Prostate Cancer Screening: 50 Percent False Positives

Monday, February 15, 2010 by: David Gutierrez, staff writer
Tags: prostate cancer, screenings, health news

(NaturalNews) As many as 50 percent of all prostate cancer diagnoses may be cases of over-diagnosis, according to a study published in the British Medical Journal.

Over-diagnosis refers to the detection of a cancer that, if left untreated, would never have any negative effects on a person's life. This happens with cancers that grow slowly and do not spread to other organs, so that a patient dies of other causes before ever experiencing any symptoms.

Because prostate cancers tend to be very slow growing, the U.S. Preventive Services Task Force has recommended against screening men over the age of 74 for prostate cancer. Treatments for the disease can have severe side effects, including impotence and incontinence, and may even increase the risk of early death.

Another paper, published in the same issue of the journal, found that the prostate specific antigen (PSA) test commonly used to assess prostate cancer risk cannot reliably predict this risk in most cases.

The PSA is a marker of prostate inflammation, which in turn is believed to be a risk factor for prostate cancer. Yet in a study on 1,540 Swedish men, researchers found that PSA levels were not correlated with prostate cancer risk. The only exception was levels below 1 nanogram per mililiter, which suggest a prostate cancer risk of almost zero.

The British National Health Service recommends referral for cancer screening such as biopsies for men between the ages of 50 and 59 who have a PSA level of 3 nanograms per mililiter or higher, and for older men who have levels of 5 nanograms per mililiter or higher.

Another recent study found that regular PSA screenings did not decrease men's risk of dying from prostate cancer.

The British Parliament has been considering promoting more regular PSA screening, but so far has declined to do so. According to general practitioner James Kingsland, a member of the government advisory group on prostate cancer risk management, the new studies lend support to this decision.

"It is using a test for something which it was never designed for, which is always dangerous," he said.

Sources for this story include: news.bbc.co.uk.