The efficacy of oxaliplatin (l-OHP)-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 adjuvant chemotherapy. In this analysis, we investigated differences in adverse events and relative dose intensity (RDI) between surgeons and medical oncologists.
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 was disease-free survival, and secondary endpoints were overall survival, safety, RDI. In this analysis, pts characteristics and safety were compared using Fisher's exact test. Dose intensity was compared using Student's t-test, and cumulative incidence of peripheral sensory neuropathy (PSN) using log-rank test.
From September 2010 to March 2013, 273 patients at 28 institutions were enrolled. In the safety analysis set (n = 265), 160 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 l-OHP was 0.632 vs 0.751 (p < 0.001) and that of bolus 5-FU was 0.641 vs 0.797 (p < 0.001). The difference in completion treatment rate of 12 cycles between two groups was not statistically significant (83.1% vs 76.2%; p = 0.206). Median cumulative dose of l-OHP until expression of grade 2≤ PSN was higher in group S than group O (980.0mg/m2 vs 765.0mg/m2; p = 0.027).
RDI of l-OHP and bolus 5-FU were significantly lower in group O than group S. There was no significant difference in adverse events. Less l-OHP dosing until presence of PSN was administered in group O than group S. This analysis had been presented at the ESMO 17th World Congress on Gastrointestinal Cancer (Iwanaga I, et al. Abstract number was P-249).
Clinical trial identification
Y. Komatsu: Honoraria: Yakult Honsha Co., Ltd., Research fund: Yakult Honsha Co., Ltd. All other authors have declared no conflicts of interest.