We evaluated the applicability of the scale and assessed the reasonableness of the generated scores in early breast cancer. Form 1 of the ESMO-MCBS v1.1 provided a generally robust tool for scoring of adjuvant breast cancer studies. Six shortcomings were identified including lack of information regarding acute and long-term toxicity, an inability to grade single arm de-escalation scales and limitations related to grading based on disease free survival (DFS). Read the paper on the ESMO Open website: http://dx.doi.org/10.1136/esmoopen-2020-000743