Projection of Breast Cancer Burden due to Reproductive/Lifestyle Changes in Korean Women (2013-2030) Using an Age-Period-Cohort Model

PURPOSE: The aim of this study was to estimate the burden of breast cancer that can be attributed to rapid lifestyle changes in South Korea in 2013-2030. MATERIALS AND METHODS: An age-period-cohort model was used to estimate the incidence and mortality. The Global Burden of Disease Study Group methodwas used to calculate the years of life lost and years lived with disability in breast cancer patients using a nationwide cancer registry. The population attributable riskswere calculated using meta-analyzed relative risk ratios and by assessing the prevalence of risk factors. RESULTS: Women’s reproductive/lifestyle changes, including advanced maternal age at first childbirth (from 37 to 85 disability-adjusted life years [DALYs] per 100,000 person-years), total period of breastfeeding (from 22 to 46 DALYs per 100,000 person-years), obesity (from 37 to 61 DALYs per 100,000 person-years), alcohol consumption (from 19 to 39 DALYs per 100,000 person-years), oral contraceptive use (from 18 to 27 DALYs per 100,000 person-years), and hormone replacement therapy use (from 2 to 3 DALYs per 100,000 person-years) were identified as factors likely to increase the burden of breast cancer from 2013 to 2030. Approximately, 34.2% to 44.3% of the burden of breast cancer could be avoidable in 2030 with reduction in reproductive/lifestyle risk factors. CONCLUSION: The rapid changes of age structure and lifestyle in South Korea during the last decade are expected to strongly increase the breast cancer burden over time unless the risk factors can be effectively modified.