Life and Death Debate
01/09/1995 at 01:00 AM EST
Women are confused, but so is the medical establishment. Breast cancer kills 46,000 American women a year—the second highest cancer killer after lung cancer—and until a year ago most doctors followed National Cancer Institute guidelines and recommended that women begin breast-cancer screening at age 40. Then in December 1993, NCI dropped its recommendation for women ages 40-49 after an international workshop decided the evidence for this category was inconclusive. Despite agreement that mammography reduces breast-cancer mortality for women over 50 by one-third, NCI declared that the studies of 175,000 women were not definitive; it could not say that women under 50 were helped by mammograms. Other experts disagreed. "There is compelling evidence that screening using mammography on a periodic basis is just as effective in reducing mortality for women ages 40-49 as for women 50-59," writes Dr. Daniel B. Kopans, a Harvard Medical School radiology professor who argues that the studies were seriously flawed.
"Women are very upset, and they have a right to be, "says Dr. Edivard Sondik, 53, acting deputy director of NCI. "The issue of mammograms for women under 50 has been a hornet's nest, one of the most divisive I've seen." Sondik, the son of a postal clerk and a homemaker, was reared in Hartford, Conn., and got a doctorate in engineering with applications in health systems from Stanford University; in his NCI job he oversees research on breast-cancer screening. Sondik discussed the mammography controversy with correspondent Jane Sims Podesta at his NCI office in suburban Maryland.
Why are doctors divided on mammograms for women in their 40s?
The crux of the problem is that, to date, statistical studies have failed to give us clear answers about whether screening can reduce deaths. Even though we'd like to make the issue less complicated and give out simple advice, we can't.
But NCI did change its guidelines to exclude women under 50. Why?
If NCI doesn't speak from the scientific data, then who else will? The fact is, we don't know whether mammography will reduce the number of deaths of women in their 40s. Organizations such as the American College of Physicians and Surgeons and the American Academy of Family Practice say that first there should be conclusive proof that deaths will be reduced. These groups also point out that the chances of a women in her 40s developing breast cancer are relatively low. In the 40-44 age bracket, 1.27 women out of every 1,000 will develop breast cancer; in the 45-49 bracket, it's 2 out of 1,000. That's compared with 2.3 at ages 50-54 and 2.7 at 55-59—and 4.8 out of every 1,000 women ages 75-79.
There's another point these organizations make: A woman screened every year during her 40s runs a 50-50 chance of having a false-positive result by the time she's 50, because mammography, like any test, isn't perfect. That might lead to a biopsy, with possible scarring of the breast tissue that could reduce the efficiency of future mammography. Finally they point out that when you screen the breast, you expose it to radiation, which itself could cause cancer—even though the risk is very, very low.
What is the argument of those who recommend mammography for younger women?
The basic point of these groups—including the American Cancer Society and the American College of Radiology—is that there is nothing magic about turning 50. They hold that because screening for women in their 50s is effective, then it should work for women in their 40s because there is little difference in the breasts of women in these two age groups. They agree that studies of women in their 40s have thus far been too weak to demonstrate how this age group is affected but believe that younger women would still benefit by the early mammography.
Is a resolution to this controversy in sight?
Perhaps. A study of 50,000 women ages 40 to 59 in Gothenburg, Sweden—half screened for breast cancer with mammograms, half not—could have a major impact on this debate. Unlike others assessed by NCI, the Gothenburg study, begun in 1982, has now been going on long enough that it may produce a statistically valid finding for 40-to 49-year-olds. Preliminary unpublished results indicate that breast-cancer mortality was 40 percent lower for women in their 40s who were screened with mammograms. The results still need to be scientifically verified, which will probably be within the year. If the study holds up, I would recommend that NCI examine the results and reconsider its position.
Can two radiologists read the same mammogram differently?
Reading a mammogram is an art. A recent Yale University study asked 10 radiologists to evaluate the same 150 mammograms. These trained radiologists disagreed on the diagnosis more than 20 percent of the time. The study was extremely important because it may explain why we haven't seen mortality reductions for women with cancer in their 40s. Part of the problem may be in the reading of mammograms.
Is it harder to read the mammogram of a younger woman?
Yes. As a woman ages, the composition of her breasts changes. She develops fat tissue; X-rays travel differently through fat than through normal breast tissue, and it becomes easier to detect cancer. Since younger women have less fat tissue in their breasts, X-rays are less able to distinguish between cancerous and noncancerous tissue.
How can a woman be sure she gets a quality mammogram?
She should ask her doctor to recommend a facility certified by the FDA under the Mammography Quality Standards Act, which has tough requirements for the entire process—from the technicians taking X-rays to radiologists reporting the results.
Is family history relevant in deciding whether to have a mammogram?
We suspect that approximately 5 percent of women have a genetic predisposition for breast cancer. If a woman has a mother or a sister—a first-degree relative—who has it, her risk doubles. The higher the risk, the more compelling the case for a mammogram.
What advice can you give to a woman in her 40s who is wondering whether to begin mammogram screening?
Until the debate is resolved, it's important for her to learn the facts and make her own decision, I'd advise her to go over the statistics about the probability of a woman her age developing breast cancer, and I'd recommend she discuss the matter with her physician. Whether she decides to have a mammogram or not, she should have an annual clinical breast exam with a professional, and many doctors recommend monthly breast self-exams. Any change in the breast—a lump, a puckering of the skin, a discharge from the nipple, a red inflammation in the breast area—should be checked promptly by a doctor. The best detection technique is for a woman to be aware of her body and its changes. She should know how her breasts look and feel. She should be informed. It's her body. The consequences are hers.