title: Adenomatous neoplasia: postsurgical incidence after normal preoperative CT colonography findings in the colon proximal to an occlusive cancer.
abstract: OBJECTIVE
  To determine the postoperative incidence of adenomatous neoplasia in the colon proximal to an occlusive colorectal cancer where preoperative computed tomographic (CT) colonography findings were normal.
  
  
  METHODS
  Institutional review board approval, with a waiver of informed consent, was obtained. This observational study included patients with occlusive colorectal cancer who underwent preoperative CT colonography between April 2007 and March 2010 that revealed normal findings (ie, no lesions ≥ 6 mm) in the proximal colon and who underwent postoperative colonoscopy. The primary outcome was postoperative colonoscopic discovery of clinically relevant lesions (ie, nondiminutive [≥ 6 mm] adenomas, advanced adenomas, or cancers) in the proximal colon. The cumulative incidence of clinically relevant lesions in preoperatively normal proximal colon over the postsurgical follow-up time was analyzed by using the Kaplan-Meier method.
  
  
  RESULTS
  The final cohort included 204 patients (102 men and 102 women; mean age, 57.3 years ± 11.3 [standard deviation]). At a total of 435 postoperative colonoscopies performed over a median follow-up of 29 months (range, 1-74 months), clinically relevant lesions were detected in the proximal colon in 30 patients: Nonadvanced adenomas were detected in 23 patients, and advanced adenomas were detected in seven patients. The cumulative incidence of clinically relevant adenomatous lesions in the preoperatively normal proximal colon 12 and 18 months after preoperative CT colonography was 8.1% (95% confidence interval [CI]: 3.9%, 12.2%) and 9.6% (95% CI: 5%, 14%), respectively. Clinically relevant adenomatous lesions found in the proximal colon within 18 months of preoperative CT colonography were nonadvanced adenomas in 10 of 15 patients.
  
  
  CONCLUSIONS
  When the portion of the colon proximal to an occlusive cancer is devoid of nondiminutive lesions at preoperative CT colonography, colonoscopy of the proximal colon following cancer resection rarely finds clinically relevant lesions and is unlikely to reveal any lesions requiring immediate removal until routine 1-year postsurgical follow-up. Online supplemental material is available for this article .
authors.affiliation: From the Department of Radiology and Research Institute of Radiology (B.K., S.H.P., S.S.L., A.Y.K., H.K.H.), Department of Pathology (J.K.), Department of Colorectal Surgery (J.C.K., C.S.Y.), and Department of Gastroenterology (S.K.Y.), University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea; Department of Radiology, University of Wisconsin Medical School, Madison, Wis (P.J.P.); and Medical Research Collaborating Center, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (S.A.).
authors.forename: Bohyun
authors.initials: B
authors.lastname: Kim
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Lee
authors.forename: Soyeon
authors.initials: S
authors.lastname: Ahn
authors.forename: Jihun
authors.initials: J
authors.lastname: Kim
authors.forename: Jin Cheon
authors.initials: JC
authors.lastname: Kim
authors.forename: Chang Sik
authors.initials: CS
authors.lastname: Yu
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.forename: Ah Young
authors.initials: AY
authors.lastname: Kim
authors.forename: Hyun Kwon
authors.initials: HK
authors.lastname: Ha
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D018365:Neoplasm, Residual / Q000000981:diagnostic imaging*; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D012189:Retrospective Studies