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4B Colorectal Cancer Screening

Description  | Specific Indicators |  Ontario Public Health Standards (OPHS) | Corresponding Health Indicator from Statistics Canada and CIHI |  Corresponding Indicators from Other Sources  |  Data Sources  | Survey Questions |  Alternative Data Sources  | Analysis Check List | Method of Calculation  | Basic Categories |  Indicator Comments | Definitions| Cross-References to Other Indicators |  Cited References | Changes Made


Proportion of people aged 50­-74 who report having a screening fecal occult blood test (FOBT) in the previous two years.

Specific Indicators

  • Colorectal cancer screening (FOBT) rate

Ontario Public Health Standards

The Ontario Public Health Standards (OPHS) establish requirements for the fundamental public health programs and services carried out by boards of health, which include assessment and surveillance, health promotion and policy development, disease and injury prevention, and health protection. The OPHS consist of one Foundational Standard and 13 Program Standards that articulate broad societal goals that result from the activities undertaken by boards of health and many others, including community partners, non-governmental organizations, and governmental bodies. These results have been expressed in terms of two levels of outcomes: societal outcomes and board of health outcomes. Societal outcomes entail changes in health status, organizations, systems, norms, policies, environments, and practices and result from the work of many sectors of society, including boards of health, for the improvement of the overall health of the population. Board of health outcomes are the results of endeavours by boards of health and often focus on changes in awareness, knowledge, attitudes, skills, practices, environments, and policies. Boards of health are accountable for these outcomes. The standards also outline the requirements that boards of health must implement to achieve the stated results.

Outcomes Related to this Indicator

  • Board of Health Outcome (Chronic Disease Prevention): The public is aware of the benefits of screening for early detection of cancers and other chronic diseases of public health importance.

Health Promotion and Policy Development Requirements Related to this Indicator

  • The board of health shall collaborate with community partners to promote provincially approved screening programs related to the early detection of cancers (Chronic Disease Prevention).
  • The board of health shall increase public awareness in the following areas: Benefits of screening for early detection of cancers and other chronic diseases of public health importance (Chronic Disease Prevention).
  • The board of health shall provide advice and information to link people to community programs and services on the following topics: Screening for chronic diseases and early detection of cancers (Chronic Disease Prevention).

Corresponding Health Indicator from Statistics Canada and CIHI

  • None

Corresponding Indicator from Other Sources

  • Ontario's Cancer System Quality Index1: Colorectal Cancer Screening (FOBT) search for "Cancer System Quality Index", then for "Access", then for "Colorectal Cancer screening".

Data Sources

Numerator & Denominator: Canadian Community Health Survey (CCHS)
Original source:
Statistics Canada
Distributed by:
1. Ontario Ministry of Health and Long-Term Care
2. Statistics Canada
Suggested citation (see Data Citation Notes):
1. Canadian Community Health Survey [year], Statistics Canada, Share File, Ontario MOHLTC
2. Canadian Community Health Survey [year], Statistics Canada, Public Use Microdata File, Statistics Canada

Survey Questions

This module was optional content in 2003 and selected by some health units in Ontario. It was optional content 
and selected by Ontario (all health units) in 2005 and 2007-08. These questions are asked of respondents 35 and over.

Data Source



Response Categories




Colorectal Cancer Screening

An FOBT is a test to check for blood in your stool, where you have a bowel movement and use a stick to smear a small sample on a special card. Have you ever had this test?

Yes, No, Don't Know, Refused







When was the last time?

Less than 1 year ago, 1 year to less than 2 years ago, 2 years to less than 3 years ago, 3 years to less than 5 years ago, 5 years to less than 10 years ago, 10 or more years ago, Don't Know, Refused 







   Why did you have it? Interviewer: Mark all that apply.

Family history of colorectal cancer, Part of regular check-up / routine screening, Age,  Race, Follow-up of problem, Follow-up of colorectal cancer treatment, Other - specify, Don't Know, Refused







CCS_83A, CCS_83B, CCS_83C, CCS_83D, CCS_83E, CCS_83F, CCS_83G

Alternative Data Source(s)

The Rapid Risk Factor Surveillance System (RRFSS) contains a module called Colorectal Screening. This module was optional from 2001-2008. These questions are only asked if the respondent is 40 years old and older. Starting in January 2009, these questions are asked of respondents 35 years old and older.

