Global and regional trends in male breast cancer burden: a comparative analysis of incidence, prevalence, mortality, and disability-adjusted life years in China and worldwide (1990-2021).

Background: Male breast cancer (MBC), though accounting for a minimal proportion of all breast cancer cases, has emerged as a growing public health concern. Its global burden has expanded steadily over recent decades, necessitating comprehensive analyses to explore its epidemiological characteristics and associated trends. This study aims to analyze and compare trends in incidence, prevalence, mortality, and disability-adjusted life years (DALYs) of MBC in China and globally from 1990 to 2021, highlighting age-specific variations, key risk factor contributions, and the impact of advancements in healthcare and treatment practices. Methods: Utilizing data from the Global Burden of Disease (GBD) 2021 database-which integrates information from national cancer registries, cohort studies, vital registration systems, and health surveys-this study applied Joinpoint regression analysis to calculate age-standardized rates (ASRs) for incidence, prevalence, mortality, and DALYs, alongside both annual percentage changes (APCs) and the estimated annual percentage change (EAPC) to quantify temporal trends. Detailed sensitivity analyses were conducted using Disease Modeling-MetaRegression (DisMod-MR) for non-fatal estimates and the Cause of Death Ensemble model (CODEm) approach for cause-of-death estimates. Additionally, trends across different age groups and the proportional contributions of key risk factors such as high alcohol use, diets high in red meat, and secondhand smoke were thoroughly examined. Results: The burden of MBC increased significantly in China and globally over the study period. In China, total incident cases and the age-standardized incidence rate (ASIR) showed substantial increases, with a marked rise in prevalence reflecting improved detection and survival. Similar upward trends were observed globally, although regional heterogeneities were evident. Mortality rates remained relatively stable, with the age-standardized mortality rate (ASMR) fluctuating slightly in China and modestly increasing on a global scale, while DALY rates exhibited a slight decline globally after 2012-indicative of enhanced disease management and treatment outcomes. Age-specific analyses consistently revealed the greatest burden among men aged 60 years and older, underscoring the roles of population aging and shifting risk factor profiles. Conclusions: The growing burden of MBC, coupled with notable regional disparities and evolving risk factor contributions, highlights the importance of targeted interventions. These include early detection, public awareness campaigns, and continued advancements in treatment and healthcare policies that are tailored to specific demographic and regional needs, in order to bridge gaps in access and improve outcomes.