Pituitary News, Issue 10 - Winter 1999.

A summary of the presentation given by Professor Michael Sheppard to the 1998 AGM.

Professor Sheppard began by outlining the four main aims of treatment as:

• Reversal of signs and symptoms
• Reduction in tumour size
• Prevention of recurrence
• Restoration of Growth hormone (GH) to normal

The three main methods of treatment are surgery (usually trans-sphenoidal, but sometimes trans-cranial), Radiotherapy and medical therapy. The latter treatment falls into two groups. There are drugs called dopamine agonists (Bromocriptine, cabergoline and quinagolide) and the Somatostatin analogues (Octreotide and Lanreotide), which reduce GH production.

Professor Sheppard gave some interesting results from various kinds of surgery. In Birmingham, the cure rate of a group of 24 patients with microadenomas (small tumours) using only surgery was 90%, which is obviously excellent. However, a 1995 survey of various groups of patients (with all kinds of tumours, not just microadenomas) gave rates of between 50% and 69%. In this case, 'cure' was defined as reducing GH levels to below 10mU/l (10 milliunits of GH per litre of blood). Most endocrinologists are not really happy with such a level and would prefer to see levels below 5mU/l.

Radiotherapy can be effective in reducing levels after surgery, but this effect happens over a number of years. In the meantime, bromocriptine can be used, but one study showed only one fifth of patients having GH levels reduced below 10mU/l with bromocriptine. On the other hand, cabergoline, a newer drug with less side effects, was shown in a Belgian study to reduce levels to less than 10mU/l in almost three quarters of the patients monitored. Of course, in addition to reducing GH levels, patients also want their symptoms reduced. The Belgian study showed this was the case for most patients.

The newest medical treatments are the long-acting version of the somatostatin analogues. These mimic the effect of natural somatostatin in reducing GH, but last longer in the system. There are two products: lanreotide (brand name Somatuline LA) and octreotide (brand name Sandostatin LAR). One product, Sandostatin LAR, is typically administered once per month (as opposed to 3-4 times per day for the previously available version) and a trial showed that over 90% of patients had their GH levels reduced below 10mU/l. Patients also reported easing of symptoms such as headaches, joint pains, and sweating. The other product, Somatuline LA, has similar effects, but is administered every 7-14 days. Unfortunately, both of these drugs are more expensive than the dopamine agonists (like bromocriptine).

Professor Sheppard concluded by describing early research being carried out on new forms of treatment. In one case, instead of drugs to reduce the production of GH, scientists are looking at the possibility of preventing the GH from 'binding' to the receptors. Without being able to do this, the GH would not be able to exert any effect. However, it will be many years before such a development could be licensed for patients' use.

The gathering closed with a lively question and answer session.