Are routine cancer tests worth it?

Medical researchers are beginning to question one of the most widely held beliefs in preventive medicine: that screening healthy people for cancer and catching it early saves lives. According to Barnett Kramer of the National Institutes of Health, the evidence shows that some screening tests are much more useful than others.

Some tests, like Pap tests for cervical cancer and tests for colon cancer, show clear benefits. But evidence for others, like mammography and a blood test for early signs of prostate cancer, is less clear, say researchers.

Tests that detect cancer cannot always discern whether the cancer is dangerous or is an indolent tumour that might never produce noticeable symptoms.

Unforeseen consequences can arise when seemingly healthy people sign up for a screening test. For example:

Very aggressive prostate cancers may be unstoppable whenever they are discovered, while others grow slowly and may not be dangerous.

Yet once a tumour is found, doctors and patients feel obliged to treat it, leaving many men incontinent and impotent.

Danish scientists found mammograms did not lower the overall death rate from breast cancer, but the women tested ended up with more surgery, including mastectomies, more radiation and chemotherapy than women who were not screened.

In addition to the risks of such procedures, widespread screening may needlessly add to the overall cost of medical care if millions of people are involved. One researcher found that scans of more than 90 percent of tobacco smokers and former smokers showed something suspicious. However, many suffered needless operations and other medical procedures for something that may have been innocuous.

The testing included chest surgery, which carries a 4 percent risk of death. And it is not even clear yet whether the early diagnosis of lung cancers helped.

Source: Gina Kolata, Questions Grow Over Usefulness of Some Routine Cancer Tests, New York Times, December 30, 2001.

For text (requires free registration)
http://www.nytimes.com/2001/12/30/health/30CANC.html
For more on Preventive Health Measures http://www.ncpa.org/iss/hea/

FMF Policy Bulletin\8 January 2002