This study aims to explore the clinical feasibility, safety and short-term efficacy of oversleeve anastomosis in natural orifice specimen extraction surgery (NOSES) for low rectal cancer after neoadjuvant chemoradiotherapy.

From October, 2018 to October, 2021, twenty low rectal cancer patients after neoadjuvant chemoradiotherapy were retrospectively enrolled in this study, who underwent NOSES using the oversleeve anastomosis technique in Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. Data regarding clinical characteristics, surgical outcomes, postoperative recovery, pathological characteristics, perioperative complications, postoperative recurrence and metastasis were collected and analyzed. The low anterior resection syndrome (LARS) score was used to evaluate anal function at the first, third and sixth months after surgery.

We successfully performed NOSES with the oversleeve anastomosis technique in 20 low rectal cancer patients after neoadjuvant chemoradiotherapy without the use of prophylactic stoma. The median distance of the tumor from the anal verge was 4.0 cm. The median operation time was 171.5 minutes, the median anastomosis time was 17.0 minutes and intraoperative blood loss was 35.0 mL. The median time to ground activity, time to fluid diet intake, time to flatus, and length of hospital stay were 18.5 hours, 12.0 hours, 30.0 hours and 7.0 days, respectively. The median hospitalization cost was 47 678.0 RMB. The postoperative pathological reports showed that the median length of tumor was 3.3 cm; the median proximal and distal resection margin was 10.3 cm and 1.0 cm; the median lymph nodes retrieved was 14.5. During the follow-up period, the colonic stump retracted back to the rectal cavity on postoperative day 11.5. One patient (5.0%) experienced anastomosis leakage five day after operation, and three patients (15.0%) experienced perianal fecal dermatitis and anal pain. All of them recovered after symptomatic treatment. One patient (5.0%) had liver metastasis one year after operation, and the other patients had no tumor recurrence or metastasis. LARS was higher in 12 patients (60%) one month after operation, but anal function gradually recovered satisfactorily three months after operation in 15 patients (75%).

This study indicates that NOSES using oversleeve anastomosis shows promise as a safe and feasible procedure with satisfactory short-term outcomes for low rectal cancer after neoadjuvant chemoradiotherapy, avoiding the use of prophylactic stoma. The anal function is satisfactory after symptomatic guidance. But the long-term outcomes need to be explored.