More Men Are Urged to Take Drug Against Prostate Cancer
Wednesday, February 25, 2009
Millions of middle-aged American men who get tested regularly for prostate cancer but show no signs of the illness might benefit from taking a drug that substantially lowers their risk of getting the disease, according to new guidelines issued by two leading medical groups that treat prostate cancer.
The recommendation is certain to add a level of complexity to one of the most vexing debates in medicine: how men older than 50 should deal with the threat of prostate cancer. Each year, about 200,000 Americans are diagnosed with the disease, and about 29,000 die. A host of complications and controversies attend nearly every dimension of the disease, from prevention to diagnosis to treatment.
In their statement, the American Society of Clinical Oncology and the American Urological Association said that taking finasteride, a drug that is widely used to treat male pattern baldness and urological problems, can reduce the risk of developing prostate cancer by as much as 25 percent.
"The goal of developing a chemo-preventive agent that can reduce the risk of prostate cancer has been achieved, and that is a major achievement," said National Institutes of Health scientist Barnett Kramer, who headed the group of scientists that issued the guidelines.
The new guidelines grew out of a study of 18,882 healthy men that found that those taking finasteride had a lower risk of developing prostate cancer than those taking sugar pills. A second benefit of taking finasteride was that it seemed to help make the most virulent cases stand out more clearly during diagnosis.
The original study, published in 2003, seemed to suggest that men taking the drug might be at risk of getting more lethal forms of the disease. The conflicting results produced confusion and prompted another intensive analysis, whose results were reported yesterday: The increased risk of lethal cancers is a statistical artifact of the drug's benefit; by shrinking the prostate and lowering the overall risk of cancer, the drug also made it more likely that the cancers detected would be the most dangerous ones.
Howard Parnes, chief of the prostate and urologic cancer research group in the Division of Cancer Prevention at the National Cancer Institute, said the new guidelines should encourage men who are regularly getting screened for prostate cancer to talk with their doctors and learn how finasteride might benefit them.
"In addition to significantly decreasing the prevalence of prostate cancer, finasteride has been shown to improve the diagnostic accuracy of screening," Parnes said.
Finasteride is sold under such brand names as Proscar and Propecia. The two medical associations stopped short of saying that healthy men older than 50 who are regularly being screened should definitely take the drug.
It is not clear whether insurance would pay for the preventive treatment, especially given that the Food and Drug Administration has not approved the drug for that purpose. It is also not clear whether it would be cost-effective to put millions of men on the drug.
About 71 men would have to take finasteride for seven years to prevent one case of prostate cancer. Kramer said a quick call to his Bethesda pharmacy showed that generic finasteride costs about $3 a day or around $1,080 a year, meaning that it could cost about half a million dollars to head off each case of prostate cancer -- while exposing dozens of men to unnecessary treatment and potential side effects, including incontinence and impotence. A small number of men taking finasteride also experience sexual side effects, such as a decrease in libido.
What makes the cost-effectiveness calculations especially problematic is that many cases of prostate cancer are best left ignored; they are innocuous and unlikely to kill a man unless he lives to be 200, said Paul F. Schellhammer, a former president of the American Urological Association and a member of the team that developed the new guidelines.
Where the balance of judgment in many countries with pressing health needs might be not to intervene at all, Schellhammer said doctors and patients in the United States tend to err on the side of doing something, rather than waiting to see what happens. As a result, he said, large numbers of men undergo surgery or radiation treatment for prostate cancer for what might be little benefit.
The problem is that scientists do not have a good way right now of telling which prostate cancers require urgent care and which are best ignored. Two large studies are underway to figure out whether regular screening pays off. Unlike the studies conducted so far, the new studies, whose results are not expected for a few years, will measure whether men who are regularly screened have a lower risk of death than those who are not, and the new studies will try to answer the question of whether intensive screening and treatment are worthwhile.
Experts who wrote the new guidelines said that their intent was not just to lower the number of deaths but also to lower the number of people diagnosed with innocuous cases of the illness. If administration of the drug not only lowered the number of prostate cancer cases but also reduced the number of unnecessary treatments, doctors would essentially get a "twofer" -- fewer false positives and fewer false negatives. Men being treated with finasteride also experience fewer urological problems, so the drug could be a threefer.
Kramer said that the medical associations thought that the cost-benefit ratio of using finasteride was positive only for men being regularly screened for prostate cancer, but not for men who did not undergo regular screening.
Howard M. Sandler, a radiation oncologist at Cedars-Sinai Medical Center and a spokesman for the American Society for Clinical Oncology, said that he would himself consider taking the medication on a trial basis: "If I tried the medication for a month or two and I got side effects, then for me, personally, the benefit would not be worth the risk," he said. "But if I was not suffering any side effects, I might consider taking the pill. . . . I might sleep a little easier at night."