title: Characteristics of missed or interval colorectal cancer and patient survival: a population-based study.
abstract: OBJECTIVE
  Colorectal cancers (CRCs) diagnosed within a few years after an index colonoscopy can arise from missed lesions or the development of a new tumor. We investigated the proportion, characteristics, and factors that predict interval CRCs that develop within 6-60 months of colonoscopy.
  
  
  METHODS
  We performed a population-based cohort study of Utah residents who underwent colonoscopy examinations from 1995 through 2009 at Intermountain Healthcare or the University of Utah Health System, which provide care to more than 85% of state residents. Colonoscopy results were linked with cancer histories from the Utah Population Database to identify patients who underwent colonoscopy 6-60 months before a diagnosis of CRC (interval cancer). Logistic regression was performed to identify risk factors associated with interval cancers.
  
  
  RESULTS
  Of 126,851 patients who underwent colonoscopies, 2659 were diagnosed with CRC; 6% of these CRCs (159 of 2659) developed within 6 to 60 months of a colonoscopy. Sex and age were not associated with interval CRCs. A higher percentage of patients with interval CRC were found to have adenomas at their index colonoscopy (57.2%), compared with patients found to have CRC detected at colonoscopy (36%) or patients who did not develop cancer (26%) (P < .001). Interval CRCs tended to be earlier-stage tumors than those detected at index colonoscopy, and to be proximally located (odds ratio, 2.24; P < .001). Patients with interval CRC were more likely to have a family history of CRC (odds ratio, 2.27; P = .008) and had a lower risk of death than patients found to have CRC at their index colonoscopy (hazard ratio, 0.63; P < .001).
  
  
  CONCLUSIONS
  In a population-based study in Utah, 6% of all patients with CRC had interval cancers (cancer that developed within 6 to 60 months of a colonoscopy). Interval CRCs were associated with the proximal colon, earlier-stage cancer, lower risk of death, higher rate of adenoma, and family history of CRC. These findings indicate that interval colorectal tumors may arise as the result of distinct biologic features and/or suboptimal management of polyps at colonoscopy.
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, Utah. Electronic address: Jewel.samadder@hsc.utah.edu.
authors.forename: N Jewel
authors.initials: NJ
authors.lastname: Samadder
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Medicine (Genetic Epidemiology), University of Utah, Salt Lake City, Utah.
authors.forename: Karen
authors.initials: K
authors.lastname: Curtin
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
authors.forename: Thérèse M F
authors.initials: TM
authors.lastname: Tuohy
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
authors.forename: Lisa
authors.initials: L
authors.lastname: Pappas
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
authors.forename: Ken
authors.initials: K
authors.lastname: Boucher
authors.affiliation: VA Cooperative Studies Epidemiology Center-Durham, Durham VAMC, Durham, North Carolina; Department of Medicine (Gastroenterology), Duke University, Durham, North Carolina.
authors.forename: Dawn
authors.initials: D
authors.lastname: Provenzale
authors.affiliation: Department of Oncology, Intermountain Healthcare, Salt Lake City, Utah.
authors.forename: Kerry G
authors.initials: KG
authors.lastname: Rowe
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Oncological Sciences, University of Utah, Salt Lake City, Utah.
authors.forename: Geraldine P
authors.initials: GP
authors.lastname: Mineau
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Oncological Sciences, University of Utah, Salt Lake City, Utah.
authors.forename: Ken
authors.initials: K
authors.lastname: Smith
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
authors.forename: Richard
authors.initials: R
authors.lastname: Pimentel
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Pediatrics at University of Utah, Salt Lake City, Utah.
authors.forename: Anne C
authors.initials: AC
authors.lastname: Kirchhoff
authors.affiliation: Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah; Department of Medicine (Gastroenterology), University of Utah, Salt Lake City, Utah; Department of Oncological Sciences, University of Utah, Salt Lake City, Utah.
authors.forename: Randall W
authors.initials: RW
authors.lastname: Burt
mesh_terms: D000236:Adenoma / Q000235:genetics / Q000401:mortality / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003111:Colonic Polyps / Q000235:genetics / Q000401:mortality / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000235:genetics / Q000401:mortality / Q000473:pathology*; D055088:Early Detection of Cancer; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D016017:Odds Ratio; D010375:Pedigree; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014589:Utah / Q000453:epidemiology
keywords: Colon Cancer; Detection; Missed or Interval Cancer; Screening