Long-course temozolomide in aggressive pituitary adenoma: real-life experience in two tertiary care centers and review of the literature

Purpose Aggressive pituitary adenomas (APAs) and pituitary carcinomas (PCs) are challenging for their invasive nature, resistance to treatment and recurrences. Temozolomide (TMZ) is used with benefit and well-tolerated toxicity profile in APAs and PCs. In most studies patients received <= 12 cycles but the best length of treatment is debated since other options after discontinuation are scarce and a second course is mainly unsuccessful. Methods We report outcomes of 8 patients with APAs and PCs treated with TMZ for more than 12 continuous cycles with a literature review. Data were retrospectively collected from Padua and Milan University Hospitals. TMZ was used as a single agent (150-200 p.o. mg/m2 daily, 5/28 days) for 14 to 45 cycles. Results Eight patients (7 M), 7 APAs and 1 PC. Previous treatments included neurosurgery and radiotherapy in all cases except two giant masses (ACTH-silent APA and prolactinoma). No patient had progression disease (PD) during long-term treatment nor toxicities. No one had complete response (CR) but four had partial response (PR). Four ACTH+ tumors maintained stable disease (SD) but the secretion pattern improved in all. After drug withdrawal, three had delayed PD (2 after 18 and one after 29 months, all ACTH+); two are still in SD. Conclusions TMZ may be useful and well-tolerated in APAs and PCs as a long-term therapy. PR appears within the first cycles with no escape throughout the treatment; most patients achieve SD. We suggest extended protocols particularly in responsive ACTH+ PAs and PCs, when further therapies may be unsuccessful.