Lymph Node Ratio and pN Staging Show Different Superiority As Prognostic Predictors Depending on the Number of Lymph Nodes Dissected in Chinese Patients With Luminal A Breast Cancer

BackgroundThe lymph node ratio (LNR) classification has shown superiority to pN staging (the number of positive lymph nodes) in breast cancers, but it has not been examined according to whether sufficient lymph nodes have been dissected.MethodsAll Chinese patients with luminal A breast cancer with positive lymph nodes seen at Sun Yat-sen University Cancer Center between 1995 and 2009 were enrolled. Disease-free survival (DFS) and overall survival (OS) were the endpoints, and the patients were further classified into 2 groups according to whether ≤ 10 or > 10 lymph nodes were dissected.ResultsFor the whole group, the OS curves of the pN stages overlapped, whereas they were separated in the LNR survival curves. LNR was an independent prognostic factor for OS and DFS, whereas the pN stage was not. In the ≤ 10 lymph nodes dissected group, both OS and DFS curves were clearly separated in the pN staging but overlapped in the LNR classification. In the > 10 lymph nodes dissected group, LNR showed no overlap in the OS curves and was an independent prognostic factor of OS and DFS when compared with pN staging.ConclusionIn Chinese patients with luminal A breast cancer, LNR classification and the pN stage show different superiority as prognostic predictors according to whether > 10 or < 10 lymph nodes are dissected.