title: Distribution of synchronous and metachronous multiple colorectal cancers.
abstract: OBJECTIVE
  Synchronous and metachronous multiple colorectal cancers are not rare occurrences. Since features of colorectal cancer depend on tumor location, we focused attention on the tumor distribution of synchronous and meta-chronous lesions in colorectal cancer.
  
  
  METHODS
  The records of 1812 patients with colorectal malignancies (either invasive colorectal cancer or high grade dysplasia) were clinicopathologically analyzed.
  
  
  RESULTS
  In one hundred and twenty patients with colorectal malignancies there were synchronous or metachronous lesions. The distribution of synchronous malignancies showed a significant shift from the proximal to the distal site, while in metachronous malignancies, the distribution of second tumors showed a significant shift from the distal to the proximal site.
  
  
  CONCLUSIONS
  Our findings suggest that different types of cancer lesions do exist, hence careful and meticulous examinations are important.
authors.affiliation: Department of Surgery and Clinical Research Institute, National Kyushu Medical Center, Fukuoka, Japan. yoikeda@qmed.hosp.go.jp
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Motonori
authors.initials: M
authors.lastname: Saku
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kawanaka
authors.forename: Toru
authors.initials: T
authors.lastname: Muranaka
authors.forename: Morishige
authors.initials: M
authors.lastname: Takeshita
authors.forename: Jiro
authors.initials: J
authors.lastname: Watanabe
authors.forename: Kohji
authors.initials: K
authors.lastname: Yoshida
authors.forename: Keizo
authors.initials: K
authors.lastname: Sugimachi
mesh_terms: D000236:Adenoma / Q000473:pathology*; D003110:Colonic Neoplasms / Q000473:pathology*; D006801:Humans; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D016609:Neoplasms, Second Primary / Q000473:pathology*; D012004:Rectal Neoplasms / Q000473:pathology*; D012189:Retrospective Studies