Longitudinal Analysis of Local Recurrence and Survival After Transanal Abdominal Transanal Radical Proctosigmoidectomy for Low Rectal Cancer Treated With Neoadjuvant Chemoradiation.

BACKGROUND: The transanal abdominal transanal radical proctosigmoidectomy was developed in 1984 as a sphincter preservation surgery in low rectal cancers after preoperative radiation. While serving as a catalyst for disruptive sphincter preservation surgery, it continues to be used and evolve. With the controversy over safety and local recurrence in other sphincter preserving surgery, review of transanal abdominal transanal radical proctosigmoidectomy long-term oncologic outcomes is warranted.

OBJECTIVE: To assess local after transanal abdominal transanal radical proctosigmoidectomy after neoadjuvant chemoradiation.

DESIGN: Retrospective cohort study of a prospectively maintained database.

SETTINGS: Tertiary rectal cancer referral center.

PATIENTS: Low adenocarcinoma (≤5 cm anorectal ring) receiving neoadjuvant chemoradiation then transanal abdominal transanal radical proctosigmoidectomy for curative resection between 1998-2021.

MAIN OUTCOME MEASURES: Local recurrence rates and overall survival rates.

RESULTS: Of 255 included, 67.8% were male (n = 173), mean 58.7 years old (standard deviation 11.5), with mean body mass index 27.1 kg/m2 (standard deviation, 5.4) and 50.2% (n = 128) American Society of Anesthesiology II. The mean tumor size was 4.8 cm (standard deviation 1.9), majority clinical T3 (81.8%, n = 184) and 52.1% had nodal disease (n = 100). The median radiation dose was 5400 cGy, with 73.7% (n = 149) achieving good response. 90.2% (n = 230) had minimally invasive surgery. Complete total mesorectal excision rate was 94.3% (n = 83/87) and 100% (n = 255) had negative distal margins. The mean examined lymph nodes were 13.9 (standard deviation, 10.7). After median follow-up of 55.4 months, 5.1% (n = 13) patients developed local recurrence, at median time of 29.6 months. The 5-year overall survival was 84.1% (95% CI 78.8-89.4).

LIMITATIONS: Retrospective review with risk of bias and lack of generalizability.

CONCLUSIONS: In this longitudinal study, the transanal abdominal transanal radical proctosigmoidectomy demonstrated excellent long-term locoregional control and survival in very low rectal cancers. The superior transanal abdominal transanal radical proctosigmoidectomy outcomes are durable over time, warranting expansion of the sphincter preserving surgery technique.