Abstract / Summary
Prolactinomas in the transition age present unique challenges; treatment strategies and long-term outcomes in this population remain incompletely characterised. This is a multicentre, retrospective study of 110 consecutive patients (33 males) with prolactinomas, aged 15-25 years, across five Italian referral centres (2010-2025). Clinical, hormonal, radiological, and treatment-related parameters were assessed at diagnosis and at follow-up. At diagnosis, the median age was 20 years; median prolactin 177 ng/mL [49-6646]; 55% of patients had micro-tumours. Male patients presented with larger tumours, higher prolactin levels, and greater invasiveness (p < .001 for all comparisons). Cabergoline was first-line therapy in 95%, achieving prolactin normalisation in 75% and significant tumour shrinkage (≥50% volume and/or diameter reduction) in 66% of patients. Partial resistance (biochemical and/or radiological) occurred in 40% of patients. Treatment discontinuation occurred in 48% of cases; 61% of patients discontinuing cabergoline after prolonged normalisation experienced recurrence, which was predicted by younger age at diagnosis (OR 0.67/year, p = .040) and shorter treatment duration (OR 0.95/month, p = .050), the latter showed 93% sensitivity for recurrence at 45.5 months. Adverse events occurred in 12%, leading to treatment discontinuation in 6%. Surgery was required in 17%, achieving long-term remission in 31%, while 21% of surgical cases required radiotherapy. At last follow-up (median 72 months), 73% remained on cabergoline while 25% achieved complete radiological resolution. Transition-age prolactinomas demonstrate high cabergoline resistance rates and frequent recurrence after discontinuation. Treatment duration ≥45.5 months before withdrawal may reduce recurrence risk. Surgical remission is achievable, especially in non-invasive tumours, although multimodal therapy is often required for disease control.