Feb. 11, 2009— -- Two recent studies remind me that frequent and early screening mammograms may not always (emphasis on "not always") be a good idea.
The first study in the Journal of the American Medical Association looked at women who received chest radiation as a child and found that only about half of the women had a screening mammogram within the previous two years, despite evidence that their exposure to radiation as children may increase their risk of breast cancer.
The article's headline seemed to suggest that women with such a risky history were in some way negligent when, in fact, they (or their doctors) may have been appropriately cautious about doing too many X-rays. An accompanying editorial wisely suggested that maybe women with childhood radiation should have less exposure to X-rays rather than more exposure. The editorial raised the question about whether perhaps breast MRIs would be a better way to screen high-risk women with a history of childhood radiation to avoid unnecessary and potentially risky X-ray exposure.
The second study questioned whether the current recommendations for women who have inherited one of the two known breast cancer genes, BRCA 1 or BRCA 2, to begin screening mammograms at age 25 or 30 makes good sense.
Researchers looked at a mathematical model calculating radiation exposure in young women receiving regular mammograms and compared this potential risk to increase breast cancer from X-rays to the potential benefit of starting mammograms at a young age. Their model suggested the increased risk of breast cancer from exposure to the radiation by doing the X-rays may outweigh any benefit of screening for young women at high risk for cancer because they have inherited one of the breast cancer genes, BRCA 1 or 2.
These studies take me back to the early 1980s when the controversy around the benefits versus the risks of mammograms took center stage in the screening debate.
The argument against mammograms back then was as follows: Because mammograms require exposure to ionizing radiation, a known risk factor for breast cancer, why would you expose a woman's breast to this radiation year after year with only marginal hope that a cancer will be detected early enough to improve outcome?
More Radiation, More Risk
Some scientists believed at the time that the risk of cancer related to radiation exposure was linear, meaning that the more radiation you were exposed to, the greater the risk. They also thought that the younger the breast tissue was when exposed to radiation, the greater the chance of damaging the breast. In fact, for this reason, most experts rarely recommend a woman younger than 35 years of age receive a screening mammogram. Of course, back then mammograms delivered much more radiation and the pictures were much less clear than mammograms done today.
Other scientists at that time believed that the small amount of radiation was not enough to pose a breast cancer risk. Yet studies from survivors of the atomic bomb and women with tuberculosis (in the days before antibiotics) who were exposed to frequent, often daily, chest X-rays for monitoring their disease did show that higher doses of radiation increased the risk of breast cancer.
These two new studies serve to remind us that screening mammograms for young women, especially very young women at increased risk for breast cancer, for example, either because of childhood radiation or genetic inheritance of a breast cancer gene, may not be a good idea. At the very least, screening any young woman before age 35 to 40 without worrisome breast signs or symptoms with a mammogram should not be routinely done.
Although mammograms for early breast cancer detection have become a major part of women's health care (just as the Pap test is for diagnosing cervical cancer), it is always good to be reminded of the risks and the benefits of preventive health care and to question whether there are newer and smarter steps to an earlier diagnosis.
For cervical cancer, which we now know is caused by one of 15 high-risk strains of the HPV virus, doing the HPV test, which checks for the high risk strains of the virus along with the Pap test for women 30 and older, is thought to provide almost complete assurance that cancer or pre-cancer is not present. Yet many doctors today are still hesitant to add the HPV test because of fear women will be confused or frightened to learn they may carry a high-risk strain of the virus (only 5 percent of women screened will test positive for the virus, and many of these women have an active infection that will go away on its own within a year to two). They also worry that this HPV screening could lead to unnecessary follow-up testing.
Looking for Peace of Mind
Most women I talk to, however, welcome the greater peace of mind that a negative test result brings.
An MRI scan of the breast for breast cancer screening is thought to be more sensitive than mammograms and, therefore, more likely to pick up subtle breast changes or early breast cancer and it is not associated with ionizing radiation. But we still do not have enough research on screening MRIs in young high-risk women to know if they are safe, effective and worth the greatly added cost (both dollar cost and cost to women of needless biopsies, scares, missed work, etc.).
I suggest that until we learn more about the benefits and risks of MRIs in young high-risk women, every woman at high risk should talk with her doctor about the pros and cons of all available tests, including routine mammogram, breast ultrasound and periodic breast MRI. Every woman's medical history and breast exam will be different and only when all aspects of a woman's history are taken into account can the best decision for screening be made.
In addition to a detailed conversation with your practitioner about the best way to be protected, all women should:
Unfortunately, with the current economic crisis, too many women are delaying routine preventive care and worse yet, delaying or avoiding more urgent care as well. I fear these two new studies will do more to confuse rather than help women and will further dissuade them from getting the necessary screening tests they may need.
How did you react to these two new studies about mammograms and possible risk of radiation in young women? Are you afraid to have a mammogram? Are you worried about the cost of screening tests and whether your insurance will pay for them?
As always, I welcome your questions and comments.
Dr. Marie Savard is an ABC News medical contributor. To learn more about Savard's health management system, download free forms and a sample letter to your doctor, visit http://www.drsavard.com and click on "Learn how to take charge of your health."