Screening for colorectal cancer: the cost to find an advanced adenoma

OBJECTIVE: Cancer Care Ontario has recommended a program to screen for colorectal cancer using fecal occult blood testing (FOBT). Patients who test positive on FOBT will require further investigation. We examined the cost of finding an advanced adenoma in these patients using four different strategies. METHODS: Using decision analysis software (DATA 3.5, TreeAge Software, Boston, MA), we considered four strategies for evaluating patients referred for a positive FOBT: 1) flexible sigmoidoscopy to the splenic flexure, 2) flexible sigmoidoscopy with air contrast barium enema (ACBE), 3) virtual colonoscopy, and 4) colonoscopy. If an adenoma was found in any of the first three methods, colonoscopy and polypectomy were performed. An advanced adenoma was defined as a villous adenoma, tubular adenoma > or = 10 mm, high grade dysplasia, or cancer. Values for probabilities, test characteristics and costs ($CDN) were estimated from a MEDLINE literature review, local costs, and OHIP fee codes. Patients with adenomas identified as well as direct medical costs from a third party payer perspective were calculated. RESULTS: Assuming a probability of adenoma of 16.9%, the cost for each strategy (compared to no investigation) was as follows: flexible sigmoidoscopy to the splenic flexure, $226; flexible sigmoidoscopy with ACBE, $424; virtual colonoscopy, $597; and colonoscopy, $387. The cost to clear a patient of adenoma(s) was $1,930, $2,840, $3,681, and $2,290, respectively. Despite being most cost-effective, the sigmoidoscopy strategy was predicted to detect 69% of cases of advanced adenomas. The radiological strategies would be less expensive if ACBE cost less than $115 or virtual colonoscopy cost less than $291. The colonoscopy strategy was more cost-effective if the probability of an adenoma was > or = 33.5%. When the incremental costs were considered to investigate 1000 patients, virtual colonoscopy and sigmoidoscopy with ACBE were both more costly then colonoscopy, and neither detected as many cases of advanced adenomas. CONCLUSION: Improved access to colonoscopy seems to be the preferred approach to deal with increased referrals.     

Use of flexible sigmoidoscopy to screen for colorectal cancer in HIV-infected patients 50 years of age and older

BACKGROUND: Although many patients with human immunodeficiency virus (HIV) infection are now living well beyond 50 years of age, there are no data available on colorectal cancer screening in this population. The aim of this study was to determine the utility of screening flexible sigmoidoscopy in patients with HIV. METHODS: Consecutive patients at average risk for colorectal cancer who were referred for screening flexible sigmoidoscopy were prospectively identified. A detailed medical history was obtained from all patients before flexible sigmoidoscopy, and colonoscopy was recommended for all subjects with positive sigmoidoscopic findings. RESULTS: A total of 2382 patients were enrolled in the study; 165 were HIV positive. The prevalence of neoplastic lesions (adenomas or adenocarcinomas) in the distal colon was significantly higher in HIV-infected patients than in control subjects (25.5% vs 13.1%, P<.001), and the odds of HIV-infected patients having a neoplastic lesion was significantly higher even after adjustment for potential confounding variables (odds ratio, 2.34; 95% confidence interval, 1.60-3.44). The prevalence of adenomas of any size (25.5% vs 12.9%, P<.001) and advanced neoplasia (7.3% vs 3.8%, P = .03) in the distal colon was significantly higher in HIV-infected patients. Among individuals with positive results on flexible sigmoidoscopy, proximal colonic neoplastic lesions on follow-up colonoscopy were more common in HIV-infected patients after adjustment for age, sex, and race/ethnicity (odds ratio, 1.88; 95% confidence interval, 1.02-3.46). CONCLUSIONS: Patients infected with HIV are more likely to have colonic neoplasms on screening flexible sigmoidoscopy than those without HIV, and these individuals should be offered colorectal cancer screening.     

