Most women have breasts that are not exactly symmetrical in size. A recent study of 504 women in the U.K. suggests that a relatively large difference in size of each breast, as determined by mammography, represents a risk factor for developing breast cancer.[1, 2]
Half of the women in the study had no personal history of breast cancer and normal mammograms.[1, 2] The other half of the women in the study initially had normal mammograms, but later developed breast cancer.
In the study, the average size of a breast, as measured by mammography, was16.9 ounces.[1, 2] Only one woman in the study had breasts that were perfectly symmetrical, whereas the average asymmetry of the breasts in the women in the study ranged from 1.2 ounces to 2.03 ounces. Estrogen levels may affect the symmetry of womenís breasts.
According to the study, the women who eventually developed breast cancer had breasts that were more asymmetrical than those of the women who remained free of breast cancer.[1, 2] For example, for each 3.38 ounce increase in breast asymmetry detected by mammography, a 50% increase in the risk of breast cancer was predicted.
Due to the small number of women in this study and previous studies on breast asymmetry, the conclusion that breast asymmetry is an independent risk factor for breast cancer remains preliminary. Future studies will involve more women.
Asymmetry in breast size is only one of many possible risk factors for breast cancer.[1, 2] The key is to not allow yourself to be consumed by worry. Regular screening (i.e., breast self-exams, clinical breast exams, and mammography), a healthy lifestyle, and a positive attitude are great contributors to maintaining breast health.
1. D. Scutt. Breast Cancer Research. Online edition. 03/20/06; Volume 8.
2. S. Boyles. Breast asymmetry points to cancer risk. 03/20/06. Accessed at www.webmd.com.