Can Lymph Node Ratio Replace pN Categories in the Tumor-Node-Metastasis Classification System for Esophageal Cancer?

• Published in: Journal of thoracic oncology Vol. 9; no. 8; pp. 1214 - 1221
• Main Authors: Tan, Zihui, Ma, Guowei, Yang, Haoxian, Zhang, Lanjun, Rong, Tiehua, Lin, Peng
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2014
• Subjects: Adult; Aged; Aged, 80 and over; Esophageal cancer; Esophageal Neoplasms - pathology; Esophageal Neoplasms - surgery; Esophagectomy; Female; Humans; Lymph Node Excision; Lymph node ratio; Lymph Nodes - pathology; Lymphatic Metastasis; Male; Middle Aged; Neoplasm Staging; pN categories; Prognosis; Retrospective Studies; Survival Rate; UICC/AJCC TNM classification; UICC/AJCC TNM classification; Esophageal cancer; Lymph node ratio; pN categories
• ISSN: 1556-0864; 1556-1380
• DOI: 10.1097/JTO.0000000000000216

We evaluated the prognostic value of lymph node ratio (LNR) in esophageal squamous cell carcinoma (ESCC) patients after tri-incisional esophagectomy by making comparisons with pN categories in the UICC/AJCC (International Union Against Cancer/American Joint Committee on Cancer) classification system (seventh edition). Seven hundred ESCC patients underwent tri-incisional esophagectomy at our center (1988–2008) without neoadjuvant therapy. The adjusted X-tile cutoff values for LNR of 0 and 0.25 were compared with those in UICC/AJCC pN categories. Univariate and multivariate analyses identified LNR as a significant prognostic factor regardless of the number of retrieved LNs. Spearman's correlation analysis showed close linear correlations between the number of examined and metastatic LNs (r = 0.205, p < 0.001), but not between the number of examined LNs and LNR (r = 0.058, p = 0.123). Significant prognostic differences were seen among LNR categories in all pT categories (p < 0.05), but not in pN categories stratified by tumor status (except T3: p < 0.001). Significant prognostic difference was seen among LNR categories in all pN categories (p < 0.05), but not between pN categories in all LNR categories (p > 0.05). Significant differences in 5-year cancer-specific survival rates were found among retrieved-node groups in the same pN category (except N2+3: p = 0.733), but not within the same LNR category (except N0: p < 0.001). LNR is an independent prognostic factor after tri-incisional esophagectomy, regardless of the number of retrieved LNs. In ESCC, LNR might reduce stage migration, have more potential for predicting patient outcomes, and compensate for deficiencies in UICC/AJCC pN categories.