title: [Clinical analysis of multiple primary carcinomas in colorectal cancer patients].
abstract: OBJECTIVE
  To explore the prevalence, clinical features and prognosis of multiple primary neoplasms in patients with colorectal carcinoma (CRC).
  
  
  METHODS
  Data of colorectal cancer patients admitted to our hospital from June 1994 to June 2002 were analyzed retrospectively. Patients were divided into multiple-cancer group (MCG) and single- cancer group (SCG). Clinical features and prognosis were compared between two groups.
  
  
  RESULTS
  The incidence of multiple cancers was 7.4 % (83/ 1125). Forty- seven patients had multiple colorectal cancers metachronous CRC(S) in 12 and synchronous CRC(S) in 35. Thirty- six patients 5 patients with synchronous cancers had malignant tumors outside colorectal tract,12 of whom were gastric carcinomas. No significant differences were found between MCG and SCG regarding gender, onset age, Dukes stage and differentiation of index CRC. Cancer family history (P=0.002) and colorectal adenoma (P=0.036) were significantly more common in MCG than those in SCG. The local recurrence or distant metastasis in MCG was significantly higher than that in SCG (P=0.047), though there was no significant difference in survival between the two groups. Forty- one percent of index tumors were located in right colon in MCG, significantly higher than that in SCG (P=0.048). The secondary tumors were mainly adenoma cancerization in MCG.
  
  
  CONCLUSIONS
  Cancer family history and colorectal adenoma seems to be at high risk for developing multiple cancers in CRC patients. Gastric cancer and colorectal adenoma cancerization were common secondary tumors of multiple primary neoplasms in patients with colorectal carcinoma.
authors.affiliation: Department of Gastrointestinopancreatic Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510089, China.
authors.forename: Chang-hua
authors.initials: CH
authors.lastname: Zhang
authors.forename: Yu-long
authors.initials: YL
authors.lastname: He
authors.forename: Wen-hua
authors.initials: WH
authors.lastname: Zhan
authors.forename: Shi-rong
authors.initials: SR
authors.lastname: Cai
authors.forename: Mei-jin
authors.initials: MJ
authors.lastname: Huang
authors.forename: Jian-ping
authors.initials: JP
authors.lastname: Wang
authors.forename: Jian-jun
authors.initials: JJ
authors.lastname: Peng
mesh_terms: D018256:Adenomatous Polyps / Q000235:genetics; D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000453:epidemiology* / Q000473:pathology; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors