Screening for colorectal cancer with fecal occult blood testing and sigmoidoscopy

Barriers to fecal occult blood testing and sigmoidoscopy among older Chinese-American women

PURPOSE

This study examined factors associated with fecal occult blood test (FOBT) and sigmoidoscopy screening use among Chinese-American women age 60 years and older.

DESCRIPTION OF STUDY

One hundred women were recruited from senior centers in two metropolitan areas on the east coast of the United States. Participants completed a questionnaire that included sections on demographics, health history, health insurance coverage, FOBT and sigmoidoscopy use, common and cultural barriers to colorectal cancer screening, and acculturation.

RESULTS

Logistic regression models found greater acculturation to be a significant predictor of having had a FOBT at least once, and found both greater acculturation and physician recommendation to be significant predictors of having had a sigmoidoscopy at least once. No significant predictors were found for regular adherence to colorectal screening guidelines, which include having undergone an FOBT in the past year and sigmoidoscopy in the past 5 years.

CLINICAL IMPLICATIONS

This study found that older Chinese-American women underuse FOBT and sigmoidoscopy screening, as is recommended by the American Cancer Society colorectal cancer screening guidelines. These findings suggest that cultural factors may influence the initiation of colorectal cancer screening for Chinese-American women but are not predictive of adherence to screening over time. Outreach efforts to promote colorectal cancer screening in this population might target women who are less acculturated to facilitate an initial entry into the Western healthcare system to obtain screening.

Colorectal cancer screening

Colorectal cancer causes significant morbidity and mortality in the United States. The incidence of colorectal cancer increases at age 50, approximately. Risk factors that have been identified include a personal history of colorectal cancer or adenomas, a family history of colon cancer or adenomas, inherited colorectal cancer syndromes, and long standing inflammatory bowel disease. Several screening tests have been developed for colorectal cancer prevention. Surveillance strategy is based on an individual's colorectal cancer risk. This article reviews fecal occult blood testing, flexible sigmoidoscopy, colonoscopy, barium enema, and genetic testing.

One-time screening for colorectal cancer with combined fecal occult-blood testing and examination of the distal colon

BACKGROUND

Fecal occult-blood testing and sigmoidoscopy have been recommended for screening for colorectal cancer, but the sensitivity of such combined testing for detecting neoplasia is uncertain. At 13 Veterans Affairs medical centers, we performed colonoscopy to determine the prevalence of neoplasia and the sensitivity of one-time screening with a fecal occult-blood test plus sigmoidoscopy.

METHODS

Asymptomatic subjects (age range, 50 to 75 years) provided stool specimens on cards from three consecutive days for fecal occult-blood testing, which were rehydrated for interpretation. They then underwent colonoscopy. Sigmoidoscopy was defined in this study as examination of the rectum and sigmoid colon during colonoscopy, and sensitivity was estimated by determining how many patients with advanced neoplasia had an adenoma in the rectum or sigmoid colon. Advanced colonic neoplasia was defined as an adenoma 10 mm or more in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. Classification of subjects according to the findings was based on the most advanced lesion.

RESULTS

A total of 2885 subjects returned the three specimen cards for fecal occult-blood testing and underwent a complete colonoscopic examination. A total of 23.9 percent of subjects with advanced neoplasia had a positive test for fecal occult blood. As compared with subjects who had a negative test for fecal occult blood, the relative risk of advanced neoplasia in subjects who had a positive test was 3.47 (95 percent confidence interval, 2.76 to 4.35). Sigmoidoscopy identified 70.3 percent of all subjects with advanced neoplasia. Combined one-time screening with a fecal occult-blood test and sigmoidoscopy identified 75.8 percent of subjects with advanced neoplasia.

CONCLUSIONS

One-time screening with both a fecal occult-blood test with rehydration and sigmoidoscopy fails to detect advanced colonic neoplasia in 24 percent of subjects with the condition.

