Endocrine Abstracts

Objective: To study the outcomeof menwith macroprolactinoma followingcabergoline treatment based on tumor size.

Design: A retrospective cohort study using a single tertiary referral center registry.

Methods: The study included 96 men with macroprolctinoma, aged 16–84 years (mean 47.3 years) treated from 1993 to 2019,for a mean follow-up of 7.5 years. The cohort was subdivided into 3 groups according to baseline adenoma diameter: group A, adenomas of 10–19 mm (n = 36), group B,20–39 mm (n = 43), and group C,giant prolactinomas ≥40 mm (n = 17). Cabergoline was started at a weekly dose of 0.5 mg and progressively increased as necessary (weekly cabergoline dose, 0.5–10 mg). Nineteen men required pituitary surgery, 3 (8%), 10 (23%), and 6 (35%) in group A, B and C, respectively.

Results: Mean prolactinoma maximal diameter at presentation was 15.0, 28.1 and 49.8 mm in group A, B and C, respectively, decreasing following treatment to 7.6, 13.6 and 16.6 mm (P < 0.01). Mean baseline prolactin levels were 685, 2,134 and 24,316 ng/ml (P < 0.01) in group A, B and C,decreasing following treatment to 15, 68 and 31 ng/ml (P = 0.48). Prolactin suppression to <3 ×ULN was achieved in 34 (94%; mean weekly cabergoline dose, 1.2 mg), 35 (81%; cabergoline dose, 2.0 mg) and 14 (82%; cabergoline dose, 2.8 mg) men (P = 0.21) in the different groups. Treatment duration until complete prolactin normalization was 10.8, 17.9 and 21.9 months, occurring in 33 (92%), 31 (72%) and 14 (82%) men in group A, B and C, respectively. Visual defect was depicted in 4 (11%), 14 (33%) and 9 (56%) patients (P = 0.03)in group A, B and C, respectively. Improvement was achieved in 4/4, 13/14 and 9/9 men. Residual visual field impairment at the end of follow-up was noticed in 0 (0%), 7 (16%), and 6 (40%) patients (P = 0.01)in group A, B and C, respectively. Low baseline testosterone was discovered in 26 (72%), 40 (93%) and 17 (100%) patients (P < 0.01) in group A, B and C. Hypogonadism following treatment persisted in 2 (6%), 5 (11%) and 2 (12%) men, respectively (P = 0.61). Sexual dysfunction at presentation was reported by 23 (68%), 33 (79%) and 14 (82%) patients in group A, B and C, respectively, but improved in 21/23 (91%), 25/29 (86%) and 10/13 (77%) patients in the different groups.

Conclusion: Cabergoline is very effective in most men with macroprolactinoma, regardless of initial tumor size.