Mammogram debate



Experts fail to agree on need for under-50 mammograms: NIH panel at odds with some cancer groups

Until recently, the medical community appeared united in its support of mammograms as a way to save women's lives by giving them early warning of breast cancer.

And, at $50-200 a test, mammograms have become a cash cow for many doctors and radiologists, particularly since many medical agencies have encouraged women as young as 40-years-old to receive the tests.

Now, however, the medical community is divided because of a serious disagreement about the wisdom of subjecting women under the age of 50 to these tests.

According to a panel of experts who gathered for the National Institutes of Health (NIH) Consensus Development Conference in January, there is no proof that the potential benefits of mammograms outweigh the risks involved for this age group.

In refusing to recommend the test for women under 50, the panel pointed out that breast cancer is relatively rare in women under 50 and that there is only a 0.3% chance of dying from the disease during this decade of their lives.

Although various medical organizations often claim that research has shown mammograms are responsible for saving and extending lives, the panel disagreed. "The information from the RCTs (randomized controlled trials) also allows an estimate of no lives extended for 1,000 women regularly screened from ages 40 to 49," the panel noted.

Of course, if the mammogram was without risk, the test might be considered nothing more than yet another unnecessary medical examination (although an expensive one). But the mammogram is not risk-free and the NIH panel experts found that the risks do NOT outweigh the very small possible benefit for a few women.

According to the draft report of the panel, "An understanding of the nature and magnitude of risks is important to both primary care providers and women making informed decisions about breast cancer screening." Some of the potential risks they listed were:

- Risks associated with false-negative examinations. "Up to one-fourth of all invasive breast cancers are not detected by mammography in 40- to 49-year- olds, compared with one-tenth of cancers in 50- to 59-year-olds," the report stated.

- Additional diagnostic testing induced by false-positive examinations. "Many mammographic abnormalities may not be due to cancer, but will prompt additional testing and anxiety," the panel found. In a Swedish study of 60,000 women aged 40-64, 726 were referred to oncologists for treatment for cancer -- but 70% of them were actually found to be cancer free! Some 86% of women under 50 who were referred for cancer treatment had actually triggered a false positive test result.

On average, every woman whose mammogram results in an "abnormal," reading is subjected to two additional diagnostic tests (e.g., diagnostic mammography, ultrasound, needle aspiration, core biopsy, or surgical biopsy), according to the NIH panel.

Compounding the problem with false positive results is the fact that estrogen therapy increases the likelihood of a false positive result by seventy-one percent!

- Psychosocial consequences. "There is concern that women having abnormal mammograms -- both true positive and false-positive -- experience psychosocial sequelae, including inconvenience, anxiety, and fear."

- Radiation exposure. "The risk of radiation-induced breast cancer has long been a concern to mammographers and has driven the efforts to minimize radiation dose per examination," the panel explained. "Radiation can cause breast cancer in women, and the risk is proportional to dose. The younger the woman at the time of exposure, the greater her lifetime risk for breast cancer.

"Radiation-related breast cancers occur at least 10 years after exposure," continued the panel. "Radiation from yearly mammograms during ages 40-49 has been estimated to cause one additional breast cancer death per 10,000 women."

Other medical research has shown that the incidence of a form of breast cancer known as ductal carcinoma in situ (DCIS), which accounts for 12% of all breast cancer cases, increased by 328% -- and 200% of this increase is due to the use of mammography!

After examining the risks from mammograms as well as the potential benefits, the panel concluded: "At the present time, the available data do not warrant a single recommendation for mammography for all women in their forties."

The NIH panel conclusions echo the decision made by the National Cancer Institute several years ago when it chose not to recommend mammograms to women under the age of 50. However, numerous other cancer groups -- including the American Cancer Society and the American College of Radiology -- continue to encourage young women to undergo the risky tests.

Article copyright The Chiropractic Journal.

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