Male Breast Cancer

Breast cancer in men is rare.  However, 1,910 new cases of male breast cancer will be diagnosed in the U.S. during 2009.  In 2005, the overall incidence of breast cancer in men was 1.2 per 100,000, compared to 122 per 100,000 in women.  Differences in mortality were equally wide: 0.3 per 100,000 in men; 24 per 100,000 in women.

As with women, invasive ductal carcinoma accounts for most of the breast cancer seen in men.  There are few cases of invasive lobular carcinoma and ductal carcinoma in situ in men. 

The strongest risk factor for male breast cancer is Klinefelter's syndrome, a condition related to high levels of estrogen.  This rare condition occurs when men are born with two X chromosomes (XXY instead of XY).  Although men with Klinefelter's syndrome may have gynecomastia (enlargement of the breast tissue), gynecomastia not related to Klinefelter's syndrome does not appear to increase the risk of breast cancer.  Similar to women, men with a mutation in the BRCA2 gene have an increased risk of breast cancer.  Chronic alcoholism, chronic liver disease and obesity may also increase the risk of male breast cancer. 

To learn more about male breast cancer, click here.