The Rochester Modified Magee Algorithm (RoMMa): An Outcomes Based Strategy for Clinical Risk-Assessment and Risk-Stratification in ER Positive, HER2 Negative Breast Cancer Patients Being Considered for Oncotype DX Testing.

Introduction: Multigene genomic profiling has become the standard of care in the clinical risk-assessment and risk-stratification of ER, HER2 breast cancer (BC) patients, with Oncotype DX (ODX) emerging as the genomic profile test with the most support from the international community. The current state of the health care economy demands that cost-efficiency and access to testing must be considered when evaluating the clinical utility of multigene profile tests such as ODX. Several studies have suggested that certain lower risk patients can be identified more cost-efficiently than simply reflexing all ER, HER2 BC patients to ODX testing. The Magee equations use standard histopathologic data in a set of multivariable models to estimate the ODX recurrence score. Our group published the first outcome data in 2019 on the Magee equations, using a modification of the Magee equations combined with an algorithmic approach-the Rochester Modified Magee algorithm (RoMMa). There has since been limited published outcome data on the Magee equations. We present additional outcome data, with considerations of the TAILORx risk-stratification recommendations.

Methods: 355 patients with an ODX recurrence score, and at least five years of follow-up or a BC recurrence were included in the study. All patients received either Tamoxifen or an aromatase inhibitor. None of the patients received adjuvant systemic chemotherapy.

Results: There was no significant difference in the risk of recurrence in similar risk categories (very low risk, low risk, and high risk) between the average Modified Magee score and ODX recurrence score with the chi-square test of independence ( > 0.05) or log-rank test ( > 0.05). Using the RoMMa, we estimate that at least 17% of individuals can safely avoid ODX testing.

Conclusion: Our study further reinforces that BC patients can be confidently stratified into lower and higher-risk recurrence groups using the Magee equations. The RoMMa can be helpful in the initial clinical risk-assessment and risk-stratification of BC patients, providing increased opportunities for cost savings in the health care system, and for clinical risk-assessment and risk-stratification in less-developed geographies where multigene testing might not be available.