NORTH/HGCSG1003: A phase II study evaluating the safety and efficacy of FOLFOX as adjuvant chemotherapy for patients with stage III colon cancer: Comparison with medical oncologists and surgeons.

Introduction: The efficacy of oxaliplatin containing regimens were confirmed in large randomized phase III trials in which they were superior to fluorouracil and leucovorin as adjuvant setting for patients with stage III colon cancer. In Japan, not only medical oncologists but also surgeons practice chemotherapy. In this analysis, we investigated differences in safety and efficacy between surgeons and medical oncologists from NORTH/HGCSG1003 study. Methods: NORTH/HGCSG1003 is a multicenter phase II study. This study enrolled patients with resected stage III colon cancer. Patients received FOLFOX4 or mFOLFOX6 repeated every 2 weeks for 12 cycles. Primary endpoint is disease-free survival, and secondary endpoints were overall survival, safety, RDI and so on. In this analysis, pts characteristics and safety were compared using Fisher’s exact test. Dose intensity was compared using Student's t-test, and DFS and RFS using log-rank test. Results: From September 2010 to March 2013, 273 patients at 28 institutions were enrolled. In the eligible population (n = 264), 159 patients were treated with chemotherapy by medical oncologists (group O) and 105 patients by surgeons (group S). Patients’ characteristics between two groups were well balanced except for bowel obstruction before surgery (8.8% in group O vs 23.8% in group S; p = 0.001). Median RDI (group O vs group S) of oxaliplatin was 0.631 vs 0.751 (p Conclusion: RDI of oxaliplatin and bolus 5-FU were significantly lower in group O than group S. The frequency of platelet count decreased (all grade) was significantly less in O. This was presumed to be because the relative dose intensity of oxaliplatin was significantly lower in O. However, there was no significant difference in the frequency of peripheral sensory neuropathy. There was no significant difference in efficacy between O and S.