Which colon cancer screening test? A comparison of costs, effectiveness, and compliance.

PURPOSE: Recent media reports have advocated the use of colonoscopy for colorectal cancer screening. However, colonoscopy is expensive compared with other screening modalities, such as fecal occult blood testing and flexible sigmoidoscopy. We sought to determine the cost effectiveness of different screening strategies for colorectal cancer at levels of compliance likely to be achieved in clinical practice. METHODS: A Markov decision model was used to examine screening strategies, including fecal occult blood testing alone, fecal occult blood testing combined with flexible sigmoidoscopy, flexible sigmoidoscopy alone, and colonoscopy. The timing and frequency of screening was varied to assess optimal screening intervals. Sensitivity analyses were conducted to assess the factors that have the greatest effect on the cost effectiveness of screening. RESULTS: All strategies are cost effective versus no screening, at less than $20,000 per life-year saved. Direct comparison suggests that the most effective strategies are twice-lifetime colonoscopy and flexible sigmoidoscopy combined with fecal occult blood testing. Assuming perfect compliance, flexible sigmoidoscopy combined with fecal occult blood testing is slightly more effective than twice-lifetime colonoscopy (at ages 50 and 60 years) but is substantially more expensive, with an incremental cost effectiveness of $390,000 per additional life-year saved. However, compliance with primary screening tests and colonoscopic follow-up for polyps affect screening decisions. Colonoscopy at ages 50 and 60 years is the preferred test regardless of compliance with the primary screening test. However, if follow-up colonoscopy for polyps is less than 75%, then even once-lifetime colonoscopy is preferred over most combinations of flexible sigmoidoscopy and fecal occult blood testing. Costs of colonoscopy and proportion of cancer arising from polyps also affect cost effectiveness. CONCLUSIONS: Colonoscopic screening for colorectal cancer appears preferable to current screening recommendations. Screening recommendations should be tailored to the compliance levels achievable in different practice settings.     

Fecal occult blood and flexible sigmoidoscopy screening for colorectal cancer: modeling the impact on colonoscopy requirements and cancer detection rates

AiM: The aim of this study was to estimate the colonoscopy requirements and the likely impact of fecal occult blood and flexible sigmoidoscopy screening on the detection of colorectal cancer by using previously published data. METHODS: Fecal occult blood and flexible sigmoidoscopy screening programs were applied to the 2.04 million subjects aged 50-65 years, at a participation rate of 40%. The following strategies were evaluated: Fecal occult blood testing with colonoscopy follow up of all positive tests; flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps; and flexible sigmoidoscopy with colonoscopy follow up of all adenomatous polyps > 10 mm in size. RESULTS: The fecal occult blood program detected 5.6% of all colorectal cancer cases at a rate of 2,914 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program detected 14% of all colorectal cancer cases at a rate of 8,160 colonoscopies/percentage of detection of colorectal cancer. The flexible sigmoidoscopy program with follow up of adenomatous polyps > 10 mm in size detected 13% of all colorectal cancer cases at a rate of 1,230 colonoscopies/percentage of detection of colorectal cancer. CONCLUSIONS: Flexible sigmoidoscopy screening followed by colonoscopic follow up of adenomatous polyps > 10 mm in size is the most efficient screening strategy in terms of colonoscopies generated and cases of colorectal cancer detected.     

Flexible sigmoidoscopy for colorectal cancer screening: valid approach or short-sighted?

Flexible sigmoidoscopy is a safe, effective test that may be delivered feasibly on a large scale for mass colorectal cancer screening. Flexible sigmoidoscopy is 67% to 80% as sensitive as colonoscopy in a screening population, but is probably 10 to 20 times safer than colonoscopy in terms of complications. Several national guidelines recommend combining flexible sigmoidoscopy with fecal occult blood tests. There is limited evidence to support this practice, and the added benefit to an existing flexible sigmoidoscopy screening program although real, may be marginal. In the future, it is likely that flexible sigmoidoscopy screening among patients aged 50 to 65 will be supplemented with total colonic screening, using molecular-based fecal tests or virtual colonoscopy, after age 65.     

