The mammogram screening controversy: When should you start?
September 27, 1999
Web posted at: 1:31 PM EDT (1731 GMT)
By Tula Karras
(WebMD) -- October is Breast Cancer Awareness Month. Learn the signs, says the medical community. Do a monthly breast self-exam. Get an annual mammogram. The recommendations sound simple, but if you are a woman between the ages of 40 and 50, the advice isn't so clear.
Whether to begin getting annual mammograms at age 40, 50 or sometime in between is still under debate. And the results of a mammogram are not 100 percent reliable. Learn what the experts say about how you can make the best decision for yourself.
The great divide
The American Cancer Society (ACS) and, more recently, the American College of Obstetrics and Gynecology, recommend annual mammogram screening beginning at age 40. The National Cancer Institute (NCI), however, recommends annual screening beginning at age 50, while suggesting that women in their 40s have screenings every one or two years, depending on individual risk factors.
Why aren't these organizations in agreement? The difference in guidelines reflects a difference in the interpretation of research data. The American Cancer Society has adopted the position on annual screening from age 40 based primarily on the results of two often-cited Swedish studies.
"The data showed that the younger women who were screened more often did better," says Joann Schellenbach, national director of media relations for the ACS. Schellenbach also points out that when younger women get breast cancer, the disease can be more aggressive, so finding it early may be imperative to successful treatment.
The NCI, on the other hand, found that the difference in mortality of women screened more regularly was not statistically significant. In their screening guidelines they state, "There is little or no reduction evident during the first 10 years after starting screening" for women in their 40s.
Drawbacks to screening younger women
Even if there are no conclusive data that annual mammograms beginning at age 40 are beneficial, why not screen women earlier just to be on the safe side? Some argue that there are several reasons why this is not necessarily beneficial:
1) The younger the woman, the less "readable" the mammogram. Mammograms are usually more difficult to read in women before they hit menopause. "The main drawback of mammography today is that it's hard to differentiate between normal, dense tissue and cancerous tissue when looking for small tumors surrounded by glandular tissue," says Gerald Dodd, M.D., emeritus professor of radiology at the M.D. Anderson Cancer Hospital in Houston. Before menopause, a woman's breasts are naturally denser, or more glandular, which makes the mammogram image appear murkier.
2) More false positives. Because mammograms are more difficult to read in younger women, they have a higher incidence of false positives and undergo more unnecessary biopsies. According to the NCI, 86 percent of women age 50 and older with an abnormal mammogram turn out not to have cancer. This number jumps to 97 percent in women between the ages of 40 and 49. While it's fortunate that these women turn out to be cancer-free, they still must undergo a painful and perhaps unnecessary procedure to -- in most cases -- rule out cancer.
3) More false negatives. There is also a higher rate of false negatives in women younger than 50. The NCI estimates that mammograms miss up to 25 percent of breast cancer in women in their 40s, as opposed to 10 percent for women in their 50s and older. A sense of false security can develop, which may lead to a woman being less vigilant about checking for cancer.
What's a 40-year-old woman to do?
The best bet, say experts, is to know your risk factors, discuss them with your doctor and make a decision together. Women with the following risk factors may need more frequent and earlier screening, according to the NCI:
A family history of breast cancer
Breast abnormalities, such as atypical hyperplasia or LCIS (lobular carcinoma in situ)
Breast density of 75 percent or more (for women over 45)
Having had chest irradiation at age 30 or younger (for conditions such as Hodgkin's disease)
Having a first child after age 30
You may be your greatest ally
All women, regardless of their risk factors, should monitor their health with annual clinical exams and monthly breast self-exams (BSEs). "One third of all women who are diagnosed with breast cancer have found the tumor themselves," notes Barbara Brenner, executive director of Breast Cancer Action, a national education and advocacy group.
Brenner was one of those women. At age 41, she found a cancer that her annual mammogram had not picked up. "The medical community has us believing that if you get a yearly mammogram, and that mammogram does not show cancer, you're cancer-free. I'm proof that that's not the case."
The next step
Because mammograms -- at any age -- are not foolproof, some believe that research money and public awareness are being steered in the wrong direction altogether. "There's been enough hoo-haw about the effectiveness of mammogram screening for women before menopause," says Brenner.
"The research is inconclusive. What we should be focusing on now is how to find a better technique of screening than what we've already got."
Copyright 1999 WebMD, Inc. All rights reserved.
RELATEDS AT :
Breast Cancer in Women
Breast Cancer Prevention and Screening
National Cancer Institute: Screening Mammograms
American Cancer Society: Mammography and Other Breast Imaging Information
Breast Cancer Action
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