection and lesion fragmentation which were combined in a composite outcome called quality resection. Perioperative complication and operative time were also investigated.

A total of 132 patients were eligible for this study of whom 63 (47.7%) underwent TAMIS and 69 (52.3%) underwent TEM. Patients were extracted for from a prospective maintained database and groups resulted homogenous after matching using propensity score in terms of size of the lesion, height from the anal verge, position within the rectal lumen, preoperative histology, neoadjuvant treatment. A multivariate logistic and linear regression analysis was carried out using those variables that have significant independent relationship with the quality of surgical resection and operative time.

The incidence of R0 resection and lesion fragmentation was similar between groups. No differences were found in terms of perioperative complication. TAMIS was associated with less setup time and less operative time compared with TEM. Variables influencing quality resection at the multivariate analysis were larger lesion (> 5 cm) and ≥ T2 stage. Variables influencing operative time were surgical procedure (TEM vs TAMIS), height from the anal verge and size of the lesion.

The present study shows that TEM and TAMIS are equally effective in terms of quality of local excision and perioperative complication. TAMIS resulted less operative time consuming compared to TEM.

Local excision (LE) has arisen as an alternative to total mesorectal excision for the treatment of early rectal cancer. Despite a decreased morbidity, there are still concerns about LE outcomes. This systematic-review and meta-analysis design is based on the "PICO" process, aiming to answer to three questions related to LE as primary treatment for early-rectal cancer, the optimal method for LE, and the potential role for completion treatment in high-risk histology tumors and outcomes of salvage surgery. The results revealed that reported overall survival (OS) and disease-specific survival (DSS) were 71%-91.7% and 80%-94% for LE, in contrast to 92.3%-94.3% and 94.4%-97% for radical surgery. Additional analysis of National Database studies revealed lower OS with LE (HR: 1.26; 95%CI, 1.09-1.45) and DSS (HR: 1.19; 95%CI, 1.01-1.41) after LE. Furthermore, patients receiving LE were significantly more prone develop local recurrence (RR: 3.44, 95%CI, 2.50-4.74). Analysis of available transanal surgical platforms was performed, finding no significant differences among them but reduced local recurrence compared to traditional transanal LE (OR:0.24;95%CI, 0.15-0.4). Finally, we found poor survival outcomes for patients undergoing salvage surgery, favoring completion treatment (chemoradiotherapy or surgery) when high-risk histology is present. In conclusion, LE could be considered adequate provided a full-thickness specimen can be achieved that the patient is informed about risk for potential requirement of completion treatment. Early-rectal cancer cases should be discussed in a multidisciplinary team, and patient's preferences must be considered in the decision-making process.

In order to assess the various surgical modalities for local resection of rectal tumors, a systematic review of the current literature and a network meta-analysis (NMA) was designed and conducted.

The present study adhered to the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions principles. Scholar databases (Medline, Scopus, Web of Science) were systematically screened up to 23/12/2019. A Bayesian NMA, implementing a Markov chain Monte Carlo analysis, was introduced for the probability ranking of the available surgical methods. Odds ratio (OR) and weighted mean difference (WMD) of the categorical and continuous variables, respectively, were reported with the corresponding 95% confidence interval (95%CI).

Overall, 16 studies and 2146 patients were introduced in our study. Transanal minimal invasive surgery (TAMIS) displayed the highest performance regarding the overall postoperative morbidity, the perioperative blood loss, the length of hospitalization, and the peritoneal violation rate. Transanal endoscopic microsurgery (TEM) was the most efficient modality for resecting an intact specimen. Although transanal local excision (TAE) had the highest ranking considering operative duration, it was associated with a significant risk for positive resection margins and tumor recurrence.

In conclusion, TEM and TAMIS display superior oncological results over TAE. Due to several limitations, validation of these results requires further RCTs of a higher methodological level.

The aim of this study was to compare the short-term outcome after Transanal Endoscopic Microsurgery (TEM) and Transanal Minimally Invasive Surgery (TAMIS) for intraluminal rectal lesions.

Retrospective analysis of a prospectively maintained database of all TEM and TAMIS procedures performed at a single institution by one surgeon between March 2009 and September 2017 was conducted. Primary outcome was operating time. Secondary outcomes were blood loss, pathological outcome, length of hospital stay, 30-day readmission and mortality.

Fifty-three patients underwent TEM procedure and 68 patients underwent TAMIS. Operating time was significantly shorter for TAMIS compared with TEM (median 45 vs 65 min, p < 0.0001). Blood loss was negligible for both TEM and TAMIS. Resection margins, lesion grade and invasion depth were comparable for both approaches. A significantly higher postoperative readmission rate was observed in the TEM group (17% vs 4.4%, p = 0.031). Mortality was zero in both groups.

TAMIS is a valuable alternative to TEM, leading to decreased operating times, because all resections can be done in lithotomy position.

Transanal excision (TAE) with conventional retractors and transanal endoscopic microsurgery (TEM) are two well established minimally invasive surgical options for the treatment of selected rectal cancers. TEM is nowadays considered the standard of care for the transanal excision of rectal tumors, since it is associated with significantly better quality of excision and lower rates of recurrence than TAE. When compared with rectal resection and total mesorectal excision, TEM has lower postoperative morbidity and better functional outcomes, with similar long-term survival rates in selected early rectal cancers. More recently, transanal minimally invasive surgery (TAMIS) has been developed as an alternative to TEM. Possible benefits of TAMIS are under evaluation.

Indications for transanal endoscopic microsurgery (TEM) have been extended to technically challenging tumors, which may be associated with an increased risk of peritoneal perforation (PP). The aim of the present study was to investigate the occurrence, management and outcome of PP in patients having TEM.

All the patients who had TEM for rectal adenoma or adenocarcinoma in our unit were included. Patients in whom PP occurred (Group A) were compared to those without PP (Group B).

From 2007 to 2015, 194 TEM (116 men, median age 66 [range 21-100] years) were divided into Groups A (n = 28, 14%) and B (n = 166). The latter group included four patients, in whom a laparoscopy did not confirm suspicion of PP made during TEM. In 2 of 28 patients (7%), the diagnosis of PP was made postoperatively during reoperation for peritonitis. For the 26 other patients (93%), routine exploratory laparoscopy was performed with suture of the peritoneal defect on the pouch of Douglas in 24 cases and a rectal suture alone in 2 cases. Independent predictive factors for PP were: distance from the anal verge >10 cm (OR = 3.6), circumferential tumor (OR = 3.0) and anterior location (OR = 2.7). Hospital stay was significantly longer in Group A (7.5 [3-31] days) than in Group B (4 [1-38] days; p < 0.0001), whereas there was no significant difference regarding postoperative morbidity and recurrence rate.

Our results suggested that PP is not a very rare event during TEM, especially in anterior, circumferential and/or high rectal tumors. Laparoscopic treatment of PP is feasible and safe. The occurrence of PP is not associated with poor oncologic results.

Since the introduction of transanal endoscopic microsurgery (TEM) in the 1980 s, the minimally invasive transanal approach has been a treatment option for selected patients with colorectal diseases. Recently, transanal minimally invasive surgery (TAMIS) was introduced as an alternative technique. TAMIS is a hybrid between TEM and single-port laparoscopy and was followed by introduction of transanal total mesorectal excision (TaTME). Although the TaTME experience remains preliminary, it appears to be an attractive minimally invasive procedure for carefully selected patients with resectable rectal cancer. The objective of this review is to describe the latest technologies which enhanced progress of minimally invasive transanal approaches for endo- and extraluminal surgery in this area of colorectal surgery.