Procedure-related abdominal discomfort in patients undergoing colorectal cancer screening: a comparison of colonoscopy and flexible sigmoidoscopy

OBJECTIVES: The aims of this study were to determine if there was a difference in procedure-related abdominal discomfort or willingness to return for subsequent screening examinations between patients undergoing colonoscopy and those undergoing flexible sigmoidoscopy. METHODS: Two groups were compared: patients referred for screening flexible sigmoidoscopy and patients referred for screening colonoscopy. All patients were asymptomatic for colorectal cancer. Four university-based gastroenterologists performed all procedures. Patients received conscious sedation for colonoscopy but not for flexible sigmoidoscopy. A research nurse blinded to the procedure performed and the study purpose administered a standardized telephone questionnaire assessing and quantifying peri-procedural discomfort. RESULTS: A cohort of 466 patients underwent screening examinations, and 87% were contacted subsequent to their examination. Procedure-related discomfort, postprocedural discomfort, or discomfort at either of these two times ("peri-procedural discomfort") occurred in 28% (68/243), 14% (34/243), and 36% (88/243) of patients undergoing colonoscopy, respectively. Procedure-related discomfort, postprocedural discomfort, or discomfort at either of these two times occurred in 58% (94/162), 16% (26/162), and 62% (100/162) of patients undergoing flexible sigmoidoscopy, respectively. Peri-procedural discomfort was significantly more common in patients undergoing flexible sigmoidoscopy than with colonoscopy (p < 0.0005). Patients undergoing screening colonoscopy were more willing to undergo the procedure again than those undergoing screening flexible sigmoidoscopy (p < 0.0005). CONCLUSIONS: Patients undergoing screening colonoscopy with conscious sedation are less likely to experience peri-procedural discomfort than those undergoing screening flexible sigmoidoscopy. Although most patients are willing to undergo subsequent screening examinations, patients undergoing screening colonoscopy are significantly more willing to undergo a subsequent examination than those undergoing screening flexible sigmoidoscopy.     

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.     

The utilization of flexible sigmoidoscopy by family practitioners after residency training

BACKGROUND: Flexible sigmoidoscopy is routinely performed by family practice physicians, most of whom receive training in postgraduate education programs. The aim of this study was to assess the utilization of flexible sigmoidoscopy by family practitioners who received training during residency. METHODS: Family practitioners who underwent training in flexible sigmoidoscopy during their residency were contacted by phone or mail and polled regarding their current use of flexible sigmoidoscopy and assessment of their previous training. RESULTS: Forty-two graduates were contacted; 76% were certified (according to our predefined criteria) during training and 74% were currently performing flexible sigmoidoscopy. Of those who were certified, 87% were currently using flexible sigmoidoscopy compared with 45% of those who did not receive certification (p = 0.02). Training during the last year of residency was more likely to be associated with current use of flexible sigmoidoscopy than earlier training (69% vs. 30%, p = 0.03). Certification was associated with more procedures during training (24.3 +/- 1.7 vs. 16.6 +/- 3.1, p < 0.05). Current users performed a mean of 4.3 +/- 0.75 procedures/month; most reached 40 cm in depth of insertion and completed the procedure in 17.2 +/- 1.2 minutes. Of patients undergoing flexible sigmoidoscopy, 13% were ultimately referred for colonoscopy. Most practitioners considered their training useful and only 9.6% had obtained additional training outside residency. CONCLUSIONS: Most family practitioners certified in flexible sigmoidoscopy during residency performed the procedure in their practices. Depth of insertion and time for completion of the procedure seem to be adequate.     

Comparison of endoscopic procedures for colorectal cancer screening in women with mammography and Pap smear

BACKGROUND: This study compared the experiences of women who underwent endoscopic screening for colorectal cancer vs. their experiences with breast and cervical cancer screening by mammography and Pap smear, respectively. METHODS: Women who had either flexible sigmoidoscopy or colonoscopy as a screening procedure for colorectal cancer were asked to return a questionnaire by mail. In the questionnaire, they were asked about the procedure they had just undergone and to compare it with recent mammograms and Pap smears. Flexible sigmoidoscopy was performed without sedating the patient; colonoscopy was performed with the patient under deep sedation (midazolam, fentanyl, and propofol administered by an anesthesiologist). RESULTS: Responses were obtained from 258 women (88%). Of these, 152 had colonoscopy and 106 had flexible sigmoidoscopy. A total of 72% of respondents found colonoscopy to be a comfortable test. Only 26% found flexible sigmoidoscopy uncomfortable, which was similar to mammography and Pap smear, at 22%. In terms of the test considered to be the most embarrassing, the highest response rate (38%) was for the Pap smear. Most women had no preference as to the gender of the endoscopist, but 46% preferred a woman doctor for a Pap smear (p < 0.001). Preparation was regarded as the worst part of the colonoscopy procedure; for flexible sigmoidoscopy, the procedure itself and the preparation were equivalent. CONCLUSIONS: Women found flexible sigmoidoscopy or colonoscopy comfortable and less embarrassing than a Pap smear or a mammography. There was no preference with respect to the gender of the physician who performed the colorectal screening procedures, unlike the Pap smear. Most respondents would have the procedure again and would recommend it to others.     

