Prostate Specific Antigen (PSA)

The Controversy and The Facts

PSA is a blood test that without question can detect prostate cancer at an early stage of the disease. It has long been thought that in all cases early detection equals improved survival. That conclusion has been called into question by the United States Preventive Services Task Force (USPSTF). The USPSTF has stated that PSA is of no value and should never be used. Nearly all observers feel that this is “throwing the baby out with the bathwater” — a conclusion that has merit. The controversy is addressed in the following facts and observations.

2009: Two articles published in the NEJM on the benefits of PSA screening, one from the US and one from the Netherlands (Andriole US/ & Schroeder Netherlands).

  • Both were 10-year studies, published prior to the 10-year completion. It is commonly accepted that no conclusions regarding prostate cancer treatment results can be made prior to 10 years of follow up.
  • The US study was conducted after PSA screening was wide spread.
  • The US study was seriously flawed:
    • This was an alleged randomized study but > 40% of the patients had already been screened with PSA.
    • Of those with an elevated PSA, approximately 40% were biopsied.

Thus, the US study began after PSA screening was common, and the “control” arm was not controlled: 40% of the patients who were randomized to no screening had undergone PSA screening and many had already been biopsied.

In October, 2011 the USPSTF published a recommendation that “PSA screening was of no value in reducing the the mortality rate from prostate cancer”. This same group stated in 2009 that screening mammography was of no value in women less than 50 years of age. The American College of Surgical Oncologists and the Komen Foundation quickly refuted this and the recommendation by the USPSTF was withdrawn.

In the USPSTF evaluation of the value of PSA screening:

  • They relied on the two incomplete studies cited above.
  • They completely ignored and did not mention the increased incidence of prostate cancer in African Americans (20% vs 16% in Caucasians).
  • They completely ignored and did not mention the increased incidence of prostate cancer in patients with a family history of prostate cancer (16% increased to 30% with a family history: father or brother).

Prior to PSA screening 20% of patients newly diagnosed with prostate cancer had spread of the cancer at diagnosis with a life expectancy of 3 years.

Today, with PSA screening, only 4% of newly diagnosed prostate cancer patients have detectable spread of their prostate cancer.

The mortality rate from prostate cancer has plummeted 40% since the introduction of PSA screening, a decrease in cancer mortality not observed in any other cancer in men or women.

Current recommendations:

  • First PSA at age 40:
    • if the PSA is less than 0.6, re-screen at age 45
    • If the PSA is greater than .6, repeat the PSA in 1 year
    • Annual screening beginning at age 50
  • The patient should be informed regarding the benefits and risks of PSA screening.

CONCLUSIONS

  • PSA is of value in detecting prostate cancer at a stage that is curable.
  • PSA and DRE screening should be offered to patients beginning at age 40.
  • The incidence of prostate cancer is increased in African American men and men with a family history of prostate cancer.
  • Given that many patients with prostate cancer do not need to be treated due to age or associated significant medical conditions, patients should be counseled about the potential benefits of early detection and the minor risks of prostate biopsy.
  • If cancer is diagnosed, there should be a thorough discussion of treatment options which take into account the patient’s age, associated medical conditions and the patients preferences.