title: Synchronous and metachronous cancers in patients with gastric cancer.
abstract: OBJECTIVE
  The purpose of this study is to investigate characteristics of synchronous and metachronous cancer in gastric cancer and to suggest appropriate methods of treatment management.
  
  
  METHODS
  We reviewed 4,593 patients who underwent operations for gastric cancer at Seoul National University Hospital from 1999 to 2005. We selected those patients who had also been diagnosed with another primary cancer and classified patients into three groups according to the date of detection of another primary cancer. We analyzed their clinicopathological features.
  
  
  RESULTS
  The incidence of synchronous or metachronous cancer in addition to gastric cancer was 3.4%. The most common another primary cancer was colorectal cancer (20.1%), followed by lung cancer and liver cancer. The majority of synchronous cancers were operated on at the same time as gastric cancer. Eighty-five percent of the synchronous group and 45% of the post-metachronous group were detected by a routine checkup, without prior symptoms. There was no postoperative mortality and the overall 5-year survival rate was 69.4%.
  
  
  CONCLUSIONS
  Synchronous cancer should be considered in the preoperative workup and combined resection should be applied whenever possible. Periodic examination for metachronous cancer is necessary during the postoperative period.
authors.affiliation: Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Bang Wool
authors.initials: BW
authors.lastname: Eom
authors.forename: Hyuk-Joon
authors.initials: HJ
authors.lastname: Lee
authors.forename: Moon-Won
authors.initials: MW
authors.lastname: Yoo
authors.forename: Jae Jin
authors.initials: JJ
authors.lastname: Cho
authors.forename: Woo Ho
authors.initials: WH
authors.lastname: Kim
authors.forename: Han-Kwang
authors.initials: HK
authors.lastname: Yang
authors.forename: Kuhn Uk
authors.initials: KU
authors.lastname: Lee
mesh_terms: D005260:Female; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D016609:Neoplasms, Second Primary / Q000453:epidemiology* / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D016019:Survival Analysis