The incidence and mortality rates of prostate cancer have stabilized or declined in most countries throughout the world in recent years, according to research presented at the American Association for Cancer Research (AACR) 2019 meeting in Atlanta.
The group, led by senior author MaryBeth Freeman from the American Cancer Society, examined data from the International Agency for Research on Cancer and found that the overall incidence of prostate cancer decreased or stabilized (i.e., did not increase) in 90.9% of the 44 countries examined during the most recent five-year period, roughly between 2008 and 2012. Examining mortality data from the World Health Organization, the researchers also discovered that rates decreased or stabilized in 95.8% of the 71 countries examined for cancer mortality.
The group's analysis of these data additionally revealed that the lowest incidence rates for prostate cancer were in India, Thailand, and Bahrain, whereas the highest rates were in Brazil, Lithuania, and Australia. The lowest mortality rates were in Thailand and Turkmenistan, and the highest rates were in the Caribbean, South Africa, Lithuania, Estonia, and Latvia.
Furthermore, Freeman and colleagues classified the data from 38 countries as "high quality," and used this information to analyze long-term trends, from 1980 through 2012, on a global scale. They found that the greatest decrease in prostate cancer incidence occurred in the U.S. during this period, largely due to changes in the use of prostate-specific antigen (PSA) testing. In the U.S., prostate cancer incidence rates increased from the 1980s to the early 1990s, then fell from the mid-2000s through 2015.
PSA screening is not as readily available in lower-income countries, and this limited availability may have contributed to delayed diagnosis and higher mortality rates in these nations, Freeman noted. Several countries have also considered scaling back their use of PSA screening because of concerns over possible overtreatment of prostate cancer, which is likely to affect future patterns of incidence and mortality.
"Overall, patients should be having an informed discussion with their providers about the benefits and harms of PSA testing for detection of prostate cancer," she said. "Future studies should monitor trends in mortality rates and late-stage disease to assess the impact of reduction in PSA testing in several countries."
