In situ male breast carcinoma in the Surveillance, Epidemiology, and End Results database of the National Cancer Institute.

BACKGROUND: In situ breast carcinoma is not so well characterized for men as for women.

METHODS: Therefore, the authors of the current study compared male and female in situ and invasive breast carcinomas in the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute to document these patterns.

RESULTS: In situ breast carcinomas composed 9.4% of all male (n = 280 of 2984) and 11.9% of all female breast carcinomas (n = 53,928 of 454,405) during the years 1973-2001. In situ rates rose 123% for men and 555% for women over this time period; whereas distant disease rates fell for both genders. Median ages at diagnosis were 62 years for in situ and 68 years for invasive breast carcinoma among men, compared with 58 years for in situ and 62 years for invasive breast carcinoma among women. Papillary in situ and invasive architectural types were more common among men than women. In contrast, lobular tumors were more common among women than men. Breast cancer-specific survival was similar among men and women, whereas overall survival was worse for men than women.

CONCLUSION: In situ male breast carcinoma is a rare disease, occurring at older ages and with different architectural types than its more common female counterpart. Gender-specific histopathologic differences probably reflect anatomic differences among the normal female and vestigial male breast. Rising in situ male breast carcinoma incidence rates over the past three decades suggest earlier detection over time, irrespective of mammography, because men do not participate in routine screening mammography. Worse overall survival for men than women possibly results from age-dependent comorbid illnesses.