Nomogram Update to Predict the High Genomic Risk Breast Cancer by Different Races

Purpose To develop a nomogram to predict the high-risk recurrence score (RS) and to customize the nomogram for different races in early-stage hormone receptor (HoR)-positive, human epidermal growth factor receptor-2 (HER2)-negative breast cancer. Methods Patients diagnosed between 2010 and 2015 were included from the Surveillance, Epidemiology, and End Results Oncotype DX Database. The nomogram was assessed with a receiver operating characteristic curve to measure the area under the curve (AUC) with a 95% confidence interval (95%CI). The nomogram was developed and internally validated for discrimination and calibration, and then validated in different races. Results A total of 48464 patients were included and randomly assigned to the training cohort (n=36370, 75.0%) and validation cohort (n=12094, 25.0%). Patients in the training cohort were identified to develop the nomogram, including 32683 (89.9%) White women, 3135 (8.6%) Black women, and 552 (1.5%) Chinese women. Five independent predictive factors for high-risk RS were included to develop the nomogram, including tumor grade, progesterone receptor status, histological subtype, race, and tumor stage. The AUC was 0.696 (95%CI 0.682-0.710) in the training cohort and 0.700 (95%CI 0.676-0.724) in the validation cohort. There was no significant difference between the training cohort and the validation cohort. When validating the nomogram classified by race, the AUC was 0.694 (95%CI 0.682-0.706) for the White cohort, 0.708 (95%CI 0.673–0.743) for the Black cohort, and 0.653 (95%CI 0.565–0.741) for the Chinese cohort. Conclusion The developed nomogram for predicting high-risk RS is available for different races in patients with HoR+/HER2- breast cancer, which could be used as qualified surrogates before ordering the 21-gene RS testing. Micro Abstract The 21-gene recurrence score (RS) assay is a predictive tool for quantitative measurement of 21-gene expression in hormone receptor-positive (HoR+), human epidermal growth factor receptor type 2-negative (HER2–), and node-negative breast cancer (BC). However, the expensive cost limited the use of RS testing in the world, especially in non-developed countries. Therefore, it was of great importance to develop a reasonable and acceptable model to predict the probability of high-risk RS without additional costs. In this study, we developed a nomogram to predict the high-risk RS in BC, and further assess whether the nomogram could be extended to patients of different races. Our study suggests that the developed nomogram for predicting high-risk RS is available for different races in patients with HoR+/HER2- breast cancer, which could be used as qualified surrogates before ordering the 21-gene RS testing.