Dr Jonathan Webster
Northern General Hospital, Sheffield

Dr Webster divided the workshop into three sections based on the large number of questions submitted by delegates. These were: background and history, clinical features, and treatment.

Prolactinomas are the commonest functioning pituitary tumours. In the majority of cases, the reason why the tumour develops is not known. Prolactinomas are almost always benign, and it appears that only a small proportion of small tumours (microadenomas) ever expand to become larger tumours (macroadenomas).

A large number of questions had been received on the effects of prolactinomas. In women, the major effects of a raised Prolactin level are irregular or absent periods and Galactorrhoea (milk secretion from the breasts). A number of women come to medical attention because of reduced fertility or symptoms related to a low Oestrogen level, including vaginal dryness. In men, the symptoms of a raised prolactin level include reduced sex drive and potency. In both sexes, the presence of a swelling within the pituitary can cause a number of symptoms, including headache, visual disturbance and underactivity of the normal Pituitary gland. There was an overwhelming consensus in the audience that prolactinomas are frequently associated with tiredness, lethargy and a tendency to gain weight. Over the long term, if a Prolactinoma is associated with Amenorrhoea in women, or a reduced Testosterone level in men, there is an increased tendency to Osteoporosis. This is corrected in most patients when the prolactinoma is treated.

Medical treatment of prolactinomas is usually with a dopamine agonist such as Bromocriptine, quinagolide or cabergoline. These are effective in controlling the prolactin level of 80-90% of cases, and in the case of larger tumours are effective in shrinking the adenoma in around 80%. The treatment can be associated with a number of side effects including headaches, nausea and dizziness on standing (caused by a fall in blood pressure). In most cases, treatment is required long-term; if the drug is discontinued, prolactin levels tend to rise, usually with a reoccurence of symptoms. In a proportion of cases, however, the drug dose can be reduced after a number of years, and very occasionally withdrawn altogether. With the low drug dosage used to treat prolactinomas, long-term side effects are rare. Surgery is an effective treatment for small prolactinomas, curing approximately 60% of patients. For larger tumours, however, surgery results in long term cure in only about 25%. The complications of surgery include hypopituitarism, requiring treatment with thyroxin, Hydrocortisone, oestrogen/testosterone (and sometimes Growth hormone) alone or in combination. On balance, medical treatment is more appropriate for larger tumours, but smaller tumours can be treated effectively either medically or surgically. A proportion of prolactinomas - small tumours causing few symptoms and without associated menstrual irregularity - may not require any treatment at all other than monitoring of prolactin levels and the tumour size.