Male breast cancer: is the incidence increasing?

BACKGROUND: Male breast cancer is rare, and little is known about state population-level patterns of incidence. The primary objective of this study was to determine the incidence of MBC in Florida in comparison with the Surveillance, Epidemiology, and End RESULTS (SEER) program data.

METHODS: Study data were obtained from the Florida Cancer Data System (FCDS). All males with pathologically confirmed invasive breast carcinoma diagnosed from 1985 to 2000 were included. Age-adjusted incidence rates, regional incidence rates, and descriptive statistics were calculated. Annual percent change (APC) for the study period was calculated with a linear model. Results were compared with the SEER data.

RESULTS: A total of 1396 cases of MBC were identified. Age-adjusted incidence rates increased from 0.9 cases per 100,000 in 1990 to 1.5 cases per 100,000 in 2000. In 2000, the highest rates were in the age groups of 70 to 75 years (7.9) and > or =85 years (12.5). Infiltrating ductal was the most common subtype (92%); less common subtypes included mucinous (2%) and papillary (2%). Localized disease accounted for 45% of all cases, with regional disease in 33%, distant metastases in 7%, and unstaged in 15%. Most incident cases were diagnosed in the Palm Beach-Broward region (23%). The number of cases increased from 56 in 1985 to 132 new cases in 2000. The APC for this 16-year period was 2.0% (95% confidence interval [CI], 1.05-3.01; P <.005). SEER data indicated no change in MBC incidence rates (APC, 0.5; NS).

CONCLUSIONS: The incidence of MBC in Florida increased significantly between 1985 and 2000. This finding is discordant with SEER incidence data. Further epidemiologic studies are warranted to investigate regional variation.