Interrupting the adenoma-carcinoma sequence: screening for adenomas and cancer, now and in the future

Screening for colorectal cancer is only beginning to receive the attention it deserves. As screening emerges into the mainstream and utilization increases, competing technologies will battle to assume a greater percentage of the market share of testing. In this review, the standards and principles with which screening tests are evaluated are outlined. Current modalities for screening, including fecal occult blood testing (FOBT), flexible sigmoidoscopy, colonoscopy, barium enema, and the combination of FOBT with sigmoidoscopy, are discussed and critically reviewed. New techniques and technologies for screening, including virtual colonoscopy and molecular methods of screening stool, are previewed. Increased attention on screening and the competition for supremacy among the modalities undergoing evaluation make the prospects for a continued diminution in colorectal cancer mortality promising.     

The role of colonoscopy in screening persons with family history of colorectal cancer

Abstract First-degree relatives of colorectal cancer patients are at increased risk for developing colorectal neoplasms. In order to assess the potentiality of colonoscopy screening in this high-risk population, 213 asymptomatic family members (age range 30-69 years, mean 42.8 years) of those patients with colorectal cancer received colonoscopic examination at Chang-Gung Memorial Hospital from April 1992 to May 1994. Twenty-eight persons with 42 lesions (polyps or cancer) were identified, including 28 adenomas, nine hyperplastic polyps and five adenocarcinomas. The positive detection rate was 9.9% for adenoma and 2.3% for cancer. Colorectal neoplasms afflicted males more frequently than females (16.7 vs 5.7%, P < 0.05) and occurred less frequently in those < 40 years of age (5.5 vs 17.2%, P < 0.05). Forty-two per cent of the detected neoplastic lesions were beyond the reach of 60 cm flexible sigmoidoscopy and 36% of adenomas were < 0.5 cm in size and would be missed if patients were screened by air contrast barium enema. Cost analysis revealed that the charges of both screening colonoscopy and screening flexible sigmoidoscopy/air contrast barium enema were approximate. Colonoscopy also has a high acceptability and safety. It appears appropriate to use colonoscopy, rather than flexible sigmoidoscopy or air contrast barium enema, as an initial screening procedure for persons with a family history of colorectal cancer, especially those > 40 years of age.     

Flexible Sigmoidoscopy: Primary Care Outcomes after Two Types of Continuing Medical Education

The office impact of two types of continuing medical education on flexible sigmoidoscopy were compared. Measured office outcomes included sigmoidoscopy utilization rates, depth of insertion, time required to perform the procedure, biopsy rates, acquisition of further training, use of electrocautery, performance of polypectomy, complication rates, and general satisfaction with office flexible sigmoidoscopy. A matched control group was randomly selected and polled for previous flexible sigmoidoscopy continuing medical education and current flexible sigmoidoscopy utilization. Outcomes as they relate to different types of course design were discussed and compared. Procedure times and depth of insertion were comparable to published studies from tertiary care centers. In the faculty intensive course, trainees utilized less procedure time for their initial 10-20 procedures. Attitudes in practice were positive with 68% of all physicians performing biopsy. A 60-cm scope length was chosen by 87% of physicians. Physicians in faculty intensive courses were more likely to obtain additional training and less likely to initiate higher risk procedures such as electrocautery, polypectomy, and colonoscopy.     

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.     

Effect of Medicare coverage on use of invasive colorectal cancer screening tests

BACKGROUND: Colorectal cancer is the second leading cause of cancer death in the United States. Screening for colorectal cancer is now widely recommended but underused. Lack of insurance coverage for screening tests may be one reason patients do not undergo these procedures. OBJECTIVE: To determine the effect of Medicare reimbursement on utilization rates of invasive screening tests. Use of fecal occult blood testing was not studied before 1998. METHODS: We performed a retrospective analysis of ambulatory claims data for Washington State Medicare beneficiaries in 1994, 1995, and 1998. We determined the proportion of patients undergoing diagnostic and screening flexible sigmoidoscopy, colonoscopy, or double-contrast barium enema in 1994, 1995, and 1998 and the proportion receiving fecal occult blood testing in 1998. RESULTS: Use of diagnostic and screening colon tests was low in all years. Fewer than 6% of beneficiaries received any colon test, and fewer than 4% received a screening test. Although more patients underwent diagnostic testing after Medicare coverage began, use of screening tests did not significantly change (odds ratio, 0.99; 95% confidence interval, 0.97-1.01 comparing 1994 and 1998 [P =.33]). Women, individuals older than 80 years, and nonwhite patients were statistically significantly less likely to be screened in all 3 years (P<.001). In 1998, fewer than 7% of patients underwent fecal occult blood testing, with men and nonwhites statistically significantly less likely to have this test (P<.001). CONCLUSIONS: Colorectal cancer screening tests are underused in the Washington State Medicare population, and insurance coverage for these tests did not substantially affect utilization rates in the period studied.     

