Spot It and Stop It Before It Starts
Screening for prostate cancer, which kills more than 30,000 men annually, is also far from clear cut. There's a lot of controversy surrounding the prostate-specific antigen (PSA) test, the primary means of detecting prostate cancer. PSA tests, which the American Cancer Society recommends for men starting at age 50 (younger in high-risk men), are excellent at spotting cancer, but it isn't yet known how many of those cancers are worth treating. That is, many men who go through invasive biopsies, painful surgery, and unpleasant side effects like impotence would probably have died of something else had their cancer never been found, says Ruth Etzioni, an epidemiologist who studies prostate cancer at Fred Hutchinson. "We don't want to pick up the whole iceberg, just the cases near the tip," she says. Rather than scrapping the PSA, researchers are looking at variations of it--measuring the rate of increase, looking at different forms of PSA in the blood--to attempt to improve its forecasting ability.
Meanwhile, men need to discuss whether to get the test with their doctors, who in turn must help their patients understand the dangers of false-positive and false-negative results, says Michael Barry, chief of general medicine at Massachusetts General Hospital in Boston. "Some people want to do everything they can regardless if we are sure that it works, while other people say, 'If you can't prove it makes a difference, I'd rather not,'" he says. Developing an accurate screening test for prostate cancer--one that separates the "good" cancers from the "bad"--is key because there is no simple rule for prevention, beyond following general good health guidelines. You know the drill: maintaining a healthy body weight, avoiding too much alcohol, exercising regularly.
Superscreen. Avoiding colorectal cancer, on the other hand, is a no-brainer from a doctor's standpoint. Nearly 30,000 men die from it every year, and the vast majority of them shouldn't. Exercise may cut the risk of the disease in half, says McTiernan, and studies suggest that a diet high in fiber and vegetables and low in red meat, fat, and alcohol also helps. And unlike lung and prostate cancer screening, whose value is debatable, colorectal cancer screening--a fecal occult blood test, double-contrast barium enema, sigmoidoscopy, or colonoscopy--really works. In fact, because doctors are looking for precancerous polyps that are easily removed, screening actually counts as prevention. "One of the biggest risk factors for colorectal cancer is having no screening," says Thomas Weber, chief of surgical oncology at Montefiore.
Based on preliminary studies, it appears that colonoscopy is the most thorough and effective way to prevent death from colon cancer, says Ernest Hawk, director of the Office of Centers, Training and Resources at the National Cancer Institute. But any screening method is better than nothing, he says.
Michael Caputo, a 62-year-old music professor from Smithtown, N.Y., says his colonoscopy was no big deal, although he was anxious about the preparation, which involves drinking a lot of fluids. "I went right home afterwards," says Caputo, who had no polyps needing removal. "It was just like a normal day." If more people followed Caputo's lead--practicing a little prevention--the number of cancer deaths would drop dramatically, even if all those busy researchers in the lab never had another breakthrough.
On the Horizon
Researchers are optimistic about several cancer treatments and therapies:
Starving tumors of blood with a drug called Avastin, which is approved for use in advanced colon cancer, recently showed positive results against lung cancer. It may perform even better when coupled with epidermal growth factor receptor (EGFR) inhibitors, which arrest tumor growth.
Combo therapy. A recent study showed that combining high doses of vitamin D and low doses of nonsteroidal anti-inflammatory drugs (NSAIDs) curbed prostate cancer growth in the lab. Human studies have already begun. Researchers are also trying to figure out if aspirin or other NSAIDs might be used to prevent colorectal cancer. Recent research shows it works but also causes stomach bleeding. The hunt is on to see if adding other drugs to the mix might blunt those effects. -K.H.
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