A lot has been said about benefits of mammography but there are more and more voices against it. After well-documented researches that lasted for years, MDs still can't agree is mammography a beneficial or harmful procedure. Where's the catch?
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Mammography, an x-ray examination of the breast that should find tumors too small to be felt, was introduced in 1960, it became useful in 1969, and by 1976 it became a standard practice. It entered medical institution around the world and it's one of the thing a medical system must have to be considered as "modern" and "advanced". Despite the fact that more than 600,000 women have participated in randomized trials with approximately 10 years of follow-up, and that those trials are calling into question some well-established opinions, some experts are not ready to embrace those findings.
There are two main questions without unified answers: When to start with mammography, and does it help in preventing deadly outcome? World Health Organization recommends mammography every one to two years for women ages 50 to 69. U.S. Preventive Services Task Force (USPSTF), a group of health experts, in its guidelines states that screening mammograms should be done every two years beginning at age 50, and screening before age 50 should be based on a woman's values regarding the risks and benefits of mammography.
USPSTF says that mammograms for women ages 40 to 49 may cause more harm than good and that potential harms may include false-positive results that lead to unneeded procedures and stress. That is backed up by data obtain in research such as the one from Karsten Juhl Jorgensen and Peter C. Gotzsche, published in the British Medical Journal. The conclusion is that in populations with organized screening for breast cancer overdiagnosis was 52 percent.
However, some other groups - the American College of Radiology, the Society of Breast Imaging, the American Cancer Society, the American Medical Association, the National Comprehensive Cancer Network, the Canadian Task Force on Preventive Health Care, and the American College of Obstetrics and Gynecology - are pushing the beginning to earlier age and recommend that women ages 40 to 49 have mammograms yearly or every other year.
Furthermore, some authors claim that mammography can actually contribute to the development of breast cancer. Dr. Charles B. Simone, a clinical associate in immunology and pharmacology at the National Cancer Institute, said that "Mammograms increase the risk for developing breast cancer and raise the risk of an existing growth." Another expert, Dr. Samuel Epstein, said something similar: "Each one rad exposure increasing breast cancer risk by about 1 percent".
That means the cumulative ten percent increased risk over a decade's screening. Indeed, mammograms can expose the tissue to radiation that can be 1,000 times greater than that from a chest x-ray.
The New England Journal of Medicine published a surprising study which revealed the effectiveness of mammograms. The research conclude that mammograms have reduced cancer death by only 0.4 deaths per 1,000 women. In another words, that number can be seen as a statistical error. To put that into perspective, 2,500 women have to be screened over ten years for one death to be avoided. Or, 2,499 women will undergo unnecessary radiation exposure and some of them will even undergo a surgical procedure they don't need.
And that is the main controversy. While some groups firmly believe that mammograms can reduce death rate for as much as 30%, the findings indicate that mammograms combined with modern treatment reduced the death rate by 10 percent, but the effect of mammograms alone reduced the death rate by just two percent.
So, there's no doubt that mammograms are reducing death rate by some percent and that every life saved is valuable, but there are some other questions to be answered. How to prevent overdiagnosis and why some associations are arguing so fiercely that screening should start at 40 are some of them. The effect of x-rays on breasts is also relatively unknown and have to be investigated. Until then, there's small chance that MDs will stop the mammography war anytime soon. ■