Background: The purpose of this analysis is to evaluate how many patients previously treated according to OncotypeDX Recurrence Score (RS) could have been spared of Chemotherapy if the TAILORx RS data had been taken into account in the clinical treatment decisions. Methods: A series of 182 patients, 34-74 years of age with early breast cancer, treated in our Breast Unit during the last 10 years, for whom treatment decisions were based on OncotypeDX RS. The Recurrence Scores of all these patients were obtained and the actual treatment decisions that were made based on the pre-TAILORx cut-offs of RS 18 and 31 were recorded. These decisions were then re-evaluated based on the after TAILORx cut-off scores, by taking also into consideration the patients’ age. Descriptive statistics were used as well as logistic regression models to estimate the potential change in treatment decisions based on the new Oncotype Dx cut-offs. Results: In the cohort of patients we analyzed that underwent Oncotype Dx testing, 34.1% (62/182) received Chemotherapy, based on the initial pre-TAILORX cut-offs of the RS. When utilizing the new cut-offs (after TAILORx results) in combination with age, we have estimated that, for the patients > 50 years of age, a 12.7% was potentially over-treated and for those ≤50 years old, 9.1% was potentially over-treated since they have received chemotherapy with a RS below 16; additionally, 30.8% of the patients of that age that have RS between 16 and 20 have received chemotherapy even though the average chemotherapy benefit for this group is 1.6% and can go up to 6.7% if they have a high clinical risk as it was defined by the investigators of the TAILORx trial. Finally, 84,6% of patients ≤50 years old with RS between 21-25 received chemotherapy with a 6.5% potential benefit demonstrated in the TAILORx trial. Conclusions: Our analysis suggests that, by using the cut-offs of TAILORx trial, adjuvant chemotherapy could had been omitted in at least a further 11.5% of patients with early breast cancer, reassuring their quality of life without declining their prognosis.