Widespread PSA Testing Has Led One Million Additional Men to be Diagnosed and Treated for Prostate Cancer, New Study Finds
September 4, 2009
Since the broad adoption of PSA testing in 1986, diagnosis of prostate cancer has increased dramatically, resulting in an additional 1 million men receiving surgical and/or radiation treatment. But almost all of those patients were treated unnecessarily, according to a new paper in the Journal of the National Cancer Institute (JNCI).
Authors H. Gilbert Welch, MD, MPH, of The Dartmouth Institute for Health Policy and Clinical Practice and the Veterans Affairs Outcomes Group, and Peter C. Albertson of the University of Connecticut School of Medicine, analyzed data of age-specific prostate cancer rates between 1986 and 2005. Their findings indicate that using the most conservative estimates, only 1 of 20 men received a benefit from treatment; more likely, they say, the number is closer to 1 in 50.
"Diagnosis of prostate cancer in the United States has risen dramatically since screening for the prostate-specific antigen (PSA) test was introduced," said Dr. Welch. The authors report a distinct shift in diagnosis from older to younger men. "While the rate of prostate cancer detection has fallen in half in men over age 80, it has more than tripled in men in the 50s-and has increased seven-fold for men younger than 50. Yet, in most cases, we are treating cancers that would never progress to cause symptoms or death."
The result of this overdiagnosis, the authors write, is that men are being exposed to the risks of treatment without getting any benefit. Risks include impotence, incontinence, and death from surgery; and impotence, urgency, painful defecation, and injury to the intestines as the result of radiation treatment.
The value of PSA screening has been increasingly called into question. Two recent studies in America and Europe concluded that PSA testing rarely saves lives. The U.S. Preventive Services Task Force has recommended against screening for men 75 or older. The web site of the Centers for Disease Control and Prevention states that there "is no medical proof" that screening for prostate disease reduces death.
Today's study is significant because it is the first to quantify the rates of diagnosis and to translate those into numbers of men likely overdiagnosed and unnecessarily treated. Since 1986, 1.3 million men have been diagnosed through PSA screening, of which more than 1 million have been treated.
Welch, the author of "Should I Be Tested for Cancer? Maybe Not and Here's Why," said, "Unfortunately, what we're seeing in this country is not an epidemic of disease, but an epidemic of diagnosis. We are turning healthy people into patients, giving them treatments that can only cause them harm."
The paper, Prostate Cancer Diagnosis and Treatment After the Introduction of Prostate-Specific Antigen Screening, may be obtained from http://jnci.oxfordjournals.org/.