MON-117 - Nadir Prolactin–guided Individualized Cabergoline Therapy for Durable Remission and Safe Pregnancy in Prolactinomas

Context: Achieving durable structural remission while preserving safe pregnancy remains a central unmet goal of prolactinoma therapy.

Objective: To prospectively evaluate individualized-dose cabergoline therapy for safe pregnancy, structural remission, and dosing optimization.

Methods: We studied 310 unselected women with prolactinomas, including 97 bromocriptine (BC)-resistant, 93 BC-intolerant, and 120 naïve patients, harboring 56 large macrotumors, 80 small macrotumors, and 174 microtumors. Cabergoline dosing was individualized to maintain nadir prolactin within the lowest achievable normal range. In 129 macrotumors and 19 microtumors at risk of gestational enlargement, prophylactic medical debulking was performed to restore the optic–pituitary (O–P) distance to >5.0 mm. Cabergoline was discontinued immediately after conception.

Results: Outcomes exceeded prior reports, including 100% biochemical normalization; 84–100% prepregnancy tumor debulking; 365 uneventful pregnancies in 295 patients (95%); absence of symptomatically enlarged tumors during pregnancy; and 72% postpartum remission overall (naïve 82%, BC-resistant 70%, BC-intolerant 61%; small macrotumors 74%, microtumors 73%, large macrotumors 68%). Responder frequency was subtype-specific across 0.25–9.0 mg/week doses with distinct ED50 values ranging from 0.66 in BC-intolerant to 3.71 in BC-resistant patients. AIC-based multivariate analysis identified nadir prolactin—markedly lower in tumor-invisible than tumor-residual cohorts (2.5 ± 1.6 vs 9.3 ± 2.7 ng/ml, P < .0001)—as the dominant determinant of tumor disappearance. No cardiac valvulopathy or impulse control disorders were observed on longitudinal follow-up.

Conclusion: Despite marked ED50 heterogeneity, nadir prolactin–guided individualized-dose cabergoline therapy safely achieved durable remission with excellent pregnancy outcomes. Integrating endocrine control with anatomy- and prolactin-guided tumor debulking provides a clinically actionable framework for achieving durable remission even in challenging prolactinomas.

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