Prognostic Significance of Lymph Node Counts in Operable Esophageal Cancer

The Prognostic Significance of Metastatic Nodal Size in Non-surgical Patients With Esophageal Squamous Cell Carcinoma

Background: The present study aimed to determine the prognostic value of the size of metastatic lymph node (LN) in non-surgical patients with esophageal squamous cell carcinoma (ESCC).

Methods: Three hundred seventy-six ESCC patients treated with definitive (chemo-) radiotherapy from January 2013 to March 2016 were reviewed. We analyzed potential associations of metastatic nodal size with responses, patterns of failure, and survival. Log-rank testing and Cox proportional hazards regression models were used to assess the impact of the clinical factors on survival.

Results: The 3-years over survival (OS) rates following a median follow-up of 28.2 months were 53.2, 46.2, 35.5, and 22.7% for the N0 group, the >0.5 to ≤1 cm group, the >1 to ≤2 cm group, and the >2 cm group, respectively. The progression-free survival (PFS) rates for 2 years were 50.9, 44.2, 26.6, and 23.4% for the N0 group, the >0.5 to ≤1 cm group, the >1 to ≤2 cm group, and the >2 cm group, respectively. The objective response rates (ORR) for the 280 patients with metastatic LNs were 43.1% for the LN >0.5 to ≤1 cm group, 46.9% for the LN >1 to ≤2 cm group, and 25.5% for the LN ≥2 cm group. The LN >2 cm group had the worst ORR of the three groups with LNs. Gross tumor volume (GTV) failure was the most common failure pattern, followed by distant failure and out of GTV LN failure, with incidences of 47.9% (180 of 376), 42% (158 of 376), and 13.8% (52 of 376), respectively. Nodal size correlated statistically with GTV failure and distant failure but not with out-of-GTV nodal failure. After adjusting for age, sex, T category, Primary tumor location, and CRT, the size of metastatic LNs was an independent prognostic factor for OS and PFS in multivariate analyses.

Conclusions: Nodal size is one of prognostic factors for non-surgical patients with ESCC and correlated statistically with GTV failure and distant failure.

Proposed revision of N categories to the 8th edition of the AJCC-TNM staging system for non-surgical esophageal squamous cell cancer

The 8th edition of the American Joint Committee on Cancer Tumor‐Node‐Metastasis (AJCC‐TNM) staging system for esophageal cancer (EC) retained the definition of N categories based on the number of metastatic lymph nodes (LN). However, it is difficult to accurately determine the number of metastatic LN without surgery. This study aimed to propose a revision to the N categories of the 8th edition AJCC‐TNM staging system that makes staging easier to perform and better represents the prognosis of non‐surgical esophageal squamous cell cancer (ESCC). We retrospectively reviewed the data of 336 patients with ESCC. The revised N categories were based on the anatomic regions of LN metastasis (cervix, thorax and abdomen). Survival was analyzed using the Kaplan‐Meier method and compared using the log‐rank test. Multivariate analyses were performed using the Cox proportional hazard model. Survival differences were adequately discriminated when the revised N categories were used. Subgroup analyses by T stage showed significant difference in overall survival between the revised N categories. Multivariate analyses demonstrated that T stage, revised N category, age, sex and treatment modality were independent risk factors, with the revised N category being the most significant variable. The revised N categories determined in this study can be used to fill gaps in the staging system for patients with non‐surgical ESCC, which can help clinicians to make better treatment decisions and more effectively predict patient prognoses. Future large‐scale studies are required to validate these results.

