Do bald men face higher risk of prostate cancer?
Researchers are reporting that bald men who underwent biopsies of the prostate were more likely to have cancer than were those with more hair on their heads.
"Bald men should be aware that they may benefit from being screened earlier and perhaps, if necessary, from being biopsied sooner," said study author Dr. Neil Fleshner, a professor of surgical urology at the University of Toronto. "In the study, the more bald people were, the more likely they were to have prostate cancer. We're 95 percent sure this is real."
However, not all doctors are ready to embrace the study's conclusions.
The possible association between male pattern baldness and prostate cancer has been considered in previous studies.
Although the precise mechanism isn't understood, researchers think male hormones known as androgens may play a role in both baldness and prostate cancer. Androgens, which include testosterone, can inhibit hair growth and trigger the development of prostate cells.
It's thought that the androgen dihydrotestosterone (DHT) increases in bald men, causing the hair follicles to shrink gradually. As the follicles get smaller, the hair weakens and eventually stops growing. DHT also has been implicated in the development of prostate cancer.
The U.S. National Cancer Institute estimates there will be more than 240,000 new cases of prostate cancer this year. The prevalence of baldness increases with age, and it affects about 40 million men in the United States.
The research was scheduled for presentation at a news conference Tuesday at the American Urological Association annual meeting in Atlanta.
The study involved 214 patients aged 59 to 70 years old with elevated prostate-specific antigen test numbers (averaging 5.8). The men had all been referred for a prostate biopsy. Baldness was assessed on a four-point scale -- just in the front, just a little on the top, moderate top and sides and severe top and sides -- before the biopsy was taken.
The more severe a man's balding pattern, the more strongly it was associated with a positive biopsy.
Men with a normal PSA were not included in the study, which found an association between baldness and prostate cancer risk, but did not prove a cause-and-effect relationship.
The researchers also sought to determine whether there is a relationship between the relative length of a man's index and ring fingers and the diagnosis of prostate cancer, a question raised by previous studies. Some researchers have thought that the level of sex hormones in the womb could prenatally affect both finger length and predisposition to prostate cancer. No association was found in this study, however.
Dr. Nelson Stone, a clinical professor of urology and radiation oncology at Mount Sinai School of Medicine in New York City, questioned the potential value of the baldness study.
Stone said the researchers should have tested for hormone levels to see what association, if any, the amount of testosterone and DHT had on the diagnosis of prostate cancer.
"The incidence of baldness goes up with age, and we know that testosterone levels fall with age, and we still don't know why," he said.
Complicating the issue is also the question of whether the men with a positive biopsy had predominantly aggressive or nonaggressive forms of prostate cancer, Stone said.
Dr. Tobias Kohler, public liaison to the American Urological Association, said that, with or without hair on their heads, men can't relax about prostate cancer.
"There is a link between baldness and prostate cancer, but it could be due to some other factor -- perhaps something in the environment or something genetic, " he said. "I would approach this study with caution."
Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
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