Temozolomide therapy for resistant prolactin-secreting pituitary adenomas and carcinomas: a systematic review

Pituitary tumors represent 10–15% of all intracranial tumors; of these, prolactinomas account for 40–50% of cases. Prolactinomas usually respond well to dopamine agonists (DA) as first-line therapy. However, treatment resistance remains a concern. Temozolomide (TMZ) is an oral alkylating agent that has shown promise in treating aggressive pituitary adenomas and carcinomas that are resistant to other therapies. To date, no control trials have been undertaken and only single case reports of pituitary tumors treated with TMZ have been published. A systematic literature search was conducted for studies reporting the use of TMZ for the treatment of prolactinomas that were resistant to standard therapy. In total, 42 reported cases were identified and included in our analysis: 23 cases of prolactin-secreting adenomas and 19 of prolactin-secreting carcinomas. Prior to TMZ administration, patients had exhibited tumor progression and had previously undergone various treatments including surgery, radiotherapy, and drug therapy. Tumor shrinkage was reported in 76% of patients. Reduced prolactin levels were observed in 75% of patients, while normalization of prolactin was reported in 8%. TMZ failure occurred in 20.6% of cases. Most patients exhibited no serious adverse effects. In conclusion, TMZ has potential for the treatment of highly aggressive and resistant prolactin-secreting adenomas and carcinomas, as demonstrated by tumor shrinkage or complete response and normalization of hormone hypersecretion, and exhibits good tolerability and few side effects.