Colorectal cancer screening: practices and opinions of primary care physicians

Abstract

Background. The Canadian Task Force on Preventive Health Care (CTFPHC), in 2001, concluded that there is good evidence to include annual or biennial fecal occult blood testing (FOBT) and fair evidence to include flexible sigmoidoscopy in the periodic health examination of asymptomatic adults more than 50 years of age.

Methods. Mailed survey of Alberta primary care physicians to determine current colorectal cancer (CRC) screening practices, familiarity with the new guideline, and opinions about, and barriers to, screening average-risk patients.

Results. Response rate was 58.0% (n = 965). Less than half (41.9%) were familiar with the new Canadian guideline. The majority (74.7%) recommended that asymptomatic patients undergo screening; however, only 35.6% offered screening to at least 75% of average-risk patients. Few (9.4%) rated fecal occult blood as an “excellent or very good” screening test. Most (64.1%) physicians would choose colonoscopy if they themselves were to undergo screening. Concerns were raised about cost-effectiveness, inconsistencies of current recommendations, and resources.

Conclusion. Although supportive of colorectal cancer screening of average-risk patients, few physicians recommend screening for the majority of their patients. Clarification of inconsistencies between guidelines, resource issues, and the availability of efficacious screening tests is required for wider acceptance of the new Canadian guideline.

Introduction

Four randomized clinical trials (RCTs) [1], [2], [3], [4], [5], [6], [7] and one meta-analysis [8] provide evidence that screening with fecal occult blood testing (FOBT) can reduce colorectal cancer (CRC) mortality, with relative risk reductions ranging from 15% to 33%. Evidence supporting the use of other screening modalities including flexible sigmoidoscopy, colonoscopy, and air-contrast barium enema (ACBE) comes from observational studies rather than RCTs. Several published models [9], [10], [11], [12], [13] and a recent review [14] of United States (US) cost-effectiveness studies concluded that all commonly recommended screening strategies for adults aged 50 and above will reduce CRC mortality at a cost of US$10,000–25,000 per life-year saved. However, it was not clear from the analysis whether one particular strategy was superior.

Several professional societies, organizations, and cancer agencies recommend screening average-risk adults for colorectal cancer [15], [16], [17], [18], [19], [20]. The Canadian Task Force on Preventive Health Care (CTFPHC) concluded, in 2001, that there is good evidence to include annual or biennial FOB testing and fair evidence to include flexible sigmoidoscopy in the periodic health examination of asymptomatic people more than 50 years of age [15]. This recommendation was based on a systematic review of the evidence [21] and graded based on the quality of published medical evidence [22]. The recommendation was widely disseminated to Canadian primary care physicians [15], [23].

Guidelines in the US take a different approach by recommending a variety of screening options and suggesting that the physician, together with the patient, determines the appropriate test strategy [16], [20]. The rationale for offering multiple screening options reflects both the lack of evidence suggesting a single test is of unequivocal superiority and the belief that allowing patients to make an informed choice that incorporates their personal preferences will increase the likelihood of screening [24].

Screening rates for CRC have changed very little [25] since the introduction of guidelines, and screening rates for CRC lag behind other, more established cancer screening tests [26], [27], [28]. Indeed, a recent US National Cancer Institute workshop identified research to address barriers to the implementation of routine CRC screening as one of the primary challenges facing cancer researchers [29].

Primary care physicians must play a key role in screening for colorectal cancer. Physician recommendation is a strong predictor of acceptance of colorectal [30], [31] and other cancer screening tests [32], [33], [34]. However, little is known about primary care physicians' attitudes towards CRC screening. The purpose of this study was to determine primary care physicians' current screening practices, familiarity with the newly released guideline, and opinions about, and key perceived barriers to CRC screening of average-risk patients.