OBJECTIVE : In breast cancer, large tumor size, positive nodal stage and a triple-negative tumor subtype are associated with reduced survival, but the interactions between these prognostic factors are not well understood. METHODS : Here we re-evaluated the impact of tumor size, nodal stage and tumor subtype on disease-free survival (DFS), overall survival (OS), distant disease-free survival (DDFS) and breast cancer specific survival (BCSS) in a retrospective analysis using data from the adjuvant SUCCESS A trial. Subgroup analyses were conducted to assess whether the effect of tumor size and nodal stage on survival depended on tumor subtype. RESULTS : Increasing tumor size, higher nodal stage and triple negative breast cancer (TNBC) were associated with unfavorable prognosis (all p < 0.001). There was no significant interaction between tumor subtype and tumor size (p > 0.5 for all four survival endpoints), but we found significant interactions between tumor subtype and nodal stage (p < 0.05 for all four survival endpoints), with no differences in survival among tumor subtypes for patients with pN0 tumors (all p > 0.05) and pronounced differences in survival among tumor subtypes for patients with positive nodal stage (all p < 0.001). CONCLUSIONS : This analysis confirms tumor size, nodal stage and tumor subtype as independent prognostic factors in high-risk early breast cancer. Nodal-positive patients with TNBC had a considerably worse outcome compared to nodal-positive patients with another tumor subtype. This underlines the importance for early detection particularly for patients with TNBC. BACKGROUND : EudraCT 2005-000490-21; ClinicalTrials.gov Identifier: NCT02181101.