The incidence of metastatic prostate cancer in older men is rising after reaching an all-time low in 2011, according to new research from Weill Cornell Medicine and NewYork-Presbyterian investigators.
The findings suggest a correlation between the increase and a change in prostate cancer screening guidelines recommending against routine prostate-specific antigen (PSA) testing.
In the study, published Dec. 29 in JAMA Oncology, the investigators used a national cancer database to identify 545,399 men over the age of 40 who were diagnosed with prostate cancer between 2004 and 2013. They found that in men over 75, both the incidence of metastatic prostate cancer and the proportion of men with aggressive cancer increased since 2011. The researchers say their results may reflect the downstream effects of the U.S. Preventative Services Task Force's (USPSTF) recommendations against routine PSA tests, and underscore the need for health care policy leaders to re-evaluate their approach to prostate cancer screenings.
"It's what most of us would have predicted, although somewhat sooner," said lead study author Dr. Jim Hu, the Ronald P. Lynch Professor of Urologic Oncology at Weill Cornell Medicine and director of the LeFrak Center for Robotic Surgery at NewYork-Presbyterian Weill Cornell Medical Center, who conducted the study in collaboration with co-senior author Dr. Art Sedrakyan, a professor of healthcare policy and research at Weill Cornell Medicine. "There was a decrease in prostate cancer metastasis and death after the advent of PSA testing. Remove the screening and the rates of serious disease rise again."
PSA tests measure the level of prostate-specific antigen in the blood; elevated levels may indicate the presence of prostate cancer. Starting in the early 1990s, PSA testing was recommended for all men over 50 and for men over 40 with a family history of prostate cancer. Since the introduction of PSA screening, the incidence of men diagnosed with metastatic disease has dropped about 70 percent, Hu said. Overall deaths from prostate cancer have decreased 50 percent.
Despite these improved outcomes, the USPSTF in 2008 recommended against PSA testing for men over 75, citing evidence that screening was not saving lives and was often leading to tests and treatments that had negative side effects, including pain, incontinence and impotence. In 2012, the USPSTF extended that recommendation to all healthy men regardless of age. As a result, PSA testing is no longer part of many men's annual physicals.
To assess the effect of these recommendations, the investigators examined data from the Surveillance, Epidemiology and End Results Program, a National Cancer Institute database that tracks cancer incidence rates. They found that the decline in PSA screening has significantly altered the way prostate cancer now presents: 12 percent of men over 75 were diagnosed with metastatic prostate cancer in 2013, compared with 7.8 percent in 2011. And the proportion of men diagnosed with aggressive cancer increased from 68.9 percent to 72 percent over the same period.
In men under 75, there was no change in the rate of prostate cancer metastases. But this does not necessarily rule out the value of screening in younger men, Hu said.
"The recommendation against PSA testing came later for younger men," he said. "So we might need to watch them over time to see the parallel with older men."
The results underscore to need to re-evaluate PSA screening guidelines based on these data and re-evaluation of prior screening trials that led to current PSA testing guidelines from the USPSTF, Hu said.
"The public health message is that after years of decline, the incidence of metastatic disease has gone up," he said. "And while the PSA test is not perfect, I don't think people should be told that this test has no value."
Prostate cancer therapy has also evolved to reduce the negative consequences of treatment. There is now recognition that some prostate cancers are slow-growing and can be managed with surveillance alone, limiting "risks" of detecting cancer.
"Currently, up to 50 percent of Americans diagnosed with prostate cancer now choose active surveillance; however, the implication of our study is that it is important to have the right to choose screening in order to know whether a man may have an aggressive or indolent prostate cancer," Hu said, who has been on speakers bureau for Genomic Health. "The burden of overtreatment and side effects may no longer be sufficient to recommend against routine screening."
Explore further: Rates of early prostate cancer continue decline after USPSTF recommendation
Jim C. Hu et al. Increase in Prostate Cancer Distant Metastases at Diagnosis in the United States, JAMA Oncology (2016). DOI: 10.1001/jamaoncol.2016.5465