Published online Dec 28, 2014. doi: 10.3748/wjg.v20.i48.18397
Revised: October 19, 2014
Accepted: November 7, 2014
Published online: December 28, 2014
AIM: To evaluate the prognostic factors and tumor stages of the 7th 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 7th 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 7th 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 7th edition is considered to be valid for patients with resected ESCC. However, the histologic grade and cancer location were not prognostic factors for ESCC.
Core tip: The 7th edition of the Union for International Cancer Control (UICC) and the American Joint Committee on Cancer (AJCC) TNM staging system for esophageal and gastroesophageal junction (GEJ) cancer is the first data-driven staging system for esophageal and GEJ cancers. It is based on the Worldwide Esophageal Cancer Collaboration database, which includes 4627 patients from a large multi-institutional collaboration involving 13 institutions and a data period ranging from the 1970s to the 2000s. Therefore, the surgical procedures, pathologic examinations, and patient follow-up can vary greatly between different institutions, resulting in inevitable bias. In this retrospective study, we used a large cohort of patients who had undergone potentially curative surgery for ESCC at a single institution and confirmed the predictive ability of the 7th edition of the UICC-AJCC TNM staging system.