Transanal Endoscopic Operation Versus Conventional Transanal Excision for Rectal Tumors: Case-Matched Study with Propensity Score Matching

Minimally invasive transanal excision for rectal tumors: technical feasibility compared to conventional approach

PURPOSE

The technique for transanal resection of rectal tumors has evolved from conventional methods to minimally invasive approaches. However, the research comparing long-term results between these approaches is limited.

METHODS

Between 2016 and 2022, a total of 133 patients who underwent transanal excision were analyzed. Patients were classified into 2 groups according to surgical approach: conventional transanal approach (CTA) and minimally invasive transanal approach (MTA). Medical records were analyzed to compare surgical and oncological outcomes between the 2 groups.

RESULTS

There were no significant differences observed in patient's demographics and tumor characteristics, except the MTA group exhibited a statistically longer distance from the anal verge. Although statistical significance was not reached, the MTA group demonstrated a 100% margin-negative rate in contrast to the CTA group, which had worse outcomes for both margin status and fragmentation. Recurrence was observed only in the CTA group containing pT1 rectal cancer and grade 1 neuroendocrine tumor, with negative margins and no fragmentation.

CONCLUSION

The minimally invasive approach did not demonstrate statistical superiority but showed technical feasibility through the absence of margin-positive cases and the use of the clip handle method. Further studies are needed to validate these findings and assess broader applicability.

Efficacy and safety of transanal endoscopic microsurgery for early rectal cancer: a meta-analysis

Background

The gold standard for the treatment of rectal cancer is radical surgery with total mesorectal excision (TME). As one of the alternatives to radical surgery, local resection has been proposed for the treatment of early rectal cancer. The purpose of this article was to evaluate the safety and efficacy of transanal endoscopic microsurgery (TEM) in the treatment of early rectal cancer.

Methods

By searching the PubMed, Cochrane Library, Web of Science, and China National Knowledge Infrastructure databases, we selected all articles on TEM for early rectal cancer. Two researchers independently completed the entire process from screening, inclusion to data extraction and performed statistical analysis using RevMan 5.3. The primary outcomes included basic patient characteristics, overall survival rate, disease-free survival rate, disease-specific survival rate, recurrence rate, and complication rate and type.

Results

A total of 33 articles were included in this meta-analysis. The results showed that the overall survival rate was 100% for T0 stage, 98.1% for Tis (carcinoma in situ) stage, and 80.2% for early stage rectal cancer patients (83.9% for T1 and 72.4% for T2). The weighted overall survival rate was 94% (RD = 0.94, 95% CI = 0.93-0.95, I 2 = 80%, P < 0.00001) for all stage patients, the weighted disease-free survival rate was 91% (RD = 0.91, 95% CI = 0.90-0.93, I 2 = 83%, P < 0.00001), and the disease-specific survival rate was 97% (RD = 0.97, 95% CI = 0.96-0.98, I 2 = 63%, P < 0.00001). The recurrence rate was 0.5% for T0 stage, 1.9% for Tis stage, and 11.9% for early stage rectal cancer patients (8.1% for T1 and 19.7% for T2). The weighted recurrence rate was 7% (RD = 0.07, 95% CI = 0.06-0.08, I 2 = 69%, P < 0.00001) for all stage patients. The weighted complications rate was 11% (RD = 0.11, 95% CI = 0.10-0.12, I 2 = 66%, P < 0.00001) for all stage patients, with Clavien-Dindo grade I accounting for 77.7%, Clavien-Dindo grade II accounting for 8%, and Clavien-Dindo grade III accounting for 14.3%.

Conclusion

The results showed that TEM has a high postoperative survival rate, low recurrence rate, and low complication rate in the T0 stage, Tis stage, and T1 stage, indicating its good safety and efficacy. For the treatment of T2 stage, TEM has a lower overall survival rate and a higher recurrence rate. Our meta-analysis results suggest that TEM alone is not recommended as a curative treatment for T2 stage; on the contrary, TME is more frequently recommended.

Early Rectal Cancer: Advances in Diagnosis and Management Strategies

Colorectal cancer (CRC) is the second most prevalent cause of cancer-related death and the third most common cancer globally. Early-stage rectal cancer is defined by lesions confined to the bowel wall, without extension beyond the submucosa in T1 or the muscularis propria in T2, with no indication of lymph node involvement or distant metastasis. The gold standard for managing rectal cancer is total mesorectal excision (TME); however, it is linked to considerable morbidities and impaired quality of life. There is a growing interest in local resection and non-operative treatment of early RC for organ preservation. Local resection options include three types of transanal endoscopic surgery (TES): transanal endoscopic microsurgery (TEM), transanal endoscopic operations (TEO), and transanal minimally invasive surgery (TAMIS), while endoscopic resection includes endoscopic mucosal resection (EMR), underwater endoscopic mucosal resection (UEMR), and endoscopic submucosal dissection (ESD). Although the oncological outcome of local resection of early rectal cancer is debated in the current literature, some studies have shown comparable outcomes with radical surgery in selected patients. The use of adjuvant and neoadjuvant chemoradiotherapy in early rectal cancer management is also controversial in the literature, but a number of studies have reported promising outcomes. This review focuses on the available literature regarding diagnosis, staging, and management strategies of early rectal cancer and provides possible recommendations.

Comparison of the transanal surgical techniques for local excision of rectal tumors: a network meta-analysis

BACKGROUND

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

An evaluation of trans-anal rectoscopic-assisted minimally invasive surgery (ARAMIS): a new platform for transanal surgery

PURPOSE

The study aimed to evaluate the feasibility and safety of a new trans-anal rectoscopic-assisted minimally invasive surgery (ARAMIS) platform to treat rectal lesions.

METHODS

ARAMIS was first compared with two transanal minimally invasive surgery platforms (SILS Port and GelPOINT Path) on human cadavers. Surgeons with different experience performed running sutures at different distances, at four quadrants, using the three platforms and gave a score to visibility, safety, and maneuverability. ARAMIS was then utilized on patients affected with rectal neoplasia who met the inclusion criteria. Patients and tumor characteristic and results were prospectively collected. The follow-up examinations included proctoscopy at 3, 6, and 12 months.

RESULTS

According to surgeons' scores, ARAMIS improves visibility and safety with respect to other platforms for distances beyond 10 cm. The procedure, which lasted an average of 59 min, was successfully carried out in 14 patients. No intraoperative or postoperative complications were reported. The mean tumor size was 3 cm; they were located a mean of 11 cm from the anal verge. Complete removal of the lesion was possible in 13/14 patients. There was one case of adenoma recurrence at follow-up.

CONCLUSION

Study results showed that ARAMIS, which is equipped with an adjustable rectoscope, can be considered a safe, effective platform for transanal surgery. The rectoscope protects the rectum during the procedure, a particularly important consideration when proximal rectal lesions are being treated. Further clinical studies are warranted to confirm these encouraging results.