Adjuvant chemoradiotherapy versus radical surgery after transanal endoscopic microsurgery for intermediate pathological risk early rectal cancer: A single-center experience with long-term surveillance.

[BACKGROUND] The choice of subsequent treatment for intermediate-risk rectal tumors after transanal endoscopic microsurgery between adjuvant chemoradiotherapy and total mesorectal excision is controversial. The present study aimed to compare survival and functional outcome between these 2 strategies.

[METHODS] This retrospective study included intermediate-risk patients with early rectal cancer after transanal endoscopic microsurgery in our center between 2010 and 2017. Patients were divided into adjuvant treatment and total mesorectal excision groups. Intermediate risk was defined as pT1 with lymphovascular invasion, poor differentiation, or large diameter (3-5 cm) or pT2 with small diameter (<3 cm). The study was based on follow-up data on survival and results from distributed validated scales for functional outcome.

[RESULTS] Postoperative overall survival and disease-free survival were comparable between the groups (P = .619 and P = .712, respectively). Pathological T stage was an independent risk factor for disease-free survival (hazard ratio 3.09, 95% confidence interval 1.66-4.18, P = .044). Anorectal symptoms, such as buttock pain, were significantly prevalent in the total mesorectal excision group (P = .030). In addition, the total mesorectal excision group presented with poorer bowel function, including stool urgency (P < .001), bowel frequency (P = .016), severity of low anterior resection syndrome (P = .039) and total low anterior resection syndrome score (P = .040). Except for a lower score of vaginal lubrication in the total mesorectal excision versus the adjuvant treatment group, sexual function was similar between the groups.

[CONCLUSION] Similar to total mesorectal excision, adjuvant chemoradiotherapy is an alternative option for intermediate-risk early rectal cancer after transanal endoscopic microsurgery and is associated with similar survival outcomes and better bowel function.