Tailored treatment strategy for locally advanced rectal carcinoma: Five-year results of the French phase II, randomized, multicenter GRECCAR4 trial.

Abstract

4014 Background: Preoperative radiochemotherapy and total mesorectal excision are the standard-of-care for locally-advanced rectal carcinoma, but some patients are over- or undertreated. Our phase II study assessed the feasibility of tailored radiochemotherapy, based on tumor response to induction high-dose chemotherapy (FOLFIRINOX). Methods: We enrolled 206 patients; good responders after chemotherapy (≥75% tumor volume reduction) were randomly assigned to immediate surgery (arm A) or standard radiochemotherapy (Cap 50: 50 Gy and oral capecitabine daily) plus surgery (arm B). Poor responders were randomly assigned to Cap 50 (arm C) or intensive radiochemotherapy (Cap 60 (60 Gy irradiation), arm D) before surgery. Results: After induction treatment, 194 patients were classified as good (n=30, 15%) or poor (n=164, 85%) responders, and included in arms A and B (16 and 14 patients) or C and D (113 and 51 patients). The primary objective was obtained: (90% CI) R0 resection rates in the four arms respectively were 100% (74–100), 100% (85–100), 83% (72–91), and 88% (77–95). At 5 years: overall survival 90% (CI: 47.3-98.5), 93.3% (CI: 61.3-99.0), 84.3% (CI: 71.0-91.8), 86.1% (CI: 71.6-93.5); disease-free survival 80% (CI: 40.9-94.6), 89.5% (CI: 64.1-97.3), 72.9% (CI: 58.5-82.9), 72.8% (CI: 57.7-83.2); local recurrence 0, 0, 2.1% (CI: 0.3-13.9), 9.3% (CI: 3.6-23.0); metastasis 20% (CI: 5.4-59.1), 10.5% (CI: 2.7-35.9), 18% (CI: 31.8-94.6), 18.8% (CI: 10.2-33.0). Late morbidity and quality of life evaluations showed no significant difference between arms. Conclusions: Tailoring preoperative radiochemotherapy based on induction treatment response is safe and promising. Early tumoral response to induction chemotherapy can discriminate tumor prognosis. Clinical trial information: NCT01333709 .