Annual screening for prostate cancer (PC) shows few differences in mortality rates, but does indicate the need to focus on men who will likely die of the disease, according to results from a 15-year follow-up study.
From 1993 to 2001, 10 academic medical centers in the U.S. screened 76,685 men and 78,216 women enrolled in the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial program. The goal was to find out if annual screening was effective at identifying cancers early and, as a result, reduce the mortality rate from the diseases.
The men and women in the study were followed-up after 15 years. These results relate to the men who underwent prostate cancer screening (NCT00002540).
Published in the journal Cancer, the results from this investigation don’t deny the importance of getting screened for prostate cancer, say the researchers, but imply there are clues in the data that could help patients and healthcare providers make better personalized decisions.
The publication is titled “Extended mortality results for prostate cancer screening in the PLCO trial with median follow-up of 15 years.”
“What we can see from these results is that most men diagnosed with prostate cancer will not die from their disease,” E. David Crawford, MD, co-author of the study and a researcher at the University of Colorado Cancer Center, said in a press release. “In 15 years, people on the study died from lots of other things. However, we can also see that now we need to focus on discovering the men that will.”
According to Crawford, in the group who received yearly screenings for prostate cancer during the trial, 255 men died of the disease since the start of the program. In the control group — those who didn’t get screened every year, but got occasional screenings — 244 men died of prostate cancer.
By comparison, 1,933 in the annual-screening group and 1,882 men in the control group died of other cancers; heart conditions were observed to be a slightly more frequent cause of death in both groups.
Crawford said the results may mean that some men might not to be screened for prostate cancer at all.
“For example, we have since shown that men with PSA lower than one have only about a 0.5 percent chance of being diagnosed with prostate cancer within 10 years,” he said.
A possible solution may be to administer a PSA (prostate-specific antigen) test first and then dismiss screening for those with results of less than one. This change could save billions of dollars in healthcare costs every year, Crawford said.
However, Crawford said these results could in fact be useful in discovering men who really do benefit from careful monitoring.
“I treated a guy who’d been diagnosed in his 40s,” he said. “We did surgery, but then a year later he was diagnosed with melanoma. It turned out that at the same time his sister was diagnosed with triple-negative breast cancer and died within the year.
“Being diagnosed with prostate cancer in your 40s is a red flag that there might be a germline mutation to blame, predisposing these men and maybe family members who share the mutation to more, and more aggressive, cancers. The PLCO shows that most men don’t benefit from screening, but if we could have used the data to spot this guy, maybe we could have even tested his sister as well,” Crawford said.
So although the extensive study showed that annual prostate screening did not change mortality rates, there is still plenty of information in the data or in follow-up studies to offer clues to stratify the risk of prostate cancer, the authors said. Screening only those men at higher risk could still save lives.