Long-term response of pituitary carcinoma to temozolomide. Report of two cases.

Pituitary carcinoma is a rare tumor characterized by poor responsiveness to therapy, leading to early death. Reported responses to standard chemotherapy have only been anecdotal, with no single agent or combination demonstrating consistent efficacy in the treatment of patients with this disease. The authors report rare examples of a persistent response to cytotoxic chemotherapy in two patients with pituitary carcinoma. One patient was a 38-year-old man with visual field loss caused by a luteinizing hormone-secreting pituitary carcinoma that had recurred despite multiple surgeries and radiation therapy. Intradural metastases to the spine that had failed to respond to radiation therapy were pathologically confirmed. The second patient was a 26-year-old man with hyperprolactinemia from a prolactin-secreting pituitary tumor. Spine magnetic resonance images obtained to search for causes of neck pain showed a vertebral tumor, which was later confirmed through pathological analysis to be a metastatic pituitary carcinoma. His disease progressed despite radiation therapy, high-dose bromocriptine, and chemotherapy. Both patients were treated monthly with temozolomide, which was administered orally on the first 5 days of a 28-day cycle. The patient in the first case underwent all 12 treatment cycles without serious side effects, and his visual field deficits improved. The patient in the second case had undergone only 10 cycles when the drug was stopped because of his severe fatigue. Nonetheless, his pain disappeared and his serum prolactin concentration decreased. Both patients continue to have partial responses and have been employed full-time for more than 1 year after discontinuing temozolomide therapy. These two examples demonstrate that temozolomide may be effective in treating pituitary carcinomas and thus should be considered in the treatment algorithm for these difficult cases.