Pituitary surgery for small prolactinomas as an alternative to treatment with dopamine agonists

Abstract

Despite the fact that consensus guidelines recommend long-term dopamine agonist (DA) therapy as a first-line approach to the treatment of small prolactinoma, some patients continue to prefer a primary surgical approach. Concerns over potential adverse effects of long-term medical therapy and/or the desire to become pregnant and avoid long-term medication are often mentioned as reasons to pursue surgical removal. In this retrospective study, 34 consecutive patients (30 female, 4 male) preferably underwent primary pituitary surgery without prior DA treatment for small prolactinomas (microprolactinoma 1-10 mm, macroprolactinoma 11-20 mm) at the Department of Neurosurgery, University of Bern, Switzerland. At the time of diagnosis, 31 of 34 patients (91%) presented with symptoms. Patients with microprolactinomas had significantly lower preoperative prolactin (PRL) levels compared to patients with macroprolactinomas (median 143 μg/l vs. 340 μg/l). Ninety percent of symptomatic patients experienced significant improvement of their signs and symptoms upon surgery. The postoperative PRL levels (median 3.45 μg/l) returned to normal in 94% of patients with small prolactinomas. There was no mortality and no major morbidities. One patient suffered from hypogonadotropic hypogonadism after surgery despite postoperative normal PRL levels. Long-term remission was achieved in 22 of 24 patients (91%) with microprolactinomas, and in 8 of 10 patients (80%) with macroprolactinomas after a median follow-up period of 33.5 months. Patients with small prolactinomas can safely consider pituitary surgery in a specialized centre with good chance of long-term remission as an alternative to long-term DA therapy.

Fig. 1

Box plots (a and b) show preoperative and postoperative PRL levels in the serum for patients with micro- (n = 24) and macroprolactinomas (n = 10). The lower and upper bars in the box plots delineate the lowest and highest measured PRL level for both groups, respectively. The box contains all PRL levels from the 25th to 75th percentile. The median PRL level is shown as a line in the box. The P-values for the preoperative (a) and postoperative PRL levels (b) between the two groups were *P = 0.0004 and P = 0.88, respectively

Fig. 2

Box-plots for long-term PRL levels in the serum for patients with micro- (n = 24) and macroprolactinomas (n = 10) were obtained by the patient’s referring physician after a median follow-up period of 33.5 months. The lower and upper bars show the lowest and highest measured long-term PRL levels for both groups, respectively. The box contains all long-term PRL levels from the 25th to 75th percentile range. The line in the box represents the median. The P-value for the long-term PRL levels between the two groups was 0.11

Fig. 3

Postoperative and long-term PRL levels in the serum for individual patients with small prolactinomas. a Twenty four individual postoperative and long-term PRL levels for patients with microprolactinomas. The values are shown by a black dots connected by a line. b Postoperative and long-term PRL values connected by a line for all 10 individual patients with microprolactinomas