Feasibility Study of a Modified XELOX Adjuvant Chemotherapy for High-Recurrence Risk Patients With Operated Stage III Colon Cancer

BACKGROUND Since 2004, a regimen of 6 months of treatment with oxaliplatin plus a fluoropyrimidine has been standard adjuvant therapy in patients with stage III colon cancer. However, since oxaliplatin is associated with cumulative neurotoxicity, a shorter duration of therapy could spare toxic effects and health expenditures. METHODS We performed a prospective, preplanned, pooled analysis of six randomized, phase 3 trials that were conducted concurrently to evaluate the noninferiority of adjuvant therapy with either FOLFOX (fluorouracil, leucovorin, and oxaliplatin) or CAPOX (capecitabine and oxaliplatin) administered for 3 months, as compared with 6 months. The primary end point was the rate of disease-free survival at 3 years. Noninferiority of 3 months versus 6 months of therapy could be claimed if the upper limit of the two-sided 95% confidence interval of the hazard ratio did not exceed 1.12. RESULTS After 3263 events of disease recurrence or death had been reported in 12,834 patients, the noninferiority of 3 months of treatment versus 6 months was not confirmed in the overall study population (hazard ratio, 1.07; 95% confidence interval [CI], 1.00 to 1.15). Noninferiority of the shorter regimen was seen for CAPOX (hazard ratio, 0.95; 95% CI, 0.85 to 1.06) but not for FOLFOX (hazard ratio, 1.16; 95% CI, 1.06 to 1.26). In an exploratory analysis of the combined regimens, among the patients with T1, T2, or T3 and N1 cancers, 3 months of therapy was noninferior to 6 months, with a 3-year rate of disease-free survival of 83.1% and 83.3%, respectively (hazard ratio, 1.01; 95% CI, 0.90 to 1.12). Among patients with cancers that were classified as T4, N2, or both, the disease-free survival rate for a 6-month duration of therapy was superior to that for a 3-month duration (64.4% vs. 62.7%) for the combined treatments (hazard ratio, 1.12; 95% CI, 1.03 to 1.23; P = 0.01 for superiority). CONCLUSIONS Among patients with stage III colon cancer receiving adjuvant therapy with FOLFOX or CAPOX, noninferiority of 3 months of therapy, as compared with 6 months, was not confirmed in the overall population. However, in patients treated with CAPOX, 3 months of therapy was as effective as 6 months, particularly in the lower-risk subgroup. (Funded by the National Cancer Institute and others.)

Given that the clinical course of oxaliplatin-induced neuropathy is not well defined, the current study was performed to better understand clinical parameters associated with its presentation.

Since the MOSAIC study, oxaliplatin-based adjuvant chemotherapy has been the standard treatment of stage III colon cancer. Combination therapy with fluoropyrimidines and oxaliplatin has improved overall survival (OS) and reduced the risk of recurrence in patients with resected stage III colon cancer. However, only 20% of patients really benefit from adjuvant chemotherapy, exposing 80% of patients to unnecessary toxicity. Recent analyses of large multicenter adjuvant studies have focused on the prognostication of OS and disease-free survival in stage III colon cancer in order to reduce over-treatment and to find more accurate prognostic tools than those used for adjuvant treatment decision-making in stage II disease. Indeed, clinical and pathological prognostic factors, although important, are not sufficient to decide which stage III patients will benefit from adjuvant therapy, and biomarkers will help select patient that need adjuvant treatment. Molecular markers such as microsatellite status and BRAF and KRAS mutations have recently been explored, and molecular signatures have been identified as promising prognostic factor for OS. Furthermore, recent studies have highlighted the prognostic value of immune infiltration. This review focuses on pathologic, immunologic and molecular prognostic markers for stage III colon cancer that could help clinicians tailor adjuvant treatment in a comprehensive transversal approach.