For the first time, leading medical groups are advising millions of healthy men who are regularly screened for prostate cancer to consider taking a drug to prevent the disease.
The advice stops short of saying men should take the drug finasteride, sold in generic form and as Proscar. It is already widely used for urinary problems from enlarged prostates as men age. Merck and Co sells it as the baldness remedy Propecia.
However, it has not been widely prescribed as a cancer preventive, and it may carry some risks. The new guidance tells men to talk to their doctors and decide for themselves if the good outweighs the bad.
This advice is bound to be confusing, doctors admit. For one thing, it doesn't apply to men who choose not to have screening with PSA blood tests, which no major medical groups recommend.
In men who are regularly screened, finasteride can cut the odds of being diagnosed with prostate cancer by about 25 percent.
"If a man is interested enough in being screened, then at least he ought to have the benefits of a discussion" about taking the drug, said Dr. Barnett Kramer, a National Institutes of Health scientist and one of the authors of the new guidelines.
They were published in two medical journals and discussed in a news briefing Tuesday in connection with a cancer conference in Florida. They were written by doctors with American Society of Clinical Oncology and the American Urological Association.
Cost could be a big issue for many men. Finasteride, which must be taken daily, costs $2 to $3 a pill and insurers may not cover it for cancer prevention. Also, to prevent a single additional case of cancer, 71 men would have to take the drug for seven years — another reason this is an individual decision, doctors say.
"There probably would be millions of different attitudes about taking a pill a day to prevent a condition that may or may not occur," said Dr. Howard Sandler, of Cedars-Sinai Medical Center in Los Angeles.
About 186,000 American men this year will be told they have cancer of the prostate. The disease often is diagnosed from a biopsy after a suspicious PSA blood test, which measures a protein. PSA can be high for many reasons, and there's no proof that screening saves lives — the reason no major cancer groups recommend it.
Most men over 55 get the test anyway, then face a dilemma if cancer is found. It usually grows so slowly it is not life-threatening, but it can prove fatal. Treatments often cause sexual or bladder control problems.
"We still don't know if screening and aggressive treatment is a good thing," but if men are getting PSA tests, taking finasteride is reasonable, said the American Cancer Society's chief medical officer, Dr. Otis Brawley.
Finasteride shrinks the prostate and curbs testosterone, a hormone that helps cancer grow. It's already used for urinary problems, and at a lower dose, it's sold as the baldness drug Propecia.
A similar drug, dutasteride, sold as Avodart, is being tested to see if it, too, prevents prostate cancer. The guideline covers the whole class of drugs but for now, doctors are focused on finasteride.
That's because it's the only one shown to prevent cancer so far. A landmark study in 2003 found fewer men who took it got prostate cancer than those on dummy pills. However, that study also raised a concern: Those on the drug who did get cancer seemed to have more aggressive tumors.
More study found that that wasn't the case. It was just that the tumors were more easy to detect among men taking the drug because it helped reduce prostate size.
The new advice to consider finasteride "is long overdue," said Dr. Eric Klein, prostate cancer chief at the Cleveland Clinic. When men are given a full picture of the drug's effects, "it's not a tough sell," he said.
Finasteride has been linked to lower sexual desire and difficulty having an erection. However, in a study of older men, those were problems for most who weren't taking the drug as well. Finasteride also gave benefits: fewer urinary problems and less incontinence.
"The overall quality of life was identical," and most side effects go away after a few weeks of use, Kramer said.
Three of the 15 guideline writers have consulted for Merck & Co., which makes Proscar, or GlaxoSmithKline PLC, which makes Avodart.
The advice is "aimed at people like me 10 years ago," said Stewart Justman, a 60-year-old literature professor at University of Montana. He is in his third battle with prostate cancer and he represented patients on the guidelines panel.
"If I had heard there was a possibility of preventing the disease, it certainly would have captured my interest," he said. But the potential risk of aggressive tumors can't be ruled out, so doctors owe men a frank talk, he said.
Ernest Bynum, a 68-year-old Cleveland man, started taking Proscar six years ago. A PSA test was a little high and he was having urinary problems. When he heard the drug might prevent cancer, it sealed his decision.
"If it's a possibility of giving me a longer life, I want that," he said.
On the Net:
Prevention study: http://www.cancer.gov/cancertopics/factsheet/pcptqa
Screening advice: http://www.ahrq.gov/clinic/cps3dix.htm#cancer
Risk calculator: http://deb.uthscsa.edu/URORiskCalc/Pages/uroriskcalc.jsp