Objective: Oxaliplatin-induced chronic neuropathy is cumulative and dose-limiting; reliable predictors and determination of the mechanism of this toxic effect are needed.
Methods: We retrospectively studied 51 Japanese adults with colorectal cancer who had received oxaliplatin-based chemotherapy to explore the pharmacogenetic association between oxaliplatin-induced neuropathy and polymorphisms of the excision repair cross-complementation Group 1 (ERCC1) and glutathione-S-transferases pi 1 (GSTP1) genes.
Results: For the ERCC1 C118T polymorphism, Grade 1 chronic neuropathy developed earlier in patients with C/T and T/T genotypes (median number of treatment cycles at onset = 6) than in those with the reference C/C genotype (7 cycles; p = 0.0162 by the generalized Wilcoxon test). For the GSTP1 Ile105Val polymorphism, chronic neuropathy developed earlier in patients with the reference Ile/Ile genotype (6 cycles) than in those with Ile/Val and Val/Val genotypes (9 cycles; p = 0.0321). ERCC1 C118T and GSTP1 Ile105Val polymorphisms were not significantly associated with an increased risk of developing Grade 2 or more severe chronic neuropathy.
Conclusions: Our results suggest that ERCC1, C118T and GSTP1 Ile105Val polymorphisms are more strongly related to the time until onset of neuropathy than to the grade of neuropathy. Most likely these polymorphisms influence patients' sensitivity to neuropathy.