Global Burden and Trends in Pre- and Post-Menopausal Breast Cancer

Abstract

Background: Breast cancer has distinct etiologies, prognoses, and patient impact at pre- and post-menopausal ages. We sought to assess the global burden and trends in breast cancer by menopausal status. Methods: Menopausal status was defined using age as a proxy, where breast cancer cases/deaths at >50 years were considered as post-menopausal. Age-standardized breast cancer incidence and mortality rates in 2018 were calculated using GLOBOCAN data. Incidence trends for 1998-2012 were assessed in 44 populations from 41 countries using CI5plus data by calculating the annual average percent change. Findings: Approximately 645,000 pre-menopausal and 1.4 million post-menopausal breast cancer cases were diagnosed in 2018, with approximately 130,000 and 490,000 deaths occurring in each menopausal group, respectively. Proportionally, Low Human Development Index (HDI) countries faced a greater burden of pre-menopausal breast cancer for both incidence and mortality compared to more developed countries. Very High HDI countries had the highest pre- and post-menopausal breast cancer incidence rates (30·6 and 253·6 per 100,000 respectively), while Low and Medium HDI countries had the highest pre-menopausal and post-menopausal mortality rates respectively (8·5 and 53·3 per 100,000 respectively). When examining incidence trends, we observed significantly increasing rates of pre-menopausal breast cancer in 20/44 populations, and significantly increasing rates of post-menopausal breast cancer in 24/44 populations. The increases exclusively at pre-menopausal ages largely occurred in the most developed countries, while the increasing post-menopausal breast cancer burden was most notable in countries under transition. Interpretation: We provide evidence of a rising burden of both pre- and post-menopausal breast cancer worldwide, and wide inequities in breast cancer care. Although early diagnosis and access to treatment remain crucial in developing countries, primary prevention efforts seeking to decrease obesity and alcohol consumption, and increase physical activity and breastfeeding, are warranted in all world regions to curb the future breast cancer burden. Funding Statement: This study was undertaken without any funding. Declaration of Interests: All authors declare no conflicts of interests. Ethics Approval Statement: Not required.