Achieving quality in flexible sigmoidoscopy screening for colorectal cancer.

BACKGROUND: Sigmoidoscopy screening, which can dramatically reduce colorectal cancer mortality, is supported increasingly by physicians and payers, and is likely to be performed more frequently in the future. As more physicians and nonphysician medical personnel learn how to perform this procedure, and with attention to quality standards, the overall impact of sigmoidoscopy screening may improve. This review describes elements that characterize high-quality examinations and identifies resources for in-depth information on performing flexible sigmoidoscopy. METHODS: The domains of quality were identified from textbooks, articles, and the professional opinions of gastroenterologists and primary care physicians. Information was obtained from MEDLINE, bibliographies in recent articles, medical professional organizations, equipment manufacturers' representatives, and focus groups of primary care physicians. RESULTS: Nine domains of quality are identified and discussed: training, logistical start-up, patient interaction, bowel preparation, examination technique, lesion recognition, complications, reporting, and processing (equipment cleaning and disinfection). CONCLUSIONS: Persons learning how to perform and to implement flexible sigmoidoscopy may use this information to help ensure the quality of screening examinations.

The practices and attitudes of primary care nurse practitioners and physician assistants with respect to colorectal cancer screening.

OBJECTIVES: Although nurse practitioners and physician assistants form a large and growing portion of the primary care workforce, little is known about their colorectal cancer screening practices. The aim of this study was to assess the colorectal cancer screening practices, training, and attitudes of nurse practitioners and physician assistants practicing primary care medicine. METHODS: All nurse practitioners (827) and physician assistants (1178) licensed by the Medical Board of the State of North Carolina were surveyed by mail. Both groups were further divided into primary care versus non-primary care by self-described roles. Self-reported practices, training, and attitudes with respect to colorectal cancer screening were elicited. RESULTS: Response rates were 71.4% and 61.2%, for nurse practitioners and physician assistants respectively. A total of 51.3% of nurse practitioners and 50.3% of physician assistants described themselves as adult primary care providers. No primary care nurse practitioners and only 3.8% of primary care physician assistants performed screening flexible sigmoidoscopy. However, 76% of primary care physician assistants and 69% of primary care nurse practitioners reported recommending screening flexible sigmoidoscopy. A total of 95% primary care physician assistants and 92% of primary care nurse practitioners reported performing fecal occult blood testing. Only 9.4% of physician assistants and 2.8% of nurse practitioners received any formal instruction in flexible sigmoidoscopy while in their training. Additionally, 41.4% of primary care physician assistants and 27.7% of primary care nurse practitioners reported that they would be interested in obtaining formal training in flexible sigmoidoscopy. CONCLUSIONS: Physician assistants and nurse practitioners are motivated, willing and underutilized groups with respect to CRC screening. Efforts to increase education and training of these professionals may improve the availability of CRC screening modalities.

Effectiveness and economic impact of screening for colorectal cancer by mass fecal occult blood testing.

OBJECTIVES: Fecal occult blood testing has been shown to reduce mortality from colorectal cancer in large randomized, controlled trials conducted in the United States, Denmark, and the United Kingdom, and mathematical simulation modeling found it to be cost-effective relative to other health care services. Before making a concerted effort to implement mass fecal occult blood testing based on this evidence alone, however, we considered it prudent to critically re-evaluate the effectiveness and economic impact of screening in the US population as a whole. METHODS: To assess the effectiveness of screening, we projected published outcomes from each of the three large randomized controlled trials of fecal occult blood testing to the US population, as if each clinical trial had been done in the population as a whole. We then determined the resource costs of detection and treatment that would be associated with the outcomes predicted from each trial. RESULTS: More than 1 million colorectal cancers could be expected to arise over 10 yr in the cohort of US residents eligible to enter a screening program in 1997, and trial outcomes indicate that > or = 60% of these cancers would be fatal. If the 60-67% compliance rate of the population-based randomized controlled trials were achieved, a fecal occult blood testing program would detect 30% of known colorectal cancers and save 100,000 lives over 10 yr. Screening would incur total costs of $3-4 billion over 10 yr, or $2,500 per life-year saved. CONCLUSIONS: Mass fecal occult blood testing is cost-effective, and, although not inexpensive, many would consider the total cost acceptable. Even with a concerted effort to achieve compliance, however, the effectiveness of fecal occult blood testing would be limited to saving the lives of < or = 15% of those who otherwise would die from their cancer in the first 10 yr after beginning mass screening. The limitations of fecal occult blood testing suggest the need to further evaluate the role of endoscopy in screening, and to develop more effective, noninvasive screening tools.

Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal findings.

