Estimation of Population Attributable Fraction by Hormone and Reproductive Factors on Female Cancer in the Republic of Korea, 2015 to 2030.

Purpose: Population attributable fractions (PAFs) for hormone and reproductive factors have been estimated in several countries. IARC designated as Group 1 and Group 2A carcinogen for hormone factors in breast, ovarian, endometrial and uterine cervix cancer. This study aimed to estimate the PAFs of hormone/reproductive factor attributed to cancer incidence and deaths in Korean women and projected trends from 2015 to 2030.

Materials and methods: The PAF was estimated with using the 2005 standardized prevalence rates and 2020 incidence and deaths with a 15-year latency. Based on the Levin's formula, prevalence rates were calculated using the Korea National Health and Nutrition Examination Survey (KNHANES) and the relative risks (RRs), which were the risk of selected female cancer associated with oral contraceptive, hormone replacement therapy and duration of breastfeeding, were estimated from the meta-analysis of studies performed in Korean women population. Studies based on the Asian and Global populations were calculated as a sensitivity analysis.

Results: The estimation PAFs for hormone was 1.02% with 1,192 cases and reproductive was 2.67% with 3,112 cases. Moreover, 0.40% (125 deaths) and 1.09% (342 deaths) in female-related cancer deaths in order. EP combined HRT accounted the most proportion in hormone factors and breastfeeding in reproductive factors. Also, the breast cancer had the highest percent in both hormone and reproductive factors.

Conclusion: Through this study, 1.02% and 2.67% of female-related cancer incidence will be reduced by encouraging avoiding the use of oral contraceptives (OCs) and hormone replacement therapy (HRT) and breastfeeding for more than 6 months in reproductive factors. Additionally, among four selected female cancers in this study, breast cancer was observed to be a significant level of prevention.