Objective To explore the clinical efficacy of transanal specimen extraction in modified Da Vinci robot-assisted anterior resection of rectosigmoid tumor.Methods The retrospective cross-sectional study was conducted.The clinicopathological data of 47 patients who underwent Da Vinci robot-assisted anterior resection of rectosigmoid tumor using transanal specimen extraction in the Second Xiangya Hospital of Central South University from March to October 2016 were collected.Excisional intestinal canal was intraoperatively taken out from the anus instead of abdominal minor incision.Observation indicators:(1) operation and postoperative recovery;(2)postoperative pathological examination situations;(3) follow-up.Follow-up using outpatient examination and telephone interview was performed to detect postoperative survival of patients and tumor recurrence or metastasis up to June 2017.Measurement data with normal distribution were represented as (x)±s.Results (1) Operation and postoperative recovery:47 patients underwent successful operations,without conversion to open surgery.Of 47patients,8 underwent coloanal ultralow anastomosis,3 underwent prophylactic terminal ilenm stoma fistulization and 1 underwent intersphincteric resection after turning inside out resectable specimen.Operation time,volume of intraoperative blood loss,time for out-of-bed activity,time to anal exsufflation and time of postoperative drainagetube removal were (222±73)minutes,(21±9)mL,(1.7-±0.8)days,(2.3±l.0)days and (6±5)days,respectively.Among 3 patients with postoperative complications,2 with anastomotic fistula were cured by conservative treatment,and 1 with urinary retention removed urethra catheter at 4 weeks postoperatively.All the 47 patients had good recovery,and duration of hospital stay was (10±4)days.(2) Postoperative pathological examination situations:number of lymph node dissected was 15-± 7,with R0 resection.Tumor pathological diagnosis:rectosigmoid adenocarcinoma was detected in 38 patients (1 with high-differentiated tumor,32 with moderate-differentiated tumor and 5 with low-differentiated tumor),mixed carcinoma in 4 patients,tubulovillous adenoma in 2 patients,mucinous adenocarcinoma in 1 patient,neuroendocrine carcinoma in 1 patient and focal cacinoma in 1 patient.The maximum diameter of tumor was (3.5± 1.5) cm.Postoperative pathological T stage:4,9,18 and 14 patients were detected in stage T1,T2,T3 and T4a.Postoperative pathological N stage:30,8 and 7 patients were detected in stage N0,N1 and N2.Postoperative pathological TNM stage:stage Ⅰ,Ⅱ and Ⅲ were respectively in 11,19 and 15 patients.There was no clinical stage in 2 patients with tubulovillous adenoma.(3) Follow-up:of 47 patients,42 were followed up for 7-15 months,with a median time of 11 months.During the follow-up,38 patients had tumor-free survival,3 had tumor recurrence or metastases and 1 died.Conclusion Transanal specimen extraction is safe and feasible in modified Da Vinci robot-assisted anterior resection of rectosigmoid tumor,with minimal invasion and satisfactory short-term outcomes.