title: Multiple primary cancers in esophageal squamous cell carcinoma: incidence and implications.
abstract: BACKGROUND
  The occurrence of multiple primary cancers in the aerodigestive tract is a well-known phenomenon. This study aims to elucidate the incidence and the therapeutic and prognostic implications of a nonesophageal primary cancer in patients with squamous cell carcinoma of the esophagus.
  
  
  METHODS
  Between 1982 and 1996, 1,055 patients with esophageal squamous cell carcinoma treated at our institution were reviewed for the presence of an additional primary cancer. The effects of the nonesophageal cancer on treatment of the esophageal carcinoma and survival were analyzed.
  
  
  RESULTS
  Among 1,055 patients, 114 nonesophageal primary cancers were documented in 100 patients (9.5%), 70% of which were aerodigestive tract cancers. Forty-seven patients had antecedent tumors and 43 had synchronous tumors. Treatment strategies for esophageal carcinoma in these patients were similar to patients without multiple tumors, not influenced by the nonesophageal tumor except in 6 patients. The overall survival of patients with antecedent tumors, synchronous tumors, and without multiple tumors was similar (median survival, 8.6, 8.5, and 8.8 months, respectively) (p = 0.84). Subsequent primary cancers developed in 10 patients (0.9%), 9 of them with previous curative resection of esophageal cancer, and all died of the subsequent cancer.
  
  
  CONCLUSIONS
  There is a high incidence of multiple primary cancers in patients with esophageal carcinoma but the treatment and prognosis of these patients are primarily determined by the esophageal carcinoma itself. Subsequent cancer is, however, a significant cause of death among patients cured of esophageal carcinoma.
authors.affiliation: Department of Surgery, The University of Hong Kong, Queen Mary Hospital, Hong Kong.
authors.forename: R T
authors.initials: RT
authors.lastname: Poon
authors.forename: S Y
authors.initials: SY
authors.lastname: Law
authors.forename: K M
authors.initials: KM
authors.lastname: Chu
authors.forename: F J
authors.initials: FJ
authors.lastname: Branicki
authors.forename: J
authors.initials: J
authors.lastname: Wong
mesh_terms: D000428:Alcohol Drinking / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D002423:Cause of Death; D016001:Confidence Intervals; D018572:Disease-Free Survival; D004938:Esophageal Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007822:Laryngeal Neoplasms / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000453:epidemiology; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D009378:Neoplasms, Multiple Primary / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D016609:Neoplasms, Second Primary / Q000453:epidemiology / Q000473:pathology / Q000628:therapy; D010166:Palliative Care; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D015996:Survival Rate