Short course chemotherapy followed by concomitant chemoradiotherapy and surgery in locally advanced rectal cancer: a randomized multicentric phase II study

Background: Induction chemotherapy has been suggested to impact on preoperative chemoradiation efficacy in locally advanced rectal cancer (LARC). To evaluate in LARC patients, the feasibility and efficacy of a short intense course of induction oxaliplatin before preoperative chemoradiotherapy (CRT). Patients and methods: Patients with T2-T4/N+ rectal adenocarcinoma were randomly assigned to arm A-preoperative CRT with 5-fluorouracil (5-FU) continuous infusion followed by surgery-or arm B-induction oxaliplatin, folinic acid and 5-FU followed by CRT and surgery. The primary end point was the rate of ypT0-1N0 stage achievement. Results: Fifty seven patients were randomly assigned (arm A/B: 29/28) and evaluated for planned interim analysis. On an intention-to-treat basis, the ypT0-1N0 rate for arms A and B were 34.5% (95% CI: 17.2% to 51.8%) and 32.1% (95% CI: 14.8% to 49.4%), respectively, and the study therefore was closed prematurely for futility. There were no statistically significant differences in other end points including pathological complete response, tumor regression and sphincter preservation. Completion of the preoperative CRT sequence was similar in both groups. Grade 3/4 toxicity was significantly higher in arm B. Conclusions: Short intense induction oxaliplatin is feasible in LARC patients without compromising the preoperative CRT completion, although the current analysis does not indicate increased locoregional impact on standard therapy.