Does tumour location influence postoperative long-term survival in patients with oesophageal squamous cell carcinoma?

OBJECTIVES The seventh edition of the American Joint Committee on Cancer (AJCC) staging system introduced tumour location for the first time as an determinant of stage grouping in pathological T2N0M0 and T3N0M0 (pT2-3N0M0) oesophageal squamous cell carcinoma (OSCC). However, the new modification remains controversial. The objective of this study was to investigate the correlation between tumour location and postoperative long-term survival in patients with OSCC in China. METHODS The clinicopathological data and over 10 years of follow-up results from a large cohort of 988 patients with OSCC undergoing radical-intent oesophagectomy from 1984 to 1995 without preoperative and postoperative chemoradiotherapy were reviewed, in which 632 patients were staged as pT2-3N0M0. Tumour location was redefined according to the seventh edition of the AJCC staging system. Survival was calculated by the Kaplan-Meier method; univariate log-rank and multivariate Cox proportional hazard models were used to further determine the impact of tumour location on long-term survival. RESULTS Univariate analysis showed that OSCC tumour location was closely associated with long-term survival for the entire cohort of 988 patients (odds ratio [OR]: 0.82; 95% confidence interval [95% CI]: 0.67-0.99; P = 0.049), and for pT2-3N0M0 patients (OR: 0.63; 95% CI: 0.48-0.84; P = 0.001). The median survival times for patients with pT2-3N0M0 OSCC in the upper, middle and lower third of the oesophagus were 38.1, 46.6 and 66.0 months, respectively, with corresponding 5-year survival rates of 40.0, 51.8 and 66.2%, respectively. Overall survival rates among three categories of patients according to tumour location in the pT2-3N0M0 patients were statistically different (P = 0.004). Multivariate analysis demonstrated that tumour location was a significant independent predictor of long-term survival for pT2-3N0M0 patients (OR: 0.53; 95% CI: 0.42-0.67; P = 0.0001), but not for the entire cohort of 988 patients (OR: 0.99; 95% CI: 0.79-1.23; P = 0.90). CONCLUSIONS Tumour location is an independent predictor of long-term survival for pathological T2-3N0M0 OSCC, and should be incorporated into the current staging system to predict long-term survival and identify high-risk postoperative patients.