PSA Screening: Risks & Benefits

Prostate cancer is the most common cancer in U.S. men–one in six men will be diagnosed with prostate cancer. Deaths from prostate cancer and advanced prostate cancer have decreased dramatically (40 to 50 percent) since prostate-specific antigen (PSA) screening came into use in 1994. Decreased death rates from prostate cancer may reflect may reflect PSA screening or improvements in therapy. While there is no perfect test for prostate cancer, PSA screening is the best indicator available.

Controversy over PSA screening

Recently the U.S. Preventive Services Task Force (USPSTF) recommended against routine PSA screening for the following reasons:

• Two PSA screening studies did not show substantial improvements in death rates.
• Screening can result in harm from biopsies, anxiety, and overtreatment (for patients who are not at risk of dying from low-risk prostate cancer).

We do not agree

At Seattle Cancer Care Alliance, we do not agree with the conclusions of the task force. Here’s why, point by point:

• “Two PSA screening studies did not show substantial improvements in death rates.”
  • The Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) study (U.S.)¹ compared screening to no screening. But 50 percent of men in the “no screening” group had received PSA screening. This study cannot be used to prove or disprove the utility of PSA screening because of this disparity in the study.
  • The European Randomized Study of Screening for Prostate Cancer² showed an improvement in cancer-related mortality but required that many men be screened to save one life. An update to the European study, along with additional analysis from the PLCO study and the Göteborg Prostate Cancer Screening Trial suggests that for healthy men, significantly fewer men needed to be screened and five to 18 patients to be treated to save one life.
• “Screening can result in harm from biopsies, from anxiety, and from overtreatment (for patients who are not at risk of dying from low-risk prostate cancer).”
  • The main harm is overtreatment of low-risk cancers, not the PSA test itself. Low-risk prostate cancer can be safely followed by active surveillance, sometimes for years without treatment.

Reasons why you should get your PSA test

SCCA doctors believe there are good reasons to continue PSA screenings.

• Early stage disease
  PSA screening has yielded a dramatic transformation in how prostate cancer patients present, which are with more early stage and more potentially curable diseases.
• Factoring age
  The USPSTF statement overlooked several studies that reveal more substantial benefits for healthier, younger men.
• It works
  Most importantly, there is no doubt that prostate cancer deaths have decreased by about 40 percent since the advent of PSA screening, shown in an National Cancer Institute investigation.³

Conculsion: get your PSA test!

Prostate cancer remains a major health problem in the U.S. and the world. PSA screening has made a difference in improved diagnosis and therapies for these patients. We do need to reduce over-diagnosis and over treatment, however eliminating PSA screening now would likely return our outcomes of this disease to pre-PSA era numbers, where mortality and morbidity were substantially worse. 

Until a better screening method is developed, the PSA test is still the best test available for early diagnosis of prostate cancer.

References

• Screening for Prostate Cancer: U.S. Preventive Services Task Force Recommendation Statement. Annals of Internal Medicine, 2012 Jul 17;157(2):120-134.
• ¹ Mortality results from a randomized prostate-cancer screening trial. New England Journal of Medicine, 360:1310-1319, 2009.
• ² Mortality results from the Göteborg randomised population-based prostate-cancer screening trial. The Lancet Oncology, 2010 Aug;11(8):725-32.
• Prostate-cancer mortality at 11 years of follow-up. New England Journal of Medicine, 366:981-990, 2012.
• Prostate Cancer Screening: Facts, Statistics, and Interpretation in Response to the US Preventive Services Task Force Review. Journal of Clinical Oncology, 2012 June 18, 2012.
• What is the true number needed to screen and treat to save a life with prostate-specific antigen testing? Journal of Clinical Oncology, 2011 Feb 1;29(4):464-7.
• Radical Prostatectomy versus Observation for Localized Prostate cancer. New England Journal of Medicine 2012 Jul 19, 367: 203.
• Long-term projections of the harm-benefit trade-off in prostate cancer screening are more favorable than previous short-term estimates. Journal of Clinical Epidemiology, 64:1412-1417, 2011.
• ³ Prediction of significant prostate cancer diagnosed 20 to 30 years later with a single measure of prostate-specific antigen at or before age 50. Cancer, 117:1210-1219, 2011.