Real-World Outcomes of Cabergoline Treatment in Non-Functioning Pituitary Adenomas: An Insight into Dose Responsiveness and Radiological Follow-Up at a UK Tertiary Centre

Introduction: Evidence on the use of dopamine agonists (DAs) for managing residual or recurrent non-functioning pituitary adenomas (NFPAs) is limited. We aim to evaluate the use of cabergoline (CAB) for NFPAs. Methods: A retrospective cohort study was conducted at a single UK centre, between November 2011 and December 2025. Twenty-six patients were identified. Ten patients were excluded due to CAB intolerance or discontinuation (n = 5), insufficient data (n = 4), or invalid scan due to patient movement (n = 1). The remaining 16 patients (mean age 68.9 ± 4 years (range 42–89 years old), 7/16 females) were included. CAB was initiated in cases where surgery or radiotherapy were not appropriate (e.g., due to age and/or comorbidities, or patient choice). Radiological response was assessed using at least two scans separated by a minimum interval of six months. Tumour shrinkage was defined as a reduction in volume of 20% or more, growth as an increase of 20% or more, and stabilisation as interval change of less than 20%. Results: Overall, tumour shrinkage was observed in 7/16 (43.8%) patients, stabilisation in the remaining 9/16 (56.3%) patients, over 503 ± 51 days (range of 117–934 days) (from the date of CAB initiation to latest MRI scan). There was a statistically significant reduction in tumour volume (p = 0.0335). In five patients with documented tumour growth prior to CAB initiation, growth rates retarded or reversed post-CAB initiation. Conclusions: Our findings in this small cohort potentially suggests that cabergoline can retard, arrest, or even reverse tumour growth in selected patients with NFPAs. Our review also highlights ongoing uncertainty regarding optimal dosing, approaches to dose up-titration, follow-up imaging intervals, and objective criteria for defining radiological response. Our results may provide a proof of concept for future, larger-scale prospective studies and controlled trials to validate the conclusions drawn.