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.     

Flexible sigmoidoscopy may be ineffective for secondary prevention of colorectal cancer in asymptomatic,average-risk men

Asymptomatic men (N=114) 50 years of age or older had screening for colorectal neoplasia with flexible sigmoidoscopy followed by colonoscopy regardless of the sigmoidoscopic result. Our study objective was to determine the prevalence of patients having isolated adenomatous polyps in a proximal colonic segment in the absence of a distal index neoplasm within reach of the sigmoidoscope. Through the combined use of sigmoidoscopy and colonoscopy, adenomatous polyps were detected in 47 of 114 individuals (41%). A total of 88 adenomas was found. Seventeen patients had isolated neoplasms in proximal colonic segments in the absence of distal adenomas. These patients represented 15% of screened subjects (17 of 114) and 20% of individuals who lacked adenomas on sigmoidoscopy (17 of 84). The majority of proximal neoplasms were small (<1.0 cm), tubular adenomas. Flexible sigmoidoscopy may be ineffective for screening asymptomatic men for neoplasia. However, it remains to be determined if a 20% miss rate (for those with a normal sigmoidoscopic examination) is significant and whether small proximal adenomas are worth finding.     

Editorial: risk scoring for colon cancer screening: validated, but still not ready for prime time

Risk stratification for colorectal cancer screening would allow us to use less expensive screening tests, such as sigmoidoscopy with or without fecal blood testing, on lower risk individuals, and reserve colonoscopy for those at higher risk. In this issue, Levitzky et al. validates a risk score that was previously developed by Imperiale et al., finding similar results among three ethnic groups. Risk scoring would detect 82-87% of proximal advanced neoplasia while decreasing colonoscopy use by 33-46%. However, before risk scoring is ready for widespread use, sigmoidoscopy access and performance issues need to be addressed, and we must be comfortable with missing some proximal neoplasms.     

Cost-effectiveness of colonoscopy in screening for colorectal cancer

BACKGROUND: Fecal occult blood testing, flexible sigmoidoscopy, and colonoscopy are used to screen patients for colorectal cancer. OBJECTIVE: To compare the cost-effectiveness of fecal occult blood testing, flexible sigmoidoscopy, and colonoscopy. DESIGN: The cost-effectiveness of the three screening strategies was compared by using computer models of a Markov process. In the model, a hypothetical population of 100 000 persons 50 years of age undergoes annual fecal occult blood testing, sigmoidoscopy every 5 years, or colonoscopy every 10 years. Positive results on fecal occult blood testing or adenomatous polyps found during sigmoidoscopy are worked up by using colonoscopy. After polypectomy, colonoscopy is repeated every 3 years until no polyps are found. DATA SOURCES: Transition rates were estimated from U.S. vital statistics and cancer statistics and from published data on the sensitivity, specificity, and efficacy of various screening techniques. Costs of screening and cancer care were estimated from Medicare reimbursement data. TARGET POPULATION: Persons 50 years of age in the general population. TIME HORIZON: The study population was followed annually until death. PERSPECTIVE: Third-party payer. OUTCOME MEASURE: Incremental cost-effectiveness ratio. RESULTS OF BASE-CASE ANALYSIS: Compared with colonoscopy, annual screening with fecal occult blood testing costs less but saves fewer life-years. A screening strategy based on flexible sigmoidoscopy every 5 or 10 years is less cost-effective than the other two screening methods. RESULTS OF SENSITIVITY ANALYSIS: Screening with fecal occult blood testing is more sensitive to changes in compliance rates, and it becomes easily dominated by colonoscopy under most conditions assuming less than perfect compliance. Other assumptions about the sensitivity and specificity of fecal occult blood testing, screening frequency, efficacy of colonoscopy in preventing cancer, and polyp incidence have a lesser influence on the differences in cost-effectiveness between colonoscopy and fecal occult blood testing. CONCLUSIONS: Colonoscopy represents a cost-effective means of screening for colorectal cancer because it reduces mortality at relatively low incremental costs. Low compliance rates render colonoscopy every 10 years the most cost-effective primary screening strategy for colorectal cancer.     

