Abstract LB-432: Validation studies for Korean breast cancer prediction model

Abstract

Abstract Background: A model for predicting breast cancer risk has been developed in Korea. Associated risk factors included in the model were 1st degree relatives with breast cancer, age at menarche, menopausal status, number of children, age at first fullterm pregnancy, mammography, and exercise for patients less than 50 years of age and 1st degree relatives with breast cancer, age at menarche, age at menopause, number of children, BMI, mammography, and exercise for patients greater than 50 years of age. The area under the curve among over 50 year olds was 0.655 and 0.611 among under 50 year old. Objectives: The objective of the study was validation of an absolute risk prediction model for breast cancer in Korea by using a large, population cohort and patient registry. Method: The Korean Multi-center Cancer Cohort (KMCC) and registry data of breast cancer patients constructed by the Korean Breast Cancer Society were used to validate the model. 12221 women more than 30 years of age at baseline answered questions about demographic characteristics, reproductive factors, lifestyle, family history since 1993 and we identified 11 and 5 incident breast cancer patient more than 50 and less than 50 years of age, respectively. Age, resident area, and included year were matched to select controls; women aged less than 50 were matched 1:20 while women aged greater than 50 were matched 1:10. In the breast cancer registry, clinical, demographic characteristics and reproductive factors of breast cancer patients were collected since 1980. We selected 2727 patients under 50 years old and 2000 patients over 50 years old matched by age and diagnostic year and calculated their 10, 20, 30, and 40 year absolute risk. Result: In the KMCC data, 10 year absolute risk was 0.39 (95% CI 0.36-0.42) among cases and 0.36 (95% CI 0.35-0.37) among controls under 50 years old and 0.16 (95% CI 0.10-0.22) among cases and 0.08 (0.07-0.09) among controls over 50 years old and it was significantly different in the median test (P-value: 0.02 in both groups). Among breast cancer patient group over 50 years old, 10, 20, 30 and 40 year absolute risk were 0.22 (95% CI 0.21-0.23), 0.35 (95% CI 0.34-0.36), 0.43 (95% CI 0.42-0.45), 0.46 (95% CI 0.44-0.48) respectively and 0.56 (95% CI 0.55-0.57), 1.18 (95% CI 1.15-1.21), 1.53 (95% CI 1.50-1.57), 1.74 (95% CI 1.70-1.78). Conclusion: Due to the short follow up time and small number of cancer incidence in the KMCC cohort, although absolute risk was small, a significant difference was confirmed. Future validation study with a large number and enough follow up cohort time is needed. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-432.