Endocrine Abstracts

Objective: Prospective study of medical treatment effect in newly diagnosed patients with large and giant prolactinomas.

Patients and methods: The study group included 45 patients with large prolactinomas (tumors more 3,6 cm) and 23 patients with giant prolactinomas (tumors more than 6 cm); from them 8 mainly cystic tumors. The treatment period was 3–24 month (mean 6). Serum prolactin level before treatment ranged between 12 990 and 1 038 000 mU/l (mean 198 000; normal 30–545 mU/l). Fifty-five men and 13 women aged 16–67 years (mean 39) were treated with cabergoline of dose from 0.5 mg to 4.0 mg/week (mean 1.5 mg). Fifty-four patients before treatment had visual impairment. Fourteen patients had optic atrophy. Fourteen patients had epileptic syndrome.

Results: Tumors, including 7 cystic, decreased in size in 55 patients. The size of 13 tumors was without any change. Decrease of prolactin occurred in all patients; serum prolactin level was 350–19 460 mU/l (mean 2500) during treatment. Forty-two patients had improved visual symptoms in the early stage of treatment, other patients showed no visual impairment. In 5 (7%) patients cerebrospinal fluid (CSF) leakage occurred within 14–30 days after initiation of treatment. In 2 patients endoscopic endonasal surgery to repair the fistula was performed.

In other patients the CSF leakage ceased with diuretic therapy and with temporarily decreases of cabergoline dosage. The drug was well tolerated by all patients and no one discontinued the therapy.

Conclusion: Cabergoline should be the first-line therapy for large and giant prolactinomas, even in patients with visual defects. Use of cabergoline results in effective reduction of prolactin, improvement of visual defects and provides tumor shrinkage (including cystic prolactinomas).

Patients with large and giant prolactinomas are at risk of CSF leakage during medical treatment with cabergoline.