Colon Cancer Screening Program Research Articles

The Importance of Quality-Assurance Methods for Competent Execution, Handling and Structuring of Colon Cancer Screening Programs - the Case of Programs Based on Stool Tests

Screening for colorectal cancer aims at the early detection of early cancer stages in individuals in a defined, otherwise healthy population. In randomized controlled trials it was possible to achieve a clinically and statistically significant reduction of colorectal cancer mortality for those citizens who participated in a quality assured screening program. It is one of the most pertinent goals of quality assurance measures to attain this success in routine settings. As Sir Muir Gray pointed out: All screening programs do harm, some do good as well [1]. Since screening of colorectal cancer is not just the test such as a test for occult blood, quality assurance has to cover all relevant steps of the program (”screening chain”).

Acceptance of Colonoscopy Requires more than Test Tolerance

Colon cancer screening, including colonoscopy, lags behind other forms of cancer screening for participation rates. The intrinsic nature of the endoscopic procedure may be an important barrier that limits patients from finding this test acceptable and affects willingness to undergo screening. With colon cancer screening programs emerging in Canada, test characteristics and their impact on acceptance warrant consideration. To measure the acceptability of colonoscopy and define factors that contribute to procedural acceptability, in relation to another invasive gastrointestinal scope procedure, gastroscopy. Consecutive patients undergoing a colonoscopy (n=55) or a gastroscopy (n=33) were recruited. Their procedural experience was evaluated and compared pre-endoscopy, immediately before testing and postendoscopy. Questionnaires were used to capture multiple domains of the endoscopy experience and patient characteristics. Patient scope groups did not differ preprocedurally for general or procedure-specific anxiety. However, the colonoscopy group did anticipate more pain. Those who had a gastroscopy demonstrated higher preprocedural acceptance than those who had a colonoscopy. The colonoscopy group had a significant decrease in scope concerns and anxiety postprocedurally. As well, they reported less pain than they anticipated. Regardless, postprocedurally, the colonoscopy group's acceptance did not increase significantly, whereas the gastroscopy group was almost unanimous in their test acceptance. The best predictor of pretest acceptability of colonoscopy was anticipated pain. The findings indicate that concerns that relate specifically to colonoscopy, including anticipated pain, influence acceptability of the procedure. However, the experience of a colonoscopy does not lead to improved test acceptance, despite decreases in procedural anxiety and pain. Patients' preprocedural views of the test are most important and should be addressed directly to potentially improve participation in colonoscopy.

Screening for Colorectal Neoplasms With New Fecal Occult Blood Tests: Update on Performance Characteristics

One type of fecal occult blood test (FOBT), the unrehydrated guaiac fecal occult blood test (GT), is recommended by the United States Preventive Services Task Force and the Institute of Medicine for use in screening programs, but it has relatively low sensitivity as a single test for detecting advanced colonic neoplasms (cancer and adenomatous polyps > or = 1 cm in diameter). Thus, improving the sensitivity of FOBT should make colon cancer screening programs that use these tests more effective. We assessed prospectively the performance characteristics of two newer FOBTs in 5841 subjects at average risk for colorectal cancer in a large group-model managed care organization. The tests evaluated included a sensitive GT, a fecal immunochemical test (FIT), and the combination of both tests. Patients with positive and negative test results were advised to have colonoscopy and sigmoidoscopy, respectively. Sensitivity and specificity for detecting advanced neoplasms in the left colon within 2 years after the FOBT screening were evaluated for the two tests administered separately and in combination. A total of 139 patients were diagnosed with advanced colorectal neoplasms (n = 14 cancers, n = 128 adenomas) within the 2 years following their initial FOBT screening. Sensitivity for detecting cancer was 81.8% (95% confidence interval [CI] = 47.8% to 96.8%) for the FIT alone and 64.3% (95% CI = 35.6% to 86.0%) for the sensitive GT and the combination test. Sensitivity for detecting advanced colorectal adenomas was 41.3% (95% CI = 32.7% to 50.4%) for the sensitive GT, 29.5% (95% CI = 21.4% to 38.9%) for the FIT, and 22.8% (95% CI =16.1% to 31.3%) for the combination test. Specificity for detecting cancer and adenomas was 98.1% (95% CI = 97.7% to 98.4%) and 98.4% (95% CI = 98.0% to 98.7%), respectively, for the combination test; 96.9% (95% CI = 96.4% to 97.4%) and 97.3% (95% CI = 96.8% to 97.7%), respectively, for the FIT; and 90.1% (95% CI = 89.3% to 90.8%) and 90.6% (95% CI = 89.8% to 91.4%), respectively, for the sensitive GT. The FIT has high sensitivity and specificity for detecting left-sided colorectal cancer, and it may be a useful replacement for the GT.

