Binary logistic regression of UGT1A1*28 with febrile neutropenia suggested that a performance status of 2 or a rectosigmoid tumour origin both significantly increased the risk of febrile neutropenia in the first cycle of IRI treatment (odds: 41.7, P=0.010 and odds: 6.5, P=0.030, respectively) in addition to the association of UGT1A1*28. This evidence concerns the gene UGT1A1 and neoplasm.