title: Invasive colorectal cancer within 5 years of negative colonoscopy in a Japanese population.
abstract: OBJECTIVE
  Colonoscopy provides imperfect protection against colorectal cancer (CRC). In an attempt to improve cancer detection we evaluated the clinical features of invasive CRC detected within 5 years of a negative colonoscopy.
  
  
  METHODS
  The details of colonoscopies performed in a rural hospital in Japan were prospectively recorded at the time of the examination. The patients were followed over 5 years for the subsequent occurrence of cancer.
  
  
  RESULTS
  In a 5-year period, 10148 patients underwent colonoscopy and 202 without previous colonoscopy were diagnosed with invasive CRC. Of 3212 patients with a colonoscopy negative for cancer, nine developed invasive cancer within 5 years. The ratios for invasive CRC detected without/with previous colonoscopy were 60:1 in the rectum, 54:1 in the sigmoid colon, 15:1 in the descending colon, 28:0 in the transverse colon, 31:5 in the ascending colon and 14:1 in the caecum (P=0.041). The ratio between left- and right-sided colonic cancer was also significantly different (129:3 and 45:6, P=0.0078). Six (67%) of the invasive CRCs were in the ascending colon or caecum. Five of six patients with invasive CRC in the ascending colon and caecum had right-sided small adenomas at prior colonoscopy.
  
  
  CONCLUSIONS
  The majority of early/missed CRCs were right-sided and associated with prior right-sided colonic adenomas. Repeated colonoscopy of patients with right-sided adenomas at a shorter surveillance interval deserves consideration.
authors: Digestive Disease Center, Showa Inan General Hospital, Komagane, Japan. horiuchi.akira@sihp.jp
authors: A
authors: A
authors: Horiuchi
authors: Y
authors: Y
authors: Nakayama
authors: M
authors: M
authors: Kajiyama
authors: T
authors: T
authors: Kamijima
authors: N
authors: N
authors: Tanaka
mesh_terms: D000236:Adenoma; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology*; D002432:Cecum / Q000473:pathology; D044682:Colon, Ascending / Q000473:pathology; D044683:Colon, Descending / Q000473:pathology; D012809:Colon, Sigmoid / Q000473:pathology; D044684:Colon, Transverse / Q000473:pathology; D003111:Colonic Polyps / Q000175:diagnosis / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000473:pathology*; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012007:Rectum / Q000473:pathology; D013997:Time Factors