Geographic variation among Medicare beneficiaries in the use of colorectal carcinoma screening procedures

OBJECTIVES: To study geographic variation in the use of recommended screening procedures for colorectal carcinoma. METHODS: All Medicare claims for fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, barium enema and two reference procedures, upper endoscopy, and upper gastrointestinal series in patients > or = 65 yr were obtained from the 1997-1999 physician-supplier and outpatient files. State-level procedure rates and the change in rates from 1997 to 1999 were calculated. RESULTS: The median annual rates were as follows: FOBT, 14.54%; flexible sigmoidoscopy, 3.03%; colonoscopy, 6.22%; barium enema, 2.21%; upper gastrointestinal endoscopy, 4.88%; and upper gastrointestinal series, 2.78%. Whereas there was at least a 50% difference between the 25th and 75th percentiles for state rates of FOBT and sigmoidoscopy, the variation in other procedures was more modest. State-level rates of colonoscopy and upper gastrointestinal endoscopy were highly correlated (r = 0.79; p < 0.0001), as were the rates of barium enema and upper gastrointestinal series (r = 0.68; p < 0.0001). Universal increases in colonoscopy use (median +25.0%) and decreases in barium enema use (median -20.9%) from 1997 to 1999 were observed among individual states. CONCLUSIONS: There is variation at the state level in the use of some, but not all colorectal procedures, as well as fairly consistent temporal trends. The etiology of the differences is not clear, but the correlation in the rates of selected procedures suggests the presence of local practice patterns.     

Is colorectal cancer screening necessary in the preoperative assessment of inguinal herniorrhaphy? a case-control study

OBJECTIVES: The question of whether patients presenting for inguinal hernia repair require pre-operative assessment for colon cancer has remained unanswered. A case-control study is necessary to assess whether the prevalence of premalignant or malignant colonic lesions is higher in patients presenting with inguinal hernia compared to the general population. METHODS: Between 1990-2000, 614 inguinal herniorrhaphies were performed at the Veterans Affairs Palo Alto Health Care System (VAPAHCS). We retrospectively studied the 149 (24%) patients from this group with no prior history of colonic polyps, malignancy, or gastrointestinal bleeding who had flexible sigmoidoscopy or colonoscopy performed during the peri-operative period. Comparison was made to 149 controls undergoing colonoscopy or sigmoidoscopy during the same time period for colon cancer (CRC) screening. RESULTS: The mean (+/-SEM) patient age was 67 +/- 0.7 (range 31-92) yr in the hernia patients and 66 +/- 0.8 (range 46-93) in the control group (p = 0.7). Eighty-two of the inguinal hernia patients had screening procedures performed preoperatively with a mean time (+/-SEM) of 1.4 +/- 0.14 yr, while endoscopy was performed in the post-operative period for the remaining 67 patients (average time 2.7 +/- 0.2 yr, p < 0.001). More patients underwent colonoscopy in the control group compared to the hernia cohort (p = 0.004). Seven (5%) patients in the hernia group were found to have colorectal cancer compared to six (4%) in the control group (p = 0.8). CONCLUSIONS: This study does not support previously published findings that patients with inguinal hernias are more likely to have premalignant colonic lesions. Patients with inguinal hernias should undergo screening for colon cancer at the same rate as the general population.     

Colorectal cancer screening

Colorectal cancer (CRC) is the third most common cause of cancer death worldwide and a major health problem. In this review, the different approaches for CRC screening will be outlined with emphasis on evidence-based medicine. Evidence from randomized trials on the effectiveness of CRC screening is summarized. Several screening tools for CRC are available. They can be categorized according to their mode of action: early detection tools such as the faecal occult blood test (FOBT) and cancer prevention tools such as flexible sigmoidoscopy and colonoscopy. Meta-analyses of randomized trials show that FOBT screening reduces CRC mortality by 16% (risk ratio 0.84; 95% confidence interval (CI) 0.78-0.9) compared with 30% (risk ratio 0.7; 95% CI 0.6-0.81) for flexible sigmoidoscopy screening. FOBT screening is cheap and noninvasive, but results in large numbers of false-positive tests and needs to be repeated frequently. Flexible sigmoidoscopy is more invasive, but is effective for once-only screening. Although colonoscopy screening is used in some countries, no randomized trials have been conducted to estimate its benefit, and therefore, it should not be recommended at the present time. Faecal occult blood test and flexible sigmoidoscopy are the two CRC screening tools that can be recommended as they have been proven to reduce CRC mortality. Colonoscopy has the potential to be superior to FOBT and flexible sigmoidoscopy, but needs to be evaluated in randomized trials before any recommendation can be provided.     