Continuous quality improvement of colorectal cancer screening

Quality assurance is a key issue in colorectal cancer screening, because effective screening is able to improve primary prevention of the cancer. The quality measure may be described in terms:how well the screening test tells who truly has a disease (sensitivity) and who truly does not have a disease (specificity). This paper raises concerns about identification of the optimal screening test for colorectal cancer. Colonoscopy vs flexible sigmoidoscopy in colorectal cancer screening has been a source of ongoing debate. A multicentre randomised controlled trial comparing flexible sigmoidoscopy with usual care showed that flexible sigmoidoscopy screening is able to diminish the incidence of distal and proximal colorectal cancer, and also mortality related to the distal colorectal cancer. However, colonoscopy provides a more complete examination and remains the more sensitive exam than flexible sigmoidoscopy. Moreover, colonoscopy with polypectomy significantly reduces colorectal cancer incidence and colorectal cancer-related mortality in the general population. The article considers the relative merits of both methods and stresses an ethical aspect of patient’s involvement in decision-making. Patients should be informed not only about tests tolerability and risk of endoscopy complications, but also that different screening tests for bowel cancer have different strength to exclude colonic cancer and polyps. The authorities calculate effectiveness and costs of the screening tests, but patients may not be interested in statistics regarding flexible sigmoidoscopy screening and from an ethical point of view, they have the right to chose colonoscopy, which is able to exclude a cancer and precancerous lesions in the whole large bowel.     

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.     

The use of screening colonoscopy for patients cared for by the Department of Veterans Affairs

BACKGROUND: Medicare data indicate an increase in colorectal cancer (CRC) screening using colonoscopy and a decline in fecal occult blood testing, flexible sigmoidoscopy, and double-contrast barium enema. Because of differences in the delivery of health care, this trend in use of colonoscopy in fee-for-service settings might not be paralleled in the Department of Veterans Affairs (VA). METHODS: National inpatient and outpatient VA databases were searched for codes indicative of colonoscopy, flexible sigmoidoscopy, fecal occult blood testing, and double-contrast barium enema during fiscal years 1998 to 2003 among VA users aged 49 to 75 years. RESULTS: The frequency of tests for CRC screening increased from 432,778 in 1998 to 1,179,764 in 2003. Of those who were screened, only the proportion of subjects screened with fecal occult blood testing increased from 81.7% to 90.4%, while screening colonoscopy declined from 5.7% to 4.7%; flexible sigmoidoscopy declined from 8.3% to 3.6%; and double-contrast barium enema declined from 4.1% to 1.3%. The total use of screening colonoscopy procedures increased from 24,955 in 1998 to 55,199 in 2003, but the proportion of colonoscopy procedures performed for CRC screening purposes increased only slightly from 34.3% to 38.4%. In regression models adjusting for age, race, and sex, there was no consistent secular trend in the likelihood of undergoing screening colonoscopy for patients cared for in the VA health care system. CONCLUSIONS: Colorectal cancer screening has dramatically increased in the VA, but unlike in other practice settings, fecal occult blood testing is the dominant mode of screening. Although screening colonoscopy more than doubled in frequency, it constitutes a small proportion of the total CRC screening procedures used in the VA health care setting.     

Cost-effectiveness of endoscopy in irritable bowel syndrome

BACKGROUND: It is unknown to what extent at what expense flexible sigmoidoscopy and colonoscopy add to the diagnosis of irritable bowel syndrome (IBS). The aim of the study was to assess the incremental cost-effectiveness of endoscopic procedures in the workup for IBS. METHODS: Using the Bayes formula, we calculated the increase in diagnostic certainty for a consecutive number of tests. We also calculated the incremental cost-effectiveness ratio, which corresponds to the test costs divided by the increment in diagnostic certainty. RESULTS: The diagnosis of IBS can be established with a relatively high probability of more than 80% relying on relatively inexpensive and noninvasive tests only. Flexible sigmoidoscopy or colonoscopy constitute the most costly portion of any workup for IBS, which amounts to 50% to 75% of the overall costs. Because of their high incremental cost-effectiveness ratio, endoscopic procedures should not be used at the beginning of the diagnostic workup. This outcome of the analysis remains largely unaffected within reasonable ranges of the sensitivity and specificity of various tests. CONCLUSIONS: In the diagnosis of IBS, inexpensive, noninvasive tests should be used first to rule out other diagnoses. Despite their high incremental cost-effectiveness ratio, flexible sigmoidoscopy and colonoscopy are indicated when a serious organic disease is reasonably likely and needs to be ruled out.