Extracapsular extension in the positive sentinel lymph node: a marker of poor prognosis in cT1-2N0 breast cancer patients?

ObjectiveThis study aims to evaluate whether extracapsular extension (ECE) in the sentinel lymph node (SLN) is associated with involvement of 4 lymph node metastases at completion axillary lymph node dissection (ALND) and the effect on 5-year disease-free survival (DFS) and 10-year overall survival (OS).Summary background dataECE in a SLN is usually a contraindication for omitting completion ALND in cT1-2N0 breast cancer patients treated with breast-conserving therapy and 1-2 positive SLN(s).MethodsAll cT1-2N0 breast cancer patients with 1-3 positive SLN(s) who underwent ALND between 2005 and 2008 were selected from the Netherlands Cancer Registry. Logistic regression analysis was used to determine the association between ECE and 4 lymph node metastases. Five-year DFS and 10-year OS were analyzed using Kaplan-Meier survival analysis. Cox regression analysis was performed to correct for other prognostic factors.ResultsA total of 3502 patients were included. Information on ECE was available for 2111 (60.3%) patients, consisting of 741 (35.1%) patients with and 1370 (64.9%) without ECE. The incidence of 4 lymph node metastases was 116 (15.7%) in the ECE group vs. 80 (5.8%) in the group without ECE (p<0.001). Five-year DFS rate was 86.4% in the ECE group compared to 88.8% in the group without ECE (p=0.085). 10-year OS rate was 78.6% compared to 83.0% (p=0.018), respectively. Cox regression analysis showed that ECE was not an independent prognostic factor for both DFS and OS.ConclusionsECE was significantly associated with involvement of 4 lymph node metastases in the completion ALND group. ECE was not an independent prognostic factor for both DFS and OS.