A population-based estimate of the extent of colorectal cancer screening in Ontario

BACKGROUND/OBJECTIVE: The incidence and mortality rates for colorectal cancer (CRC) in Canada are among the highest in the world. For individuals >/=50 yr, CRC screening is effective in reducing both CRC incidence and mortality. The goal of this research was to conduct a Canadian population-based study of the use of tests and procedures to evaluate the large bowel to estimate the extent of CRC screening. METHODS: We identified an inception cohort of all residents of Ontario aged 50-59 on January 1, 1995, without a previous history of CRC or large-bowel evaluation by five tests or procedures: fecal occult blood test (FOBT), barium enema, rigid sigmoidoscopy, flexible sigmoidoscopy, and colonoscopy. We followed these individuals to December 31, 2000, identified all tests received, and determined the proportion that received one or more tests or procedures of each type. Data were obtained from three sources: the Ontario Health Insurance Plan (OHIP) database, the Canadian Institute for Health Information-Discharge Abstract Database (CIHI-DAD), and the Registered Persons Database (RPDB). RESULTS: We identified 982,443 individuals in our inception cohort without prior CRC or large bowel evaluation. The proportion that had at least one test or procedure was less than 10% for each type. The largest proportion (9.3%) had one or more FOBTs. Classified according to the initial test received, 14.5% had a non-endoscopic test (FOBT, barium enema) and 6% had an endoscopic test (rigid sigmoidoscopy, flexible sigmoidoscopy, colonoscopy). The majority (79.5%) had no test or procedure to evaluate the large bowel. CONCLUSION: An extraordinarily low proportion (<20.5%) of screen-eligible 50-59-yr-old men and women in Ontario were screened for CRC during a 6-yr follow-up. Given the high burden of CRC in Canada a major opportunity exists to improve the health of Canadians by increasing our screening efforts.     

Case-control study of screening colonoscopy in relatives of patients with colorectal cancer

OBJECTIVES: The efficacy of colonoscopic screening and polypectomy for the prevention of colorectal cancer (CRC) is well accepted but has never been documented in a prospective, controlled study. Screening by sigmoidoscopy has been found to reduce mortality from cancer of the rectum and distal colon. Case-control studies provide an alternative method for determining the efficacy of screening methods. METHODS: Between 1998 and 2000, a total of 40 subjects were found to have CRC (study group) and 160 had a normal colon (control group) among asymptomatic individuals participating in a screening colonoscopy program for a high-risk population of first-degree relatives of CRC patients. We compared these groups for screening by fecal occult blood testing, flexible sigmoidoscopy, barium enema, and colonoscopy in the 10-yr period before the index colonoscopy. RESULTS: Screening colonoscopy was performed in only 2.5% of the case subjects and 48.7% of controls (p < 0.0001), and all screening procedures in 12.5% and 73.7%, respectively (p < 0.0001). A statistically significant difference was also found for screening with fecal occult blood test, but not for flexible sigmoidoscopy or barium enema. Significant adenomatous polyps >1 cm in diameter were detected and removed in 19% of the control group within 10 yr of the index colonoscopy. Six (15%) of the patients in the study group died of CRC. CONCLUSIONS: Screening by colonoscopy can prevent progression to CRC from adenomatous polyps and may reduce the mortality associated with this devastating disease.     

