New Lymph Node Parameters and a Comparison with the American Joint Committee on Cancer N-Stages in Breast Cancer

Abstract

BACKGROUND/AIMS: The N-stage of TNM systems considers only the number of metastatic lymph nodes (NMLN) in breast cancer (BC). However, new lymph node parameters refer to the number of harvested lymph nodes (NHLN) and negative lymph nodes (NNLN), which have had an increasing significance in the current literature. This study aimed to compare NHLN, NNLN, lymph node ratio (LNR), modified lymph node ratio (mLNR), and log odds of positive lymph nodes (LODDS) against the standard American Joint Committee on Cancer (AJCC) N-stage for the prognosis of BC patients. MATERIALS AND METHODS: This study was designed retrospectively. The socio-demographic data, clinical features, histopathological factors, treatment modalities, receptor status of BC, and lymph node related parameters (AJCC N, LNR, mLNR, LODDS) were identified. Then, lymph node related parameters were compared for cancer-related mortality (CRM), cancer recurrence, disease-free survival (DFS), and overall survival (OS). RESULTS: Eight hundred seven women who underwent surgery for BC were included in this study according to its eligibility criteria. The mean follow-up period was 113.34 +/- 74.85 (range: 6-378) months. The NHLN was 21.24 +/- 9.22, the NMLN was 4.85 +/- 7.38, the NNLN was 16.39 +/- 9.48, the LNR was 0.23 +/- 0.29, the mLNR was 5.38 +/- 7.38 and the LODDS was -0.74 +/- 0.80 on average. During the follow-up period, 42 (5.2%) patients had local recurrence, 188 (23.3%) had distant metastases, and 252 (31.2%) patients died due to BC. NMLN, LNR, mLNR, and LODDS were found to be significantly higher, and NNLN was significantly lower in those patients with cancer recurrence and CRM ( p<0.001). AJCC N-stages, and also LNR, mLNR, and LODDS groups according to the calculated cut-off values, were significant for DFS and OS according to survival analysis. In Cox regression analysis, only LODDS was a significant independent risk factor for OS [p=0.014, heart rate (HR)=3.78, 95% confidence interval (CI) for HR: 1.30-10.94)]. CONCLUSION: The results indicated that LODDS was more successful compared to other lymph node staging systems, especially for OS. However, randomized prospective controlled studies with larger samples and homogeneous study groups are needed to create standard classification systems as alternatives to AJCC N.