The 21-gene recurrence score assay improved MDT compliance in HR+/ HER2- breast cancer patients：An analysis of 2323 patients

The 21-gene Recurrence Score (RS) could guide adjuvant chemotherapy decisions in multidisciplinary treatment (MDT) of early breast cancer patients. This study aimed to evaluate the influence of the 21-gene RS assay on patients’ compliance with MDT and its association with disease outcome. Patients diagnosed with pN0-1, hormonal receptor-positive, human epidermal growth factor receptor-2 (HER2)-negative breast cancer between January 2013 and June 2019 were enrolled. The logistic regression model was used to identify the parameters associated with treatment adherence. Prognostic indicators were evaluated by using cox proportional hazard models. After the assay, patients were less likely to violate the treatment plan (14.9% vs. 23.1%, P <0.001), and higher compliance rates were observed for chemotherapy (P = 0.042), radiotherapy (P = 0.012), and endocrine therapy (P <0.001). Multivariable analysis demonstrated that the 21-gene RS assay (OR = 1.43, 95% CI = 1.09-1.88, P = 0.009) was independently associated with MDT compliance. Moreover, compliance to MDT was independently associated with better disease-free survival (HR = 0.43, 95% CI 0.29-0.64, P < 0.001), regardless of 21-gene RS assay (interaction P = 0.842).The 21-gene RS assay improved the MDT compliance rate in early breast cancer patients. Adherence to MDT was associated with a better prognosis.