In the bivariate analysis, the AA genotype (AA vs. G) of the GSTP1 rs1695 polymorphism was found to be associated with severe overall toxicity (p = 0.03; OR = 2.55; 95% CI = 1.02–6.70) and neutropenia (grades I–IV) (p = 0.02; OR = 2.64; 95% CI = 1.11–6.50). This evidence concerns the gene GSTP1 and Decreased total neutrophil count.