Predicting Hypogonadotropic Hypogonadism Persistence in Male Macroprolactinoma

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

Design:
Retrospective cohort study.

Methods:
Male patients diagnosed with macroprolactinoma and HH that received cabergoline treatment, and reached normoprolactinemia, were included: 46 men that achieved eugonadism, and 12 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 diameter of 25.9±14.8 mm were followed for a median of 5.6 years. Twelve men (21%) suffered from HH persistence at the end of follow-up.

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. Suprasellar tumor invasion (RR=6.6, p<0.01), visual field defect (RR=3.8, p=0.01) and hypopituitarism (RR=6.3, p<0.01) were associated with HH persistence.

In a multivariate logistic regression model, baseline testosterone below 1 ng/ml (OR=24.2, p=0.01), visual field defect (OR=37.6, p=0.01), and hypopituitarism (OR=22.1, p=0.02) remained independent predictors of HH persistence.

Conclusions:
In our cohort of male macroprolactinoma that reached normoprolactinemia under cabergoline treatment, 21% had HH persistence. Low baseline testosterone, visual field defect and hypopituitarism were independently associated with HH persistence.