March 2004

Many cancer screening tests are ineffective -- and can cause harm

For decades, the medical profession has urged women to conduct breast self‑exams and men to receiving screenings for prostate cancer, claiming they could detect early signs cancer and alert patients to the need for treatment. These and several other cancer screening tests are useless and should be discontinued, according to Professor Malcolm Law at the Wolfson Institute of Preventive Medicine.

The blood test for cancer of the prostate (PSA) is an example, Law stated. Despite there being no

published trials showing that early detection reduces mortality, and separate evidence that it may not reduce mortality, many healthy men have been tested and have received treatment that can cause incontinence, impotence, and other complications.

Breast and testicular self examination are further examples of the failure to apply scientific rigor to screening, he said.

Self‑examination has been widely advocated on the assumption that it must be beneficial and cannot do harm. Yet, in a recent large trial, breast self examination did not reduce mortality from breast cancer but caused more surgical biopsies and thereby more anxiety. This result should discourage prostate and testicular screening.

Giving information to people considering these unproven screening tests when the only honest information is complete uncertainty is useless, argues Law, while encouraging people to decide for themselves is ducking the issue.

SOURCE: "Screening without evidence of efficacy," by Malcolm Law. BMJ, Feb. 7, 2004.

NOTE: This article appeared in the World Chiropractic Alliance Health Watch electronic newsletter. To receive this free newsletter each week, sign up at wcanews.com.