Impact of Genomic Assay Testing and Clinical Factors on Chemotherapy Use After Implementation of Standardized Testing Criteria

AbstractBackground.For clinically appropriate early‐stage breast cancer patients, reflex criteria for Oncotype DX ordering ("the intervention") were implemented at our comprehensive cancer center, which reduced time‐to‐adjuvant chemotherapy initiation. Our objective was to evaluate Oncotype DX ordering practices and chemotherapy use before and after implementation of the intervention.Materials and Methods.We examined medical records for 498 patients who had definitive breast cancer surgery at our center. The post‐intervention cohort consisted of 232 consecutive patients who had Oncotype DX testing after reflex criteria implementation. This group was compared to a retrospective cohort of 266 patients who were diagnosed and treated prior to reflex criteria implementation, including patients who did and did not have Oncotype DX ordered. Factors associated with Oncotype DX ordering pre‐ and post‐intervention were examined. We used multivariate logistic regression to evaluate factors associated with chemotherapy receipt among patients with Oncotype DX testing.Results.The distribution of Oncotype DX scores, the proportion of those having Oncotype DX testing (28.9% vs. 34.1%) and those receiving chemotherapy (14.3% vs. 19.4%), did not significantly change between pre‐ and post‐intervention groups. Age ≤65 years, stage II, grade 2, 1–3+ nodes, and tumor size >2 cm were associated with higher odds of Oncotype DX testing. Among patients having Oncotype DX testing, node status and Oncotype DX scores were significantly associated with chemotherapy receipt.Conclusion.Our criteria for reflex Oncotype DX ordering appropriately targeted patients for whom Oncotype DX would typically be ordered by providers. No significant change in the rate of Oncotype DX ordering or chemotherapy use was observed after reflex testing implementation.Implications for Practice.This study demonstrates that implementing multidisciplinary consensus reflex criteria for Oncotype DX ordering maintains a stable Oncotype DX ordering rate and chemotherapy rate, mirroring what was observed in a specific clinical practice, while decreasing treatment delays due to additional testing. These reflex criteria appropriately capture patients who would likely have had Oncotype DX ordered by their providers and for whom the test results are predicted to influence management. This intervention serves as a potential model for other large integrated, multidisciplinary oncology centers to institute processes targeting patient populations most likely to benefit from genomic assay testing, while mitigating treatment delays.

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