Endocrine Abstracts

Contemporary management of macroprolactinomas relies heavily on the use of dopamine agonist (DA) therapy. However, historically a proportion of patients may have undergone surgery and/or pituitary radiotherapy. We aimed to determine the long-term outcome in terms of tumour control and prolactin normalisation in a large cohort of patients with macroprolactinoma who received various treatment modalities. 80 patients (54 male) with macroprolactinoma (tumour diameter >10 mm, prolactin >6000 mU/l) were identified as being treated at this centre between 1980–2005. Mean (± S.E.) age at diagnosis was 42.7±1.8 years (men) and 40.4±3.6 years (women). Median (range) duration of follow-up was 8.0 (0.67–31.0) years. Serum prolactin at diagnosis ranged from 8,000 – 1,160,000 mU/l. Visual fields were abnormal in 58%. DA therapy was used at some point in 79 patients, however 22.5% also had pituitary surgery, 7.5% radiotherapy, and 10% combination surgery and radiotherapy. In all those patients who had initial surgery, prolactin levels remained high post operatively, necessitating initiation of DA therapy. In addition, 71.4% of those who had pituitary radiotherapy required long-term and on going treatment with a DA to control prolactin hypersecretion. At the most recent clinic visit 94% of patients were taking a DA and 61% had achieved a normal prolactin. Five patients (6%) were not taking a DA, but only one (treated by radiotherapy) had normal prolactin levels. One patient had evidence of uncontrolled tumour growth despite receiving radiotherapy followed by DA treatment. No patients treated with initial DA therapy alone had uncontrolled tumour growth. Despite utilising surgery and/or radiotherapy in the early management of patients with macroprolactinomas, most required long-term use of DA therapy. From this large cohort, there appears to be no rationale for treating macroprolactinomas with anything other than first line DA therapy.