The number of colorectal cancers diagnosed after a colonoscopy remained consistent at approximately 8% over a 15-year period despite the introduction of quality improvement measures, according to data from a population-based cohort study of more than 1 million individuals in Canada.
“It is believed that the majority of PCCRCs [postcolonoscopy colorectal cancers] arise due to cancers or near cancers that were either missed or incompletely treated during colonoscopy,” wrote Sanjay K. Murthy, MD, of the University of Ottawa, and colleagues.
Established quality improvement measures included adenoma detection rate, cecal intubation rate, colonoscopy withdrawal time, and endoscopy training standards, but how well the measures have been implemented remains uncertain, the researchers said. In a study published in Gastrointestinal Endoscopy (2018 Jan 6. doi: 10.1016/j.gie.2017.12.027), the researchers assessed data from 1,093,658 eligible adults aged 50-74 years over a 15-year period. The time period was divided into three sections: July 1, 1996, to June 30, 2001; July 1, 2001, to June 30, 2006; and July 1, 2006, to Dec. 31, 2010.
Overall, the number of colonoscopy procedures increased during the study period, from 305 per 10,000 people in 1996-1997 to 870 per 10,000 people in 2010-2011, and the percentage of individuals who underwent complete colonoscopies increased from 67% in the 1996-2001 period to 88% in the 2006-2010 period. “There was a considerable increase in the proportion of colonoscopies performed in younger age groups and community clinics in successive study periods,” the researchers noted.
Comparing the 2006-2010 and 1996-2001 time periods yielded adjusted odds of PCCRC, distal PCCRC, and proximal PCCRC of 1.14, 1.11, and 1.14, respectively; the trends were not affected by endoscopist specialty or institutional setting.
“Our findings are concerning for lack of improvement in colonoscopy practice quality in Ontario, particularly in the wake of greater emphasis having been placed on colonoscopy quality metrics during the study period,” the researchers said. The findings contrast with the decline in PCCRC rates in the United Kingdom reported in a previous study of a similar time period, they noted.
The study findings were limited by several factors, including possible patient and outcome misclassification, an unvalidated definition for PCCRC, and unmeasured confounders such as changes in practice or changes in the definition of PCCRC. Although more research is needed in other jurisdictions to confirm, the results “call for increased population-based practice audit as well as endoscopy educational programs and certification requirements.”
The study was supported by a research grant to Dr. Murthy from the University of Ottawa. The researchers had no financial conflicts to disclose.
SOURCE: Murthy S et al. Gastrointest Endosc. 2018 Jan 6. doi: 10.1016/j.gie.2017.12.027