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Winnipeg Free Press - PRINT EDITION

Admit it or not, mammography unreliable

By: W. Gifford-Jones MD.

Posted: 12/9/2011 1:00 AM | Comments: 0

THE ASSOCIATED PRESS ARCHIVES Mammography can�t detect early malignancy, only lumps in the breast. (CP)

Several years ago, a friend asked if I'd talk to a women's organization about breast cancer, how mammography could detect malignancy in its early stages. But when I gave her a short version of what I intended to say, she remarked, "But they would not like to hear that!" End of the talk. So what do women not want to hear?

Any time I've questioned the use of mammography, it's been like damning motherhood and apple pie. Now, a blue-ribbon panel of experts reports that women under 50 years of age should not have mammograms, and that post-menopausal women should submit to this procedure only every two or three years rather than annually.

The blunt fact is that if mammography had been a drug, it would have been removed from the market long ago due to its ineffectiveness. For instance, Dr. Peter Goetzsche, a leading Danish researcher, claims there is no convincing evidence that annual mammograms decrease the risk of death from breast cancer.

But how could a procedure that costs half a billion dollars every year in Canada be such a loser? There's an easy explanation. We could wipe out cancer of the cervix if all women had a Pap smear at regular intervals. That is because this test is a "cellular diagnosis." It obtains cervical mucus and is able to detect precancerous cells years before they cause a malignancy. But mammography is a "lump diagnosis." There's no way to obtain cells from breast tissue.

So for years it's been stretching the truth to tell women mammography results in early diagnosis of breast cancer. How could it, when it takes about six or more years for cancer to be large enough to be detected by mammography? This provides time for malignant cells to metastasize to other areas.

Another untruth is the number of women's lives saved by mammography. The cruel truth is that whatever way you slice the cake, the decrease in the number of cancer deaths is modest. Experts agree that 2,000 women must be screened for 10 years to get one benefit! One can always argue that saving one life is worthwhile. But wouldn't it be better to use the funds saved from 20,000 inefficient mammograms to find a more efficient way to diagnose or prevent breast cancer?

Another misconception is the failure to inform women of the several negative aspects of mammograms. For instance, one study showed women who had regular mammograms during a 10-year period had a 49 per cent chance of requiring a breast biopsy during that time because of a suspicious mammogram. These are odds worse than Las Vegas.

I've all too often witnessed the profound anxiety of a woman whose report requires a second mammogram due to a suspicious area. The wait for the report and apprehension of a breast biopsy to determine whether a malignancy is present causes undue anxiety. Often, this scenario is the result of over-diagnosis.

On the other hand, when a mammogram is reported normal, it provides women with a false sense of security. But is she secure? For instance, in women 40 to 49 years of age, mammography misses 30 per cent of malignancies.

Proponents of mammography also tend to glide over the radiation risk of this procedure. I'm not a radiation expert, but I've talked to international experts who believe excessive radiation may cause malignant change. The problem is not just the regular mammogram, but the extra ones that are needed to recheck a suspicious lesion.

If there's one thing in life I hate, it's hypocrisy, and there's been plenty of this dished out to women regarding mammography. These new guidelines are at least a step in the right direction.

Nevertheless, it's my prediction that women's groups and those with a vested interest in mammography will not give up this sacred cow without a fight. And tens of thousands of women will continue to have mammograms because "Gifford-Jones, we don't want to hear that!"

www.docgiff.com

Republished from the Winnipeg Free Press print edition December 9, 2011 A23

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