Three versus six months adjuvant oxaliplatin plus fluoropyrimidine chemotherapy for patients with stage III colon cancer: The Hellenic Oncology Research Group (HORG) participation to the International Duration Evaluation of Adjuvant (IDEA) chemotherapy project.

Abstract

730 Background: The IDEA international collaboration aimed to combine data from 6 randomized trials to investigate 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: HORG-IDEA randomized patients between 3Mand 6M of CT with mFOLFOX6 or CAPOX. DFS was estimated using the Kaplan–Meier method and described using 3 years DFS rate. Results: In total708 patients were randomized between May 2009 and October2015, 354in each arm. Among them the basic characteristics was: median age 63.9 years; mFOLFOX6: 41.8% and CAPOX 58.2%, N1: 74.9%, N2: 25.2%; T1-3: 86.4%, T4: 13.6%. DFS median follow-up was 54.2 months. There were 214 DFS events (109in 3M and 105 in 6M arm) leading to a 3-year DFS rate of 73.2% in the 3M vs. 74.9% in the 6M (HR = 1.03; 95%CI 0.80–1.43, p = 0.622).For patients receiving mFOLFOX6, 3-year DFS rate was 71.8% in the 3M vs.77.7% in the 6M (HR = 1.18; 95%CI 0.74–1.88 p = 0.478). For patients receiving CAPOX 3-year DFS rate was 74.7% in the 3M vs. 74.8% in the 6M (HR = 0.99; 95%CI 0.69–1.45 p = 0.994).94.2% and 78.0% of pts completed 3 and 6 months of CT, respectively. Overall, 96.9% and 89.5% of patients completed 3 months (arm A) and 6 months (arm B) of CT, respectively. Median oxaliplatin doses intensity were 97.3% in 3M and 73.2% in 6M (505.0 and 738.3 mg/m2).Overall maximum neuropathy during treatment grade 2/3-4 was 23.9/5.9%in 3M and38.7/13.7%in 6M; p < 0.0001. In addition, worst grade 2/3-4 diarrhea was 11.1/4/0 in 3M and in 12.3/7.36M; p = 0.03. Conclusions: Since the HORG-IDEA study was designed in order to contribute patients in the IDEA project, the result on the study should be interpreted together with those of the whole IDEA project. Nevertheless, the results of the HORG-IDEA study are in line with those of the whole IDEA project, indicating that the results are depended on the administered adjuvant regimen, and the choice of regimen and duration should be depended on tumor characteristics and patient preference. Clinical trial information: NCT01308086.