Screening with faecal occult blood test (FOBT) for colorectal cancer: assessment of two methods that attempt to improve compliance

Screening with the faecal occult blood test (FOBT) has been shown in randomized control trials to be effective in reducing mortality from colorectal cancer. Compliance to this test recommendation, however, by the general population is usually low. To evaluate different methods of increasing compliance with FOBT, using mailed test kits or order cards, with or without information leaflets, subjects were randomly assigned to receive a test kit or a kit request card. An information leaflet was included in half of the mailings. All participants were contacted for interview. Compliance was evaluated through the central computer system of the study's FOBT laboratory. Self-initiated compliance with FOBT in the year preceding the study was 0.6% of the study participants. The overall compliance rate with the programme invitation was 17.9%, with a somewhat higher, though non-significant response to the mailed kit (19.9%) over the kit request card (15.9%). Women complied with the test significantly more than men, older participants more than younger. Compliance to FOBT is low among the Israeli population aged 50-74 who receive a formal invitation to carry out this screening. Mailing a kit request card within the framework of a screening programme can achieve a substantial increase (to 17.9%) in the level of compliance for the relatively low cost of postage. More effort is needed to study additional means of convincing the non-responders to take part in this potentially life saving activity.

Efficacy in standard clinical practice of colonoscopic polypectomy in reducing colorectal cancer incidence

BACKGROUND

Colorectal cancer is one of the leading causes of death from cancer in Western countries. Removal of adenomas is based on the assumption that it could lead to a reduction in the incidence of colorectal cancer, as demonstrated by the National Polyp Study in the USA. A critical issue is whether the benefit observed in clinical trials can also be observed in standard clinical practice. To address the issue, a multicentre Italian collaborative study was organised.

METHODS

The study cohort comprised 1693 subjects of both sexes, aged 40-69 years, enrolled between 1980 and 1987 following a total colon examination (TCE) (that is, total colonoscopy or colonoscopy and double contrast barium enema), with removal of at least one adenoma larger than 5 mm in diameter. Exclusion criteria were genetic syndromes, previous adenomas or colorectal cancer, previous colonic resection, inflammatory bowel disease, or sessile adenomas more than 3 cm in diameter. Follow up ended in December 1996 by TCE or telephone interview, and review of the medical records, clinical files, or death certificates. Incidence ratios for colorectal cancer were compared with expected age and sex specific incidences in the Italian general population.

RESULTS

Follow up data were obtained for 97.3% of cases for a total of 14 211 person/years. Mean follow up was 10.5 years. Six colorectal cancer cases (four in males, two in females) at various stages were ascertained (one at 29 months, two at five years, one at seven years, one at eight years, and one at 10 years from the index examination). The number of cancers expected in the reference population was 17.7 for an incidence ratio of 0.34 (confidence interval 0.23-0.63; p<0.01).

CONCLUSIONS

Colonoscopic polypectomy substantially reduced the incidence of colorectal cancer in the cohort compared with that expected in the general population. These results are of particular relevance considering that those with adenomas are at increased risk of colorectal cancer and that this retrospective study was performed on data obtained in standard clinical practice. This observation strengthens the concept of effective population screening in view of the fact that adenomatous polyps are the most frequent neoplastic outcome of screening and their removal is associated with a decrease in the incidence of colorectal cancer.

Colorectal cancer screening by obstetrician-gynecologists

OBJECTIVE

Our purpose was to evaluate colorectal screening practices among obstetrician-gynecologists.

STUDY DESIGN

Retrospective chart review of patients > or =50 years old, of the Boston University Residency Program in Obstetrics and Gynecology for compliance with guidelines from The American College of Obstetricians and Gynecologists.

RESULTS

A total of 2038 encounters yielded 557 annual/health maintenance examination. Overall rates of screening were as follows: rectal examination, 43%; guaiac (single), 37%; fecal occult blood testing (x3), 1.6%; flexible sigmoidoscopy, 5.4%; and Papanicolaou test, 98%. Analysis by type of provider demonstrated a significant difference only of the medical student-resident combination offering sigmoidoscopy to 14.3% of patients versus 5.4% for other providers. A significant increase in overall screening since 1996 was demonstrated (P =.014). Among patients returning for care, screening frequency increased significantly only for the rectal examination.

