Endocrine Abstracts

Background: Macroprolactinomas account for 10% of prolactin secreting tumours. There are few studies looking at the long-term outcome of these tumours. This study analysed clinical, endocrine and radiological characteristics of macroprolactinomas and evaluated the long-term management of these patients in a tertiary care centre.

Methods: Retrospective audit of 21 consecutive cases of macroprolactinomas diagnosed between 1995 and 2007 in Teesside.

Results: The cohort comprised 12 men and 9 women. Median incidence over 12 years was two cases per annum. Mean (S.D.) age at diagnosis was 44 years (20.4) in women and 51years (16.5) in men (P=0.44). Visual field defects were evident in 71% of patients. Mean prolactin at presentation was 55718 MU/l. Mean prolactin at diagnosis was higher in men (78372 MU/l) than in women (25511 MU/l; P=0.04). 24% had normal pituitary function on presentation. 67% of patients (Males 79%) were hypogonadal at presentation. Mean time to commencement of androgen therapy in men was 20.3 months (range 1–69) after diagnosis. 85% (n=18) of patients were treated medically. Cabergoline was the main dopamine agonist used. Median starting dose of cabergoline was 250 mcg per week (range 250–2000). Median final dose of cabergoline was 1000 mcg per week (range 250–6000). Mean time for normalisation of prolactin was 14.5 months (range 1–94). Median nadir prolactin was 108 MU/l and median final prolactin was 267 MU/l. In subjects treated medically, radiological evidence of tumour shrinkage was evident in 66% of patients. There were four deaths in the cohort. Deaths were due to other carcinomas, sepsis and pneumonia respectively.

Conclusions: Dopamine agonists are an effective therapy for macroprolactinomas. Despite this, visual disturbance, headaches, erectile dysfunction, reduced libido and menstrual irregularities persisted as long term sequelae in 43% of patients. This emphasises the need for long-term surveillance of these patients.