title: Synchronous multiple colorectal adenocarcinomas.
abstract: BACKGROUND
  The object of the present work was to characterize clinical features and the quality of preoperative examinations in patients with synchronous colorectal carcinomas, and to compare the incidence of associated benign polyps with our findings in patients with a single malignant lesion.
  
  
  METHODS
  A retrospective evaluation of 225 patients with primary colorectal carcinoma revealed 9 cases (4.0%) of synchronous colorectal carcinomas.
  
  
  RESULTS
  The synchronous colorectal carcinomas were located in the same anatomical segment in 7 patients and were divided into different segments in 2 patients. The accuracy of preoperative diagnosis was 55.6% by endoscopy alone and 66.7% by double contrast barium enema (DCBE) alone, while the rate was 77.8% when colonoscopy and DCBE were combined. There was a higher incidence of associated benign polyps in the group with synchronous colorectal carcinomas (55.6%) versus 28.7% for a single carcinoma (P < 0.05). The main reason why multiple lesions could not be identified preoperatively was that the distal lesions prevented examination of the proximal lesions.
  
  
  CONCLUSIONS
  At the time of surgical resection, it is important to ascertain preoperatively whether or not a second lesion exists. If synchronous polyps are present in patients with synchronous colorectal carcinomas, they should be ablated to reduce the risk of metachronous colorectal carcinoma.
authors.affiliation: Institute of Gastroenterology of Hofu, Yamaguchi, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Takeuchi
authors.forename: T
authors.initials: T
authors.lastname: Toda
authors.forename: S
authors.initials: S
authors.lastname: Nagasaki
authors.forename: T
authors.initials: T
authors.lastname: Kawano
authors.forename: Y
authors.initials: Y
authors.lastname: Minamisono
authors.forename: Y
authors.initials: Y
authors.lastname: Maehara
authors.forename: K
authors.initials: K
authors.lastname: Sugimachi
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001466:Barium Sulfate; D003110:Colonic Neoplasms / Q000175:diagnosis*; D003111:Colonic Polyps / Q000175:diagnosis*; D003113:Colonoscopy; D004733:Enema; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary; D012004:Rectal Neoplasms / Q000175:diagnosis*; D012189:Retrospective Studies
chemical_list: D001466:Barium Sulfate