Predictors of colorectal cancer screening participation in the United States

OBJECTIVE: Our aim was to identify predictors of colorectal cancer screening in the United States and subgroups with particularly low rates of screening. METHODS: The responses to a telephone-administered questionnaire of a nationally representative sample of 61,068 persons aged >/=50 yr were analyzed. Current screening was defined as either sigmoidoscopy/colonoscopy in the preceding 5 years or fecal occult blood testing (FOBT) in the preceding year, or both. RESULTS: Overall, current colorectal cancer screening was reported by 43.4% (sigmoidoscopy/colonoscopy by 22.8%, FOBT by 9.9%, and both by 10.7%). The lowest rates of screening were reported by the following subgroups: those aged 50-54 yr (31.2%), Hispanics (31.2%), Asian/Pacific Islanders (34.8%), those with education less than the ninth grade (34.4%), no health care coverage (20.4%), or coverage by Medicaid (29.2%), those who had no routine doctor's visit in the last year (20.3%), and every-day smokers (32.1%). The most important modifiable predictors of current colorectal cancer screening were health care coverage (OR = 1.7, 95% CI = 1.5-1.9) and a routine doctor's visit in the last year (OR = 3.5, 95% CI = 3.2-3.8). FOBT was more common in women than in men (OR = 1.8, 95% CI = 1.6-2.0); sigmoidoscopy/colonoscopy was more common in Hispanics (OR = 1.4, 95% CI = 1.1-1.7) and Asian/Pacific Islanders (OR = 2.4, 95% = CI 1.5-3.9) relative to whites, in persons without routine doctor's visits in the preceding year (OR = 3.3, 95% CI = 2.8-4), and in persons with poor self-reported health (OR = 1.3, 95% CI = 1.2-1.5). CONCLUSIONS: Interventions should be developed to improve screening for the subgroups who reported the lowest screening rates. Such interventions may incorporate individual screening strategy preferences.     

Physician-reported reasons for limited follow-up of patients with a positive fecal occult blood test screening result

OBJECTIVE: Fecal occult blood testing (FOBT) screening can reduce colorectal cancer (CRC) mortality when patients with an abnormal result [FOBT(+)] undergo a complete diagnostic evaluation (colonoscopy or double-contrast barium enema with or without flexible sigmoidoscopy). The aim of this study was to determine common reasons for nonperformance of a complete diagnostic evaluation. METHODS: We identified 544 FOBT(+) patients, aged 50 yr or older, who had participated in a managed care organization-sponsored CRC screening program. The performance of a complete diagnostic evaluation was determined from a patient-specific follow-up form and managed care organization claims data. Physicians were asked to report whether patients submitted to a complete diagnostic evaluation. When an evaluation was not done, the physicians were also asked to state the reasons for nonperformance. RESULTS: A total of 248 (46%) patients did not undergo a complete diagnostic evaluation. Physicians provided reasons for nonperformance for 50% (123/248). Factors accounting for nonperformance of a complete diagnostic evaluation were classified as follows: primary care physician decision (50%); specialist decision (28%); patient decision (17%); and other (practice-related) (5%). Many failures to complete an appropriate diagnostic evaluation were due to providers deciding to repeat the FOBT, perform a sigmoidoscopy, or not to proceed with any further testing. CONCLUSION: Many patients with a positive FOBT do not receive a complete diagnostic evaluation. The reasons for nonperformance most frequently have to do with physician decision making. Many physician-related explanations do not conform to expert recommendations for appropriate follow-up.     

The Norwegian Colorectal Cancer Prevention (NORCCAP) screening study: baseline findings and implementations for clinical work-up in age groups 50-64 years

BACKGROUND: Randomized controlled trials of sufficient power testing the long-term effect of screening for colorectal neoplasia only exist for faecal occult blood testing (FOBT). There is indirect evidence that flexible sigmoidoscopy (FS) may have a greater yield. The aim of this study was to determine the diagnostic yield of screening with FS or a combination of FS and FOBT in an average-risk population in an urban and combined urban and rural population in Norway. METHODS: 20,780 men and women (1:1), aged 50-64 years, were invited for once-only screening (FS only or a combination of FS and FOBT (1:1)) by randomization from the population registry. A positive FS was defined as a finding of any neoplasia or any polyp > or = 10 mm. A positive FS or FOBT qualified for colonoscopy. RESULTS: Overall attendance was 65%. Forty-one (0.3%) cases of CRC were detected. Any adenoma was found in 2208 (17%) participants and 545 (4.2%) had high-risk adenomas. There was no difference in diagnostic yield between the FS and the FS and FOBT group regarding CRC or high-risk adenoma. Work-up load comprised 2821 colonoscopies in 2524 (20%) screenees and 10% of screenees were recommended later colonoscopy surveillance. There were no severe complications at FS, but six perforations after therapeutic colonoscopy (1:336). CONCLUSIONS: The present study bodes well for future management of a national screening programme, provided that follow-up results reflect adequate proof of a net benefit. It is highly questionable whether the addition of once-only FOBT to FS will contribute to this effect.     

