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

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 developed, such as Magee equations (ME), the Predict model (PM), and the Tennessee nomogram score (TNS). To evaluate the concordance between 21-GRSA, ME, PM and TNS. 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). 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%). 21-GRSA can be omitted in women older than 50 years with LTEBC classified with low risk scores on all three predictive models.