CONCLUSION

Since the publication of Guidelines for Women's Health Care, by The American College of Obstetricians and Gynecologists in 1996, there has been an increase in colorectal cancer screening among obstetrician-gynecologists. However, flexible sigmoidoscopy and fecal occult blood testing, the most effective means of achieving mortality reduction, remain underutilized. To fully realize the preventability of colorectal cancers in women, we should apply flexible sigmoidoscopy and fetal occult blood testing with the same vigilance currently given to the Papanicolaou test.

Cost-effectiveness of colorectal cancer screening

PURPOSE

To determine the most cost-effective colorectal cancer screening strategy costing less than $100,000 per life-year saved and to determine how available strategies compare with each other.

MATERIALS AND METHODS

Standardized methods were used to calculate incremental cost-effectiveness ratios (ICERs) from published estimates of cost and effectiveness of colorectal cancer screening strategies, and the direction and magnitude of any effect on the ratio from parameter estimate adjustments based on literature values were estimated.

RESULTS

Strategies in which double-contrast barium enema examination was performed emerged as optimal from all studies included. In average-risk individuals, screening with double-contrast barium enema examination every 3 years, or every 5 years with annual fecal occult blood testing, had an ICER of less than $55,600 per life-year saved. However, double-contrast barium enema examination screening every 3 years plus annual fecal occult blood testing had an ICER of more than $100,000 per life-year saved. Colonoscopic screening had an ICER of more than $100,000 per life-year saved, was dominated by other screening strategies, and offered less benefit than did double-contrast barium enema examination screening.

CONCLUSION

Double-contrast barium enema examination can be a cost-effective component of colorectal cancer screening, but further modeling efforts are necessary.

Screening for the major malignancies affecting women: current guidelines

Throughout their lifetimes, many women rely on the obstetrician-gynecologist to provide them with regular health care. Therefore the obstetrician-gynecologist should be able to provide comprehensive information regarding consensus screening recommendations for the major malignancies that occur in women. Additionally, a woman's health care provider should continually refine his or her cancer risk--assessment skills and should remain apprised of high-risk habits, family histories, and other cancer-predisposing factors that allow identification of those women in whom heightened surveillance or intervention may be appropriate. This article reviews the epidemiologic and risk factors associated with the major malignancies that affect women today and provides screening guidelines.

Colonic screening and surveillance

Screening for colorectal cancer has not obtained worldwide acceptance in spite of its proven survival benefit for average-risk persons and some high-risk groups. The incidence of and mortality from colorectal cancer are worrying in Europe as well as in the USA, Australia and Japan. The best evidence-based studies are those published on screening using faecal occult blood tests, endoscopic methods and different tumour markers having been evaluated to a lesser degree. Feasibility studies are necessary before massive screening can be undertaken because the results obtained from randomized studies may not be reproduced to a satisfactory degree in average- as well as high-risk populations. Primary prevention by dietary intervention and drugs has been studied in great detail, so far without any major breakthrough. This chapter will address different screening methods in populations with a varying risk of colorectal cancer, together with providing a short review of prevention and intervention strategies.

Racial and ethnic colorectal cancer patterns affect the cost-effectiveness of colorectal cancer screening in the United States

BACKGROUND & AIMS

Colorectal cancer screening beginning at age 50 is recommended for all Americans considered at "average" risk for the development of colorectal cancer.

METHODS

We used 1988-1995 California Cancer Registry data to compare the cost-effectiveness of two 35-year colorectal cancer screening interventions among Asians, blacks, Latinos, and Whites.

RESULTS

Average annual age-specific colorectal cancer incidence rates were highest in blacks and lowest in Latinos. Screening beginning at age 50 was most cost-effective in blacks and least cost-effective in Latinos (measured as dollars spent per year of life saved), using annual fecal occult blood testing (FOBT) combined with flexible sigmoidoscopy every 5 years and using colonoscopy every 10 years. A 35-year screening program beginning in blacks at age 42, whites at age 44, or Asians at age 46 was more cost-effective than screening Latinos beginning at age 50.

