Fewer men are being diagnosed with prostate cancer and fewer are dying of it, with the largest decline in incidence (new cases) occurring in the United States, according to study findings presented at the 2019 American Association for Cancer Research (AACR) annual this week in Atlanta.
Although the study does not include the past several years, it points to long-term trends that may be influenced by prostate cancer screening practices, said MaryBeth Freeman, MPH, of the American Cancer Society surveillance research team.
Prostate cancer is the most common cancer in U.S. men after skin cancer and the second leading cause of cancer death. Around 174,600 men are expected to be diagnosed with prostate cancer and about 31,600 will die from it this year, according to the American Cancer Society.
Freeman’s group looked at patterns of prostate cancer incidence and mortality across five continents using incidence data from the International Agency for Research on Cancer GLOBOCAN database and mortality data from the World Health Organization from 1980 through 2012.
The researchers analyzed long-term trends for 38 countries that provide “high-quality” data (considered accurate, timely and complete) and short-term trends—usually five years—for 44 countries with available incidence data and 71 countries with available mortality data.
Among the 44 countries with incidence data, prostate cancer rates decreased during the five-year period ending in 2012 in seven countries, with the United States showing the largest decrease, according to an AACR press release.
Incidence rose in four countries, led by Bulgaria. The new case rate remained stable in 33 countries. Brazil, Lithuania and Australia had the highest prostate cancer incidence while India, Thailand and Bahrain had the lowest.
Among the 71 countries with mortality data, the prostate cancer death rate fell over the same five years in 14 countries, rose in three countries and remained stable in 54 countries. Caribbean countries (Barbados, Trinidad and Tobago, and Cuba), South Africa and Latvian countries (Lithuania, Estonia and Latvia) had the highest prostate cancer mortality while Thailand and Turkmenistan had the lowest.
Despite these encouraging trends, prostate cancer was the most commonly diagnosed cancer among men in 96 countries in 2012 and the leading cause of cancer death in 51 countries.
Trends in deaths may be explained in part by prostate-specific antigen (PSA) screening, which can detect cancer at an early stage. This allows for treatment before it progresses to advanced disease, thereby reducing mortality.
However, widespread screening also catches many cases of early, slow-growing prostate cancer that never would have progressed—or the men would have died of other causes—which can lead to “overtreatment” and its resulting negative impact on quality of life.
For this reason, the United States Preventative Services Task Force (USPSTF) in 2012 recommended against routine PSA screening for average-risk men ages 55 to 69. After weighing new evidence that screening is associated with reduced mortality, the USPSTF now recommends that PSA screening should be an individual decision between a man and his doctor, taking into account risk factors and personal preferences.
In the United States, prostate cancer screening started to decline after the USPSTF recommendation against routine screening. Trends since that 2012 change are not reflected in this analysis. Some other high-income countries also plan to scale back screening, Freeman noted. PSA screening is less available in lower-income countries, contributing to diagnosis at later stages and higher 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,” Freeman 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.”
Click here to read the AACR study abstract.
Click here to learn more about prostate cancer.