Breastfeeding and Breast Cancer

What is Breast Cancer?

Breast cancer is an uncontrolled growth of breast cells. Breast cancer is the second leading cause of cancer death and, excluding skin cancers, the most frequently diagnosed cancer among women in Indiana and in the United States – with an estimated 246,660 new cases diagnosed nationwide during 2016. During 2014, there were 4,653 new cases of breast cancer diagnosed in Indiana. African-American females are at increased risk for poor outcomes relating to breast cancer, in part, because they are more often diagnosed at a younger age, at a later stage of disease, and with more aggressive forms of breast cancer. Breast cancer is rare among males; however, because males are prone to ignoring warning signs, they are often diagnosed at later stages and have poorer prognoses.

Who gets Breast Cancer Most Often?

Sex and age are the two greatest risk factors for developing breast cancer. Women have a much greater risk of developing breast cancer, and that risk increases with age. Some additional risk factors include genetics, race, estrogen exposure, history of menopausal hormone therapy, alcohol intake, weight gain and exercise habits, and pregnancy and breastfeeding history. In addition, research also indicates that long-term, heavy smoking increases breast cancer risk, particularly among women who start smoking before their first pregnancy.

Breastfeeding and Breast Cancer

Breastfeeding provides protection from cancer in several ways. In 2013, an analysis of 69 studies concluded that the chance of developing breast cancer was 11 percent lower among women who had breastfed compared to women who never breastfed. In addition, a 2007 review published by the Agency for HealthCare Research and Quality concluded that there was an overall risk reduction for breast cancer in women who breastfed their infants. Though the studies did not measure exclusive breastfeeding, they do report a decreased risk of breast cancer in women with a lifetime breastfeeding duration of more than 12 months. Breastfeeding also causes anovulation (an absence of ovulation), which is thought to help prevent ovarian cancer. Breastfeeding may also offer protection from endometrial cancer.

Breast Cancer Resources


Additional and online resources:


Breastfeeding Resources



  1. Indiana State Cancer Registry Statistics Report Generator. Accessed online at on August 7, 2016.
  2. American Cancer Society. Cancer Facts and Figures 2016. Atlanta: American Cancer Society; 2016. Accessed online at on September 21, 2015.
  3. Indiana Cancer Consortium, Indiana State Department of Health and the American Cancer Society Great Lakes Division; Indiana Cancer Facts and Figures 2015. April, 2015. Available at Updated cancer statistics are available online from the Indiana State Cancer Registry Statistics Report Generator at
  4. Indiana Cancer Consortium, Indiana State Department of Health; Indiana Cancer Control Plan 2010-2014. January, 2010. Available at
  5. Anothaisintawee, T, et al. (2013). “Risk Factors of Breast Cancer: A Systematic Review and Meta-Analysis.” Asia-Pacific Journal of Public Health. 25(5): 368-387.
  6. Ip S, Chung M, Raman G, et al. Breastfeeding and Maternal and Infant Health Outcomes in Developed Countries. Rockville, MD: Agency for Healthcare Research and Quality (US); 2007 Apr (Evidence Reports/Technology Assessments, No. 153). Accessed online on September 23, 2013 at