What You Should Know About Mammograms
Mammography is a method of examining the breasts by using low-dose x-ray. Currently it is the best screening method widely available. There has been much debate about the use of screening mammography—x-rays given to healthy women without any symptoms of breast problems. To make an informed decision about mammograms, women must be aware of the following facts:
Mammograms do not prevent breast cancer.
They detect cancer that already exists. Most breast cancers have been present for six to eight years by the time they appear on mammograms.1
Mammography is a form of ionizing radiation.
Radiation is a known cause of cancer, and the effects of small amounts may accumulate in the body. This does not mean you should never have an x-ray, but rather that you should be thoughtful of your exposure to radiation. The risk of harm from radiation is highest in tissue where cells are rapidly changing, such as the growing breast tissue of adolescent females.2
The quality of mammography screening varies widely.
Quality depends on many factors including the age and maintenance of the equipment, and the expertise of the radiologist who interprets the films. For your first mammogram, do not hesitate to ask to meet with your radiologist to discuss how readable your mammogram is or isn’t. Newer machines are tested to ensure they emit lower amounts of radiation. A single view dose should not exceed 3.0 milligray or 0.3 rad. Call before getting a mammogram to make sure that the center you're using is certified by the Food and Drug Administration (FDA).
Mammography is an imperfect test.
Mammograms do not always detect breast cancer, causing “false negative” results. In day-to-day practice, mammograms can miss more than a quarter of all tumors.3 Premenopausal women are more likely to have dense breast tissue which makes their mammograms especially difficult to read. The “false positive” rate—the frequency of unnecessary biopsies—is 12 times higher among women under 50 than women over 50.4 As many as three-fourths of all post-mammogram biopsy results turn out to be non-cancerous lesions.5
The benefit of routine mammograms for healthy premenopausal women is unproven.
Healthy premenopausal women should not have mammograms as a routine matter. The risk of radiation, combined with the high incidence of both false negatives and positives, means that routine mammography for premenopausal women may well do more harm than good.
Clinical breast exam and self breast exam are important detection methods.
Mammograms, when used, should be combined with monthly self breast exams and annual clinical breast exams by a trained professional. For premenopausal women, the most powerful detection method may very well be their own two hands.
Notes:
1 Love, Susan M. with Karen Lindsey, Dr. Susan Love’s Breast Book, 2nd Edition, p. 251. Merloyd Lawrence, 1998.
2 Love, Susan M., Dr. Susan Love's Breast Book, 3rd Edition, Perseus Publishing: MA. 2000; p. 125.
3 28% cited in Poplack S et al., "Mammography in 53,803 Women from the New Hampshire Mammography Network," Radiology, 2000 Dec; 217:832-840.
4 Love, Susan M. with Karen Lindsey, Dr. Susan Love’s Breast Book, 2nd Edition, p. 258, Merloyd Lawrence, 1998.
5 Institute of Medicine/National Resource Council, Mammography and Beyond, National Academy Press: Washington, DC. 2001; p. 39.
Glossary:
Biopsy: removal of breast tissue to check for the presence of cancer cells. Mammograms alert doctors to possibly cancerous tumors. A biopsy is the only way to be sure whether or not the abnormality is cancer.
Cancer: a term for diseases in which abnormal cells divide without control.
Ionizing radiation: radiation that can change molecules when exposed to it, turning them into electrically charged particles (ions). X-rays are one form of ionizing radiation, nuclear waste also generate ionizing radiation.
Resources
California Breast Cancer Early Detection Program
(free screening for low-income women over 40)
1-800-511-2300
Bay Area Breast Cancer Network, San Jose
Charlotte Maxwell Complementary Clinic
(free complementary therapies for low-income women with cancer)
510-601-7660
Community Breast Health Project, Palo Alto
Marin Breast Cancer Watch
National Breast and Cervical Cancer Early Detection Program
The Wellness Community, Walnut Creek
Women’s Cancer Resource Center, Berkeley
For Free Second Opinion in the Bay Area
Regional Cancer Foundation
For Legal Assistance
California Women’s Law Center
Patient Advocate Foundation
National Support/Health Groups
National Y-ME
(referrals to local support groups)
1-800-221-2141
National Latina Health Organization
510-534-1362
National Lymphedema Network
National Women’s Health Network
[Updated October 2004]