Transanal down-to-up dissection of the distal rectum as a viable approach to achieve total mesorectal excision in laparoscopic sphincter-preserving surgery for rectal cancer near the anus: A study of short- and long-term outcomes of 127 consecutive patients from a single Japanese institution

Background: In rectal cancer (RC) surgery, the complexity of total mesorectal excision (TME) in laparoscopic sphincter-preserving surgery (lap-SPS) for RC near the anus has been a critical issue. Recently, technical assistance via the anus for complete TME has been receiving attention. This study aimed to clarify the transanal down-to-up dissection viability for achieving TME in lap-SPS for RC near the anus. Methods We evaluated surgical and oncological outcomes of a total of 127 consecutive patients undergoing either a transanal rectal dissection under direct vision (TARD) mobilizing the most difficult portion of TME via the anus or the transanal TME by using an endoscopic system (TaTME) for achieving TME in lap-SPS for RC near the anus between January 2006 and February 2021. Results A total of 127 consecutive patients (87 men), with a median age of 66 years (range 33–86 years), were included. TARD and TaTME were performed for 51 (40.2%) and for 76 (59.8%) patients, respectively. Preoperative treatment was performed for 41 (32.3%) patients, resulting in a complete pathological response in 5 (3.9%) patients. Intersphincteric resection was performed significantly in the TARD group (p < 0.001). Although the TaTME group needed a longer operative time at the transanal portion (p < 0.001), the median blood loss was inferior (p < 0.001). Postoperative complications of the Clavien–Dindo classification grade ≧ 2 developed in 56 (44.1%) patients. Urinary dysfunction (13.4%) was found most frequently, followed by stoma-related complications (12.6%). More patients needing medication for urinary dysfunction were found in the TARD group, but a significant difference was not observed (11.8% vs. 6.6%, p = 0.347). The quality of TME was good for almost all patients. Recurrence developed in 18 (14.2%) patients. The 5-year OS and DFS rates in 127 patients were 90.4% and 83.2%, respectively. The 5-year OS between the two groups was comparable, but the 5-year DFS in the TaTME group was significantly poorer (p = 0.024). Conclusions Our data suggested that a transanal down-to-up dissection of the distal rectum might be a viable approach in lap-SPS for RC near the anus. Further studies need to examine the differences between TARD and TaTME.