Tuesday, September 9, 2014

PSA screening: A public health disaster?!

  1. A friend of mine had an elevated PSA (Prostate Specific Antigen) level some years ago. He was naturally worried. He had some prostatic symptoms, so he underwent a transurethral resection of prostate which was found to be negative for cancer. Another friend also had an elevated PSA. After few years of worry and repeated tests he had a needle biopsy of the prostate which was negative. He decided not to do the test again. A third friend, a pathologist, also had an elevated PSA and decided to ignore it. He said too many prostates had been removed unnecessarily because of the test, sometimes with tragic consequences like incontinence and impotence.
  2. Dr. Richard Ablin, who discovered the prostate specific antigen in 1970, recently published a book about it titled "The great prostate hoax"(1). In the book and prior to that in an article in the New York Times(2) he described screening for prostate cancer using PSA as a "public health disaster"!
  3. In a thought provoking interview with Dr. Ablin on Medscape on  August 8, 2014(3) he told the story of the test, a story that makes one scratch his head:
    1. In 1970 he, an immunologist, was working with two urologists studying freezing prostates (cryosurgery) as a treatment of prostate cancer. They noticed that cryosurgery in animals induced an immune response which increased when freezing was repeated. They also noticed that in some patients with metastasizing prostate cancer who underwent cryosurgery of prostate, metastasis were reduced in size which may have been, they thought, due to antibodies induced by the surgery. Dr. Albin could then isolate the antigen responsible for the immune response. He thought first it was a cancer specific antigen but later realized it was a tissue specific antigen (i.e. prostate specific) and not cancer specific because it was also present in normal prostate tissue and in benign prostatic hypertrophy. He also noticed that in cancer patients its concentration decreased with treatment and increased again with recurrence which makes it suitable for following patients and detecting recurrence. In 1986 the test was approved by the FDA (Food and Drug Administration) as a harbinger of recurrence.
    2. In 1989, Schering-Plough Company paid $1.2 million to a marketing firm to promote PSA screening in asymptomatic men to detect prostate cancer. Primary care physicians were brainwashed that they needed to order PSA tests for patients. Many doctors started to use the test, off label, for detecting prostate cancer!
    3. In 1994 it was approved by the FDA as a test to detect cancer in spite of the fact that it was pointed out to the group discussing its approval that the test has a false positive rate of 78% i.e. it is wrong in nearly 80% of the time!!
    4. The latest statistics show that the annual budget for the National Cancer Institute (of the USA) is about $5.1 billion; of that, approximately $300 million goes for urologic research. Compared to this, every year $3 billion are spent, in the United States on PSA screening in asymptomatic men!(3)

  1. Ablin RJ, Piana R. The Great Prostate Hoax: How Big Medicine Hijacked the PSA Test and Caused a Public Health Disaster. New York: Macmillan Publishers; 2014.
  2. http://www.nytimes.com/2010/03/10/opinion/10Ablin.html
  3. http://www.medscape.com/viewarticle/828854?src=