Time Trends in Male Breast Cancer Incidence, Mortality, and Survival in Austria (1983-2017).

ABSTRACT

Background: Male breast cancer (MBC) comprises less than 1% of all breast cancer cases globally and remains understudied with persisting sex-specific survival disadvantages. We aim to contribute to better understanding of MBC with a comprehensive analysis of time-trends over several decades in Austria. Methods: We used Austrian National Cancer Registry data on 1648 cases of MBC cases diagnosed between 1983 and 2017 in Austria. Overall incidence, mortality, and survival rates, as well as age-, stage-, and period-specific incidence and survival rates were calculated. Joinpoint regression was performed to assess trends. Results: MBC incidence rates increased throughout the whole observation period (1983-2017) with an annual percent change (APC) of 1.44% (95% confidence interval, CI 0.77 to 2.11). During the same period, morality rates were stable (APC -0.25, 95% CI -0.53 to 0.60). Ten-year survival rates showed three phases of decreasing increases with an average APC of 2.45%, 1983-2009 (95% CI 2.1 to 2.74). Five-year survival rates improved until 2000 (APC 2.31, 95% CI 1.34 to 3.30) and remained stable thereafter (APC 0.10, 95% CI -0.61 to 0.80). Stage-specific analyses showed a single trend of stable incidence rates of distant disease MBC (APC -0.03, 95% CI -1.67 to 1.65). Further, we observed increases in localised, regional, and unknown stage cancer incidence and increases in incidence rates across all age groups over the whole observation period. However, the estimates on these subgroup-specific trends (according to age- and stage) show wider 95% CIs and lower bounds closer to zero or negative in comparison to our findings on overall incidence, mortality, and survival. Conclusion: Despite improvements in survival rates, MBC mortality rates remained largely stable between 1983 and 2017 in Austria, possibly resulting from a balance between increasing overall incidence and stable incidence rates of distant disease MBC.