Prognostic value of nodal ratios in node-positive breast cancer

Purpose The American Joint Committee on Cancer staging system for breast cancer was recently updated to reflect the impact of increasing the absolute number of positive lymph nodes on prognosis. However, numerous studies suggest that nodal ratios (absolute number of involved nodes-number of nodes resected) may have greater prognostic value than absolute numbers of involved nodes. Here we examine the data supporting the use of nodal ratios in breast cancer prognosis and consider the potential advantages and disadvantages of including nodal ratios in breast cancer staging. Methods A systematic review of the literature was conducted using the following search engines: http://www.google.com; Thomson's ISI Web of Science; PubMed. Results In multiple reports from both prospective and retrospectively collected data sets, nodal ratios have been shown to be significant predictors of outcome, including locoregional recurrence and overall survival. These studies span all stages of breast cancer and include various treatments as well as various statistical approaches. Conclusion There is considerable data supporting the use of nodal ratios in breast cancer prognosis. A thorough and methodological evaluation of the potential prognostic importance of nodal ratios in large multicenter data sets is merited and is currently being undertaken by the International Nodal Ratio Working Group.