Size Reduction of Extrasellar Pituitary Tumors During Bromocriptine Treatment

Abstract

The well-known size-reducing effect of bromocriptine on prolactinomas was tested on 5 types of large, extrasellar pituitary tumors. Twenty patients were treated prospectively for up to 4.5 yr with bromocriptine, 30 or 60 mg/day (2 patients received 15 mg and 160 mg, respectively). The effect on the size of the pituitary tumors was quantitated by planimetry of computed tomographic scans before and during treatment. The immediate success rate was 16 of 20 tumors. Eleven nonsecreting tumors were reduced by a median of 32% (range of reduction for 50% of cases, 18%-41%) with an immediate success rate of 9 of 11. Nine secreting tumors (4 that secreted prolactin; 3, growth hormone; 1, ACTH; 1, TSH) were reduced by a median of 51% (range of reduction for 50% of cases, 25%-72%). The reduction in tumor size was significantly associated with pretreatment size (r = 0.6360, P < 0.005), but not with the serum concentration of any hormones assayed or previous radiation treatment. Bromocriptine causes a clinically significant reduction in size of nonsecreting and secreting pituitary tumors with the same success rate as that of conventional treatments.