196

COLORECTAL CANCERS AFTER A NEGATIVE COLONOSCOPY

H Singh, D Turner, L Xue, LE Targownik, CN Bernstein
Department of Medicine, University of Manitoba, Winnipeg, Manitoba

BACKGROUND: In a recent study we determined that the risk of developing colorectal cancer (CRC) after performance of a negative colonoscopy remains low even beyond ten years after the index procedure (JAMA May 2006). Factors predisposing to the development of CRC after a negative colonoscopy need to be further evaluated.
AIM: To determine the risk factors for development of CRC after a negative colonoscopy.
METHODS: We analyzed a) the demographic features of individuals in our negative colonoscopy cohort that developed CRC, and b) characteristics of the endoscopists performing the initial negative colonoscopy including their specialty, rural vs urban site of performance of the procedures and the annual volume of colonoscopies performed.
RESULTS: 0.55% (72/13170) males and 0.48% (91/19,033) females in the negative colonoscopy cohort developed CRC (p=0.4). Individuals who underwent their initial endoscopy at a rural facility were twice as likely to be subsequently diagnosed with CRC as compared to individuals who received their index colonoscopy in an urban setting (0.8% vs 0.4%; p<0.001). Those individuals who had their initial colonoscopies performed by general practitioners in the rural facilities had the highest rate of subsequently developing CRC [1% (13/1242)]. Otherwise specialty of the initial endoscopist did not influence the subsequent rate of development of CRC (GP 0.7%, Internists 0.5%, Surgeons 0.5%; p=0.3). The annual volume of colonoscopies performed by the practitioner was not predictive of CRC following a negative colonoscopy (<50/ year: 0.7%, 50-200/ yr: 0.5%, > 200/yr: 0.5%; p=0.7).
CONCLUSION: Patients undergoing colonoscopy at rural facilities are significantly more likely to develop CRC following an apparently negative colonoscopy than subjects whose colonoscopies were performed in urban settings. This is possibly due to the quality of endoscopy being performed by physicians practicing in rural settings. Further research is required to ensure all persons undergoing colonoscopy are able to receive equivalent quality of care.

PREVIOUS NEXT