Total Mesorectal Excision (TME) Study

Total mesorectal excision (TME) is an integral part of any radical resection of rectal cancer. This procedure is of importance in patients with rectal cancer with clinical stage I to III rectal cancer below the peritoneal reflection. Some centers are experimenting with transanal TME (TaTME).

In a randomized trial of 116 patients undergoing laparoscopic rectal surgery for cancer, TaTME resulted in a lower conversion rate to open surgery than the standard transabdominal approach (LaTME; 2 versus 11 percent), with similar overall morbidity rates. This multicentric study is reported in Annals of Surgery. This study assumes significance, as it is the first reported multicenter RCT with sufficient power to directly compare TaTME with LaTME.

Study Design

A randomized, open-label, phase 3, noninferiority trial was performed at 16 different hospitals in 10 Chinese provinces. The primary endpoints were 3-year disease-free survival and 5-year overall survival. The morbidity and mortality within 30 days after surgery, and pathologic outcomes were compared based on a modified intention-to-treat principle.

Results

Local recurrence rates were not significantly different (TaTME: one patient [1.8 percent], LaTME: three patients [6.1 percent]), although median follow-up was only 39 months. Despite no significant differences in postoperative hospital stay [median: 8.0 days vs 9.0 days], patients undergoing TaTME displayed faster postoperative recovery, as indicated by less time to first flatus. There was no significant difference in the overall postoperative complication rate of 13.4% in the TaTME and 12.1% in the LaTME groups. Based on the Clavien-Dindo classification of surgical complications, the distribution of severity between the two groups did not differ. Specifically, the overall rate of anastomotic leakage was 6.2% vs 5.3% between the two routes.

Key Points

• TaTME could yield similar surgical safety and pathologic outcomes as LaTME, and thus it generally seems to be safe and feasible for skilled surgeons.
• TaTME has the potential to improve the quality of resected specimens with superior radicality, particularly for patients with distal rectal cancer, visceral obesity, bulky tumors, or a narrow pelvis.
• Pathologic outcomes indicated that TaTME could yield adequate surgical resection, similar to LaTME.

Disadvantages

• Because TaTME carries a steep learning curve (about 40 cases), it should be reserved for high-volume centers. Most centers should continue to perform standard LaTME.
• A higher rate of intersphincteric resection was found in patients receiving TaTME in this trial, and the sacrifice of the internal sphincter could potentially impair functional outcomes.

Conclusion

TaTME in selected patients with rectal cancer can be safely performed by experienced surgeons and provide satisfactory oncologic radicality. However, the applicability of TaTME to rectal cancer patients should continue to be considered until the long-term oncologic outcomes from this well-established RCT are analyzed.

Source: Liu H et al. Chinese Transanal Endoscopic Surgery Collaborative (CTESC) Group. Morbidity, Mortality, and Pathologic Outcomes of Transanal Versus Laparoscopic Total Mesorectal Excision for Rectal Cancer Short-term Outcomes From a Multicenter Randomized Controlled Trial. Ann Surg. 2023 Jan 1;277(1):1-6