Strategies in screening for colon carcinoma

Colorectal cancer is the second most common cancer in Europe and meets the criteria for population screening. Population screening should lead to a reduction in CRC-related mortality and incidence. Several options are available for CRC screening, which can be itemised as stool-based tests and structural exams. Stool-based tests include guaiac and immunochemical faecal occult blood tests and DNA -marker tests. Structural exams comprise endoscopic techniques (flexible sigmoidoscopy, colonoscopy and capsule endoscopy) and radiological exams (double contrast barium enema, CT colonography and MR colonography). Each test has its own test performance characteristics and acceptability profile, which affect the participation and effectiveness of the associated screening programmes. Faecal occult blood tests (FOBT ) and flexible sigmoidoscopy (FS) are the only methods with a demonstrated mortality reduction during a ten-year period (FOBT 16% and FS 31%) while flexible sigmoidoscopy is the only screening test with a demonstrated reduction in CRC incidence (23%). It is likely that other screening techniques such as colonoscopy and CT colonography will also be effective in the reduction of CRC-related mortality. DNA -marker tests, capsule endoscopy and MR colonography are possible options for the future.     

A population-based, community estimate of total colon examination: the impact on compliance with screening for colorectal cancer

OBJECTIVE: Colorectal cancer screening is underutilized. Total colon examination (TCE), such as with colonoscopy, can have a significant effect on the measured compliance with screening, as colonoscopy may be able to be performed as infrequently as once every 10 yr. In a population-based survey we determined the prevalence and validated the self-reporting of TCE and assessed its impact on compliance with screening. METHODS: We interviewed an age- and sex-stratified random sample of 50- to 79-yr-old residents in two communities in southwestern Pennsylvania. Subjects reported ever having had and duration since last use of fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), rigid proctoscopy, barium enema, and colonoscopy. Self-reports of colorectal testing were validated via retrieval of procedure reports. RESULTS: Out of 1223 individuals sampled, 496 completed a telephone interview (40.6% overall and 58.3% of eligible contacts). In those without personal or family histories of colorectal cancer or personal histories of polyps (n = 377), 50%, 19.6%, 39.8%, and 17.5% reported ever having had FOBT, FS, barium enema, and colonoscopy, respectively. Thirty-one percent reported having FOBT within the previous year or FS within the previous 5 yr. Including TCE within the previous 5 yr increased the measured compliance to 39.7%. Compliance was significantly greater among subjects with family histories of colorectal cancer (62.9% vs 39.7%, odds ratio = 2.6, 95% CI = 1.3-5.2). Self-reports of recent colonoscopy were verified in 29 of 35 instances (83%). CONCLUSION: The prevalence of TCE in this population was significant, and including TCE substantially increased measured compliance with colorectal cancer screening. Self-reported use of colonoscopy was validated as accurate.     

Barriers to colorectal cancer screening in Latino and Vietnamese Americans

OBJECTIVE: To identify current colorectal cancer (CRC) screening practices and barriers to screening in the Latino, Vietnamese, and non-Latino white populations. METHODS: We conducted a telephone survey of Latino, non-Latino white, and Vietnamese individuals living in San Jose, California. We asked about demographics, CRC screening practices, intentions to be screened, and barriers and facilitators to screening. RESULTS: Seven hundred and seventy-five individuals (40% white, 29.2% Latino, and 30.8% Vietnamese) completed the survey (Response Rate 50%). Overall, 23% of respondents reported receipt of fecal occult blood test (FOBT) in the past year, 28% reported sigmoidoscopy (SIG) in the past 5 years, and 27% reported colonoscopy (COL) in the past 10 years. Screening rates were generally lower in Latinos and Vietnamese. Vietnamese were less likely than whites to have had SIG in the past 5 years (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.09 to 0.72), but ethnicity was not an independent predictor of FOBT or COL. Only 22% of Vietnamese would find endoscopic tests uncomfortable compared with 79% of whites (P <.05). While 21% of Latinos would find performing an FOBT embarrassing, only 8% of whites and 3% of Vietnamese felt this way (P <.05). Vietnamese were more likely than whites to plan to have SIG in the next 5 years (OR, 2.24; 95% CI, 1.15 to 4.38), but ethnicity was not associated with planning to have FOBT or COL. CONCLUSIONS: Rates of CRC screening are lower in ethnic minority populations than in whites. Differences in attitudes and perceived barriers suggest that culturally tailored interventions to increase CRC screening will be useful in these populations     

