Oxaliplatin-Based Adjuvant Chemotherapy for Rectal Cancer After Preoperative Chemoradiotherapy (ADORE): Long-Term Results of a Randomized Controlled Trial

Abstract

Purpose: We evaluated the role of oxaliplatin as adjuvant chemotherapy in patients with rectal cancer who received preoperative chemoradiotherapy (CRT) with fluoropyrimidine monotherapy and total mesorectal excision (TME).

Methods: The ADORE trial (adjuvant oxaliplatin in rectal cancer) is a multicenter, randomized trial in patients with postoperative ypStage II (ypT3-4N0) or III (ypT_anyN1-2) rectal cancer after fluoropyrimidine-based preoperative CRT and TME. Patients were randomly assigned (1:1) to receive adjuvant chemotherapy either with FL (fluorouracil 380 mg/m² and leucovorin 20 mg/m²) or FOLFOX (oxaliplatin 85 mg/m², leucovorin 200 mg/m², and fluorouracil bolus 400 mg/m² on day 1, fluorouracil infusion 2,400 mg/m² for 46 hours). Stratification factors included ypStage and participating center. Primary end point was disease-free survival (DFS).

Results: A total of 321 patients were enrolled between November 19, 2008, and June 12, 2012. Six-year DFS rates were 68.2% in the FOLFOX arm versus 56.8% in the FL arm, with a stratified hazard ratio of 0.63 (95% CI, 0.43 to 0.93; P = .018) by intention-to-treat analysis. In the subgroup analysis for DFS, FOLFOX was favorable versus FL in patients with ypStage III, ypN1b, ypN2, high-grade histology, minimally regressed tumor, and an absence of lymphovascular or perineural invasion. Six-year overall survival rate was 78.1% in the FOLFOX arm versus76.4% in the FL arm (hazard ratio, 0.73; 95% CI, 0.45 to 1.19; P = .21). In the subgroup analysis for OS, FOLFOX was favorable versus FL in patients with ypN2 and minimally regressed tumor.

Conclusion: Adjuvant FOLFOX improved DFS in patients with rectal cancer with ypStage II and III disease after preoperative CRT. Adjuvant FOLFOX may be considered on the basis of the postoperative pathologic stage in those who received preoperative CRT and TME.

Trial registration: ClinicalTrials.gov NCT00807911.