Endocrine Abstracts

Objective: To study the baseline characteristics predicting hypogonadotropic hypogonadism (HH) persistence in men with macroprolactinoma following medical treatment with cabergoline.

Design: Retrospective cohort study conducted in a tertiary pituitary center.

Methods: Male patients diagnosed with macroprolactinoma and HH that received cabergoline treatment with subsequent prolactin normalization were included: men that achieved eugonadism, and men that remained hypogonadal. Patient’s demographic, clinical and biochemical parameters, sellar magnetic resonance imaging (MRI) and visual fields tests were obtained. Univariate analyses and multivariate logistic regression models for HH persistence were developed to investigate the relative contribution of the predicting factors.

Results: Fifty-eight male patients (age, 49.2±12.6 years) with a median baseline prolactin of 1154 ng/ml (IQR, 478-2763 ng/ml) and adenoma (maximal) diameter of 25.9±14.8 mm were followed for a median of 5.6 years (IQR, 3.0-10.7). All men achieved normoprolactinemia with cabergoline treatment. 12 men (21%) suffered from HH persistence at the end of follow-up, and 46 men achieved eugonadism.

Baseline testosterone (1.6±0.7 vs 0.7±0.6 ng/ml; P<0.01), luteinizing-hormone (1.8±1.5 vs 0.4±0.2 mIU/ml; P<0.01) and follicle stimulating-hormone (3.4±2.9 vs 0.9±0.7 mIU/ml; P<0.01) were lower, and prolactinoma diameter (23.7±12.8 vs 34.6±18.9 mm;P=0.02) was larger in men with HH persistence. In addition, suprasellar tumor invasion (RR=6.6; 95% CI 1.6–27.8), visual field defect (RR=3.8; 95% CI 1.5–9.3) and hypopituitarism (RR=6.3; 95% CI 2.6–14.8) were associated with HH persistence. 42 out of 46 men (91%) accomplished eugonadism within the first year following prolactin normalization. In a multivariate logistic regression model, the presence of either VFD and/or hypopituitarism (OR=11.5; 95% CI 1.88–71.32) and baseline testosterone levels (OR=0.12; 95% CI 0.02–0.64) remained independent predictors of HH persistence. Adenoma maximal diameter (OR 1.02; 95% CI 0.96–1.07) did not predict HH persistence.

Conclusion: In our cohort of men with macroprolactinoma that reached prolactin normalization with cabergoline treatment, 21% had HH persistence. Low baseline testosterone levels, visual field defect and pituitary hormone deficiency were independently associated with HH persistence. 91% of men accomplished eugonadism within the first year following prolactin normalization. These findings support informed clinical decisions regarding testosterone replacement initiation in men with macroprolactinomas.