Concordance between 21-gene recurrence score assay and clinicopathological predictive models in early-breast cancer patients cared for at a cancer center in Colombia

Abstract

Introduction: The genomic-based 21-gene recurrence score assay (21-GRSA) allows to determine the usefulness of adjuvant chemotherapy in patients with luminal-type early breast cancer (LTEBC). Additional predictive models have also been devel-oped, such as Magee equations (ME), the Predict model (PM), and the Tennessee nomogram score (TNS). Objective: To evaluate the concordance between 21-GRSA, ME, PM and TNS. Methods: Patients with unifocal LTEBC and 21-GRSA, ME, PM and TNS results were included. A subgroup analysis of women older than 50 years was carried out. Concordance between the models and 21-GRSA was evaluated using Cohen’s kappa index (KI). Results: One-hundred and twenty-two women were included. Concordance between 21-GRSA and ME (KI = 0.35) and PM (KI = 0.24) was fair (p < 0.001). Concordance between 21-GRSA and TNS was inferior (KI = 0.16, p = 0.04). Eighty patients older than 50 years with sufficient data to calculate all three predictive models were included. Concordance was found between the low-risk classification on 21-GRSA and all three combined models in 36/37 patients (negative predictive value of 97.3%). Conclusion: 21-GRSA can be omitted in women older than 50 years with LTEBC classified with low risk scores on all three predictive models.