Recovery from hypogonadism in men with prolactinoma treated with dopamine agonists

In men with prolactinoma treated with dopamine agonists (DA), the extent, timeline, and predictive factors of gonadotropic axis recovery are still unclear.

We analyzed data of 97 men with a prolactinoma treated with DA (77/97 macroprolactinomas). We excluded patients with primary hypogonadism, surgery < 12 months after DA initiation, and patients with tumors < 5 mm or prolactin < 45 µg/l at diagnosis.

Among the 97 patients, 12 had normal total testosterone (NT group) and 85 had low testosterone at diagnosis (LT group). In the NT group, testosterone rose from a mean of 13.5 nmol/l to 17.1nmol/l at 6 months (n = 11; p < 0.05) then remained stable at 12 months (n = 8). In the LT group, testosterone rose from a mean of 5.2 nmol/l to 9.6 nmol/l at 6 months (n = 66; p < 0.001) and further to 13.1nmol/l at 12 months (n = 40; p < 0.001) then remained stable. Recovery from hypogonadism occurred in 43%, 50%, and 54% of patients at 6, 12 and 24 months, respectively (61%, 69 and 69% if prolactin was normal). Factors independently associated with persistent hypogonadism at 12 months were at baseline the presence of visual field deficit and lower testosterone levels, while the most significant independent predictor of persistent hypogonadism at one year was a testosterone level < 7.4 nmol/l at 6 months, with 91% sensitivity and 94% specificity.

Testosterone levels recover in a small majority of men with prolactinoma mostly during the first year of DA treatment. However, testosterone replacement could be considered earlier in patients with large and compressive tumors, and in whom testosterone remains below 7.4 nmol/l after 6 months of DA treatment.