SUN-449 Medical versus Surgical Treatment of Macroprolactinomas (MP): Indications, Efficacy, and Safety

Introduction: Prolactinomas are primarily treated with medical therapy. Given the efficacy of dopamine agonists (DAs), surgery has remained a second-line treatment option. Objective: to evaluate the indications, efficacy, and safety of both treatments in MP. Methods: We performed a retrospective analysis of all patients with MP treated at our institution from January 2007 to October 2018. We divided the patients into two groups: medical treatment with DA (Group 1) and surgery (Group 2). Results: Prolactinomas (n: 69) constituted 36.9% of the total population of pituitary adenomas of our hospital (n: 187). 81.2% were MP (n: 56), from which 53.6% were included in Group 1 (n: 30) and 46.4% in Group 2 (n: 26). The mean follow-up was 50.9 months. There were no significant differences in age, sex, initial prolactin (PRL) value and tumor size between groups. Within the surgical indications (n:24), 29.2% were operated due to uncertain diagnosis, 29.2% due to visual impairment, 25% due to failure of medical treatment, 4.2% due to DAs intolerance, 4.2% due to apoplexy, 4.2% due to fistula and 4.2% due to the patient choice. 68.2% of the patients received DA therapy prior to surgery (15/22). There were no significant differences in the complication rate between both groups (66.7% Group 2 vs 40.7% Group 1, p: 0.09), although panhypopituitarism was significantly more frequent in Group 2 (54.2% vs 25.9%, p: 0.049, RR: 2.089). There were no significant differences between age, sex, tumor reduction and evolution between both groups. Invasive tumors (Knosp 4) were more frequent in Group 2 (59% vs 32%, p: 0.0149). Patients with biochemical persistence were younger (m: 25.5 ± 11 vs 40.7 ± 13.3 years, p: 0.01) and had a higher Knosp value (median 4 vs 3, p: 0.04) than patients in remission. Patients with postsurgical complications had a higher Knosp value in the initial image (median 4 vs 3, p: 0.04). Only 17.4% of the patients in group 2 were able to remain off DA after surgery. Conclusion: The percentage of patients with MP in our series is greater than that reported in the literature. As a neurosurgical reference center, we generally receive patients with more complex tumors. Although we had a high percentage of surgeries in patients with MP, this was due to the tumor characteristics or to an inadequate response to the DAs in our series. The patients who required surgical treatment had more invasive tumors, and coincidentally, these had the greatest number of complications. However, the only statistically significant complication between the two groups was panhypopituitarism. Despite the fact that only a small group of the operated patients could remain without medical treatment and that there were no differences in the evolution, surgery remains an alternative effective treatment option particularly for those patients with intolerance to DAs or highly invasive or resistant tumors.