Metadata supporting data files of the related article: Oncotype DX recurrence score implications for disparities in chemotherapy and breast cancer mortality in Georgia

This study evaluated the contribution of Oncotype DX recurrence scores (ODX RS) as a possible mechanism to explain the racial disparity in breast cancer (BC) mortality among women diagnosed with hormone receptor-positive (HR+) breast cancer in Georgia.

Data access: Datasets gaodx_eligible.sas7bdat and odx_eligible_recode2018.sas7bdat are not publicly available to protect patient privacy, but can be accessed from the corresponding author on request. Corresponding author details are: Lindsay J Collin, Department of Epidemiology, 1518 Clifton Rd NE Atlanta GA 30322; Email: lindsay.jane.collin@emory.edu. Data will be made available from the Georgia Center for Cancer Statistics at Emory University to authorized researchers who have an approved institutional IRB application and have obtained approval from the Georgia Department of Public Health IRB committee. Please email: dph-datarequest@dph.ga.gov for access to the data.

Study approval and patient consent: This study was conducted in accordance with the Declaration of Helsinki and has been approved by the institutional review board (IRB) of Emory University (IRB00099875) on 24 October 2017. Participant consent was not required due to the registry-based nature of the study.

Study aims and methodology:

Racial disparities in breast cancer outcomes in the US are well-documented, with non-Hispanic black (NHB) women more likely to die from breast cancer than their white counterparts. The mechanism of the disparity remains unresolved but may be due, in part, to the underlying genomic heterogeneity, whereby NHB women are more likely to be diagnosed with tumors with greater intratumoral heterogeneity captured by gene expression patterns. ODX RS may help to identify more aggressive tumors, further elucidating the underlying mechanism of this disparity in stage I–IIIa, hormone receptor (HR) positive tumors. To further explore these findings among early stage, HR+ tumors, this study aimed to: 1. Describe differences in Oncotype DX testing by race and patient characteristics, 2) Describe the distribution of ODX RS of NHB and NHW women, 3) Examine differences in receipt of chemotherapy by ODX RS between NHB and non-Hispanic white (NHW) women, and 4) Examine differences in breast cancer-specific mortality by ODX RS between NHB and NHW women diagnosed with breast cancer in Georgia.

A total of 12,081 non-Hispanic White (NHW) and non-Hispanic Black (NHB) Breast cancer patients in Georgia (from 2010–2014) were identified that were eligible to receive an ODX RS. Logistic regression was used to estimate the odds of chemotherapy receipt by race and ODX RS. Cox proportional hazard regression was used to calculate the hazard ratios (HRs) comparing BC mortality rates by race and recurrence score.

For more details on the methodology and statistical analyses, please refer to the published article.

Description of datasets: Dataset gaodx_eligible.sas7bdat is in SAS file format and supports figure 1 of the published article. Dataset odx_eligible_recode2018.sas7bdat is in SAS file format and supports figures 2 and 3, tables 1, 2 and 3, and supplementary tables 1, 2 and 3.

Dataset gaodx_eligible.sas7bdat describes the criteria used in the identification of the eligible study population using the Georgia Cancer Registry (GCR) resources (2010–2014).

Dataset odx_eligible_recode2018.sas7bdat includes the following data about NHW and NHB women diagnosed with HR+/HER2- BC in Georgia (2010-2014):

-ODX recurrence scores

-Age-adjusted survival data by ODX RS risk group and race.

-Patient demographic and clinicopathological characteristics

-Age and multivariable-adjusted odd ratios (OR) and 95% confidence intervals (95% CI) for receipt of chemotherapy according to race and ODX RS group (in women diagnosed with lymph node negative HR+/HER− breast cancer)

-Age and stage-adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for breast cancer-specific death according to race and ODX RS.

Software needed to access datasets: Files gaodx_eligible.sas7bdat and odx_eligible_recode2018.sas7bdat require the SAS software or the R software to be accessed.