Three versus six months 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

3500 Background: The IDEA aimed to investigate whether a 3-month (3M) of oxaliplatin/fluoropyrimidines-based adjuvant chemotherapy (CT) is non-inferior to the 6-month (6M) in 3-year disease free survival (DFS) in stage high risk stage II and in stage III colon cancer (CC). Methods: HORG-IDEA randomized patients between 3M and 6M of CT with FOLFOX4 or CAPOX with primary end point the 3 years DFS (3yDFS). Results: In total 1121 patients, 413 with high risk stage and 708 with stage IIICC, were randomized between May 2009 and October 2015. The median follow-up was 67 (38-126) months. There were 79 DFS events (43 in 3M and 38 in 6M arm) in high risk stage II patients leading to 3yDFS rate of 82.7 and 83.4% for 3M and 6M, respectively (HR: 1.05; 95%CI: 0.68-1.63, p = 0.829). Similarly, 214 DFS events (161 in 3M and 153 in 6M arm) has been recorded in stage III patients, leading to a 3yDFS rate of 72.9% in the 3M vs. 74.1% in the 6M (HR = 1.06; 95%CI: 0.81–1.42, p = 0.622). For high risk stage II patients receiving FOLFOX4, 3yDFS rate was 76.7% in the 3M vs.79.3% in the 6M (HR = 1.21; 95%CI: 0.54–2.70 p = 0.641). For high risk stage II patients receiving CAPOX 3-year DFS rate was 85.4% in the 3M vs. 83.8% in the 6M (HR = 0.99; 95%CI: 0.59–1.67 p = 0.968). For stage III CC patients receiving mFOLFOX6, 3-year DFS rate was 71.5% in the 3M vs.77.3% in the 6M (HR = 1.18; 95%CI: 0.74–1.86 p = 0.479). For stage III CC patients receiving CAPOX 3-year DFS rate was 74.5% in the 3M vs. 74.7% in the 6M (HR = 0.99; 95%CI: 0.70–1.44 p = 0.991). Conclusions: The results of the HORG-IDEA study are in line with those of the global IDEA project, indicating that 3yDFS is depended on the administered adjuvant regimen, and the choice of regimen and duration should be personalized. Clinical trial information: NCT01308086.