SUN-075 - Cabergoline'S Effect on Non-Functioning Pituitary Adenomas' Volume and Visual Fields: A Single-Center Experience

Introduction
Cabergoline seems to be a promising and effective medical treatment for non-functioning pituitary adenomas (NFPAs) by reducing or maintaining tumor size long term. This may be particularly important in aggressive tumors or in patients unsuitable for further surgery or radiotherapy. Here, we present the experience of our center.
Methods
We retrospectively studied 15 adult patients with NFPAs ≥1 cm attending our clinic the last 16 years (median follow-up 56 months, range 20 to 191 months), in whom cabergoline was initiated due to contraindication to surgery or radiotherapy, or because of residual or regrown macroadenoma. Six (6/15) patients had prior pituitary surgery (transsphenoidal, and 2/6 an additional transcranial) for aggressive adenomas compressing the optic chiasm, histological and immunohistochemical findings negative for intact pituitary hormone expression and significant residual tumor or tumor regrowth post surgery. The other 9/15 had macroadenomas approaching the optic chiasm. Cabergoline was initiated at 0.5 mg/week and titrated according to response and tolerance (mean dose 2.38 ± 0.53 mg/week). Tumor volume (cm³), visual fields, and pituitary function were assessed before and eighteen months after cabergoline’s initiation. Tumor volume was calculated using the ellipsoid formula. Tumor shrinkage >20% from baseline was considered significant, while shrinkage ≥10% or stabilization was considered clinically important.
Results
Mean age was 65.5 ± 6.1 years, and 53.3% of patients were male. Mean baseline tumor volume was 6.66 ± 2.52 cm³, which decreased to 5.66 ± 2.43 cm³ during cabergoline treatment (mean reduction 21.8% ± 10.7%, p< 0.001). Tumor volume reduction >20% was observed in 8/15 patients (53.3%), reduction ≥10% in 10/15 (66.7%), stabilization in 1/15 (6.7%), and minimal increase ( < 5%) in 1/15 (6.7%). Visual fields improved in 7/15 patients (46.7%) and remained stable in 8/15 (53.3%); no deterioration was observed. Pituitary hormonal function remained unchanged in all patients. No clinically significant adverse effects were reported.
Conclusion
Our data indicate that cabergoline may represent a beneficial and safe therapeutic option for selected patients with non-functioning pituitary adenomas, leading to significant tumor shrinkage or long-term stabilization and improvement of visual outcomes. However, long-term prospective studies with larger cohorts are needed for more reliable conclusions.

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