Fecal DNA testing compared with conventional colorectal cancer screening methods: a decision analysis

BACKGROUND & AIMS: Fecal DNA testing is an emerging tool to detect colorectal cancer (CRC). Our aims were to estimate the clinical and economic consequences of fecal DNA testing vs. conventional CRC screening. METHODS: Using a Markov model, we estimated CRC incidence, CRC mortality, and discounted cost/life-year gained for screening by fecal DNA testing (F-DNA), fecal occult blood testing (FOBT) and/or sigmoidoscopy, or colonoscopy (COLO) in persons at average CRC risk from age 50 to 80 years. RESULTS: Compared with no screening, F-DNA at a screening interval of 5 years decreased CRC incidence by 35% and CRC mortality by 54% and gained 4560 life-years per 100,000 persons at USD $47,700/life-year gained in the base case. However, F-DNA gained fewer life-years and was more costly than conventional screening. The average number of colonoscopies per person was 3.8 with COLO and 0.8 with F-DNA. In most 1-way sensitivity analyses and Monte Carlo simulation iterations, F-DNA remained reasonably cost-effective compared with no screening, but COLO and FOBT dominated F-DNA. Assuming fecal DNA testing sensitivities of 65% for CRC and 40% for large polyp, and 95% specificity, a screening interval of 2 years and a test cost of USD $195 would be required to make F-DNA comparable with COLO. CONCLUSIONS: Fecal DNA testing every 5 years appears effective and cost-effective compared with no screening, but inferior to other strategies such as FOBT and COLO. Fecal DNA testing could decrease the national CRC burden if it could improve adherence with screening, particularly where the capacity to perform screening colonoscopy is limited.     

Comparison of patients' experiences during imaging tests of the colon.

BACKGROUND: Physical discomfort, anxiety, embarrassment, and other aspects of patient experience impact on future compliance for colonic imaging tests. Therefore, a prospective study was performed comparing patient experiences during air contrast barium enema (ACBE), flexible sigmoidoscopy, and colonoscopy. METHODS: Immediately after each procedure, patients completed a questionnaire assessing pretest anxiety, difficulty with preparation, pain, cramping, bloating, overall discomfort, loss of dignity, willingness to repeat the test, and overall satisfaction. A follow-up questionnaire was administered within 48 hours. Nurses and physicians also completed questionnaires to assess the provider impression of patient experience. RESULTS: Four hundred ten patients (80 ACBE, 202 sigmoidoscopy, 128 colonoscopy) were prospectively enrolled. Sigmoidoscopy caused more pain than ACBE (Odds ratio [OR] 2.64: 95% CI [1.63, 4.27]) or colonoscopy (OR 1.83: 95% CI [1.21, 2.77]). ACBE and colonoscopy did not differ in the degree of pain. Although overall satisfaction appeared to be similar for all tests, patients were less willing to repeat ACBE than sigmoidoscopy (OR 1.85: 95% CI [1.13, 3.02]) or colonoscopy (OR 1.82: 95% CI [1.07, 3.09]). Initial and follow-up pain ratings by patients were highly correlated (Spearman correlation 0.81); however, correlation of pain assessments between staff and patients was poor (Spearman correlation 0.48). CONCLUSIONS: Sigmoidoscopy was more painful than other colonic imaging modalities. Although ACBE and colonoscopy caused similar pain, patients were less willing to repeat ACBE. In aggregate, the data suggest that patients perceive colonoscopy as the most acceptable colonic imaging procedure. Better methods are required to allow staff to adequately assess discomfort experienced by patients during these procedures.     

