Oncologic outcomes and perioperative clinicopathologic results after robot-assisted tumor-specific mesorectal excision for rectal cancer

Background: Robot-assisted surgery is a new and emerging surgical procedure for rectal cancer patients. However, there is a lack of information regarding oncologic outcomes for this procedure. We aimed to evaluate oncologic and perioperative clinicopathologic outcomes of surgical resection using robotic instruments for rectal cancer. Methods: Data from rectal cancer patients (n = 370) diagnosed with stage I-IV disease sited below 15 cm from the anal verge who underwent robot-assisted tumor-specific mesorectal excision consecutively from June 2006 to December 2010 were evaluated. Clinicopathologic and follow-up data were recorded prospectively and analyzed retrospectively. Perioperative clinicopathologic outcomes, postoperative complications, 3-year overall survival rate, and 3-year disease-free survival rate were analyzed. Results: All patients underwent robot-assisted tumor-specific mesorectal excision. Of all postoperative pathologic stages, 15 (4.1 %) were stage 0 (pathologic complete remission), 126 (34.1 %) stage I, 95 (25.7 %) stage II, 118 (31.9 %) stage III, and 16 (4.3 %) stage IV. The 3-year overall survival rate was 93.1 % (pathologic complete remission = 100 %, stage I = 99.2 %, stage II = 97.1 %, stage III = 90.1 %, and stage IV = 48.4 %). The 3-year disease-free survival rate was 79.2 % (pathologic complete remission = 100 %, stage I = 93.7 %, stage II = 79.8 %, stage III = 69.6 %, and stage IV = 0.0 %). The 3-year cumulative local recurrence rate was 3.6 % (n = 10). The circumferential resection margin positive rate was 5.7 % (n = 21). Local recurrence developed in one patient and systemic recurrence developed in five patients. The total number of patients with postoperative complications was 86 (23.2 %). Conclusions: These data show the feasibility and safety of robot-assisted tumor-specific mesorectal excision for rectal cancer in terms of oncologic outcomes.