Data Source



Response Categories





Colorectal Screening


Have you ever had a test for blood in your stool, that is a test where you have a bowel movement and use a stick to smear a small sample of it on a special card.  Have you had this test? 

Don't know,





Did you have this test in the last two years?

Don't know,





What was the reason for having this test (a test for blood in your stool)? Was it because of a family history of colorectal cancer, your age, a regular check-up or routine visit, ongoing or past bowel problems, concern about a possible problem, or was there some other reason?

Family history of colorectal cancer,
Regular check-up or routine visit,
Ongoing or past bowel problems,
Concern about possible problems,
Other specify,
Don't know,



What was the reason for having this test (a test for blood in your stool)?    

Was it...                                                                     

ONE:  a regular check-up or routine visit,                                    

TWO:  was it because of ongoing or past bowel problems, or                   

THREE: concern about a possible problem?

Other (specify),
A regular check-up or routine visit,
Because of ongoing or past bowel problems,
Concern about possible problems,
Don't know,



Analysis Check List

  • The numerator is defined as people aged 50-74 who report having had an FOBT in the previous two years for one or more of the following reasons: family history of colorectal cancer, part of regular check-up / routine screening, age, race. These respondents must not have had an FOBT in the previous two years for follow-up of a problem, follow-up of colorectal cancer treatment, or ‘other’ reason.
  • If using RRFSS for 2001-2008, the response “regular check-up or routine visit” is the reason that is meant to capture screening FOBT, and should form the numerator.
  • It is recommended that public health units use the Share File provided by the Ministry of Health and Long-Term Care rather than public use file (PUMF) provided by Statistics Canada. The Share File has a slightly smaller sample size because respondents must agree to share their information with the province to be included; however, the share file has more variables and fewer grouped categories within variables. The Share File is a cleaner dataset for Ontario analysis because all variables that were not common content, theme content or optional content for Ontario have been removed.
  • There may be slight differences between results from the share file and data published on the Statistics Canada website for the Health Indicators because rates calculated for Health Indicators use the master CCHS data file.
  • Not applicable respondents should be excluded; however, it is important to understand who these respondents are from the questionnaire skip patterns to be able to describe the relevant population.
  • Users need to consider whether or not to exclude the ‘Refusal, 'Don't Know' and ‘Not Stated' response categories in the denominator. Rates published in most reports, including Statistics Canada's publication Health Reports generally exclude these response categories.  In removing not stated responses from the denominator, the assumption is that the missing values are random, and this is not always the case.  This is particularly important when the proportion in these response categories is high.
  • Estimates must be appropriately weighted (generally the share weight for the CCHS) and rounded.
  • Users of the CCHS Ontario Share File must adhere to Statistics Canada's release guidelines for the CCHS data when publishing or releasing data derived from the file in any form. Refer to the appropriate user guide for guidelines for tabulation, analysis and release of data from the CCHS. In general, when calculating the CV from the share file using the bootstrap weights, users should not use or release weighted estimates when the unweighted cell count is below 10. For ratios or proportions, this rule should be applied to the numerator of the ratio.  Statistics Canada uses this approach for the tabular data on their website. When using only the Approximate Sampling Variability (CV) lookup tables for the share file, data may not be released when the unweighted cell count is below 30. This rule should be applied to the numerator for ratios or proportions.  This provides a margin of safety in terms of data quality, given the CV being utilized is only approximate.
  • Before releasing and/or publishing data, users should determine the CV of the rounded weighted estimate and follow the guidelines below:
    • Acceptable (CV of 0.0 - 16.5) Estimates can be considered for general unrestricted release. Requires no special notation.
    • Marginal (CV of 16.6 - 33.3) Estimates can be considered for general unrestricted release but should be accompanied by a warning cautioning subsequent users of the high sampling variability associated with the estimates. Such estimates should be identified by the letter E (or in some other similar fashion).
