asco@alo33:162017 JSONTXT

Background: Mesorectal excision ME is the standard surgery for loer rectal cancer. Hoever, lateral pelvic lymph node metastasis is occasionally found, and ME ith lateral lymph node dissection LLND is the standard procedure in Japan. We conducted a randomized trial to confirm the non-inferiority of ME alone to ME ith LLND in terms of efficacy and reported the ME group tended to sho loer postoperative morbidity than the ME+LLND group. This is the primary analysis of the relapse-free survival RFS as the primary endpoint. Methods: Eligibility criteria included histologically proven rectal cancer; clinical stage IIIII; main lesion located in the rectum and the loer margin belo the peritoneal reflection; no lateral pelvic lymph node selling; PS of 0 or 1; patient age 20-75 years. After surgeons had confirmed R0 resection by the ME procedure, patients ere randomized intraoperatively to ME alone or ME ith LLND. The primary endpoint as RFS and the non-inferiority margin of the hazard ratio HR as 1.34. The planned sample size as 700 ith a poer of 75 percent and a one-sided alpha of 5 percent. Results: A total 701 patients enrolled from 33 institutions ere randomized to ME+LLND n=351 or ME n=350 beteen June 2003 and August 2010. The 5-year RFS as 73.4 percent and 73.3 percent in the ME+LLND group and the ME group, respectively. The HR as 1.07 [90.9 percent CI 0.84-1.36 1.34 ]; thus the non-inferiority of ME as not confirmed p=0.055 . The 5-year overall survival OS and the 5-year local-recurrence-free survival LRFS ere shon in the Table. The numbers of patients ith local recurrence ere 25 7.1 percent and 44 12.6 percent in the ME+LLND group and the ME group, respectively p=0.02 . Conclusions: The non-inferiority of ME to ME ith LLND as not confirmed. ME ith LLND significantly reduced local recurrence after surgery compared ith ME alone. Clinical trial information: C000000034.ME+LLND 95 percent CI ME 95 percent CI HR 95 percent CI 5-year RFS73.4 percent 68.5-77.7 percent 73.3 percent 68.3-77.6 percent 1.07 0.81-1.41 5-year OS92.6 percent 89.3-94.9 percent 90.2 percent 86.5-92.9 percent 1.25 0.85-1.84 5-year LRFS87.7 percent 83.8-90.7 percent 82.4 percent 78.0-86.1 percent 1.37 0.98-1.93 ,J Clin Oncol 34, 2016 suppl; abstr 3508 ,C000000034,00:00.0,Gastrointestinal Colorectal Cancer