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Colorectal Cancer Screening Participation Methodology

Colorectal Cancer Screening Percentage Overdue for Screening
Short description of Indicator Percentage of Ontario screen-eligible individuals, 50 to 74 years old, who were overdue for colorectal screening
Rationale for measurement Regular screening using fecal occult blood tests (FOBT) can reduce colorectal cancer mortality by detecting cancer earlier when treatment is more likely to be successful.[1] [2] [3] [4]. Screening can also lower the incidence of colorectal cancer (through the detection of polyps that can be removed before they become cancerous).[5]

The European Guidelines for Quality Assurance in Colorectal Cancer Screening recommend overdue for screening as a more appropriate measure of screening participation than FOBT participation when there has been opportunistic screening with colonoscopy prior to the introduction of an organized colorectal cancer screening program.[6]
Evidence/references for rationale
  1. Hewitson P, Glasziou P, Watson E, Towler B, Irwig l. Cochrane systematic review of colorectal cancer screening using the fecal occult blood test (Hemoccult): an update. Am J Gastroenterol. 2008;103(6):1541–9.
  2. Mandel JS, Church TR, Ederer F, Bond JH. Colorectal cancer mortality: Effectiveness of biennial screening for fecal occult blood. J National Cancer Inst. 1999 Mar 3;91(5):434–7.
  3. Ontario Health Technology Advisory Committee. OHTAC recommendation: screening methods for early detection of colorectal cancers and polyps [Internet]. Toronto: The Committee; 2009 [cited 2015 Dec 1]. Available from: http://www.hqontario.ca/Evidence/Publications-and-OHTAC-Recommendations/Ontario-Health-Technology-Assessment-Series/Screening-Methods-for-Early-Detection-of-Colorectal-Cancers-and-Polyps
  4. Jorgensen OD, Kronborg O, Fenger C. A randomised study of screening for colorectal cancer using faecal occult blood testing: Results after 13 years and seven biennial screening rounds. Gut. 2002 Jan;50(1):29–32.
  5. Mandel JS, Church TR, Bond JH, Ederer F, Geisser MS, Mongin SJ, et al. The effect of fecal occult-blood screening on the incidence of colorectal cancer. N Engl J Med. 2000;343(22):1603-7.
  6. Moss S, Ancelle-Park, R, Brenner H. Evaluation and interpretation of screening outcomes. In: Segnan N, Patnick J and von Karsa L, editors. European Guidelines for quality assurance in colorectal cancer screening and diagnosis: First edition. Luxembourg: Publications Office of the European Union; 2010. p. 72–102.
Calculations for the indicator (Total number of Ontario screen-eligible individuals, 50–74 years old, who were overdue for colorectal screening by the end of the calendar year / Total number of Ontario screen-eligible individuals, 50–74 years old) X 100
Standardized Rate Calculation The 2011 Canadian population
Unit Percentage (%)​
Data sources
  • OHIP CHDB (Claims History Database) – Colectomy claims, non-CCC and CCC FOBT, colonoscopy, flexible sigmoidoscopy
  • CIRT (Colonoscopy Interim Reporting Tool) – CCC program colonoscopy records
  • GI Endo DSP (Gastrointestinal Endoscopy Data Submission Portal) – hospital colonoscopy records
  • LRT (Laboratory Reporting Tool) – CCC FOBTs
  • OCR (Ontario Cancer Registry) - Resolved invasive colorectal cancers
  • RPDB (Registered Persons Database) – Demographics
  • PCCF+, version 6D - Residence and socio-demographic info
Time Frame 2014 - 2017​
Geographic Scale

Provincial (Ontario)​

Denominator description Total number of Ontario screen-eligible individuals, 50 to 74 years old in each calendar year
  • Ontario residents ages 50 to 74 at the index date
  • Index date was defined as January 1 of a given year


Exclusions:

  • Individuals with a missing or invalid HIN, date of birth, sex, postal code or LHIN
  • Individuals with an invasive colorectal cancer prior to January 1 of the calendar year of interest; prior diagnosis of colorectal cancer was defined as: ICD-O-3 codes C18.0, C18.2-C18.9, C19.9, C20.9, a morphology indicative of colorectal cancer, microscopically confirmed with a path report
  • Individuals with a total colectomy prior to January 1 of the calendar year
  • Total colectomy was defined in OHIP by fee codes S169A, S170A, S172A
Numerator description Total number of Ontario screen-eligible individuals, 50 to 74 years old, who were overdue for colorectal screening by the end of the calendar year
  • Individuals were considered overdue for colorectal screening if they:
    1. did not have an FOBT within the last 2 years (January 1 of the previous year to December 31 of the calendar year of interest) AND
    2. did not have a colonoscopy in the last 10 years (January 1, 9 years prior to the calendar year of interest to December 31 of the calendar year of interest) AND
    3. did not have a flexible sigmoidoscopy in the last 10 years (January 1, 9 years prior to the calendar year of interest to December 31 of the calendar year of interest)

    For example: at the end of 2014, an individual would be considered overdue for colorectal screening if he or she did not have an FOBT test in 2013-2014, or flexible sigmoidoscopy in 2005-2014, or a colonoscopy in 2005-2014

  • Identifying FOBTs:
    Program CCC FOBT was identified in LRT or OHIP:
    • L179A ColonCancerCheck Fecal Occult Blood Testing

    Non-program FOBT was identified using fee codes in OHIP:

    • L181A Lab Med - Biochem - Occult Blood
  • Colonoscopies were identified using fee code Z555A, Z491A- Z499A in OHIP, in CIRT or in GI Endo DSP
  • Flexible sigmoidoscopies were identified using fee code Z580A in OHIP
  • Multiple claims with the same Health Insurance Number (HIN) and service date were assumed for a single procedure
  • Each individual was counted once regardless of the number of tests performed
Considerations N/A​
Data availability & limitations
  • Historical RPDB address information is incomplete; therefore, the most recent primary address was selected for reporting, even for historical study periods
  • FOBTs in hospital labs could not be captured
  • A small proportion of FOBTs performed as diagnostic tests could not be excluded from the analysis
CSQI Year 2019