CONCLUSIONS

Colorectal cancer screening programs beginning at age 50, using either FOBT and flexible sigmoidoscopy or colonoscopy in each racial or ethnic group, are within the $40,000-$60,000 per year of life saved upper cost limit considered acceptable for preventive strategies. Screening is most cost-effective in blacks because of high age-specific colorectal cancer incidence rates.

Design of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial

The objectives of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial are to determine in screenees ages 55-74 at entry whether screening with flexible sigmoidoscopy (60-cm sigmoidoscope) can reduce mortality from colorectal cancer, whether screening with chest X-ray can reduce mortality from lung cancer, whether screening men with digital rectal examination (DRE) plus serum prostate-specific antigen (PSA) can reduce mortality from prostate cancer, and whether screening women with CA125 and transvaginal ultrasound (TVU) can reduce mortality from ovarian cancer. Secondary objectives are to assess screening variables other than mortality for each of the interventions including sensitivity, specificity, and positive predictive value; to assess incidence, stage, and survival of cancer cases; and to investigate biologic and/or prognostic characterizations of tumor tissue and biochemical products as intermediate endpoints. The design is a multicenter, two-armed, randomized trial with 37,000 females and 37,000 males in each of the two arms. In the intervention arm, the PSA and CA125 tests are performed at entry, then annually for 5 years. The DRE, TVU, and chest X-ray exams are performed at entry and then annually for 3 years. Sigmoidoscopy is performed at entry and then at the 5-year point. Participants in the control arm follow their usual medical care practices. Participants will be followed for at least 13 years from randomization to ascertain all cancers of the prostate, lung, colorectum, and ovary, as well as deaths from all causes. A pilot phase was undertaken to assess the randomization, screening, and data collection procedures of the trial and to estimate design parameters such as compliance and contamination levels. This paper describes eligibility, consent, and other design features of the trial, randomization and screening procedures, and an outline of the follow-up procedures. Sample-size calculations are reported, and a data analysis plan is presented.

The effect of fecal occult-blood screening on the incidence of colorectal cancer

BACKGROUND

Both annual testing for fecal occult blood and biennial testing significantly reduce mortality from colorectal cancer. However, the effect of screening on the incidence of colorectal cancer remains uncertain, despite the diagnosis and removal of precancerous lesions in many persons who undergo screening.

METHODS

We followed the participants in the Minnesota Colon Cancer Control Study for 18 years. A total of 46,551 people, most of whom were 50 to 80 years old, were enrolled between 1975 and 1978 and randomly assigned to annual screening, biennial screening, or usual care (the control group). Those assigned to the screening groups were asked to prepare and submit two samples from each of three consecutive stools for guaiac-based testing. Those with at least one positive slide in the set of six were offered a diagnostic examination that included colonoscopy. Screening was conducted between 1976 and 1982 and again between 1986 and 1992. Study participants have been followed with respect to newly diagnosed cases of colorectal cancer and deaths. Follow-up has been more than 90 percent complete.

RESULTS

During the 18-year follow-up period, we identified 1359 new cases of colorectal cancer: 417 in the annual-screening group, 435 in the biennial-screening group, and 507 in the control group. The cumulative incidence ratios for colorectal cancer in the screening groups as compared with the control group were 0.80 (95 percent confidence interval, 0.70 to 0.90) and 0.83 (95 percent confidence interval, 0.73 to 0.94) for the annual-screening and biennial-screening groups, respectively. For both screening groups, the number of positive slides was associated with the positive predictive value both for colorectal cancer and for adenomatous polyps at least 1 cm in diameter.

CONCLUSIONS

The use of either annual or biennial fecal occult-blood testing significantly reduces the incidence of colorectal cancer.

Preventable cancers: the role of obstetrician gynecologists in colorectal cancer screening

Colorectal cancer is second only to lung cancer as a cause of cancer deaths in the United States, and is the third most common cause of cancer deaths in U.S. women. Effective screening and intervention programs exist and, if followed, could halve the number of annual deaths from this disease. Detection of early-stage disease and, more important, premalignant polyps, is possible by following the recommendations of several national societies, including the American College of Obstetricians and Gynecologists. Recommended screening consists of identification of special risk factors, annual fecal occult blood testing, and flexible sigmoidoscopy every 5 years. Alternatively, a dual-contrast barium enema every 5 to 10 years or colonoscopy every 10 years are options. This article reviews the evidence underlying current screening guidelines, highlights emerging trends in screening, and analyzes the growing need for women's health care providers to understand and promote colorectal cancer screening as part of an optimal health maintenance program.

