Prostate Cancer Test Deemed Unnecessary by Government Panel

Ben Leach
Published: Thursday, Dec 08, 2011

PSA testingAfter decades of use, a routine test used for diagnosing prostate cancer has come under fire after a government panel questioned its safety, causing a controversy among many oncologists, urologists, and others in the medical community as to what is best for the patient.

Diagnostic techniques for various forms of cancer can often be uncomfortable or time-consuming procedures that patients undergo reluctantly and sometimes skip altogether. When it comes to testing for prostate cancer, however, that has not been an issue since the discovery of the prostate-specific antigen, or PSA. The protein is produced by the prostate gland and can be tested for during routine blood tests. The protein is often found in higher levels in men with prostate tumors, thereby making it an important biomarker for the disease.

Or does it? That’s the question that was put forth by the United States Preventive Services Task Force (USPSTF), a panel of nonfederal experts in the prevention of disease. The USPSTF performs extensive scientific reviews of preventive healthcare services, including screening, counseling, and preventive medications. In October, after a rigorous evaluation of the evidence regarding PSA testing, the panel released a draft recommendation that states that “there is moderate certainty that the harms of PSA-based screening for prostate cancer outweigh the benefits,” and the panel “now recommends against PSA-based screening for prostate cancer in all age groups.”1

Because PSA testing has been a routine blood test used to screen thousands of patients over the last few decades, this recommendation has caused oncologists and urologists to take sides. On one side, some firmly believe that the test helps people and the recommendations change nothing. On the other side, others feel that the recommendations were based on sound science and that PSA testing should not be considered the gold standard in prostate cancer screening. Ultimately, patients have been caught in the middle, and new dialogues are taking place as they try to decide what is right for them.

Evidence-Based Science

The USPSTF reviewed a number of large studies before making its draft recommendation. The 2 studies at the center of its decision were the European Randomized Study of Screening for Prostate Cancer (ERSPC) and the US Prostate Lung, Colorectal and Ovarian (PLCO) cancer screening trial.

In reviewing the studies for the USPSTF, the panelists considered the following questions2:

  • Does PSA screening decrease mortality?
  • Does PSA screening cause harm?
  • What benefits exist from treating earlystage or screening-detected prostate cancer?
  • What are the harms associated with such treatment?
The PLCO trial randomly assigned 76,693 men between the ages of 55 and 74 to annual PSA screening plus digital rectal examination compared with usual care. After 7 years of follow-up, the study found that PSA screening was associated with increased prostate cancer incidence (relative risk [RR], 1.2; 95% CI, 1.2-1.3), but had no effect on prostate cancer-specific (RR 1.1; CI, 0.75-1.7) or all-cause (RR, 0.98; CI, 0.92-1.0) mortality. Physical harms associated with PSA-based screening included bleeding or pain from digital rectal examination; bruising or fainting due to venipuncture; and biopsy complications, such as infection, bleeding, and urinary difficulties. The PLCO trial also found that after 4 PSA tests, the cumulative risk for at least 1 false-positive was 13%.

The ERSPC trial results, which randomly assigned 182,000 men aged 50 to 74 years from 7 countries to PSA testing every 2 to 7 years or to usual care, found that prostate cancer incidence was higher in the screened group (net increase, 34 per 1000 men), but there was no statistically significant difference in prostate cancer-specific mortality (RR, 0.85; CI, 0.73-1.0). One testing center in Göteborg, Sweden, was excluded because it reported results separately that were not reflective of what was being observed at the other testing centers in Europe. Across the entire ERSPC trial, 76% of prostate biopsies performed for elevated PSA levels found no cancer.

After analyzing the results of the PLCO and ERSPC trials and the results of other studies evaluating PSA testing, the USPSTF found that prostatectomies were associated with a decreased risk in prostate cancer-specific mortality. However, prostatectomies were also associated with urinary incontinence and erectile dysfunction, as well as other surgical complications.

Anger on 2 Levels

The highly publicized release of the USPSTF draft recommendations has led to different reactions from virtually every stakeholder involved in PSA testing. However, the news of the recommendations concerns patients the most, and is prompting many patients to question both PSA testing and the validity of these recommendations.

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