Treatment Efficacy Score—continuous residual cancer burden-based metric to compare neoadjuvant chemotherapy efficacy between randomized trial arms in breast cancer trials

•We developed a statistical tool to compare two RCB distributions giving a single metric named Treatment Efficacy Score (TES).•TES identifies a regimen with a higher pCR rate and also captures the downstaging effects of treatment on residual cancer.•TES correlates with event-free and distant recurrence-free survival better than pCR rate difference.•TES could serve as a better early surrogate for trial arm level survival than pCR rate difference.•We created a free web tool (http://dssoftware.aei.polsl.pl/TES/TES/) to plot RCB distributions and calculate TES statistic.