So if you're a middle-aged man, what should you do? If you're a woman, should you encourage the men in your life to be screened?
Although the average age at the time of diagnosis is 72, prostate cancer does occur in the prime of life. And, when it strikes early, it often moves swiftly. But even a slow-growing tumor can pose problems for a man in his 40s, 50s, or early 60s.
The National Cancer Institute isn't a fan of early screening, saying there's insufficient evidence that it helps reduce deaths. The American Cancer Society says doctors should offer the test to men over age 50 and provide them with information "regarding potential risks and benefits of intervention." Men at high risk for prostate cancer may consider testing in their mid-40s.
Dr. Kantoff doesn't think anyone will have the answer any impact to the mortality rate becomes apparent. Since prostate cancer typically grows slowly, it takes at least a decade to notice a difference in the death toll. Widespread screening has only been available since 1992.
However, Dr. Kantoff believes the data will fall squarely on the side of screening. "I'm laboring under the assumption it will," he says. "Right now, the PSA test is the best thing we have."
He says only elderly men whose doctors predict will live 10 or more years should consider screening. And, he says, it should be done only if they understand what can happen as a result of taking the test. About 20 percent of men over age 50 who undergo a digital rectal exam and PSA test get an abnormal finding. Often, an ultrasound and biopsy follow. Then, between 2 to 6 percent of these patients are diagnosed with cancer, and must then make difficult decisions.
"It is possible that PSA screening may save lives," says Dr. Kantoff. "But it's also probable it will alter the quality of your life."
Yet, one fact remains. A growing group of men, including Bob Watson, are certain they wouldn't be healthy today if it weren't for the PSA test.