    • Unacceptable (CV greater than 33.3) Statistics Canada recommends not to release estimates of unacceptable quality. However, if the user chooses to do so then estimates should be flagged with the letter F (or in some other fashion) and the following warning should accompany the estimates: "The user is advised that...(specify the data) not meet Statistics Canada's quality standards for this statistical program. Conclusions based on these data will be unreliable and most likely invalid". These data and any consequent findings should not be published. If the user chooses to publish these data or findings, then this disclaimer must be published with the data.
  •  Caution should be taken when comparing the results from Cycle 1.1 (2000/01) to subsequent years of the survey, due to a change in the mode of data collection.  The sample in Cycle 1.1 had a higher proportion of respondents interviewed in person, which affected the comparability of some key health indicators.  Please refer to for a full text copy of the Statistics Canada article entitled "Mode effects in the Canadian Community Health Survey: a Comparison of CAPI and CATI".
  • Users should refer to the most recent RRFSS Manual of Operations for a complete list of RRFSS analysis guidelines.
  • Denominator Data - cell size less than 30 not to be released (based on unweighted data).
  • Numerator Data - cell size less than 5 not to be released (based on unweighted data).
  • Coefficients of variation (CV) should be calculated for every estimate. The following categories determine the release of the data:
  • CV between 0 and 16.5:  estimate can be released without qualification.
  • CV between 16.6 and 33.3:  estimate can be released with qualification:  interpret with caution.  High variability.
  • CV greater than 33.3:  estimate should not be released, regardless of the cell size.
  • 95% confidence intervals should accompany all released estimates.  In general the simple computation of the C.I. for a proportion assuming SEp = sqrt(pq/n) and CI95% = p +/- 1.96*SEp is sufficient. However, if estimates are close to 0 or 100% and the simple computation confidence intervals include values less than zero or greater than 100 then the Fleiss 2nd edition computation for skewed estimates should be employed.
  • Weighting:
    • General household weight will be applied for questions related to the individual. 
    • Household weight is to be applied for questions about households when we wish to determine the population/number of people affected. 
    • Household weight is not to be applied for child proxy questions (bicycle helmet use, car seat safety), dog and cat immunization modules, or other questions that relate to the household rather than the respondent. 
    • Household weights are not required to be recalculated for sub-population based questions; for example mammography in women ages 35+ years and 50-74 years.
    • If the weights supplied with the data set (health unit wave specific, health unit cumulative total, all health units combined wave specific, all health units combined cumulative total) are not appropriate for the required analysis, then a time-specific weight must be calculated.  For example, a new weight is required for all seasonal modules.
  • If the cell size of ‘Don't Know' responses is 5% or greater, ‘Don't Know' responses should be included in the denominator of the analyses and reported separately.
  • If the cell size of ‘Refusal' responses is 5% or greater, ‘Refusal' responses should be included in the denominator of the analyses and reported separately.
  • When an indicator is being compared between groups (e.g. health units, time periods, gender), if any one group has ‘Don't Know' and/or ‘Refusal' responses that are 5% or greater, ‘Don't Know' and/or ‘Refusal' responses should be included in the denominator of the analyses and reported separately for all groups.
  • A provincial sample is not available with the RRFSS.
  • Refer to the RRFSS Data Dictionaries at for more information about module questions and indicators.

Method of Calculation

Number of people aged 50-74 reporting having had a screening FOBT in past two years
Total number of people aged 50-74
 X 100

This is defined as people in the CCHS who report having had an FOBT in the previous two years for one or more of the following reasons:

1 Family history of colorectal cancer (CCS_83A=1)
2 Part of regular check-up / routine screening (CCS_83B=1)
3 Age (CCS_83C=1)
4 Race (CCS_83G=1)

and not for any of the following reasons

5 Follow-up of problem (CCS_83D=2)
6 Follow-up of colorectal cancer treatment (CCS_83E=2)
7 Other - Specify (CCS_83F=2)

Basic Categories

  • Sex: male, female
  • Geographic areas of patient residence: public health unit

