title: New Perspectives in Multiple Primary Colorectal Cancer: A Surgical Approach.
abstract: BACKGROUND
  We identify the features of multiple primary colorectal cancer (MPCC), synchronous colorectal cancer (SCRC) and metachronous colorectal cancer (MCRC), and distinguish between the cases that require a more extensive surgery and those where the parameters of SCRC might be important to prevent the development of MCRC.
  
  
  METHODS
  We gathered up consecutive individuals with MPCC, 50 for each category, and 100 consecutive individuals diagnosed with 'single' colorectal cancer. Clinical and familiar information was obtained. We classified both SCRC and MCRC according to locations.
  
  
  RESULTS
  MPCC were associated with polyps, both in earlier stages and as sporadic forms. SCRC located in the right colon were most frequently of the mucinous type. MCRC developed SCRC in 24%, along the entire colon, with familiar cancer antecedents. SCRC patients undergoing a total colectomy were younger, with the cancer spread throughout the entire colon and a larger number of polyps, whereas MCRC were predominantly adenomatous polyps. We found 2 risk factors for SCRC that led to the development of MCRC: rectal location and higher number of polyps.
  
  
  CONCLUSIONS
  SCRC possibly involves more than an environmental component. MCRC appears to be the producer of polyps that evolve into cancer at different times, emphasising the idea of a genetic predisposition. Studies are required to find biomarkers that define patients with higher risk of developing MCRC within SCRC.
authors.affiliation: Coloproctology Unit, Department of Surgery, Hospital Universitario 12 de Octubre, Madrid, Spain.
authors.forename: Lorena
authors.initials: L
authors.lastname: Brandariz
authors.forename: Cristina
authors.initials: C
authors.lastname: Alegre
authors.forename: Daniel
authors.initials: D
authors.lastname: Rueda
authors.forename: Maria
authors.initials: M
authors.lastname: Arriba
authors.forename: Laura
authors.initials: L
authors.lastname: Alonso
authors.forename: Anisa
authors.initials: A
authors.lastname: Nutu
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Rodríguez
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Pajares
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ferrero
authors.forename: Javier
authors.initials: J
authors.lastname: García-Borda
authors.forename: José
authors.initials: J
authors.lastname: Perea
mesh_terms: D000368:Aged; D003082:Colectomy / Q000379:methods; D003111:Colonic Polyps / Q000000981:diagnostic imaging / Q000601:surgery*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009378:Neoplasms, Multiple Primary / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors