SUN-098 - Prolactinomas in Uruguay: 10-Year Follow-Up Study

Introduction: Prolactinomas account for approximately 40% of all pituitary tumors and 50-60% of hormone-secreting pituitary adenomas. In Uruguay, no epidemiological data on the prevalence of prolactinomas have been published to date.

Objectives: To describe the demographic characteristics, clinical presentation, and treatment outcomes of patients with prolactinoma managed at a tertiary referral hospital in Uruguay.

Methods: We conducted a retrospective, observational, descriptive study based on medical record review of patients diagnosed with prolactinoma between January 2014 and December 2023. Demographic, clinical, biochemical, and imaging variables were collected at diagnosis and throughout follow-up.

Results: Twenty-three patients were included (52% women), with a mean age of 38 years (range 18-69). Macroadenomas were most frequent (52%), followed by microprolactinomas (26%) and giant prolactinomas (21%). Larger tumors predominated in men and older patients. In microprolactinomas, 83% of patients were women, and galactorrhea (83%) and menstrual disturbances (80%) were the most common presenting symptoms, whereas headache predominated in macroprolactinomas (58%). The gonadal axis was the most frequently affected pituitary axis. Tumor diameter correlated positively with serum prolactin levels (p < 0.05). Except for one patient who underwent surgery at diagnosis, all patients received dopamine agonists as first-line therapy. Maximum cabergoline doses were 0.6, 2.9, and 2.8 mg/week for micro-, macro-, and giant prolactinomas, respectively. Only one patient required surgery due to treatment resistance. Gonadal function recovered in 60% with baseline hypogonadism, with a similar rate of improvement in visual field defects. At six months, prolactin normalization was achieved in 80% of microprolactinomas, 41.7% of macroprolactinomas, and 20% of giant prolactinomas. Overall, 73.6% of patients achieved normoprolactinemia. Tumor shrinkage >50% was observed in 66.6% of adenomas ≥1 cm and 40% of tumors < 1 cm. Adverse effects were infrequent, and no serious events were reported.

Conclusions: In this Uruguayan cohort, prolactinomas frequently presented as macroprolactinomas, reflecting the role of our institution as a referral center for complex cases. Cabergoline was highly effective and well tolerated, achieving substantial rates of prolactin normalization and tumor reduction. This study provides novel real-world and relevant data on prolactinomas in Uruguay and highlights the need for national research to optimize management strategies.

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