The Norwegian Colorectal Cancer Prevention (NORCCAP) Screening Study

Background: Randomized controlled trials of sufficient power testing the long-term effect of screening for colorectal neoplasia only exist for faecal occult blood testing (FOBT). There is indirect evidence that flexible sigmoidoscopy (FS) may have a greater yield. The aim of this study was to determine the diagnostic yield of screening with FS or a combination of FS and FOBT in an average-risk population in an urban and combined urban and rural population in Norway. Methods: 20,780 men and women (1:1), aged 50-64 years, were invited for once-only screening (FS only or a combination of FS and FOBT (1:1)) by randomization from the population registry. A positive FS was defined as a finding of any neoplasia or any polyp &#83 10 &#114 mm. A positive FS or FOBT qualified for colonoscopy. Results: Overall attendance was 65%. Forty-one (0.3%) cases of CRC were detected. Any adenoma was found in 2208 (17%) participants and 545 (4.2%) had high-risk adenomas. There was no difference in diagnostic yield between the FS and the FS and FOBT group regarding CRC or high-risk adenoma. Work-up load comprised 2821 colonoscopies in 2524 (20%) screenees and 10% of screenees were recommended later colonoscopy surveillance. There were no severe complications at FS, but six perforations after therapeutic colonoscopy (1:336). Conclusions: The present study bodes well for future management of a national screening programme, provided that follow-up results reflect adequate proof of a net benefit. It is highly questionable whether the addition of once-only FOBT to FS will contribute to this effect.     

Options for screening for colorectal cancer

Unlike other types of cancer, there are several options for screening for colorectal cancer (CRC). The most extensively examined method, faecal occult blood testing (FOBT), has been shown, in three large randomized trials, to reduce mortality from CRC by up to 20% if offered biennally and possibly more if offered every year. Recently published data from the US trial suggest that CRC incidence rates are also reduced by up to 20%, but only after 18 years. In this study, the number of positive slides was associated with the positive predictive value both for CRC and adenomas larger than 1 cm, suggesting that the reduction in CRC incidence was caused by the identification and removal of large adenomas. In this respect, this study supports the concept that removing adenomas prevents CRC. More efficient methods of detecting adenomas include the use of colonoscopy or flexible sigmoidoscopy (FS). Considerable evidence exists from case-control and uncontrolled cohort studies to suggest that endoscopic screening by sigmoidoscopy reduces incidence of distal colorectal cancer. However, in the absence of evidence from a randomized trial, several countries have been reluctant to introduce endoscopic screening. Three trialsare currently in progress (in the UK, Italy and the US) to address this issue. Two of these trials are examining the hypothesis that a single FS screen at around age 55-64 might be a cost-effective and acceptable method for reducing CRC incidence rates. Recruitment and screening are now complete in both studies and the first analysis of results on incidence rates is expected in 2004. Colonoscopy screening at 10-year intervals has recently been endorsed in the US on the basis that the reductions in incidence observed with distal CRC screening can be extrapolated to the proximal colon. However, data are lacking and a pilot study for a trial of the acceptability and efficacy of colonoscopy screening is in progress in the US. It has also been suggested that FOBT testing should be used to detect proximal CRC missed by sigmoidoscopy screening, but the small amount of published data suggest that supplementing FS with FOBT offers very little advantage over FS alone. Other forms of CRC screening are under investigation and represent exciting options for the future. Extraction of DNA from stool is now feasible and a number of research groups have shown high sensitivity for CRC using a panel of DNA markers including mutations in k-ras, APC, p53 and BAT26. Data so far indicate that, with the exception of k-ras, these markers are highly specific and therefore represent a significant improvement over FOBT. Whether these tests will replace or supplement existing methods of screening has yet to be determined. It has been suggested that BAT26, which is a marker of microsatellite instability, a feature of proximal sporadic CRC, might be a useful adjunct to sigmoidoscopy screening. Others have suggested that a test for occult blood should be included with the DNA markers to further increase sensitivity. It is not yet known how sensitive these markers are for adenomas--it is only by detecting adenomas that CRC incidence rates can be reduced. A final exciting new option for screening is virtual colonoscopy (VC), which by screening out people without neoplasia allows colonoscopy to be reserved for patients requiring a therapeutic intervention. The sensitivity of VC for large adenomas and CRC appears to be high, although results vary by centre and there is a steep learning curve. Sensitivity for small adenomas is low, but perhaps it is less essential to find such lesions. Some groups have suggested that virtual colonoscopy might be a useful option for investigating patients who test positive with stool-based screening tests. Whichever CRC screening method is finally chosen (and there is no reason why several methods should not ultimately be available), high quality endoscopy resources will always be required to investigate and treat neoplastic lesions detected.     

