Original article
General thoracic
Comparison of the 6th and 7th Editions of the American Joint Committee on Cancer Tumor-Node-Metastasis Staging System in Patients With Resected Esophageal Carcinoma

https://doi.org/10.1016/j.athoracsur.2010.01.017Get rights and content

Background

The 7th edition American Joint Committee on Cancer tumor-nodes-metastasis (AJCC TNM) staging system was published recently. We aim to evaluate its predictive ability and to compare the performance of the 6th and 7th editions of the AJCC TNM staging systems in esophageal cancer.

Methods

A total of 392 esophageal squamous cell carcinoma patients receiving primary surgical resection between 1995 and 2006 were included. Patients were staged using the 6th and 7th edition staging systems. Survival analysis was performed with a Cox regression model. The homogeneity, discriminatory ability, and monotonicity of gradients of two staging systems were compared using linear trend χ2, likelihood ratio χ2 statistics, and Akaike information criterion calculation.

Results

The overall five-year survival rate for the entire cohort was 27.1%. Female gender, “T,” “N,” and “M” classifications according to the 7th edition staging system definition were independent prognostic factors in multivariate analysis. But histology grade and cancer location had no significant influence on patient survival. The 7th edition staging system has the highest linear trend χ2 and likelihood ratio χ2 scores. Compared with the 6th edition, the 7th edition staging system also has a smaller Akaike information criterion value, which represented the optimum prognostic stratification.

Conclusions

The strength of the 7th edition AJCC TNM staging system is the new descriptors for “N” and “M” classifications. However, we did not find histologic grade and cancer location to be significant prognostic factors in our cohort. Overall, the 7th edition AJCC TNM staging system has better performance than the previous edition.

Section snippets

Patients

The Institutional Review Board of Taipei-Veterans General Hospital approved this study and granted a waiver of the informed consent process. A total of 392 ESCC patients receiving primary surgical resection through the triincisional approach between 1995 and 2006 in Taipei-Veterans General Hospital were included in this study. The diagnosis workup and surgical procedures were as described previously [8]. In brief, all patients received preoperative studies, including physical examination,

Results

Mean follow-up time was 32.8 months (median follow-up time, 17.0 months). Overall five-year survival rate was 27.1 % with median survival of 20 months. In Table 2 the patient characteristics are summarized. The majority of patients had reconstruction with a gastric tube through the retrosternal route. The substitute organ and reconstruction route had no impact on patient survival (p = 0.113 and 0.642, respectively). Nine patients were incidentally found to have distant metastasis (lung, liver,

Comment

The 7th edition staging system strengthens the role of positive lymph nodes, by which the N classification is subdivided into N0 to N3. Therefore, a standardized extent of lymph node dissection and pathologic examination should be made in order to prevent the bias caused by inadequate lymph node evaluation. However, the evidence for routine three-field lymph node dissection is lacking. How extensive should lymph node dissection be for the thoracic esophageal cancer staging remains an important

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