Temozolomide in the treatment of aggressive pituitary tumours - an overview of existing knowledge and future perspectives

Abstract

The management of aggressive pituitary tumours remains a challenge, however, the recent identification of temozolomide as a chemotherapeutic agent with significant efficacy against these tumours has heralded a new therapeutic era. There has been an exponential growth in the international experience with temozolomide over the past five years, now totalling 50 published cases. Overall, 67% of cases demonstrated a response to temozolomide. Prolactin- and adrenocorticotrophic hormone (ACTH)-secreting tumours respond more frequently than non-functioning tumours. Response is typically evident in the first three months of treatment. Adverse effects occur in almost half of patients, although the majority are mild. The expression of a DNA repair enzyme, 06-methylguanine-DNA methyltransferase (MGMT), as determined by immunohistochemistry, appears to be the primary determinant of response to temozolomide in pituitary tumours. There is suggestion that MGMT may also play a role in pituitary tumorigenesis. Over the next few years we will see temozolomide used earlier in the treatment algorithm of aggressive pituitary tumours, making it imperative to collect global long-term data on its use. © TOUCH MEDICAL MEDIA 2012.