Promoting use of colorectal cancer screening tests

BACKGROUND: Colorectal cancer (CRC) screening is underutilized despite evidence that screening reduces mortality. OBJECTIVE: To assess the effect of an intervention targeting physicians and their patients on rates of CRC screening. DESIGN: A randomized clinical trial of community physicians and their patients. PARTICIPANTS: Ninety-four community primary care physicians randomly assigned to an intervention consisting of academic detailing and direct mailings to patients or a control group. Patients aged 50 to 79 years in the intervention group physicians received a letter from their physician, a brochure on CRC screening, and a packet of fecal occult blood test (FOBT) cards. MEASUREMENTS: After 1 year we measured receipt of the following: (1) FOBT in the past 2 years, (2) flexible sigmoidoscopy (SIG) or colonoscopy (COL) in the previous 5 years, and (3) any CRC screening. We report the percent change from baseline in both groups. RESULTS: 9,652 patients were enrolled for 2 years, and 3,732 patients were enrolled for 5 years. There was no increase in any CRC screening that occurred in the intervention group for patients enrolled for 2 years (12.7 increase vs 12.5%, P=.51). Similar results were seen for any CRC screening among patients enrolled for 5 years (9.7% increase vs 8.6%, P=.45). The only outcome on which the intervention had an effect was on patient rates of screening SIG (7.4% increase vs 4.4%, P<.01). CONCLUSION: With the exception of an increase in rates of SIG in the intervention group, the intervention had no effect on rates of CRC screening. Future interventions should assess innovative approaches to increase rates of CRC screening.     

Are Physicians’ Recommendations For Colorectal Cancer Screening Guideline-Consistent?

BACKGROUND  

Many older adults in the U.S. do not receive appropriate colorectal cancer (CRC) screening. Although primary care physicians’ recommendations to their patients are central to the screening process, little information is available about their recommendations in relation to guidelines for the menu of CRC screening modalities, including fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), colonoscopy, and double contrast barium enema (DCBE). The objective of this study was to explore potentially modifiable physician and practice factors associated with guideline-consistent recommendations for the menu of CRC screening modalities.     

Family history and colorectal cancer screening: a survey of physician knowledge and practice patterns

OBJECTIVES: Risk stratification is essential to effective implementation of colorectal cancer (CRC) screening strategies. The objectives of this study were to assess and compare the current knowledge and practice patterns of gastroenterologists and primary care physicians regarding familial risk of CRC. METHODS: We conducted a survey of regional gastroenterologists and a sample of university- and community-based primary care physicians. The survey instrument assessed physician knowledge of screening recommendations and current practices for individuals with family histories of CRC, adenomatous polyps (APs), familial adenomatous polyposis (FAP), and hereditary nonpolyposis cancer (HNPCC). The instrument also elicited data about familial risk assessment, documentation, and notification of at-risk family members. RESULTS: Thirty-five gastroenterologists (65%) and 58 primary care physicians (92%) completed the survey. Most gastroenterologists and primary care physicians (85% vs 72%) chose age 40 as the appropriate age to begin screening for a family history of CRC, but relatively few (37% vs 36%) recommended screening at age 40 for a family history of APs. Gastroenterologists were significantly more likely to recommend screening for FAP at puberty (80% vs 27%, p < 0.001) and for HNPCC at age 25 (73% vs 50%, p = 0.04). Colonoscopy was the preferred screening strategy by both groups for family histories of CRC (97%), HNPCC (97%), and APs (77%); primary care physicians also preferred colonoscopy for family histories of CRC (72%) and HNPCC (76%) but flexible sigmoidoscopy plus fecal occult blood testing for a family history of APs (38%). Gastroenterologists were more likely to recommend genetic testing for persons at risk of FAP (91% vs 71%, p = 0.03) and HNPCC (72% vs 57%, p = 0.18), routinely inquire about a family history of CRC or APs (93% vs 63%, p < 0.001), and recommend notification of at-risk first-degree relatives with family histories of CRC (94% vs 55%, p < 0.001) or AP (53% v.s 6%, p < 0.001). CONCLUSION: Although gastroenterologists are more likely than primary care physicians to elicit a family history of colorectal neoplasia and implement appropriate screening strategies, overall compliance with recommended guidelines and notification of at-risk relatives are suboptimal. Novel approaches for improving awareness of the available screening guidelines are needed.