BACKGROUND AND METHODS: The clinical significance of a distal colorectal polyp is uncertain. We determined the risk of advanced proximal neoplasia, defined as a polyp with villous features, a polyp with high-grade dysplasia, or cancer, among persons with distal hyperplastic or neoplastic polyps as compared with the risk among persons with no distal polyps. We analyzed data from 1994 consecutive asymptomatic adults (age, 50 years or older) who underwent colonoscopic screening for the first time between September 1995 and December 1998 as part of a program sponsored by an employer. The location and histologic features of all polyps were recorded. Colonoscopy to the level of the cecum was completed in 97.0 percent of the patients. RESULTS: Sixty-one patients (3.1 percent) had advanced lesions in the distal colon, including 5 with cancer, and 50 (2.5 percent) had advanced proximal lesions, including 7 with cancer. Twenty-three patients with advanced proximal neoplasms (46 percent) had no distal polyps. The prevalence of advanced proximal neoplasia among patients with no distal polyps was 1.5 percent (23 cases among 1564 persons; 95 percent confidence interval, 0.9 to 2.1 percent). Among patients with distal hyperplastic polyps, those with distal tubular adenomas, and those with advanced distal polyps, the prevalence of advanced proximal neoplasia was 4.0 percent (8 cases among 201 patients), 7.1 percent (12 cases among 168 patients), and 11.5 percent (7 cases among 61 patients), respectively. The relative risk of advanced proximal neoplasia, adjusted for age and sex, was 2.6 for patients with distal hyperplastic polyps, 4.0 for those with distal tubular adenomas, and 6.7 for those with advanced distal polyps, as compared with patients who had no distal polyps. Older age and male sex were associated with an increased risk of advanced proximal neoplasia (relative risk, 1.3 for every five years of age and 3.3 for male sex). CONCLUSIONS: Asymptomatic persons 50 years of age or older who have polyps in the distal colon are more likely to have advanced proximal neoplasia than are persons without distal polyps. However, if colonoscopic screening is performed only in persons with distal polyps, about half the cases of advanced proximal neoplasia will not be detected.

Licensure, use, and training of paramedical personnel to perform screening flexible sigmoidoscopy.

BACKGROUND: The purpose of this study was to assess the state board of nursing guidelines about the performance of flexible sigmoidoscopy by nurses and to determine the current use and training of paramedical personnel in flexible sigmoidoscopy at gastroenterology fellowship programs in the United States. METHODS: Separate one-page questionnaires were sent to state boards of nursing and directors of endoscopy at gastroenterology fellowship programs in the United States. RESULTS: Twenty percent (10 of 50) of state boards of nursing explicitly approve the performance of sigmoidoscopy by registered nurses, and 50% (25 of 50) explicitly approve the practice by nurse practitioners. Forty-six percent (23 of 50) of state boards of nursing have no written policy but allow nurses to use a "decision making model" to determine whether the performance of sigmoidoscopy is allowed. Fifteen percent (24 of 164) of gastroenterology fellowship programs in the United States use paramedical personnel to perform flexible sigmoidoscopy. Sixty-three percent (15 of 24) of these programs started since 1995, and 67% (16 of 24) require that the paramedical personnel perform 50 or more supervised sigmoidoscopies during their training. Forty-five percent (5 of 11) of programs with physician assistants/nurse practitioners use these personnel to perform colonoscopy or endoscopy. CONCLUSIONS: Nurses are allowed to perform flexible sigmoidoscopy in most states based on current state board of nursing guidelines. The use of paramedical personnel to perform endoscopic procedures is increasing rapidly.

What can we conclude from the randomized controlled trials of fecal occult blood test screening?

The results of three published randomized controlled trials of fecal occult blood testing (FOBT) provide unequivocal proof of the principle that screening reduces mortality from colorectal cancer (CRC). However, several interesting questions remain in interpreting and applying the results of the clinical trials, including: how well does FOBT screening work (i.e. how much can CRC mortality be reduced), how does it work, when is it worthwhile and worthwhile doing, and how can technique be optimized? The answers to these questions have important practical and clinical implications.

Lessons from the mammography screening controversy: can we improve the debate?

The debate about breast cancer screening for women in their 40s has become so contentious that effective communication and rational discussion on this topic have been compromised. This contentiousness might be defused by understanding the reasons for it. The debate is less about facts than it is about perceptions and values. There is disagreement about how to fairly describe facts about risk and how to avoid misperceptions that may distort assessment of risk. Other sources of disagreement concern the potential harms of screening, the relative roles of physicians and patients in decision making, and how to factor cost into screening decisions. The entire decision-making process has also been highly charged by single-issue advocacy groups and a kind of gender rivalry. Several approaches might help defuse the debate and improve discussion. First, those on both sides of the debate might agree on several things: 1) that the evidence from clinical trials is widely agreed-upon and thus that a main task now is to factor in the values of individual women who are making decisions; 2) that the values of women may differ substantially and that those differences should be respected; 3) that both individuals and the public should be fully and fairly informed about the pros and cons of screening; and 4) that cost-effectiveness should at least be considered during the decision-making process. Lessons from this debate may apply to other medical problems that have small degrees of risk and whose management is strongly debated.

Early detection of prostate cancer. Serendipity strikes again.

