The grades of neurosensory adverse events (NSAEs) induced by FOLFOX4 treatment were compared between Asian and Western colorectal cancer patients and correlated with cumulative oxaliplatin doses. A total of 3359 patients treated with FOLFOX4 were analyzed: 1515 from two Asian studies (Japanese Post Marketing Surveillance [J-PMS] and MASCOT) and 1844 from four Western studies (EFC2962, N9741, EFC4584, and MOSAIC). The onset of NSAEs was analyzed in terms of treatment duration and cumulative dose of oxaliplatin. The incidence of grade ≥3 NSAEs ranged from 2.0% to 4.4% in Asian studies and 9.3% to 19% in Western studies. The cumulative doses of oxaliplatin that induced grade ≥3 NSAEs in 10% of patients were higher in Asian studies (1526 mg/m(2) or not reached) than in Western studies (805-832 mg/m(2)). No significant correlations were noted between occurrence of grade ≥3 NSAEs and demographic/baseline characteristics. The frequency of escalation from grade 0 to 1 in J-PMS was statistically significantly lower than that in EFC4584, and that from grade 0 to 1 and from grade 1 to 2 in MASCOT lower than that in MOSAIC. The cumulative oxaliplatin doses administered during grade escalation in J-PMS were similar to those in EFC2962 or EFC4584. All grade-3 NSAEs in MASCOT and 96% of those in MOSAIC improved to grade 2 or less within 12 months of follow-up. The Asian populations accrued to these studies appear to be less susceptible to the neurotoxicity of oxaliplatin than the mainly Caucasian populations in the Western studies.
Keywords: Colorectal cancer; FOLFOX4; ethnic difference; neurotoxicity; oxaliplatin.