Impact of sentinel node tumor burden on outcome of invasive breast cancer patients

Abstract

Background: The tumor status of the axillary lymph nodes is one of the most important prognostic factors in women with early breast cancer (BC). Sentinel lymph node (SLN) biopsy has become the standard staging procedure for patients with invasive BC, largely replacing axillary lymph nodes dissection (ALND). The exact impact on prognosis of SLN tumor burden is still object of controversy. The aim of this study was to correlate the tumor burden in the SLN with the outcome in a large cohort of women.

Patients and methods: 1040 consecutive patients with clinical stage I-III invasive BC were prospectively collected on our Institutional BC database from January 2001 to January 2007. Patients were stratified into the following four groups based on the tumor burden of the SLN: macrometastases, tumor deposit ≥2 mm; micrometastases, tumor deposit ≥0.2 mm and <2 mm; isolated tumor cells (ITC), isolated tumor cells or tumor deposit <0.2 mm; negative, in case of patients with no evidence of tumor.

Results: At a median follow-up of 8.5 years, the tumor burden of SLN metastases resulted significant predictor of DFS (P < 0.0001) and OS (P = 0.042). Multivariate analysis showed that the tumor burden of SLN metastases and Ki 67 proliferative index maintained the statistical significance.

Conclusion: Patients with SLN micrometastases or ITC, do not seem to have a worse DFS or OS compared with SLN negative cases. There is a significant decrease in DFS and OS in patients with macrometastatic disease in the SLN.

Keywords: Invasive breast cancer; Lymphadenectomy; Macrometastases; Micrometastases; Sentinel lymph node; Tumor burden.