Several recent studies have raised questions about the value of prostate cancer screening.
The controversy arises from the fact that doctors are now finding cancers in earlier stages. Some of these are low-volume, low-grade cancers that may not cause any problems. A single screening result does not provide enough information to inform a treatment decision.
“The problem is that there is currently no way to tell which cancers will cause a problem and which ones won’t,” says Dr. Stephen E. Strup, chief of urology at the University of Kentucky College of Medicine.
The current method of screening for prostate cancer uses a blood test that measures levels of a protein called prostate specific antigen, or PSA. Since the PSA test was introduced in 1986, an additional 1 million men have been diagnosed with and treated for prostate cancer.
Some studies have confirmed that “active observation” for appropriate low-risk cancers is safe, so not every positive finding warrants aggressive treatment, Strup says. However, between 20 percent and 30 percent of men who choose to “watch and wait” will eventually go on for treatment of cancer.
“Over the years, we’ve used the PSA test differently,” Strup says. “At first we relied on absolute numbers for the level of PSA, but it’s hard to fit one number to everyone. More recently, we’ve used the PSA as an individual test, for a baseline, similar to what’s done in mammogram screenings.
“With follow-up screenings, we watch what happens to the level. If it’s a flat curve, we know the individual’s risk for cancer is lower. If it’s a steeper curve, there is more cause for concern.”
Strup recommends men get a baseline PSA screening at age 40. After that, if everything is normal, he recommends annual PSA screenings. If results continue to be normal, testing frequency can be adjusted over time.