Clinical usefulness of testing for UDP glucuronosyltransferase 1 family, polypeptide A1 polymorphism prior to the inititation of irinotecan-based chemotherapy.

An association between UDP glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1) polymorphisms and irinotecan-induced neutropenia has been previously reported. In this study, we assessed the clinical usefulness of testing for UGT1A1 polymorphisms prior to the initiation of irinotecan-based chemotherapy, as this remains a controversial subject. A total of 136 lung cancer patients who were treated with a combination of nedaplatin and irinotecan as initial chemotherapy were assessed. Following exclusion of patients exhibiting low UGT1A1 enzyme activity, 70 patients were treated after UGT1A1 polymorphism testing (test group) and 66 patients were treated without UGT1A1 polymorphism testing (non-test group). We retrospectively analyzed and compared the adverse events between the test and the non-test groups and observed no reduction in hematological or non-hematological toxicities in the test group compared to that in the non-test group. Of the 9 patients with grade 4 or 5 non-hematological toxicity, 6 patients had febrile neutropenia (FN). All the patients with FN were aged >70 years. The incidence of adverse events was significantly higher among patients aged >70 years compared to that among younger patients. In conclusion, in patients treated with nedaplatin and irinotecan combination chemotherapy, UGT1A1 polymorphism testing prior to the initiation of chemotherapy did not reduce the incidence of adverse events. Therefore, UGT1A1 polymorphism testing alone may not be sufficient to predict the occurrence of severe adverse events and it may be more important to effectively manage adverse events, particularly in elderly patients.