175P Global burden, trends and risk factors of premenopausal breast cancer from 1990 to 2019 with prediction until 2039

Despite the known increasing incidence of breast cancer around the world, the burden of disease for premenopausal breast cancer is not well understood, considering the different impact of attributable risk factor by age and socioeconomic status. Data on the burden of disease and risk factors for premenopausal breast cancer in each region were extracted from Global Burden of Disease dataset 1990-2019, and the trend of disease burden was analyzed using the Joinpoint regression model. A Bayesian age-period-cohort model was used to predict the disease burden until 2039 and we also compared the degree of contribution of each risk factor to the disease burden. The incidence of premenopausal breast cancer was highest in countries with high Socio-Demographic Index (SDI) (52.19/100,000 person-years), while the mortality and disability-adjusted life year were highest in countries with medium-low SDI (7.51/100,000 person-years and 371.69/100,000 person-years, respectively). The burden of disease has been rising in recent years except in high SDI areas, and the increase is likely to continue by 2039. The main attributable risk factor were secondhand smoke in the medium and medium-low SDI areas and alcohol intake in the remaining areas. Globally, the contribution of all the modifiable risk factors rises with age. The global burden of premenopausal breast cancer is increasing and will continue to increase until 2039. The varying main attributable risk factors in different SDI countries emphasize the importance of specific measures to address the growing burden of premenopausal breast cancer.