How common is breast cancer in men?
The American Cancer Society estimates that in 2009 about 1,910 new cases of invasive breast cancer will be diagnosed among men in the United States. Breast cancer is about 100 times less common among men than among women. (cancer.org)
While we mainly think of women having breasts, men do indeed have them as well. Breast cancer is less common in men because their breast duct cells are (obviously) less developed than women’s breast duct cells.