Differential prognostic relevance of patho-anatomical factors among different tumor-biological subsets of breast cancer: Results from the adjuvant SUCCESS A study.

OBJECTIVES

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.

MATERIAL AND 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.

TRIAL REGISTRATION

EudraCT 2005-000490-21; ClinicalTrials.gov Identifier: NCT02181101.