- Breast cancer is the second most common form of cancer in women and the most common cause of death due to cancer in women. Approximately 1 in 8 women in the United States will develop breast cancer. About 178,000 new cases of breast cancer are found every year and approximately 41,000 deaths per year are attributed to breast cancer.

· According to a new study, women who breastfed have a reduced risk of developing premenopausal breast cancer.
This study was published in the latest issue of the medical journal Archives of Internal Medicine.

· Investigators studied information from over 60,000 women and 600 cases of premenopausal breast cancer (breast cancer that occurred prior to entering menopause).
Women in the study who had previously breastfed were 25% less likely to develop breast cancer.  Women who had a family history of breast cancer and breastfed were 60% less likely to develop breast cancer compared to other women with a family history of breast cancer.

· This study shows us that breastfeeding can reduce the risk of breast cancer.  The study is powerful in that it analyzed data from over 60,000 women.  The study is limited in that it only analyzed premenopausal breast cancer and it did not include breast cancer that occurs after menopause.
It is likely that there is also a risk reduction in post menopausal breast cancer but we can not conclude this with the current study and it will need to be confirmed by additional medical studies.

Cristopher Geiler, M.D.
Reference
Archives of Internal Medicine; vol 169: pp 1364-1371.