Pathologic lymph node ratio is a predictor of esophageal carcinoma patient survival: a literature-based pooled analysis

The positive lymph node ratio (LNR) has been suggested as a predictor of survival in patients with esophageal carcinoma (EC). However, existed evidences did not completely agree with each other. We sought to examine whether LNR was associated with overall survival (OS). Electronic database was searched for eligible literatures. The primary outcome was the relationship between LNR and OS, which was presented as hazard ratio (HR) with 95% confidence intervals (CIs). All statistical analyses were performed using STATA 11.0 software. A total of 18 relevant studies which involved 7,664 cases were included. Patients with an LNR of 0.3 or greater had an increased risk of death compared to those with an LNR of less than 0.3(HR = 2.33; 95% CI 2.03-2.68; P<0.01). Similarly, patients with an LNR greater than 0.5 was also associated with a decreased OS(HR = 1.95; 95% CI 1.52-2.50; P<0.01). No publication bias was found. This meta-analysis confirmed that LNR was a significant predictor of survival in patients with EC and should be considered in prognostication.

Assessment of Lymph Node Ratio to Replace the pN Categories System of Classification of the TNM System in Esophageal Squamous Cell Carcinoma

INTRODUCTION

The seventh edition of the TNM staging system for esophageal cancer outlined by the American Joint Committee on Cancer (AJCC) defines the N classification on the basis of the number of metastatic lymph nodes. However, this classification is dependent on the actual number of examined lymph nodes. Here in this study, we have focused on revising this N classification system with the metastatic lymph nodes ratio (LNR) and also assessing whether this modification to the current AJCC staging system can better define the prognostic characteristics of esophageal squamous cell carcinoma (ESCC).

METHODS

We retrospectively reviewed 916 patients with ESCC who underwent curative resection. Prognostic performance of two staging systems was compared using the Akaike information criterion value and receiver operating characteristics curve. In addition, decision curve analysis evaluated the clinical practical usefulness of the prediction models by quantifying their net benefits.

RESULTS

The univariate and multivariate Cox regression analyses indicated that LNR was an independent risk factor for overall survival. The modified staging system based on LNR had better discriminatory ability, monotonicity, homogeneity, and stratification than the TNM staging system in determining the prognosis of patients with ESCC. However, the decision curves analysis suggested that the modified staging based on LNR has poor clinical practical value over the AJCC TNM staging system.

CONCLUSIONS

LNR can supplement the pN categorization system for more effective evaluation of prognosis. But the modified staging system based on LNR has a poor clinical practical value for patients with ESCC compared with the current TNM system and is not superior to AJCC pN staging for ESCC.

Proposed Modification of Nodal Staging as an Alternative to the Seventh Edition of the American Joint Committee on Cancer Tumor-Node-Metastasis Staging System Improves the Prognostic Prediction in the Resected Esophageal Squamous-Cell Carcinoma

INTRODUCTION

The 7th American Joint Committee on Cancer (AJCC) tumor-node-metastasis staging system for esophageal cancer defined N classification based on the number of metastatic lymph nodes (LNs). However, this classification might neglect the extent of LNs metastasis. This study aimed to revise N classification based on the extent of LNs metastasis and propose a modification to the current AJCC staging system for better representing the prognostic characteristics of Chinese esophageal squamous-cell carcinoma (ESCC).

METHODS

We retrospectively reviewed 1993 ESCC patients who underwent curative resection. The proposed N categories based on the number of LNs metastasis stations were compared with the current staging system by univariate and multivariate Cox regression analyses. Homogeneity, discriminatory ability, and monotonicity of gradients of two staging systems were compared using likelihood ratio χ statistics and Akaike information criterion calculations.

RESULTS

The survival differences were not significant for N2 versus N3 category (p = 0.231) and stages IIIB versus IIIC (p = 0.713) based on the 7th AJCC staging system. When the modified staging system was adopted, the survival difference for N2 versus N3 and IIIB versus IIIC could be well discriminated. Statistical analysis showed that the modified staging system had higher likelihood ratio χ scores and smaller Akaike information criterion values than the 7th AJCC staging system, which represented the optimum prognostic stratification.

CONCLUSIONS

The modified staging system with the revised N categories based on the number of LNs metastasis stations better predicts the survival of Chinese ESCC population than the 7th AJCC staging system. Further studies are required to confirm this result.