title: The prognostic significance of tumor laterality in patients with esophageal squamous cell carcinoma.
abstract: BACKGROUND
  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.
authors.affiliation: Department of Gastroenterological Surgery, Cancer Institute Hospital, Tokyo, Japan. shinji.mine@jfcr.or.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Mine
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamada
authors.forename: Heike
authors.initials: H
authors.lastname: Grabsch
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sano
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Ishiyama
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Hirasawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Hiki
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D004938:Esophageal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D016629:Esophagectomy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome