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Racial variation in adjuvant chemotherapy initiation among breast cancer patients receiving oncotype DX testing.

ABSTRACT: It is unknown whether racial differences exist in adjuvant chemotherapy initiation among women with similar oncotype DX (ODX) risk scores. We examined whether adjuvant chemotherapy initiation varied by race. Data come from the Phase III, Carolina Breast Cancer Study, a longitudinal, population-based study of North Carolina women diagnosed with breast cancer between 2008 and 2014. We used modified Poisson regression and report adjusted relative risk (aRR) and 95% confidence intervals (95%CI) to estimate the association between race and adjuvant chemotherapy initiation across ODX risk groups among women who received the test (n = 541). Among women who underwent ODX testing, 54.2, 37.5, and 8.3% of women had tumors classified as low-, intermediate-, and high-risk groups, respectively. We observed no racial variation in adjuvant chemotherapy initiation. Increasing ODX risk score (aRR = 1.39, 95%CI = 1.22, 1.58) and being married (aRR = 2.92, 95%CI = 1.12, 7.60) were independently associated with an increased likelihood of adjuvant chemotherapy in the low-risk group. Among women in the intermediate-risk group, ODX risk score (aRR = 1.15, 95%CI = 1.11, 1.20), younger age (aRR = 1.95, 95%CI = 1.35, 2.81), larger tumor size (aRR = 1.70, 95%CI = 1.22, 2.35), and higher income were independently associated with increased likelihood of adjuvant chemotherapy initiation. No racial differences were found in adjuvant chemotherapy initiation among women receiving ODX testing. As treatment decision-making becomes increasingly targeted with the use of genetic technologies, these results provide evidence that test results may drive treatment in a similar way across racial subgroups.

SUBMITTER: Roberts MC

PROVIDER: S-EPMC4562432 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

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Racial variation in adjuvant chemotherapy initiation among breast cancer patients receiving oncotype DX testing.

Roberts Megan C MC Weinberger Morris M Dusetzina Stacie B SB Dinan Michaela A MA Reeder-Hayes Katherine E KE Troester Melissa A MA Carey Lisa A LA Wheeler Stephanie B SB

Breast cancer research and treatment 20150728 1

It is unknown whether racial differences exist in adjuvant chemotherapy initiation among women with similar oncotype DX (ODX) risk scores. We examined whether adjuvant chemotherapy initiation varied by race. Data come from the Phase III, Carolina Breast Cancer Study, a longitudinal, population-based study of North Carolina women diagnosed with breast cancer between 2008 and 2014. We used modified Poisson regression and report adjusted relative risk (aRR) and 95% confidence intervals (95%CI) to e ...[more]

PMID: 26216535

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Project description:ImportanceAdjuvant chemotherapy improves outcomes of patients with breast cancer. However, the optimal timing of chemotherapy initiation is unknown. Delayed administration can decrease the benefit of cytotoxic systemic therapies.ObjectiveTo identify the determinants in delayed chemotherapy initiation and to determine the relationship between time to chemotherapy (TTC) and outcome according to breast cancer subtype. We hypothesized that prolonged TTC would be associated with adverse outcomes.Design, setting, and participantsIn an observational, population-based investigation using data from the California Cancer Registry, we studied a total of 24 843 patients with stage I to III invasive breast cancer diagnosed between January 1, 2005, and December 31, 2010, and treated with adjuvant chemotherapy. Data analysis was performed between August 2014 and August 2015.Main outcomes and measuresTime to chemotherapy was defined as the number of days between surgery and the first dose of chemotherapy, and delayed TTC was defined as 91 or more days from surgery to the first dose of adjuvant chemotherapy. We evaluated overall survival and breast cancer-specific survival. Logistic regression and Cox proportional hazard models were used.ResultsIn all, 24 843 patients were included. Median age at diagnosis was 53 years, and median was TTC was 46 days. Factors associated with delays in TTC included low socioeconomic status, breast reconstruction, nonprivate insurance, and Hispanic ethnicity or non-Hispanic black race. Compared with patients receiving chemotherapy within 31 days from surgery, there was no evidence of adverse outcomes among those with TTC of 31 to 60 or 60 to 90 days. Patients treated 91 or more days from surgery experienced worse overall survival (hazard ratio [HR], 1.34; 95% CI, 1.15-1.57) and worse breast cancer-specific survival (HR, 1.27; 95% CI, 1.05-1.53). In a subgroup analysis according to subtype, longer TTC caused patients with triple-negative breast cancer to have worse overall survival (HR, 1.53; 95% CI, 1.17-2.00) and worse breast cancer-specific survival (HR, 1.53; 95% CI 1.17-2.07).Conclusions and relevanceFor patients with breast cancer, adverse outcomes are associated with delaying initiation of adjuvant chemotherapy 91 or more days. Delayed TTC was particularly detrimental among patients with triple-negative breast cancer. The determinants of delays in chemotherapy initiation appeared to be sociodemographic, and clinicians should provide timelier care to all patients.

Project description:BackgroundGene-expression companion diagnostic tests, such as the Oncotype DX test, assess the risk of early stage Estrogen receptor (ER) positive (+) breast cancers, and guide clinicians in the decision of whether or not to use chemotherapy. However, these tests are typically expensive, time consuming, and tissue-destructive.MethodsIn this paper, we evaluate the ability of computer-extracted nuclear morphology features from routine hematoxylin and eosin (H&E) stained images of 178 early stage ER+ breast cancer patients to predict corresponding risk categories derived using the Oncotype DX test. A total of 216 features corresponding to the nuclear shape and architecture categories from each of the pathologic images were extracted and four feature selection schemes: Ranksum, Principal Component Analysis with Variable Importance on Projection (PCA-VIP), Maximum-Relevance, Minimum Redundancy Mutual Information Difference (MRMR MID), and Maximum-Relevance, Minimum Redundancy - Mutual Information Quotient (MRMR MIQ), were employed to identify the most discriminating features. These features were employed to train 4 machine learning classifiers: Random Forest, Neural Network, Support Vector Machine, and Linear Discriminant Analysis, via 3-fold cross validation.ResultsThe four sets of risk categories, and the top Area Under the receiver operating characteristic Curve (AUC) machine classifier performances were: 1) Low ODx and Low mBR grade vs. High ODx and High mBR grade (Low-Low vs. High-High) (AUC = 0.83), 2) Low ODx vs. High ODx (AUC = 0.72), 3) Low ODx vs. Intermediate and High ODx (AUC = 0.58), and 4) Low and Intermediate ODx vs. High ODx (AUC = 0.65). Trained models were tested independent validation set of 53 cases which comprised of Low and High ODx risk, and demonstrated per-patient accuracies ranging from 75 to 86%.ConclusionOur results suggest that computerized image analysis of digitized H&E pathology images of early stage ER+ breast cancer might be able predict the corresponding Oncotype DX risk categories.

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Racial variation in adjuvant chemotherapy initiation among breast cancer patients receiving oncotype DX testing.

Publications

Racial variation in adjuvant chemotherapy initiation among breast cancer patients receiving oncotype DX testing.

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