Rapid regression of pituitary prolactinomas during bromocriptine treatment.
Therapy for large prolactinomas remains controversial. Surgery is often unsuccessful in restoring endocrine function to normal. However, medical therapy with bromocriptine, a dopamine agonist, not only suppresses PRL levels, but may also lead to a reduction in tumor size. Previous reports have demonstrated radiographic evidence of tumor regression only after 3 or more months of bromocriptine therapy. We have now documented, for the first time, objective evidence of extremely rapid reduction in tumor size in two patients harboring large PRL-secreting pituitary tumors (mean pretreatment serum PRL levels, 2350 and 3900 ng/ml) who were prospectively treated with bromocriptine (7.5 mg/day) in preference to surgical intervention despite marked visual impairment in one of the patients. After 2 and 6 weeks of therapy, respectively, marked reduction in tumor size was demonstrated radiographically in both patients. Headache, visual acuity, and visual fields had improved after only 3 days. Although the mechanism of bromocriptine's antitumor activity is unclear, we believe that a large prospective trial to study the effects of bromocriptine therapy on the size of PRL-secreting macroadenomas is urgently needed to determine whether medical therapy should become the primary modality of treatment to reduce tumor size as well as restore endocrine function.
D000236:Adenoma / Q000188:drug therapy* / Q000378:metabolism; D000328:Adult; D001971:Bromocriptine / Q000627:therapeutic use*; D006801:Humans; D007700:Kinetics; D008297:Male; D010911:Pituitary Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism*; D013973:Thyrotropin-Releasing Hormone
D001971:Bromocriptine; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin