Hair loss drug linked to high-grade cancer

June 25 2003

A major overseas study has found a drug prescribed to thousands of Australian men for hair loss and enlargement of the prostate increases the risk of aggressive, high grade prostate cancer.

US researchers stopped a seven-year trial of finasteride involving 18,000 low risk men 15 months before its anticipated conclusion, saying its objectives had been met.

The Prostate Cancer Prevention Trial (PCPT) was designed to test whether finasteride, which affects testosterone levels, could reduce the risk of prostate cancer.

In a special early release from the New England Journal of Medicine to coincide with the National Cancer Institute's announcement of the termination of trial, researchers say the drug appears to delay the development of cancer but increases the risk of developing more deadly tumours.

The study found overall 6.4 per cent of men on finasteride had high grade cancers compared to 5.1 per cent of men receiving placebos.

"The study results suggest that finasteride may accelerate the growth of high grade cancers, which may pose a threat to life and health," writes Peter Scardino of the Memorial Sloan-Kettering Cancer Centre in New York in an accompanying editorial.

"Should finasteride now be recommended to men in order to lower their risk of prostate cancer?

"Several disturbing findings ... argue we should not."

Finasteride, marketed as Proscar, is prescribed to an estimated 10,000 - 20,000 Australian men to treat a condition known as benign prostatic hyperplasia (BPH), or enlargement of the prostate gland, said Phil Stricker a urologist from Sydney's St Vincent's Hospital.

But a spokeswoman from the drug's maker, Merck Sharp and Dohme, said company figures indicated only 1,000 men were on the drug.

She said the study found finasteride reduced the overall incidence of cancer by 25 per cent.

"It was stopped primarily because of its positive outcome," she said.

The spokeswoman said the results of the study should not be applied to the hair loss treatment Propecia because it was given at only one fifth the dose used in the study.

The condition known as BPH causes urinary problems and affects one in every four men over the age of 50.

The drug is also prescribed in low doses to prevent hair loss under the brand name Propecia. Finasteride is not used to prevent prostate cancer.

Dr Stricker said men who were currently on Proscar for BPH should not stop taking the medication, because the study showed it was effective in treating symptoms.

However he said it underscored the need for constant monitoring.

"It's going to be a more complex discussion with people before you put them on finasteride," he told AAP.

"You shouldn't tell people they shouldn't be on it, but ... they can never leave the supervision of their GP and specialist.

"You can't just whack a person onto tablets and forget about it."

Professor Ian Olver, director of the Royal Adelaide Hospital Cancer Centre, said he doubted there would be "a huge rush" to take men off finasteride for BPH.

However he said there may be a need to review its use for baldness.

"Whether you want to use it for male pattern baldness or not is a different matter," he said.

"I think it adds a concern about a potential toxicity that wasn't appreciated before."

Dr Stricker said the finasteride study should not be compared to last year's Hormone Replacement Therapy scare, where thousands of menopausal women dumped their medication after a study found it increased the risk of cancer.

However he said it opened a "pandora's box" regarding the manipulation of hormones.

"It's opening a pandora's box of what we're really doing if we're going to start manipulating hormones," he said.

- AAP

This story was found at: http://www.theage.com.au/articles/2003/06/25/1056449276027.html