Cases of advanced prostate cancer have increased among American men ages 50 and older, while cases of early-stage disease have declined, a study published Wednesday found.
The study looked at cases diagnosed between 2005 and 2016, during which time federal guidelines began recommending against prostate-specific antigen, or PSA, screening for prostate cancer detection because of concerns that the overall benefits of the once routinely recommended blood test did not outweigh the risks.
The prostate cancer trends observed in the new study “likely” resulted from the recommendations against screening, leading to undetected cases that advanced, lead author Ahmedin Jemal, scientific vice president for surveillance and health services research at the American Cancer Society, speculated.
Each year in the United States, there are about 192,000 new cases of prostate cancer and 33,000 deaths. Thankfully, most cases are slow-growing and not life-threatening. Many cases can take a decade or more to show symptoms, if at all, and may never be fatal.
So there have been concerns that diagnosing too many early cancers can lead to unnecessary worry, biopsies and treatments than can leave men with side effects such as incontinence and impotence. But there’s also concern that not screening may miss aggressive cancers that become deadly.
In 2008, the U.S. Preventive Services Task Force recommended against PSA screening for men ages 75 and older, and in 2012 advised against routine screening for all men. Then in 2018, the group issued further changes, recommending individual decision-making for men ages 55 to 69 and against screening for men 70 and up.
Jemal said other risk factors for advanced prostate cancer, such as family history of the disease or obesity, probably can’t explain the increases seen in his study.
“These data illustrate the trade-off between higher screening rates and more early-stage disease diagnoses (possibly overdiagnosis and overtreatment) and lower screening rates and more late-stage (possibly fatal) disease,” Jemal and his colleagues wrote in the study released in the Journal of the National Cancer Institute, or JCNI.
The researchers analyzed nationwide data on more than 2 million prostate cancer cases, mostly early-stage disease, diagnosed in men 50 and older between 2005 and 2016. They found that the incidence of early-stage cancer among men 50 to 74 decreased by 6.4 percent per year from 2007 to 2016 while incidence among men 75 and up declined by 10.7 percent per year from 2007 to 2013, then stabilized through 2016. The researchers did not have data on prostate cancer cases beyond 2016.
By comparison, the incidence of advanced cancers that had spread beyond the prostate gland — known as regional-stage or distant-stage cancers — increased at “an alarming rate,” Jemal told NBC News.
For instance, among men 50 to 74, the incidence of distant-stage, metastatic cancers increased by 2.4 percent per year from 2008 to 2012 and by 5.6 percent per year from 2012 to 2016. Among men 75 and older, the incidence of distant-stage disease increased by 5.2 percent per year from 2010 to 2016.
Statistics show that PSA testing rates in men 50 and older declined from 40.6 percent in 2008 to 38.3 percent in 2010 and 31.5 percent in 2013, the researchers noted. Rates remained unchanged in 2015.
Jemal said he hopes current federal screening recommendations will prompt men to talk with their doctors about the pros and cons of PSA screening so more aggressive cancers may be caught. “There has to be a balance,” he said.
The American Cancer Society advises men to start these conversations beginning at age 50 for most or earlier if they have risk factors such as a family history of the disease or they are African American. The group says men whose life expectancy is less than 10 years probably won’t benefit from screening because tumors often grow slowly. While the average life expectancy for men of all races in the U.S. is 76.1 years, according to the Centers for Disease Control and Prevention, PSA screening advice is based more on each man’s individual life expectancy.
Dr. Edward Schaeffer, chair of urology at Northwestern University Feinberg School of Medicine, said the new study adds to earlier research, including his own 2016 study, that raised concerns about an increasing incidence of advanced prostate cancer.
Though the explanation is unclear and could potentially include environmental, lifestyle or other factors, he said he believes the changing screening guidelines were a driving factor. “When you relax screening, these are the downstream effects,” he said. “There are more cancers that show up in a more advanced stage.”
Schaeffer says that because aggressive cancers are so deadly when they spread, he advises men to talk with their doctors about the best time to get PSA screening.
While overtreatment concerns remain, doctors today have knowledge and tools to help minimize invasive tests and treatment, he said. Patients, for instance, may undergo “active surveillance” in which doctors aim to keep tabs on a tumor without rushing into treatment.
Dr. Jonathan Simons, president of the Prostate Cancer Foundation, said the study findings point to the need for more “precision screening.”
The foundation recommends men start talking to their doctors about screening at age 40 if they have a family history of prostate cancer – or breast, ovarian, pancreatic or other cancers that may be genetically linked -- or are African American. If men are not in these higher risk categories, they should start the conversation at 45, the group says.
“One size does not fit all men for prostate cancer screening,” Simons said.