Technical Information

Percentage of Ontario screen-eligible individuals, 50-74 years old, who were overdue for colorectal screening in each calendar year

Figures 1 and 2

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 (1­–4). Screening can also lower the incidence of CRC (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)

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.

​(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 = Percentage overdue for screening

2011 Canadian population

​Percentage (%)

• OHIP’s CHDB (Claims History Database) – Colectomy claims, non-CCC and CCC FOBT, colonoscopy, flexible sigmoidoscopy
• CIRT (Colonoscopy Interim Reporting Tool) – CCC program colonoscopy records
• LRT (Laboratory Reporting Tool) – CCC FOBTs
• OCR (Ontario Cancer Registry) - Resolved invasive colorectal cancers
• RPDB (Registered Persons Database) – Demographics
• PCCF+, version 6C - Residence and socio-demographic info

​2008-2015

• Provincial (Ontario)
• LHIN of residence
• Public Health Unit (PHU)

Total number of Ontario screen-eligible individuals, 50–74 years old in each calendar year

• Ontario residents aged 50–74 at the index date
• Index date was defined as Jan 1 of a given year
• LHIN assignment was determined using PCCF+, version 6C; residential postal code was used to identify LHIN and individuals with unknown/missing LHINs were excluded from the analysis
• Public Health Unit data was determined using PCCF+, version 6C

Exclusions:

• Individuals with a missing or invalid HIN, date of birth, sex or postal code
• Individuals with an invasive colorectal cancer prior to Jan 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 Jan 1 of the calendar year of interest
• Total colectomy was defined in OHIP by fee codes S169A, S170A, S172A

Total number of Ontario screen-eligible individuals, 50–74 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 two years (Jan 1 of the previous year to Dec 31st of the calendar year of interest) AND
  2. did not have a colonoscopy in the last ten years (Jan 1 nine years prior to the calendar year of interest to Dec 31st of the calendar year of interest) AND
  3. did not have a flexible sigmoidoscopy in the last ten years (Jan 1 nine years prior to the calendar year of interest to Dec 31st of the calendar year of interest)
  For example: at the end of 2013, an individual would be considered overdue for colorectal screening if he or she did not have an FOBT test in 2012-2013, or flexible sigmoidoscopy in 2004-2013, or a colonoscopy in 2004-2013
• 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
• 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

​N/A

• 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