Liver cysts are hollow, fluid-filled sacs which cause the organ to swell to up to three times its normal size - about six kilos or more than 4.5 litres. Polycystic liver disease, where multiple cysts are present, usually goes together with polycystic kidney disease, but Flanders and the Netherlands form an exception. Because of a genetic mutation, the liver variant is much more common here than elsewhere. The condition has nothing to do with alcohol use or abuse.

Patients tend to be women in their 30s and 40s and, while the cysts do not affect liver function, the swelling affects other organs, leading to severe pain. Surgery to remove tissue is dangerous.

Now Dr. Nevens and his team have discovered that a single monthly injection of a hormone called somatostatin can reverse the growth of cysts. In tests, patients given the drug saw their livers shrink by 2.9% in six months, equivalent to about 350 ml. Over a more extended time-frame, Dr. Nevens said, the relief offered is substantial. "From my practice I know that a difference of one litre brings a noticeable improvement in quality of life," he said.

The team's results will be published in next month's issue of the journal Gastroenterology.