It has been shown that part of the lymph fluid from the right/dorsal side of the esophagus drains directly into the thoracic duct, whereas the lymph fluid from the left/ventral side has to pass through lymph nodes before entering the duct. We hypothesized that patients with right/dorsal tumors have a poorer prognosis than those with left/ventral tumors because cancer cells from the right/dorsal quadrant may easily enter the systemic circulation.Methods
A total of 77 patients with pT1b- or pT2-staged cancers treated by esophagectomy without neoadjuvant treatment were enrolled in this study. Tumor laterality was determined endoscopically.Results
The tumor location was right/dorsal in 45 patients and left/ventral in 32. The right/dorsal group had a lower lymph node stage (pN, P = 0.043) and shorter disease-free survival (P = 0.027). Multivariate analysis demonstrated that tumor laterality [hazard ratio (HR): 0.052, 95% confidence interval (CI): 0.007–0.37, P = 0.003], pN (HR: 3.8, 95% CI: 1.7–9.1, P = 0.001), and tumor size (HR: 1.02, 95% CI: 1–1.04, P = 0.02) were independent prognostic factors.Conclusions
This is the first study to demonstrate a relationship between tumor laterality and prognosis in patients with esophageal squamous cell carcinoma. These findings need to be validated in a prospective large study.