Abstract 3298: Oncotype DX recurrence score: Implications for disparities in receipt of chemotherapy and breast cancer-specific mortality in Georgia
Authors: Collin Lindsay J. , Crawford Brittany , Yan Ming , Jiang Renjian , Ward Kevin , Torres Mylin , Gogineni Keerthi , Subhedar Preeti , McCullough Lauren E. 
Published: August 2019

Background: Among women diagnosed with stage I-IIIa, node negative or positive (1-3), hormone receptor positive (HR+) and HER2 negative breast cancer (BC), the Oncotype DX recurrence score is used to guide chemotherapy treatment decisions. There is limited evidence on differences in the distribution of recurrence scores among non-Hispanic Black women (NHB), and whether this could contribute to the well-documented racial disparities in BC-specific mortality. The objective of this study was to evaluate the role of Oncotype DX recurrence score on racial disparities in BC-specific mortality between black and white women in Georgia.

Methods: In this study, patients were identified from the Georgia Cancer Registry. We included 4562 non-Hispanic White (NHW) and 1353 NHB women with an initial diagnosis of stage I-III HR+ breast cancer in Georgia (2010-2014), with a corresponding Oncotype DX recurrence score from Genomic Health, Inc. Logistic regression was used to estimate the odds of chemotherapy receipt between NHB and NHW women by Oncotype DX recurrence score (low [&lt;18], medium [18-30], and high [≥31]). Cox proportional hazard regression was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) comparing BC-specific mortality rates by both race and recurrence score.

Results: Compared with NHW breast cancer patients, NHB women were more likely to be classified with a high recurrence score (11% vs. 7%), and less likely to be classified with a low risk of recurrence (53% vs. 59%). In the age-adjusted models, NHB women with a high recurrence score were less likely to receive chemotherapy (OR=0.60, 95%CI 0.35, 1.04), however there was no difference in receipt of chemotherapy between NHB and NHW women with low or medium recurrence risk scores. After adjusting for age, we observed that NHB women with a low recurrence score had 3.05 times the hazard of BC-specifc mortality (95%CI 1.29, 7.04) compared to NHW women. Among women with a medium or high recurrence score we did not observe a racial disparity in BC mortality (HRhigh vs. low=1.49, 95%CI 0.51, 4.37).

Conclusion: Our results indicate variation in receipt of chemotherapy by race, particularly among NHB women with a high Oncotype DX score. However, we observed the most pronounced racial disparity in BC-specific mortality among women with low Oncotype Dx recurrence scores. These findings should be replicated in larger studies with robust numbers of NHB women. Additional research is needed to understand differences in chemotherapy treatment decisions and validation of the Oncotype DX recurrence score cut points in diverse populations.

Citation Format: Lindsay J. Collin, Brittany Crawford, Ming Yan, Renjian Jiang, Kevin Ward, Mylin Torres, Keerthi Gogineni, Preeti Subhedar, Lauren E. McCullough. Oncotype DX recurrence score: Implications for disparities in receipt of chemotherapy and breast cancer-specific mortality in Georgia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3298.