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BREAST CANCER

AWARENESS

Causes of Breast Cancer: How did this happen?

When you’re told that you have breast cancer, it’s natural to wonder what may have caused the disease. But no one knows the exact causes of breast cancer. Doctors seldom know why one woman develops breast cancer and another doesn’t, and most women who have breast cancer will never be able to pinpoint an exact cause. What we do know is that breast cancer is always caused by damage to a cell's DNA.

Breast cancer in the U.S.

Women

In 2013, it is estimated that among U.S. women there will be:

  • 232,340 new cases of invasive breast cancer (This includes new cases of primary breast cancer among survivors, but not recurrence of original breast cancer among survivors.)
  • 64,640 new cases of in situ breast cancer (This includes ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS), of those, about 85 percent will be DCIS. DCIS is a non-invasive breast cancer and LCIS is a condition that increases the risk of invasive breast cancer. Learn more about DCIS and LCIS.)
  • 39,620 breast cancer deaths

Rates of breast cancer among women vary by:

  • Pregnant women

Men

Breast cancer in men is rare, but it does happen. In 2013, it is estimated that among men in the U.S. there will be:

  • 2,240 new cases of invasive breast cancer
  • 410 breast cancer deaths

Rates of breast cancer incidence (new cases, including new cases of primary breast cancer among survivors, but not recurrence of original breast cancer among survivors) and mortality (death) are much lower among men than among women. For example, in 2010 (most recent data available):

Incidence (new cases) Mortality (deaths)
Men
Incidence (new cases)
1.3 per 100,000
Mortality (deaths)
0.3 per 100,000
Women
Incidence (new cases)
120.9 per 100,000
Mortality (deaths)
21.9 per 100,000

Survival rates for men are about the same as for women with the same stage of cancer at the time of diagnosis. However, men are usually diagnosed at a later stage because they are less likely to report symptoms. Learn more about the symptoms of breast cancer in men.
Treatment for men is the same as treatment for women and usually includes a combination of surgery, radiation, chemotherapy, hormone therapy and/or targeted therapy. Learn more about treatment for breast cancer in men.