With the release of a new draft document, the U.S. Preventative Services Task Force (USPSTF) has proposed a change in its stance on the advisability of PSA prostate cancer screening for men ages 55 to 69. The new recommendations are based on evidence that supports some benefit to such screenings for the early detection of aggressive prostate cancer. However, the USPSTF also acknowledges offsetting harms from the invasive testing and treatment that may follow a positive PSA screen.
USPSTF Draft of Updated Recommendation on Prostate Cancer Screening
The USPSTF draft document details proposed revisions to the 2012 recommendations concerning prostate-specific antigen (PSA) screenings for prostate cancer. These recommendations revise the USPSTF grades assigned to the use of routine PSA-based prostate cancer screening in two age categories:
- Men ages 55 to 69 years
- Men ages 70 years & older
The previous grade for both age groups was “D,” recommending against such routine screening. The new draft recommendation retains the “D” designation for men 70 and older but revises the grade to “C” for men in the younger category.
Informed Decision-Making by Individual Patients
The USPSTF makes recommendations on the effectiveness of preventative care services such as PSA prostate cancer screening based on evidence of both benefit and harm. For men 55 to 69 years, the proposed grade of “C” indicates a balance between potential benefit from early cancer detection and the possible harmful outcomes that may result from screening. These include:
- False-positive results leading to additional testing
- Overdiagnosis & overtreatment
- Treatment complications
The USPSTF urges clinicians to discuss the advantages and potential risks of PSA screening with their patients, so individuals in the 55 to 69 age category have the information they need to make an informed decision about proceeding with PSA testing.
Limited Potential Benefits from Standard PSA Screening
Although prostate cancer is one of the most common cancers in men, not all prostate cancers are aggressive or likely to metastasize. Some men who have been screened and identified as having cancer showed no symptoms and may not have been aware of the condition if they had not been screened. Autopsies performed on men who died of other causes reveal an incidence of prostate cancer by age group of:
- 25% for men ages 55 to 69
- 33% for men ages 70 & over
The USPSTF has found adequate data from random clinical trials that screening may prevent some cases of metastasized cancer deaths: up to three cases per 1000 men (55 to 69 years of age) screened over a 13-year period. The draft recommendation notes that PSA screening is ineffective at distinguishing between aggressive cancers that are likely to metastasize and cancer that either does not progress or progresses so slowly that the patient never experiences symptoms. The proposed recommendation also notes that further research is needed for developing and studying different diagnostic tests and protocols.
False-Positive Cancer Diagnosis & Overdiagnosis
According to the draft recommendation of the USPSTF, the potential benefit of routine PSA screening for men ages 55 to 69 is offset by these severe shortcomings in test interpretation:
- Conditions like an enlarged prostate (benign prostatic hyperplasia) and inflammation of the prostate (prostatitis) also deliver elevated PSA readings. A false-positive PSA reading puts men at risk for side effects and complications from further diagnostic testing procedures.
- A positive PSA screening result may lead to overdiagnosis and overtreatment of cancer in men whose prostate cancer would never have become symptomatic while they lived. In such cases, these men would receive no benefit from treatment. The USPSTF draft cites large randomized trials that indicate that 20% to 50% of men diagnosed with prostate cancer through screening may represent overdiagnosis of the condition.1
Harmful Outcomes from Additional Diagnostic Tests & Overtreatment
According to the USPSTF draft document, there is adequate evidence that further diagnostic testing and cancer treatment may result in a moderate chance of harm. Additional testing and biopsy due to false-positive PSA results may include pain, infection, hematospermia (blood in semen or ejaculate), and complications severe enough to require hospitalization. Men undergoing prostate cancer treatment are also subject to unpleasant health and lifestyle side effects including long-term sexual impotence, urinary incontinence, and bowel urgency or bowel incontinence.
USPSTF Grade-Change Considerations
Data from random trials, cohort studies and decision analysis models reviewed by USPSTF support the conclusion that the benefit of PSA-based screening for men ages 55 to 69 depends on the value judgments of individual men. Although PSA screening has the potential for early detection and treatment that may save lives, that potential is balanced by the possibility of overdiagnosis, false-positive indications, and complications of treatment that could affect quality of life.
USPSTF’s recommended grade change to “C” for men in the younger screening age group is an acknowledgment that men should have an opportunity to make informed decisions about PSA screening results and the need for further tests or treatments following a positive result. The draft proposal also provides study information for men with a higher risk of developing prostate cancer, including African American men and men with a family history of the disease. The USPSTF supports the role of the clinician in providing updated, evidence-based information and providing all groups with the full picture for making decisions about PSA-based prostate cancer screening.
1 Fenton JJ, Weyrich MS, Durbin S, Liu Y, Bang H, Melnikow J. Prostate-Specific Antigen-Based Screening for Prostate Cancer: A Systematic Evidence Review for the U.S. Preventive Services Task Force. Evidence Synthesis No. 154. AHRQ Publication No. 17-05229-EF-1. Rockville, MD: Agency for Healthcare Research and Quality; 2017.