Prostate Cancer Screening - Clinical Practice Guidelines

Clinical Practice Guidelines

Clinical practice guidelines for prostate cancer screening are controversial because the benefits of screening may not outweigh the risks of follow-up diagnostic tests and cancer treatments:

• The United States Preventive Services Task Force (USPSTF) recommended against PSA screening in healthy men in October 2011 finding that the potential risks outweigh the potential benefits. This recommendation, released in October 2011, is based on a review of evidence and concludes that "prostate-specific antigen–based screening results in small or no reduction in prostate cancer–specific mortality and is associated with harms related to subsequent evaluation and treatments, some of which may be unnecessary."
• American Cancer Society, in its cancer screening guidelines says that it does not support routine screening for prostate cancer. This is because the benefits are unclear or unproven. Instead it recommends that doctors discuss the pros and cons of testing and that men should be offered the possibility of a DRE and a PSA test if they are over 50 with a life expectancy of more than 10 years (or over 40 if they are in a high risk group). It recommends that men should sit down with their physician and weigh the benefits and risks of the test before a decision is made. Men at high risk for prostate cancer such as African-American men should discuss this with their doctor at age 45. Men who have a first-degree relative (father, brother, or son) diagnosed with prostate cancer at an early age (younger than age 65) and men with several first-degree relatives diagnosed at an early age should begin the discussion at age 40.

In the European Randomized Study of Screening for Prostate Cancer (ERSPC) initiated in the early 1990s, the intention was to evaluate the effect of screening with prostate-specific antigen (PSA) testing on death rates from prostate cancer. The trial involved 182,000 men between the ages of 50 and 74 years in seven European countries randomly assigned to a group that was offered PSA screening at an average of once every 4 years or to a control group that did not receive such screening. During a median follow-up of almost 9 years, the cumulative detected incidence of prostate cancer was 820 per 10,000 in the screening group and 480 per 10,000 in the control group. Deaths from these cancers in this time was much lower. There were 214 prostate cancer deaths in the screening group and 326 in the control group, a difference of 7.1 men per 10,000 in the tested group compared to the control. The researchers concluded that PSA-based screening did reduce the rate of death from prostate cancer by 20%, but that this was associated with a high risk of overdiagnosis, which means that 1410 men would need to be screened and 48 additional cases of prostate cancer would need to be treated to prevent just one death from prostate cancer within 9 years. However, the number needed to treat to prevent one progression to metastatic disease was only 24, and both numbers are expected to fall as patients in the study are followed for longer periods of time. Furthermore, the benefit for screening was greater (30% rather than 20%) with adjustment for noncompliance and contamination (i.e., men who were randomized to get PSA tests but did not, and those who were in the control arm but actually received PSA tests during the study period). One recent analysis of the ERSPC data suggested that projecting over a 25-year time horizon, which is more appropriate for a man in his 50s than the 9 years reported to date from the trial, the number needed to screen falls to 186-220, and the number needed to treat to prevent a death falls to between 2 and 5 men.

In addition to the 20 percent reduction in prostate cancer mortality shown by the ERSPC study, a more recent study has shown greater effectiveness in how screening has reduced the prostate cancer death rate. A study published in the European Journal of Cancer (October 2009) documented that prostate cancer screening reduced prostate cancer mortality by 37 percent. By utilizing a control group of men from Northern Ireland, where PSA screening is infrequent, the research showed this substantial reduction in prostate cancer deaths when compared to men who were PSA tested as part of the ERSPC study.

The American Urological Association said in early 2009 that "The decision to screen is one that a man should make in conjunction with his physician, and should incorporate known prostate cancer risk factors, such as family history of prostate cancer, age, ethnicity/race, and whether or not a man has had a previous negative prostate biopsy. These factors are different for every man and, therefore, the benefits of screening should be considered in the broader perspective." The organization will review its best practice guidelines later in 2009.

• The 2008 recommendations of the U.S. Preventive Services Task Force (USPSTF) concluded that routine screening for prostate cancer using PSA testing or digital rectal examination (DRE) was not recommended for men over 75 and that the evidence was insufficient to recommend for or against screening for men under 75 years old. The previous 1995 USPSTF recommendation was against routine screening.
• The American Cancer Society (ACS) has recently updated its guidelines making clear that it does not recommend routine prostate cancer screening for all men. It recommends that the risks and benefits of screening need to be weighed, and discussions should start early for those in high risk groups. Screening should take place only wíth informed consent of the patient in full knowledge of both benefits and risks. The revised guidelines reflect the concerns about the potentially down-played risks and over-blown claims for the success of prostate cancer screening.

The American Cancer Society (ACS) does not support routine testing for prostate cancer at this time. ACS does believe that health care professionals should discuss the potential benefits and limitations of prostate cancer early detection testing with men before any testing begins. This discussion should include an offer for testing with the prostate-specific antigen (PSA) blood test and digital rectal exam (DRE) yearly, beginning at age 50, to men who are at average risk of prostate cancer and have at least a 10-year life expectancy. Following this discussion, those men who favor testing should be tested. Men should actively take part in this decision by learning about prostate cancer and the pros and cons of early detection and treatment of prostate cancer. This discussion should take place starting at age 45 for men at high risk of developing prostate cancer. This includes African American men and men who have a first-degree relative (father, brother, or son) diagnosed with prostate cancer at an early age (younger than age 65). This discussion should take place at age 40 for men at even higher risk (those with several first-degree relatives who had prostate cancer at an early age). If, after this discussion, a man asks his health care professional to make the decision for him, he should be tested (unless there is a specific reason not to test).

• Some U.S. radiation oncologists and medical oncologists who specialize in treating prostate cancer recommend obtaining a baseline PSA in all men at age 35 or beginning annual PSA testing in high risk men at age 35.
• The American Urological Association Patient Guide to Prostate Cancer.

Since there is no general agreement that the benefits of PSA screening outweigh the harms, the consensus is that clinicians use a process of shared decision-making that includes discussing with patients the risks of prostate cancer, the potential benefits and harms of screening, and involving the patients in the decision.