Breast Cancer

Overview: Breast cancer is the most common type of cancer in women. It can sometimes spread to involve the lymph nodes around the breast. These lymph nodes are found in the underarm area and next to the breastbone (sternum).

Causes: Breast cancer more commonly affects older women, although younger women can also develop breast cancer. A woman's risk for breast cancer may be influenced by hormonal factors such as high estrogen exposure and by reproductive factors including age at first pregnancy and age at menopause. Being overweight also increases the risk of breast cancer in older women. In addition, genetic mutations may be inherited that greatly increase the risk of developing breast cancer in some families, such as mutations in the BRCA1 or BRCA2 genes.

Symptoms: Common symptoms of breast cancer may include a mass in the breast or underarm area. However, with mammograms, many breast cancers are now found before they cause symptoms.

Treatment: Surgery is a standard part of treatment for most women with breast cancer. Doctors may also treat patients with chemotherapy, radiation therapy, and/or targeted therapies.

Risk of Radiation Cardiotoxicity: Women with cancer of the left breast or with cancer in the lymph nodes near the breastbone (sternum) may be at a higher risk for radiation cardiotoxicity. Radiation therapy to these areas can affect the heart. The risk of radiation cardiotoxicity may be increased by the use of certain chemotherapy drugs, such as anthracyclines (for example, doxorubicin).