Prognostic Value of Number of Removed Lymph Nodes, Number of Involved Lymph Nodes, and Lymph Node Ratio in 7502 Breast Cancer Patients Enrolled onto Trials of the Austrian Breast and Colorectal Cancer Study Group (ABCSG)

Abstract

The number of removed axillary lymph nodes and the ratio of involved to removed lymph nodes are described as independent prognostic factors beside the absolute number of involved lymph nodes in breast cancer patients. The correlation between these factors and prognosis were investigated in trials of the Austrian Breast and Colorectal Cancer Study Group (ABCSG). This retrospective analysis is based on the data of 7052 patients with endocrine-responsive breast cancer who were randomized in four trials of the ABCSG in the years 1990-2006 and underwent axillary lymph node dissection. The prognostic value of number of removed nodes (NRN), number of involved nodes (NIN), and ratio of involved to removed nodes (lymph node ratio, LNR) concerning recurrence-free survival and overall survival was analyzed. A total of 2718 patients had node-positive disease. No correlation was found between NRN and prognosis. Increasing NIN and LNR were significantly associated with worse recurrence-free survival and overall survival in univariate and multivariate analyses (P < .001). Only in the subgroup of patients with one to three positive lymph nodes and treated with mastectomy (n = 728) was LNR an additional prognostic factor in univariate and multivariate analyses. For breast cancer patients stringently medicated in the framework of prospective adjuvant clinical trials and requiring a mandatory minimum of removed nodes, NRN does not influence prognosis, and LNR is not superior to NIN as prognostic factor. In patients with one to three positive lymph nodes and mastectomy, LNR could play a role as an additional prognostic factor.