(MansTaTME) Trans-anal Versus Laparoscopic Total Mesorectal Excision for Mid and Low Rectal Cancer

Colorectal cancer (CRC) is considered the third most common type of cancer all over the world and the fourth common cause of cancer-specific mortality.Surgical management for rectal cancer is challenging due to the narrow pelvis and extreme proximity to contiguous organs hence, recurrence rates are commonly reported.

The advent of total mesorectal excision (TME) together with minimally invasive techniques such as laparoscopic colorectal surgery have not only improved surgical results but have also improved surgical technique, operative ability and surgical visibility. Lap TME has been shown to give similar results to the classical open approach with regard to peri-operative morbidity, surgical margins, quality of the surgical specimen, and number of resected lymph nodes, local recurrence and overall survival.

However, laparoscopic resection of mid and low rectal cancer is technically difficult due to tapering of the mesorectum in the pelvis and the forward angle of the distal rectum rendering this part of the rectum less accessible from the abdominal cavity. This may lead to incomplete mesorectal excision and involved circumferential resection margins (CRMs), with consequent local recurrences.Previous pelvic radiation can make laparoscopic pelvic dissection more difficult, and tumors located on the anterior rectal wall have an increased risk of inadequate oncological clearance. The use of laparoscopic staplers in a narrow pelvis is difficult and the multiple firings of staples across the low rectum is of concern.

Trans-anal Total Mesorectal Excision (TaTME) was recently developed to overcome technical difficulties associated with Lap TME and open TME. It may address some of the difficult aspects of laparoscopic or open TME, such as exposure, rectal dissection, and distal cross-stapling of the rectum and sphincter preservation. It does not only facilitate dissection of the difficult distal part of the TME dissection in the narrow pelvis but it also allows clear definition of safe, tumor-free, radial and longitudinal margins. Moreover, the specimen could be extracted through the anus excluding the need for minilaparotmy.