The Significance of Extent of Extracapsular Extension in Patients with T1-2 and N1 Breast Cancer.

Objective: The prognostic importance of extracapsular extension (ECE) in breast cancer is not yet clear, especially in patients with pathological T1-2 and N1 (pT1-2N1) disease. We aimed to investigate whether the extent of ECE was an independent prognostic factor for survival outcomes in patients with pT1-2N1 breast cancer.

Materials and Methods: A total number of 131 patients with pT1-2N1 breast cancer treated between 2009 and 2015 were retrospectively evaluated. A single pathologist re-analyzed the histologic examples of all cases. The extent of ECE was graded from 0 to 4.

Results: There was a significant correlation between the number of lymph nodes involved and ECE grade (p=0.004). According to the univariate analysis, lymphovascular invasion (LVI) and ECE grade were the significant prognostic factors for overall survival (OS); age, number of metastatic lymph nodes, menopausal status, and ECE grade were the prognostic factors for disease-free survival (DFS). With a median follow-up of 46 months, grade 3-4 ECE seems to be notably associated with a shorter OS and DFS in multivariate analysis. The mean OS was 85 months for the patients with grade 0-2 ECE vs 75 months for the patients with grade 3-4 ECE (p=0.003). The mean DFS was 83 months for the patients with grade 0-3 ECE vs 68 months for the patients with grade 4 ECE (p=<0.0001).

Conclusion: This research has shown that the extent of ECE is an important prognostic factor for survival in pT1-2N1 breast cancer patients and grade 3-4 ECE seems to be notably associated with a shorter OS and DFS.