Three- versus six-month adjuvant FOLFOX or CAPOX for high-risk stage II and stage III colon cancer patients: the efficacy results of Hellenic Oncology Research Group (HORG) participation to the International Duration Evaluation of Adjuvant Chemotherapy (IDEA) project.

Abstract

The International Duration Evaluation of Adjuvant Chemotherapy (IDEA) aimed to investigate whether a 3 months (3M) of oxaliplatin/fluoropyrimidine-based adjuvant chemotherapy (CT) is non-inferior to the 6-month (6M) administration in 3-year disease-free survival (3yDFS) in high-risk (HR) stage II or stage III colon cancer (CC). Hellenic Oncology Research Group (HORG)-IDEA randomized patients between 3M and 6M of CT with FOLFOX4 or CAPOX. In total 1115 patients, 413 with HR stage II and 702 with stage III CC, were randomized. The median follow-up was 67.0 (38.3-126.0) months. Overall, 394 DFS events (202 in 3M arm and 192 in 6M arm) where recorded. The 3yDFS rate was 77.2% [95% confidence interval (CI) 72.1% to 82.3%] for 3M and 77.9% (72.6% to 82.5%) for 6M of treatment [hazard ratio (HR) 1.05 (95% CI 0.61-1.55); P = 0.647]. Eighty DFS events (3M N = 41; 6M N = 39) were observed in HR stage II patients for a 3yDFS rate of 82.7% and 83.4%, respectively (HR 1.05; 95% CI 0.68-1.63, P = 0.829). For stage III patients, 314 DFS events (3M N = 161 and 6M N = 153) were observed, for a 3yDFS rate of 72.9% for 3M versus 74.1% for 6M (HR 1.06; 95% CI 0.81-1.42, P = 0.622). For HR stage II patients receiving FOLFOX4, 3yDFS rate was 76.7% for 3M and 79.3% for 6M (HR 1.21; 95% CI 0.54-2.70). For HR stage II patients receiving CAPOX the 3yDFS rate was 85.4% for 3M and 83.8% for 6M (HR 0.99; 95% CI 0.59-1.67). For stage III patients receiving FOLFOX4, the 3yDFS rate was 71.5% for 3M and 77.3% for 6M (HR 1.18; 95% CI 0.74-1.86). For stage III patients receiving CAPOX, the 3yDFS rate was 74.5% for 3M and 74.7% for 6M (HR 0.99; 95% CI 0.70-1.44). The results of the HORG-IDEA study are in line with those of the global IDEA project, indicating that the 3yDFS is dependent on the administered adjuvant regimen and the choice and duration of regimen should be personalized. NCT01308086.