Severe and prolonged myelosuppression during concomitant temozolomide and radiotherapy treatment in a patient with glioblastoma multiforme

Aims: We describe the case of a patient with glioblastoma (GBM) who developed severe and prolonged myelosuppression during concomitant daily temozolomide (TMZ) and radiotherapy (RT) treatment. Analysis of polymorphisms in genes correlated with TMZ-induced myelotoxicity was also performed. Presentation of the Case: A 67–year-old man with diagnosis of GBM undergoing concomitant RT-TMZ treatment developed severe and prolonged pancytopenia that led to discontinuation of TMZ and required frequent platelet and red cells transfusions. Analysis of single nucleotide polymorphisms (SNPs) in the genes NAD(P)H dehydrogenase, quinone 1 (NQO1) and glutathione S-transferase pi 1 (GSTP1) was carried out. Both SNPs were found to be wild-type. Discussion: TMZ is an oral alkylating agent used for the treatment of glioblastoma. TMZ is usually considered well tolerated and safe, with nausea and mild myelosuppression being the most common side effects. However, severe haematologic adverse events have been also reported. Recently, there has been growing interest in gene polymorphisms that might be associated with an increased risk of hematologic toxicity. Conclusion: Myelosuppression is a side effect that can occur relatively early during concomitant TMZ treatment and can negatively impact on patient’s quality of life. Further studies are warranted to find out a correlation between genetic factors and the occurrence of severe hematologic toxicity.