An underappreciated characteristic of prostate cancer screening is that it may detect some prostate cancers solely by serendipity or chance. Serendipity, previously described in the detection of colonic neoplasms, could affect prostate cancer detection when a screening test result is abnormal for reasons other than the presence of prostate cancer, but prostate cancer is coincidentally detected during the subsequent evaluation of the abnormal screening result. We reviewed published articles about prostate cancer screening, searching for evidence of serendipity. We defined serendipity in digital rectal examination (DRE) screening as the discovery of a prostate cancer by the random biopsy of an area of the prostate gland other than the palpable suspicious area that prompted the biopsy. We defined serendipity in prostate-specific antigen (PSA) screening as the discovery of a prostate cancer by the random biopsy of a nonpalpable (stage T1c) prostate cancer less than 1.0 cm3 in volume, since tumors less than 1.0 cm3 are generally too small to cause elevated PSA levels. We found that serendipity may be responsible for the detection of more than one quarter of apparently DRE-detected prostate cancers and up to one quarter of apparently PSA-detected cancers. Additionally, serendipity played a larger role in the detection of smaller tumors that are common but of uncertain clinical significance. We conclude that serendipity-detected prostate cancers contribute to an overestimation of the true information value of DRE and PSA screening. Whether serendipity is advantageous in prostate cancer screening depends on the as yet uncertain outcomes for men with smaller prostate cancers. However, given our estimates of the potential magnitude of the impact of serendipity, the currently popular DRE- and PSA-based screening strategy may not be optimal. If smaller prostate cancers are important, then we are not finding enough; if they are unimportant, then we are finding too many that we may feel compelled to treat aggressively.

Screening for colorectal cancer with the fecal occult blood test: a background paper. American College of Physicians.

PURPOSE: Screening for colorectal cancer with fecal occult blood tests or sigmoidoscopy can reduce mortality rates. If occult blood testing is done, clinicians must decide how to interpret the results and plan further management. If the results are positive, a decision must be made about evaluating the colon. This report provides information that can be used to perform fecal occult blood tests, interpret the results of those tests, and plan patient management. DATA SOURCES: The MEDLINE database was searched for data relevant to optimizing the technique of fecal occult blood testing. Studies were also identified from the bibliographies of published articles about test performance and the interpretation of test results, particularly sensitivity, specificity, and the probability of colorectal cancer after a positive test result. STUDY SELECTION AND DATA EXTRACTION: Studies were selected and data were extracted on the basis of the authors' combined judgment. DATA SYNTHESIS: When used for screening, fecal occult blood tests have positive results about 1% to 16% of the time, depending on such factors as the age of the person being tested, whether the sample is rehydrated, and whether the test is used for initial screening or for rescreening. When the colons of persons who have positive test results are evaluated, the rate of finding any colorectal cancer is about 2% to 17% and the rate for early colorectal cancer (Dukes stage A or B) is about 2% to 14%. CONCLUSIONS: These results suggest that, in general, persons who have positive results on a fecal occult blood test should have a full colonic examination. More research is needed to understand and improve the sensitivity and specificity of the fecal occult blood test.

Metachronous colon cancer in persons who have had a large adenomatous polyp.

OBJECTIVE: To determine, among persons who have had a large colon polyp, the risk of subsequent colon cancer at a site distant from that polyp. METHODS: Follow-up was done for 226 persons at the Mayo Clinic who had had a > or = 1-cm polyp demonstrated on barium enema between 1965 and 1970 and for whom yearly colon surveillance examination was recommended. Information was collected from Mayo Clinic records and from contact with patients, physicians, and other hospitals regarding the results of surveillance examinations and the development of colon cancer. Colon surveillance was routinely done at the Mayo Clinic using the technique of single contrast barium enema with vigorous manual fluoroscopic examination and proctoscopy. The expected rate of colorectal cancer (CRC) was calculated based on previously published rates for this community. RESULTS: Patients received, on average, four colon examinations in addition to the examination that discovered the index polyp. During 2126 person-years of follow-up, 16 persons developed a colon cancer at a location other than the site of the index polyp, in comparison with 4.0 expected cases, for a standardized incidence ratio of 4.0 (95% CI,2.3, 6.4). The cancers were large (mean 4.5cm) at presentation, and eight of the 16 cancers had been preceded within 3 yr by at least one negative barium enema. CONCLUSIONS: The rate to develop colon cancer in persons who have had a large colon polyp es about 4 times the expected rate, suggesting that such persons should be considered for aggressive colonoscopic surveillance. The failure to detect early cancer or its precursors by surveillance barium enema is probably explained by inherent insensitivity of single contrast barium enema.

Evaluating risk: a primer for gastroenterologists.

OBJECTIVE: To review the various types of risk measures and to illustrate how interpretations may vary depending on how risk is presented. METHODS: We define different types of risk estimates and provide examples of their use from the recent gastroenterological literature. RESULTS: Calculations of absolute risk and the number of patients who must receive treatment to prevent one patient from experiencing a disease state (number needed to treat) provide useful information in assessing the utility of fecal occult blood testing for prevention of colorectal cancer and in estimating small bowel cancer rates for individuals with familial adenomatous polyposis. CONCLUSIONS: Measures such as relative risk and the odds ratio are best used in analyzing causality but may not be helpful in guiding clinical decisions. Absolute risk and attributable risk reveal the actual number of cases that can be explained by a given exposure and can thereby measure the impact of a clinical intervention for both the population and the patient. These measures should be the criteria for decision-making.