We found that an exceptionally low proportion (17.6%) of eligible Canadians reported having received colorectal cancer screening within the recommended time frame. The proportion varied significantly among provinces, but it was low in all of the provinces sampled. Increased self-reported contact with a family physician was associated with an increased likelihood of colorectal cancer screening. However, even among patients who reported more than 4 physician contacts in the 12 months before the survey, up-to-date colorectal cancer screening was reported by only one-fifth of the respondents. Fewer women than men, and fewer non-white than white respondents, reported receiving colorectal cancer screening. However, women and non-white respondents reported having more contact with physicians.
From 1995 to 2000, administrative and billing data indicate that less than 20.5% of Ontario residents aged 50–59 years were screened for colorectal cancer.7
In an Ontario survey8
performed during 1998–2000, 23% of respondents aged 50 years or older reported ever receiving colorectal cancer screening. Despite the current evidence and the publication of the recommendations of the Canadian Task Force on Preventive Health Care in 2001, our study suggests that participation in colorectal cancer screening programs is essentially unchanged.
Participation in colorectal cancer screening and the development of organized screening programs varies widely between regions and countries. In Canada, several provinces have announced colorectal screening programs, but no national strategy exists. In the United States, screening programs exist, but they vary considerably in terms of coverage and completeness.11
About 15% of Americans aged 50 years or older have undergone fecal occult blood testing for screening purposes and almost 21% have undergone endoscopy.12
In the United Kingdom, a nationally administered colorectal screening program and a recall system have recently been instituted. Pilot data from this program indicate uptake of almost 60%.13
Similar to the pilot program underway in Manitoba, in the United Kingdom people receive kits for fecal occult blood testing directly by mail instead of having to obtain them from a family physician.
The majority of physicians recommend screening for adults at average risk of colorectal cancer, and physicians themselves actively participate in screening.14,15
A recent Canadian survey found that 53% of physicians had undergone colorectal cancer screening and that 56% of all physicians and 91% of gastroenterologists chose to be screened by colonoscopy.15
In a separate Canadian study, 70% of physicians reported that colonoscopy was the only screening test that they themselves would undergo or recommend to their patients.16
Screening guidelines and approaches must evolve if specialists are choosing one modality when the official guidelines recommend another. This dichotomy may be confusing to family physicians, and it is likely to compromise the clarity and completeness with which they pursue colorectal cancer screening for their patients.
Our study has several limitations. It is based on self-reported data; thus, it is vulnerable to factors such as recall and misclassification bias. We feel that it is unlikely that respondents would systematically forget receiving fecal occult blood testing or sigmoidoscopy/colonoscopy, given the level of participation that these tests require. Self-reporting of colorectal cancer screening has been shown to provide accurate and reliable estimates of previously performed interventions.17
Our results for Ontario are also remarkably consistent with previously published analyses.7,8
Physician contact in this study included both visits and telephone calls. Although these methods of contact are unlikely to represent equivalent screening opportunities, this limitation is unlikely to cause bias in the overall findings of this study. Participation in colorectal cancer screening remained low over a range of physician contacts.
In conclusion, the proportion of people at average risk who reported having colorectal cancer screening in Canada is exceptionally low. This is true despite published guidelines and a widespread belief among physicians that screening for colorectal cancer is worthwhile. Contact with a family physician increases the odds of screening.
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