On average, women with breast cancer lived two years longer than men in the biggest study yet of the disease in males.
The study found that men's breast tumors were larger at diagnosis, more advanced and more likely to have spread to other parts of the body. Men were also diagnosed later in life; in the study, they were 63 on average, versus 59 for women.
Many men have no idea that they can get breast cancer, and some doctors are in the dark, too, dismissing symptoms that would be an automatic red flag in women, said study leader Dr. Jon Greif, a breast cancer surgeon in Oakland, Calif.
The American Cancer Society estimates 1 in 1,000 men will get breast cancer, versus 1 in 8 women. By comparison, 1 in 6 men will get prostate cancer, the most common cancer in men.
The researchers analyzed 10 years of national data on breast cancer cases, from 1998 to 2007. A total of 13,457 male patients diagnosed during those years were included, versus 1.4 million women. The database contains about 75 percent of all U.S. breast cancer cases.
The men who were studied lived an average of about eight years after being diagnosed, compared with more than 10 years for women. The study doesn't indicate whether patients died of breast cancer or something else.
The causes of breast cancer in men are not well-studied, but some of the same things that increase women's chances for developing it also affect men, including older age, cancer-linked gene mutations, a family history of the disease, and heavy drinking.
Men's breast cancer usually shows up as a lump under or near a nipple. Nipple discharge and breasts that are misshapen or don't match are also possible signs that should be checked out.