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Post-colonoscopy colorectal cancer in Alberta

Colonoscopies are often performed to screen and survey for colorectal cancers. There are many measures of quality in the provision of colonoscopy services. One of these is interval or missed cancer rates. Interval cancers are those not detected (potentially missed) after a screening colonoscopy or that develop within the recommended time interval between colonoscopies.

Completed
  • Choosing Wisely
  • Gastroenterology

Do not repeat colorectal cancer screening (by any method) for 10 years after a high-quality colonoscopy is negative in average-risk individuals.

Choosing Wisely

Background & Aim

Colonoscopies are often performed to screen and survey for colorectal cancers.  There are many measures of quality in the provision of colonoscopy services.  One of these is interval or missed cancer rates.  Interval cancers are those not detected (potentially missed) after a screening colonoscopy or that develop within the recommended time interval between colonoscopies.

By undertaking this project PLP aims:

  • To provide endoscopy units or physicians who perform colonoscopy with comparative provincial, zonal, facility and/or individual (depending on overall numbers and local factors) interval colorectal cancer rates, as a reflection of colonoscopy quality and meeting standards of care
  • To determine if colonoscopy quality and interval cancer rates are acceptable in Alberta

Facts

  • Colorectal cancer is the second most prevalent cancers in Canada contributing to 13% of all cancer cases. An estimated 26,800 colorectal cancer cases were diagnosed in 20171.
  • An estimated 2220 colorectal cancer cases (1,250 males; 970 females) were estimated to be diagnosed in Alberta in 20171
  • In Canada, gastroenterologists and general surgeons perform 97% of all colonoscopies. Gastroenterologists are the primary providers of colonoscopies in large urban areas, whereas surgeons are the primary providers in smaller urban and rural areas2
  • An estimated 8% of colorectal cancers develop despite a colonoscopy without detection of neoplasia within the preceding 3 years. Women may have a higher rate of missed/early colorectal cancers after a negative colonoscopy.  Predictors of these cancers include older age and performance of index colonoscopy by a non-gastroenterologist3
Canadian Cancer Statistics Advisory Committee. Canadian Cancer Statistics 2018. Toronto, ON: Canadian Cancer Society; 2018. Available at: cancer.ca/Canadian-Cancer-Statistics-2018-EN (accessed October 2018).
Hilsden RJ, Tepper J, Moayyedi P et al. Who provides gastrointestinal endoscopy in Canada? Can J Gastroenterol 2007;21:843–846.
Singh H, Nugent Z, Demers AA, et al. Rate and predictors of early/missed colorectal cancers after colonoscopy in Manitoba: a population-based study. Am J Gastroenterol 2010;105:2588 – 2596.

Methods

This study focused on Alberta residents aged 40 years and older with a first-time diagnosis of Colorectal Cancer (CRC) in 2013. First-time cases of CRC diagnosed in 2013 were identified through the Alberta Cancer Registry. These cases were linked to the National Ambulatory Care Reporting System, Discharge Abstract Database, and Alberta Ambulatory Care Reporting System databases to determine the dates of previous colonoscopies.

 

Defining post-colonoscopy colorectal cancer

A post-colonoscopy colorectal cancer (PCCRC) is a cancer diagnosed between six month to 60 months after a colonoscopy reports no cancer.

Post-colonoscopy colorectal cancer in Alberta

Frequently Asked

How Will You Protect My Data?

The report was generated by the Physician Learning Program (PLP) using Alberta Health Services (AHS) datasets (National Ambulatory Care Repository, Discharge Abstract Database). Confidentiality was of the utmost importance; this data is strictly for the participating physicians use and reflection. PLP Data reports on individual participating physicians are never shared with AHS, department heads, regulatory bodies or other stakeholders.

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