Quality Assurance in Flexible Sigmoidoscopy

Introduction: Flexible sigmoidoscopy (FS) is already part of colon cancer screening programmes in the USA. Quality assurance in FS is important and completion to descending colon is a significant indicator. However, it is generally believed that clinical assessment of of position in colon and hence completion during flexible sigmoidoscopy is highly inaccurate. We therefore performed this study with the aims of determining completion rates with flexible sigmoidoscopy and the correlation between clinical and visual impression with actual position of the scope and to determine role of endomucosal clips with follow-up x-rays in objectively documenting completion and hence quality assurance. Methods: The study was approved by local ethics committee, and undertaken to good clinical practice standards. All patients undergoing elective flexible sigmoidoscopy except those with surgical resection were included. During FS, the endoscopist applied an endomucosal clip at the most proximal bowel reached and both endoscopist and attending nurse voiced their independent opinion about the position of the clip. Post procedure, all patients underwent an abdominal x-ray, which was reported by a consultant radiologist, blinded to the outcome of FS. The radiology results were then compared with the endoscopist and nurse assessment. A complete examination was defined as one where descending colon was reached. All data was analysed using SPSS V14.0. Results: 42 patients underwent FS, with a median age of 56 years. The endoscopist was accurate in his assessment of position in colon in 33 patients (79%). The attending nurse was accurate in only 25% of cases. The differences between endoscopist assessment and radiological opinion were not significant (p = 0.3, paired sample t-test). The descending colon was reached in 22 patients and the splenic flexure in 10 patients, giving a crude completion rate of 78%. and a corrected completion rate of 89%. There was no correlation between the length of the scope and its position in the colon. Conclusion: We believe that the clinical impression of endoscopist during flexible sigmoidoscopy regarding position is very accurate and the length of scope inserted should not be regarded as important. Use of endomucosal clips with follow-on abdominal x-ray is safe and effective method of determining completion, and is an excellent objective measure of quality assurance in flexible sigmoidoscopy. We recommend that this technique should be used to determine completion whenever the endoscopist is in doubt, and repeat flexible sigmoidoscopies performed if proven incomplete.

Familial risk of colon and rectal cancer in Iceland: Evidence for different etiologic factors?

The aim of this study was to characterize the familial risk of colon and rectal cancer using 2 population-based registries in Iceland, the Icelandic Cancer Registry and a genealogy database. The standardized incidence ratio (SIR) was used to estimate the risk among relatives of colorectal cancer index cases diagnosed in Iceland over a 46-year period (1955-2000). The 2,770 colorectal cancer patients had 23,272 first-degree relatives. Among first-degree relatives, there was an increased risk of both colon (SIR 1.47, 95% confidence interval (CI) 1.34-1.62) and rectal cancer (SIR 1.24, 95% CI 1.04-1.47). An increased risk of colon cancer was observed among siblings of colon cancer patients (SIR 2.03, 95% CI 1.76-2.33), whereas no such increase was observed for parents or offspring. Furthermore, the risk of rectal cancer was only increased among brothers (SIR 2.46 95% CI 1.46-3.89) of rectal cancer patients and not among their sisters (SIR 1.0 95% CI 0.40-2.06). The added risk of colon cancer among first-degree relatives was independent of site of colon cancer in the proband. Our results confirm that family history of colorectal cancer is a risk factor for the disease. However, family history has a different association with colon cancer than with rectal cancer, suggesting that the 2 cancer types may have different etiologic factors. Our results have implications for colon and rectal cancer screening programs.

Beliefs associated with fecal occult blood test and colonoscopy use at a worksite colon cancer screening program.

Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. Although regular screening can decrease morbidity and mortality from CRC, screening rates nationwide are very low. This descriptive study assessed beliefs associated with fecal occult blood test and colonoscopy use among participants of a worksite colon cancer screening program. Randomly selected employees, aged 40 and older, were mailed a survey on CRC screening-related beliefs. Instruments were tested for reliability and validity. Results indicated that fecal occult blood test use was significantly associated with being female, Caucasian, having low perceived barriers, and provider recommendation. Colonoscopy use was significantly associated with higher knowledge, lower barriers, higher benefits, higher self-efficacy, and provider recommendation. Findings may be used to develop interventions designed to improve CRC screening rates.

4489 Patient tolerance of unsedated colonoscopy vs. flexible sigmoidoscopy in colon cancer screening.

BACKGROUND: Colonoscopy has not been utilized in screening programs of average risk adults because of higher costs (physician time, conscious sedation with intensive monitoring, and patient recovery time) and risks associated with conscious sedation. Unsedated colonoscopy has not been employed because of concern for patient comfort. It is important to make a screening procedure tolerable enough that patients will return for future screening exams. AIMS: Randomized, single blinded study of patient tolerance of unsedated colonoscopy with pediatric colonoscopes in a colon cancer screening program. METHODS/PATIENTS: 140 patients referred to our center for routine screening flexible sigmoidoscopy were randomized to standard 70 cm flexible sigmoidoscopes (group 1), 160 cm pediatric colonoscopes inserted to a maximum of 70 cm (group 2), or 160 cm pediatric colonoscopes to full insertion (group 3). Exams were continued until above insertion points or the endoscopist determined patient discomfort was sufficient to warrant discontinuation. Bowel prep consisted of Fleets phosphasoda and bisacodyl. Procedures were performed by staff gastroenterologists. Patient discomfort was assessed immediately after the procedure with a visual analog scale of 1 to 10. Secondary endpoints were depth of scope insertion, exam duration, and patient willingness to undergo future screening endoscopies. RESULTS: As seen in the table, more colon was visualized in patients randomized to colonoscopy (group 3) with comparable discomfort and slightly longer exam duration. In group 3, 8 patients (19%) had complete colonoscopies to the cecum. There was no significant difference in refusal of future exams among the groups. CONCLUSION: Unsedated exams by experienced endoscopists using pediatric colonoscopes provide greater visualization of the colon compared to standard flexible sigmoidoscopes, with minimal difference in patient comfort or exam duration.

E109 職域における胃ガン・大腸ガン検診の実態と産業医の意識調査

E109 職域における胃ガン・大腸ガン検診の実態と産業医の意識調査

Patient Satisfaction With Conscious Sedation for Ambulatory Colonoscopy in a Community Hospital

Patient acceptance of ambulatory colonoscopy is important for colon cancer screening programs to be successful. The goal of this study was to assess patient satisfaction with the method of conscious sedation that is standard in most endoscopy units. The authors also attempted to identify patient characteristics associated with a poor sedation experience. The findings suggest that 90% of ambulatory patients undergoing colonoscopy are adequately sedated with the standard meperidine midazolam regimen. The only patient characteristic found to predict poor sedation response was the preceding use of a prescription narcotic as an outpatient.

The costs and effects of screening for cancer among asbestos-exposed workers

Several million workers previously exposed to asbestos are at risk each year for developing asbestosis or cancer as a result of this exposure. We have reviewed the data on the general effectiveness of screening for the two most common cancers found in these workers (lung cancer and colo-rectal cancer) and have compared the relative benefits expected from screening workers for colon or lung cancer 10, 15, 20 or 25 yr after their initial exposure. Although lung cancer is common, there is little evidence at present that screening for this disease is effective in reducing mortality. Colon cancer is less common, there is more evidence that screening is effective, and the relatively high risk of dying from this disease in asbestos workers makes screening useful. The cost per additional year of life extended by screening is only a few hundreds of dollars, making colon cancer screening programs for asbestos workers considerably more cost-effective than most other screening programs. We conclude that occupational safety agencies should consider implementing screening programs for colon cancer in workers exposed to asbestos over 10 yr ago.