Evaluation of the 7th edition of the TNM classification in patients with resected esophageal squamous cell carcinoma

Abstract

Aim: To evaluate the prognostic factors and tumor stages of the 7(th) edition TNM classification for esophageal cancer.

Methods: In total, 1033 patients with esophageal squamous cell carcinoma (ESCC) who underwent surgical resection with or without (neo)adjuvant therapy between January 2003 and June 2012 at the Thoracic Surgery Department II of the Beijing Cancer Hospital, Beijing, China were included in this study. The following eligibility criteria were applied: (1) squamous cell carcinoma of the esophagus or gastroesophageal junction identified by histopathological examination; (2) treatment with esophagectomy plus lymphadenectomy with curative intent; and (3) complete pathologic reports and follow-up data. Patients who underwent non-curative (R1) resection and patients who died in hospital were excluded. Patients who received (neo)adjuvant therapy were also included in this analysis. All patients were restaged using the 7(th) edition of the Union for International Cancer Control and the American Joint Committee on Cancer TNM staging systems. Univariate and multivariate analyses were performed to identify the prognostic factors for survival. Survival curves were plotted using the Kaplan-Meier method, and the log-rank test was used to evaluate differences between the subgroups.

Results: Of the 1033 patients, 273 patients received (neo)adjuvant therapy, and 760 patients were treated with surgery alone. The median follow-up time was 51.6 mo (range: 5-112 mo) and the overall 5-year survival rate was 36.4%. Gender, "pT" and "pN" descriptors, (neo)adjuvant therapy, and the 7(th) edition TNM stage grouping were independent prognostic factors in the univariate and multivariate analyses. However, neither histologic grade nor cancer location were independent prognostic factors in the univariate and multivariate analyses. The 5-year stage-based survival rates were as follows: IA, 84.9%; IB, 70.9%; IIA, 56.2%; IIB, 43.3%; IIIA, 37.9%; IIIB, 23.3%; IIIC,12.9% and IV, 3.4%. There were significant differences between each adjacent staging classification. Moreover, there were significant differences between each adjacent pN and pM subgroup. According to the pT descriptor, there were significant differences between each adjacent subgroup except between pT3 and pT4 (P = 0.405). However, there was no significant difference between each adjacent histologic grade subgroup and between each adjacent cancer location subgroup.

Conclusion: The 7(th) edition is considered to be valid for patients with resected ESCC. However, the histologic grade and cancer location were not prognostic factors for ESCC.

Keywords: Esophageal squamous cell carcinoma; Prognosis; Staging; Surgery; Survival; TNM.

Figure 1

Survival curves of patient subgroups stratified by pT, pN and pM descriptors according to the 7^th edition TNM classification. The 5-year survival rate, the number of patients in each subgroup, and the P-value for comparison between each adjacent subgroup are indicated. A: With respect to the pT descriptor, there were significant differences between each adjacent subgroup except between pT3 and pT4 (P = 0.405); B: With respect to the pN descriptor, there were significant differences between each adjacent subgroup; C: With respect to the pM descriptor, there were significant differences between pM0 and pM1.

Figure 2

Survival curves for patient subgroups stratified by pG (histologic grade) and cancer location according to the 7^th edition TNM classification. The 5-year survival rate, the number of patients in each subgroup, and the P-value for comparison between each adjacent subgroup are indicated. A: With respect to pG, there was no significant difference between each adjacent pG classification; B: With respect to cancer location, there was no significant difference between each adjacent caner location classification.

Figure 3

Survival curves for patient subgroups stratified according to the 7^th edition TNM pStage groupings. The 5-year survival rate, the number of patients in each subgroup, and the P-value for comparison between each adjacent subgroup are indicated. The survival curves showed stepwise reduction as the pStage increased, and there were significant differences between each adjacent pStage group.