Three versus six months adjuvant oxaliplatin-based chemotherapy for patients with stage III colon cancer: The French participation to the International Duration Evaluation of Adjuvant chemotherapy (IDEA) project.

Abstract

3500 Background: The IDEA international collaboration was established to combine data from 6 randomized trials to assess whether a 3-month (3M) of oxaliplatin/fluoropyrimidines-based adjuvant chemotherapy (CT) is non-inferior to the 6-month (6M) for 3-year disease free survival (DFS) in stage III colon cancer (CC). Methods: French IDEA randomized patients (pts) between 3M and 6M of CT with mFOLFOX6 or XELOX (physician/pts choice). DFS was estimated using the Kaplan–Meier method and described using 3 years DFS rate. Results: Among 2022 randomized pts between May 2009 and May 2014, 2010 (99.4%) received CT and were enrolled in the mITT population: 49.9 and 50.1% in 3M and 6M, respectively. 99.5% of the mITT pts had stage III (N1: 74.9%; N2: 25.2%); median age 63.9 years; mFOLFOX6: 90% and XELOX 10% of pts. DFS median follow-up is 50.2 months. There were 578 DFS events (314 in 3M and 264 in 6M arm) leading to a 3-year DFS rate of 72.1% in the 3M vs. 75.7% in the 6M (HR=1.24; 95%CI 1.05–1.46, p=0.0112). For pts receiving mFOLFOX6, 3-year DFS rate was 72.0% in the 3M vs. 76.3% in the 6M (HR=1.27; 95%CI 1.07–1.51 p=0.0069). 94.2% and 78.0% of pts completed 3 and 6 months of CT, respectively. Median oxaliplatin doses intensity were 96.9% in 3M and 72.1% in 6M (495.0 and 735.1 mg/m2). By considering the neuropathy grade with 15375 neuropathy longitudinal measurements the overall maximal neuropathy grade 0-1/2/3-4 was 63.6/28.5/7.9% in 3M and 33.4/41.3/25.3% in 6M; p<0.0001. At last follow-up assessment, with a median of 43.1 months, final residual grade 2/3-4 neuropathy was 2.1/0.4% in 3M and 5.4/1.3% in 6M; p<0.0001. Conclusions: The IDEA France study, with 90% of patients treated with mFOLFOX6 regimen has shown that 6 months adjuvant treatment is superior to 3 months treatment. IDEA France study results should be considered in line with the international IDEA project that will also be presented at ASCO 2017. Clinical trial information: 2009-010384-16.