Male breast cancer: a nation-wide population-based comparison with female breast cancer

Describe prognostic parameters of Danish male breast cancer patients (MBCP) diagnosed from 1980-2009. Determine all-cause mortality compared to the general male population and analyze survival/mortality compared with Danish female breast cancer patients (FBCP) in the same period.

The MBCP cohort was defined from three national registers. Data was extracted from medical journals. Data for FBCP is from the DBCG database. Overall survival (OS) was quantified by Kaplan-Meier estimates. Standardized mortality ratios (SMRs) were calculated based on mortality rate among patients relative to the mortality rate in the general population. The association between SMR and risk factors were analyzed in univariate and multivariable Poisson regression models. Separate models for each gender were used for the analyses.

We found a marked difference in OS for the two genders. For the total population of MBCP, 5- and 10-year survivals were 55.1% and 31.7%, respectively. For FBCP, the corresponding figures were 76.8% and 59.3%. Median age at diagnosis for FBCP was 61 years and 70 years for MBCP. By applying SMR, the difference in mortality between genders equalized and showed pronounced age-dependency. For males <40 years, SMR was 9.43 and for females 19.56 compared to SMR for males 80 + years (0.95) and females 80 + years (0.89). During the period 1980-2009, the risk of dying gradually decreased for FBCP (p < .0001). The risk 1980-1984 was 35% higher than 2005-2009 (RR 1.35). Although the risk of dying for MBCP was also lowest in 2005-2009, there was no clear tendency (p = .1439). The risk was highest in 1990-1994 (RR =2.48).

We found better OS for FBCP than for MBCP. But SMR showed similar mortality rate for the two genders, except for very young FBCP, who had higher SMR. Furthermore, significantly improved survival over time for FBCP was observed, with no clear tendency for MBCP.