Risk Factors

Research is increasing regarding what we know about breast cancer. Scientists are learning more about its causes. Yet, despite this knowledge, the majority of breast cancer still develops spontaneously.

The following are common risk factors for breast cancer:

  • Family History and Genetic Susceptibility – About 5-10% of all breast cancers are a result of a hereditary genetic mutation. Women with the BRCA1 and BRCA2 gene mutations have an increased risk of developing breast cancer and breast cancer. People with a strong history should seek more information on if they should be screened for a genetic mutation. A strong family history includes when multiple first-degree relatives (sisters, mother, daughters and grandmothers), on either the maternal or paternal side, have a history of breast cancer. This is especially important if any member of the family was diagnosed with breast cancer pre-menopausally, of there is a family history of breast cancer, or any male in the family has been diagnosed with breast cancer.

For more information on BRCA1 and BRCA2, check out Frankly Speaking About Cancer: BRCA1/BRCA2 Mutations

  • Personal History of Breast Abnormalities - Ductal carcinoma in situ (DCIS) is associated with an increased risk. Lobular neoplasia is considered a marker of increased risk.
  • Age - The risk of developing breast cancer increases with age. The majority of breast cancer cases occur in women older than age 60.
  • Age at First Menstrual Period - Women who had their first menstrual period before age 12 have a slightly increased risk of breast cancer.
  • Breast Density – Women with dense breasts may have an increased risk of developing breast cancer than women with average breast density. Many states now require that the radiologist send a letter to inform the person of their increased risk and this may lead to additional screening with ultrasound or even MRI. This is an area that is currently changing and practices may vary depending on location and standards of practice.
  • Child Birth – Women who have never given birth or who gave birth to their first child after age 30 are at a slightly increased risk of developing breast cancer.
  • Race - White women have a greater risk of developing breast cancer than black women. However, black women diagnosed with breast cancer are more likely have an aggressive subtype of breast cancer.


Updated June 3, 2015