The Consequences of a Decline in PSA Testing

From 1992-2011, there was a 47% decrease in prostate cancer mortality. Yet, the 2009 and 2012 recommendations from the U.S. Preventive Services Task Force (USPSTF) discouraged the use of PSA testing to screen men for prostate cancer. Now, current research is examining the impact of a decline in PSA testing in the period after the USPSTF statement was released.

Increased rates of higher-risk prostate cancer

A study presented at the 2015 Genitourinary Cancers Symposium in Orlando, Florida found that the rates of intermediate- and high-risk prostate cancer are rising among men in the U.S.

Researchers analyzed 87,562 men diagnosed with prostate cancer between January 2005 and June 2013. From 2005 to 2011, the proportion of men with prostate cancer and PSA greater than 10 decreased gradually. However, between 2011 and 2013 they found a nearly 6% increase in higher- risk cases.

“Given the rise in intermediate and high-risk prostate cancers seen in our analysis during this timeframe, men who are at increased risk for prostate cancer, especially those with a family history of prostate cancer, should consider talking with their doctor about PSA screening.”

– Dr. Timothy E. Schultheiss

Based on 233,000 new prostate cancer cases predicted in 2014 in the U.S., the study authors estimated that this trend could translate to 14,000 additional higher-risk prostate cancer diagnoses in 2014 as compared to 2011. They also predicted that at least 1,400 additional men might die from prostate cancer each year. This estimation took into account 10-year prostate cancer survival rates, which are about 95% for low-risk, 75-90% for intermediate-risk and 60-80% for highrisk cancer.

Statistical modeling shows potential increase in prostate cancer death

Eliminating screening eliminates overdiagnosis, but by 2025 there could be twice as many metastatic cases of prostate cancer and a 13-20% increase in preventable prostate cancer deaths.

Statistical models predicted that continuing recent screening rates will overdiagnose 710,000-1,120,000 men but will avoid 36,000-57,000 prostate cancer deaths from 2013-2025. Discontinuing screening for men older than 70 years would eliminate 64-66% of overdiagnoses but would fail to prevent 36-39% of avoidable prostate cancer deaths.

Source: Gulati R. et al. Expected population impacts of discontinued prostate-specific antigen screening. Cancer. 2014; 120(22):3519-26.

Researchers defined higher-risk disease as prostate cancer with a blood PSA level greater than 10, which indicates either intermediateor high-risk prostate cancer.

The study was led by Dr. Timothy E. Schultheiss, PhD, of Radiation Physics at City of Hope in Duarte, California. He said, “Our study is the first to measure the changes in prostate cancer presentation in the period following the U.S. Preventive Services Task Force’s PSA screening recommendations.”

The authors emphasized that the findings must be confirmed through further research. They plan to update their analysis as new registration data become available.

Early diagnosis is key for a cure

The best chances of survival occur when prostate cancer is caught while it is still localized within the prostate. A recent Canadian study raised concerns that lack of testing after the USPSTF recommendations could lead to missing the window for early diagnosis.1

Researchers conducted a time series analysis of prostate biopsies performed at the University Health Network from 2008 to 2013. They saw a decrease in the number of biopsies performed after the USPSTF recommendations were released. The median number of biopsies per month decreased by 39%, while the median number of men undergoing first-time biopsies decreased by 44%.

The study authors said the sudden 43% decrease in the detection rate of Gleason 7-10 prostate cancers was “concerning.” There was also a decrease in the median number of lowrisk prostate cancers detected per month, by 35%.

Support for PSA testing programs

Dr. Catalona’s Opinion

There is a price to be paid for not doing PSA testing. We have learned from the cancer statistics in the United States and from randomized clinical trials in Europe that PSA testing can cut the prostate cancer death rate nearly in half. The strategy for success is to detect the prostate cancer early, when it is curable. If doctors and patients do not work together to ensure appropriate PSA testing and treatment in an organized and routine fashion, there will be more unnecessary suffering and death from incurable prostate cancer in the near future.

An examination of data from the Göteborg screening study found that organized screening programs for prostate cancer were more effective than opportunistic testing.2

In the study, 10,000 randomly selected men were invited for PSA testing every 2 years, with prostate biopsy recommended for men with a PSA ≥2.5 ng/ml. The control group of 10,000 additional men was exposed to increased opportunistic PSA screening over time.

After 18 years, organized screening resulted in a 42% relative reduction in prostate cancer death. To prevent one prostate cancer death in the organized screening group, 139 men needed to be invited for screening and 13 men needed to be diagnosed. In the control group, 493 men needed to be invited for screening and 23 diagnosed in order to prevent one prostate cancer death.

Organized screening reduced prostate cancer mortality but was associated with overdiagnosis. However, opportunistic PSA testing had little—if any—effect on prostate cancer mortality, but resulted in more overdiagnosis. Almost twice the number of men in the control group needed to be diagnosed in order to prevent one death from prostate cancer.