Long term follow-up of women with surgically treated prolactin-secreting pituitary tumors.

To examine the long term effectiveness of transsphenoidal microsurgery for patients with PRL-secreting pituitary tumors, we studied 54 women at yearly intervals after transsphenoidal surgery. Five years after surgery, 19 women (35%) had normal serum PRL concentrations, and 23 (43%) had persistent hyperprolactinemia. Hyperprolactinemia recurred in 12 of 31 patients (39%) who had normal PRL concentration 6 weeks after surgery. None of the patients with recurrent hyperprolactinemia had radiographic evidence of tumor regrowth, and only 3 of 12 had amenorrhea. A serum PRL level below 6 ng/ml 6 weeks after surgery occurred more frequently in cured patients than in those who had a recurrence. PRL responses to TRH were normal in cured patients 1 and 5 yr after surgery and abnormal in those who had recurrent hyperprolactinemia. The PRL responses to chlorpromazine- and insulin-induced hypoglycemia were blunted in patients with normal as well as elevated PRL levels. Patients with recurrent, as well as those with persistent, hyperprolactinemia had no nocturnal rise in serum PRL 5 yr after surgery. The 39% recurrence rate of hyperprolactinemia and persistent abnormalities in pituitary-hypothalamic regulation of PRL secretion after transsphenoidal surgery raise important questions about the choice of primary therapy for patients with PRL-secreting tumors.