5 x 5 Gy and consolidation chemotherapy vs long-course preoperative chemoradiation for locally advanced rectal cancer: An interim analysis of a randomized phase III study.

e15006Background: To present an interim analysis of a phase III trial comparing short-course radiotherapy followed by chemotherapy with long-course chemoradiotherapy in locally advanced rectal cancer. Methods: Patients with distal or middle third, MRI diagnosed cT3-T4 or N+ rectal adenocarcinomas were randomized to either 5 x 5 Gy and 4 courses of CAPOX (experimental group) or 50 Gy delivered in 25 fractions given concurrently with capecitabine (control group). Total mesorectal excision (TME) in both groups was performed 6-8 weeks after neoadjuvant treatment. This is an interim analysis of acute toxicities for the first 127 patients who finished neoadjuvant therapy, as well as the pCR and surgical complications for the first 100 patients who received surgery. Results: From 08/30/2015 to 12/11/2016, 63 patients in experimental group and 64 in control group from 10 Chinese hospitals were analyzed. During preoperative treatment, any acute toxicities were 100% in both groups and grade III-IV 19.0% vs. 6.3% (p...