Indicator Comments

  • Screening is checking for a disease or condition when there are no symptoms. Diagnosis is identifying a disease or condition from its signs and symptoms. Some cancer detection tests may be performed for either screening or diagnostic reasons.
  • The specification of the numerator in "Method of calculation", above, assumes that, when both screening and diagnostic reasons for FOBT are reported, the reason is diagnostic. This is a conservative method, recommended since self-report is usually considered an overestimate (Loraine Marrett, Michael Spinks, Beth Theis, Cancer Care Ontario, 2006).
  • The National Committee on Colorectal Cancer Screening recommends that screening be offered to a target population of adults aged 50 to 74 years of age, using unrehydrated Hemoccult II or equivalent as the entry test, and that individuals be screened at least every two years.4
  • A systematic review found that population-based screening with FOBT offered every two years lowered colorectal cancer mortality by 16%.5
  • Colorectal cancer (CRC) is one of the four most common cancers in Ontario. Incidence increases rapidly with age, especially after age 50. 7
  • The data used for this indicator are self-reported. The rate of FOBT screening may therefore be over or under-estimated. Self-report data may be subject to errors in recall, or over or under-reporting due to social desirability. Despite these potential shortcomings, estimates of 11% of Ontario men and women screened in 2001-2002, and 14% of men and 15% of women screened in 2003-2004 (all in the 50-74 age range) prepared from the Ontario Health Insurance Plan and Registered Persons databases for the Cancer System Quality Index is in a similar range to estimates of 14% of men and 10% of women aged 50 and older from the 14 Ontario public health units using the FOBT question in CCHS 2003, calculated by the method described above, which is used by staff at both Cancer Care Ontario and the Public Health Agency of Canada.1,2,3
  • This question was not asked of proxy respondents.
  • ColonCancerCheck, Ontario's colorectal screening program, was launched in January 2007 by the Ministry of health and Long-Term Care in collaboration with Cancer Care Ontario. It offers screening with FOBT every two years for Ontarians aged 50-74 at average risk of colorectal cancer.6
  • An analysis of CCHS 2003 found that FOBT screening rates, while generally low in Canada, were higher among males and those with aged 65 and older. No urban vs rural difference was observed.8
  • A similar analysis of CCHS 2003 found rates of FOBT screening in the previous two years in Ontario (14 health units selected this module for CCHS 2003) similar to rates in British Columbia, slightly higher than in Saskatchewan and considerably higher than in Newfoundland and Labrador.3


FOBT test - A fecal occult blood test (FOBT) tests for blood in the stool. Small samples of stool are placed on special cards and sent to a laboratory for testing. Blood in the stool may be a sign of colorectal cancer. 10% of people with a positive FOBT are found to have cancer during a follow-up colonoscopy.6

Cross-References to Other Indicators

Cited References

  1. Cancer Care Ontario: Cancer System Quality Index. Colorectal Cancer Screening (FOBT) Participation, 2008. Available online at: (Accessed January 23, 2009).
  2. The Provincial Cancer Prevention and Screening Council. Report on Cancer 2020. Canadian Cancer Society, Ontario Division, and Cancer Care Ontario, 2006. Available online at: January 23, 2009).
  3. Canadian Cancer Society/National Cancer Institute of Canada. Canadian Cancer Statistics 2006. April 2008. Special Topic: Progress in Cancer Control: Screening, 71-19.
  4. Public Health Agency of Canada. Reducing Canadian Colorectal Cancer Mortality Through Screening. 2002. Available online at: (Accessed January 23, 2009).
  5. 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. American Journal of Gastroenterology 2008;103:1541-49.
  6. Government of Ontario. Ministry of Health and Long-Term Care. ColonCancerCheck. (Accessed January 23, 2009).
  7. Cancer Care Ontario. Insight on Cancer. News and Information on colorectal cancer and screening in Ontario. Toronto: Canadian Cancer Society (Ontario Division), December, 2008. Available online at: (Accessed May 22, 2009)
  8. Sewitch MJ, Fournier C, Ciampi A, Dyachenko A. Colorectal cancer screening in Canada: results of a national survey. Chronic Dis Can 2008;29(1):9-21.

Changes Made

DateFormal Review or Ad Hoc?Changes made byChanges
June 25, 2009Formal Review Cancer, Smoking and Sun Safety subgroup of Core Indicators. This is a new indicator. 
June 29, 2009Ad hocHarleen Sahota on behalf of CIWGRemoved an out-of-date point in the Analysis Check List on how the Health Indicators department at Statistics Canada handles 'Not Stated' respondents when using CCHS data.


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