Prostate cancer is more common than breast cancer is in women and poses a similar death risk, but women have pretty clear-cut recommendations about screening and treatment for breast cancer while men are often left with difficult and confusing choices. Several new studies don't exactly clarify matters. One published Wednesday in the British Medical Journal found that the widely used PSA test, which measures the amount of prostate specific antigen in the blood, not only doesn't save lives but also increases the risk of being treated for cancers that aren't life-threatening. Two other studies, one in BMJ and another in the journal Cancer, suggest that regular PSA screening may be useful—but only in men determined to be at increased risk of prostate cancer.
"If all men get screened for prostate cancer and all of those with low-risk disease get treated, there's simply going to be too many treatments that are unjustifiable," says prostate cancer researcher Matthew Nielsen, assistant professor of surgery at UNC School of Medicine in Chapel Hill. That is why the American Cancer Society stopped recommending routine PSA screening more than a decade ago and last March declared that men should talk to their doctors about the pros and cons of PSA testing before choosing to be screened. The studies out this week suggest that men in their 50s might want to have a baseline PSA test to determine if they are candidates for routine screening. Those with somewhat elevated levels—which studies define as above 2 or 4 nanograms per milliliter—are more likely to develop life-threatening prostate cancers than are those with lower levels and may benefit most from yearly PSA testing to see if levels continue to rise.
Many men, however, may be daunted by the prospect of leaving hidden cancers undetected—and of leaving those found untreated. After all, with breast cancer, doctors still surgically remove every tumor and precancerous growth even though some breast tumors vanish on their own, while others grow too slowly to be deadly, research has shown. But prostate tumors tend to be even more slow-growing than breast cancers, strike later in life, and are less likely to kill. One study found that 90 percent of men with untreated low-grade tumors were still alive 20 years after the initial prostate cancer diagnosis. "Men hear 'cancer' and assume it's a bad scenario, but with prostate cancer that's not always the case," says oncologist Mark Scholz, an assistant clinical professor of medicine at the University of Southern California, and coauthor of the recently-released book Invasion of the Prostate Snatchers.
While a wide range of slow-growing cancers may be overtreated, prostate cancer poses a particular quandary because its treatments often cause nasty and lasting side effects. Surgery to remove the prostate gland, called a radical prostatectomy, leaves an average of 33 percent of patients with erectile dysfunction due to nerve damage—which can't be remedied with drugs like Viagra—and causes permanent urinary incontinence in 7 to 10 percent of patients. Inexperienced surgeons tend to have even higher complication rates. "Radical prostatectomy is a very difficult operation to perform, and studies show that it takes 250 surgeries for a surgeon to be proficient," says Scholz. "About 80 percent of surgeons who perform this procedure only do 10 per year," so it might take two decades for the typical surgeon to become proficient. A newer nerve-sparing technique has reduced rates of impotence, but few surgeons have been trained in the tricky procedure. Radiation treatments, such as implanted radioactive seeds, have lower rates of side effects, but some patients still experience impotence and rectal bleeding, which can last months or years after treatment.
When Ralph Blum was diagnosed with prostate cancer 20 years ago, his urologist wanted to operate right away despite the fact that his cancer was small and slow-growing. "I kept watching my PSA and it wasn't going up," says the 78-year-old anthropologist, who wrote Prostate Snatchers with Scholz. "I wanted to take responsibility for my own condition" and was very comfortable with frequent monitoring, he says. When his tumor began to enlarge, he opted for anti-testosterone treatments, which stopped the growth but sapped his sex drive.
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Watchful waiting for small, non-aggressive tumors has become far more acceptable nowadays. Guidelines issued this year by the National Comprehensive Cancer Network, a nonprofit alliance of 21 cancer centers, recommend that men with small, early-stage tumors and low PSA levels consider frequent monitoring, consisting of an annual physical exam, annual biopsies, and PSA testing every six months. In men over 65, cancers can be treated only if they progress, whereas younger men may still want to consider treatment. "In men who have a greater than 20-year life expectancy, we don't feel as comfortable leaving those cancers untreated," says Patrick Walsh, professor of urology at Johns Hopkins Hospital, who pioneered the nerve-sparing technique for prostate surgery. "We don't know that any cancer won't spread during that period of time, and a 55-year-old could eventually pay the price by having life-threatening metastases."
Still, every man diagnosed with prostate cancer should ask his doctor whether or not he's a candidate for active monitoring, since Walsh says doctors continue to overtreat prostate cancer. If surgery is the only option, a man should make sure his surgeon has performed the requisite 250 procedures. Walsh, who says he has performed an average of 100 prostatectomies a year during his 45-year career, notes that his patients have a 1 to 2 percent incidence of incontinence after surgery and about a 10 percent incidence of long-term impotence.