Prostate cancer screening not reliable

The prostate specific antigen (PSA) test should not be used to screen prostate cancer in men who have no known risk factors for the disease, said professor  Richard Ablin of the University of Arizona College of Medicine who developed the method.

Dr. Ablin said the method is not indicated to screen prostate cancer in healthy people because it is not accurate enough to detect prostate cancer nor it can tell doctors whether a cancer is aggressive or benign.

He called use of his prostate cancer screening method "a hugely expensive public health disaster", which costs the U.S. at least $3 billion each year paid mostly by Medicare and the Veterans Administration.

One study reported in the journal Cancer in 1997 and cited in a media report by LiveScience, which was published on FoxNews, found that of men who had PSA levels greater than 4, 65 to 75 percent of them were actually cancer-free.

Another study published in 2004 in the New England Journal of Medicine showed on the other hand that 15 percent of men with PSA levels below 4 actually had prostate cancer.

Many studies have showed that early detection of prostate cancer by the PAS testing does not cut the prostate cancer mortality.

One U.S. study found that annual PSA screening together with a  digital rectal exam did not affect the risk of death from prostate cancer during a period of 11 follow-up years.

One European study did find that PSA testing every four years reduced deaths from the disease by 20 percent.  But for one life to be saved, 1,410 men had to get the screening and 48 men needed to undergo unneccessary treatment.

Still some doctors did not agree with the findings, arguing that PSA testing has lowered the cases of advanced prostate cancer.

Stuart Holden, the medical director of the Prostate Cancer Foundation, was cited by LiveScience as saying that the number of metastatic tumors used to be 70 to 80 percent of all prostate cancer cases compared to 15 to 20 percent today.

A health observer suggested that this argument can be misleading. The key point he said is that the death risk has not be reduced regardless of the current low rate of advanced prostate cancer.

Still, many healthy men want to use the PSA testing.

Sixty percent of men ages 76 or older who had no history of prostate cancer received a prostate-specific antigen or PSA test in a year, according to a recent study led Li J and colleagues from the Centers for Disease Control and Prevention and published in the July 2010 issue of Preventing Chronic Disease.

The U.S. Preventive Services Task Force in 2008 updated prostate cancer screening guidelines to recommend against screening for prostate cancer in men aged 75 or older. 

The American Cancer Society posted a press release on March 3 2010 saying  men who expect to live 10 years or less don't have to bother to get prostate cancer screening because chances are good that they may die from another health condition.  

The ACS still recommends that "men with no symptoms of prostate cancer who are in relatively good health and can expect to live at least 10 more years have the opportunity to make an informed decision with their doctor about screening after learning about the uncertainties, risks, and potential benefits associated with prostate cancer screening." and the talks should start at the age of 50 years.

The ACS also say that men at high risk such as African-American men and men who have a male in his family diagnosed with prostate cancer before age 65 should begin talking to their doctors at the age 45. If multiple family members have been diagnosed with the disease, then they need to be screened starting at age 40. 

By David Liu