Radiosurgery for PRL-secreting pituitary adenomas refractory to medical and surgical treatment

Abstract Objective Radiotherapy is seldom required in patients with prolactinoma, except in few cases resistant to standard treatment. We report the long-term outcome of Gamma Knife radiosurgery in a consecutive series of patients with prolactinoma resistant to both dopamine agonists and surgery. Design Observational study. Tertiary reference center for surgery and radiosurgery in patients with pituitary adenoma. Methods We investigated 44 consecutive patients with prolactinoma resistant or intolerant to drugs who underwent radiosurgery at our center between 1994 and 2024. End points of the study were normalization of prolactin either on or off medical therapy, control of tumor growth, and toxicity. Results After a median follow-up of 92 months, the 5- and 10-year-probability of remission off drug therapy was 35.7% (95% confidence interval, 18.7–52.7%) and 49.0% (95% confidence interval, 29.6–68.4%), respectively, while the 5- and 10-year-probability of remission in the 20 patients on drug therapy was 51.1% (95% confidence interval, 26.7–75.5%) and 58.5% (95% confidence interval, 33.1–83.9%), respectively. Twelve of the 13 women with infertility (92.3%) spontaneously conceived during follow-up. Recurrence of the tumor occurred in 3 patients (6.8%). The 5- and 10-year-recurrence free survival was 93.5% (95% confidence interval, 84.5 - 100%) and 88.6% (95% confidence interval, 75.8 - 100%), respectively. Severe trigeminal neuralgia lasting for six months occurred in one patient. New pituitary deficits occurred in two patients. Conclusions Gamma Knife radiosurgery provides durable tumor control and hormonal improvement in patients with prolactinoma refractory to medical and surgical therapy. Side effects, including hypopituitarism, are uncommon.