Mammograms May Not Matter

Reuters
3:00 a.m. 7.Jan.2000 PST

Mammography, one of the most widely used screening tests for breast cancer, is next to useless in reducing the death rate from the disease, Danish researchers said on Friday.

Mammography uses a series of X-rays to detect abnormalities, such as tumors, in the breasts.

The two researchers said they decided to take a hard look at the procedure because a study in Sweden had shown no decrease in breast cancer death rates since a nationwide screening program was introduced in 1985.

They re-examined eight previously published trials that randomly assigned women either for mammographic screening or to an unscreened control group.

Six of those trials found that mammography decreased the risk of death by about 25 percent while two showed no significant effect.

But the scientists said only those two -- conducted in Canada and the Swedish city of Malmo -- met widely accepted criteria for an adequate randomisation process.

In each study, the women in the two randomly selected groups had similar characteristics that affect the risk of breast cancer -- age, family history of the disease, previous lumps in the breast, pregnancies, menopause, education, and birthplace.

Several of the other six trials done in the Scottish city of Edinburgh, New York and other areas of Sweden had inadequate randomisation procedures as the groups of women differed substantially in age or other risk factors.

But not all of Gotzsche and Olsen's contemporaries agreed with their conclusions.

"Although the issue focused on by Gotzsche and Olsen is very important, they have disregarded the fact that other factors probably have a more important part in lowering the mortality rate through screening," Dr Harry de Koning of the Rotterdam Department of Public Health in the Netherlands wrote.

In a commentary, he said that breast cancer mortality in Dutch women aged 60-69 was falling, although no statistically significant decrease was expected or found during the first nine years of a screening program in the Netherlands.

Britain's Department of Health said there was "no new evidence" in the report by the Danish researchers.

"The data has already been considered by expert committees on breast screening who found significant beneficial effects from screening women for breast cancer," it said in a statement.

 TOP