A US study finds several doctors shy away from prescribing finasteride for prostate disease even though it was found to be effective in reducing cancer risk by at least 25 percent.

The reluctance to prescribe finasteride was based on a misplaced notion among physicians that it could cause more aggressive prostate tumours, says a study by the Veterans Administration. The researchers surveyed 325 urologists and 1,200 primary care doctors on their prescribing practices.

While 57 percent of the urologists and 40 percent of primary care physicians said they prescribed finasteride more often, only two percent said the Prostate Cancer Prevention Trial (PCPT), trial results had influenced their decision.

PCPT trials conducted in 2003 involving more than 18,000 patients, had found that finasteride cut incidence of prostate cancer by 25 percent. However, a follow-up analysis suggested that the drug might actually raise the possibility of developing aggressive prostate tumours.

Also, among the surveyed physicians 64 percent of urologists and 80 percent of primary care physicians said they never prescribed finasteride as a means to prevent prostate cancer.

As many as 55 percent of those surveyed were wary about the drug causing high-grade tumor, while 52 percent didn't really know that finasteride could be used to prevent prostate cancer.

"There was a concern that it [finasteride] may have made worse the number of cases of more severe prostate cancer," says the lead researcher of the new study, Dr. Linda Kinsinger, who works as chief consultant for preventive medicine at the Veterans Health Administration National Center for Health Promotion and Disease Prevention in Durham, N.C.

Dr Kinsinger revealed that further analysis of the data suggested that finasteride did not raise the risk for an aggressive tumor. But it helped make prostate screening more sensitive, so these tumors were spotted more readily.

However, the results of re-analysis conducted in 2008 may not have reached all levels of doctors and patients today, the researchers noted. This is unfortunate because "there does seem to be a benefit and it could be more widely used," Kinsinger wrote in the September issue of Cancer Epidemiology, Biomarkers & Prevention.

Finasteride, which is sold under the brand names Proscar and Propecia, is approved to treat the non-cancerous condition called benign prostatic hyperplasia, also known as enlarged prostate in men.

The study was funded by the VA National Center for Health Promotion and Disease Prevention and the U.S. Department of Defense - Prostate Cancer Research Program.