Adjuvant chemotherapy with oxaliplatin/5-fluorouracil/leucovorin (FOLFOX) versus 5-fluorouracil/leucovorin (FL) in patients with locally advanced rectal cancer after preoperative chemoradiotherapy followed by surgery: A randomized phase II study (The ADORE).

Abstract

3570 Background: Preoperative chemoradiotherapy (Pre-CRT) with fluoropyrimidines (Fp) followed by surgery is one of the standard treatments for patients (pts) with locally advanced rectal cancer (LARC); however, the role of adjuvant chemotherapy is still controversial. The aim of this study is to investigate the efficacy of adjuvant FOLFOX for LARC pts who underwent Fp-based Pre-CRT and complete total mesorectal excision (TME). Methods: This randomised phase II study accrued LARC pts whose ypStage was II (ypT3-4/ypN0) or III (any ypT/ypN1-2) after Fp-based Pre-CRT followed by TME. Pts were randomly assigned (1:1) to receive adjuvant chemotherapy either with FL (5-FU 380 mg/m2, leucovorin 20 mg/m2 on D1-5 q 4 weeks X 4 cycles) or FOLFOX (oxaliplatin 85 mg/m2, leucovorin 200 mg/m2 on D1, 5-FU bolus 400 mg/m2 on D1, 5-FU infusion 2400 mg/m2 for 46 hours q 2 weeks X 8 cycles). The primary endpoint was disease-free survival (DFS). Results: A total of 320 pts were randomly assigned (161 FL and 159 FOLFOX) between November 2008 and June 2012, the arms were balanced. By intent-to-treat analysis, estimated 2-year DFS rate was 82.0% in FOLFOX arm and 69.4% in FL arm (HR 0.46 [95% CI, 0.28-0.76], p=0.002) after the median follow-up duration of 22.5 months. The statistical improvements of DFS were maintained regardless of ypStage: 2-year DFS rate was 89.7% (FOLFOX) vs 76.4% (FL) in pts (n=122) with ypStage II (HR 0.32 [0.10-0.98], p=0.035), and 78.1% (FOLFOX) vs 64.4% (FL) in pts (n=198) with ypStage III (HR 0.49, [0.27-0.86], p=0.011). All grade leucopenia (32% vs 22%), neutropenia (70% vs 46%), thrombocytopenia (26% vs 2%) and sensory neuropathy (71% vs5%) were more frequently observed in FOLFOX arm; however, grade 3/4 adverse events (AE) were not different between arms. Conclusions: Adjuvant FOLFOX improved 2-year DFS relative to FL for LARC pts whose ypStage II or III after Fp-based Pre-CRT followed by TME. Significant AEs were not different between arms. The DFS results will be updated in the presentation. Clinical trial information: NCT00807911.