Colorectal cancer update. Prevention, screening, treatment, and surveillance for high-risk groups

Great advances have been made in understanding the cause and molecular genesis of colorectal cancer. The disease can be prevented by a healthful diet and lifestyle or by resecting the precursor of most of these cancers, the advanced adenomatous polyp. Screening the average-risk population plus special surveillance for high-risk groups now is recommended by evidence-based guidelines. Surgery is highly curative for patients without distant metastases, and adjuvant therapy improves survival in selected patients with advanced cancers.

CT colonography: the next colon screening examination?

Computed tomographic (CT) colonography is a new-generation technique for detecting colorectal neoplasms by using volumetric CT data combined with specialized imaging software. Patient examinations require full colonic preparation, insufflation, and data acquisition with the patient in the supine and prone positions. Current CT technology allows a single image of the colon to be acquired in as little as 20 seconds with a minimum of patient discomfort. Specialized computer software for interpretation usually combines transverse, multiplanar reformation, and three-dimensional endoluminal images for the optimal visualization of the colon and rectum. As of the time this article was written, CT colonography was competitive as a full structural colonic examination for the detection of polyps and cancer. To the authors' knowledge, no study results have yet been reported in a screening population. The unique capabilities of CT colonography include the display of the proximal colon that is inaccessible at colonoscopy because of obstructing colonic lesions or because of incomplete endoscopic examinations and the assessment of extracolonic abdominal and pelvic organs. This abdominopelvic survey potential provides radiologists with an opportunity to discover other potentially life-threatening, asymptomatic conditions. Further technologic developments and validation studies are in progress. CT colonography is an exciting and promising technique with an enormous potential for colorectal screening in the future.

Prospective, randomized, single-blind comparison of two preparations for screening flexible sigmoidoscopy

BACKGROUND

The best and most cost-effective bowel cleansing regimen for patients undergoing flexible sigmoidoscopy is not known. The aim of this study was to compare patient tolerance, quality of preparation, and cost of 2 bowel cleansing regimens for flexible sigmoidoscopy.

METHODS

Two hundred fifty consecutive patients referred for screening flexible sigmoidoscopy were randomized to receive an oral preparation (45 mL oral sodium phosphate and 10 mg bisacodyl) or an enema preparation (2 Fleet enemas and 10 mg bisacodyl). Tolerance of the preparation was graded as easy, tolerable, slightly difficult, extremely difficult, or intolerable. The endoscopist was blinded to which preparation the patient received and graded the quality of the preparation as poor, fair, good, or excellent. Cost was calculated by adding the cost of the medications and the cost for the nursing time required to prepare the patient for endoscopy.

RESULTS

Patients in the oral preparation group were more likely to grade the preparation as easy or tolerable when compared with the enema group (96.8% vs. 56.4%, p < 0.001). The endoscopist graded the quality of the preparation as good or excellent in 86.5% of the patients in the oral preparation group compared with 57.3% in the enema group (p < 0.001). In the oral preparation group, the mean nursing time (34.6 vs. 65.3 minutes, p < 0.001) and cost ($16.39 vs. $31.13, p < 0.001) were significantly less than in the enema group.

CONCLUSIONS

An oral sodium phosphate preparation results in a superior quality endoscopic examination that is better tolerated and more cost-effective than enemas in patients undergoing screening flexible sigmoidoscopy.

Utilization of K-ras mutations identified in stool DNA for the early detection of colorectal cancer

Colorectal cancer is one of the most common malignancies in the western world. About 60,000 Americans die of colorectal cancer each year. The annual incidence rate in Israel is 40 per 100,000 persons, namely a total of 2,000 new cases each year. An important step in the progression of colorectal cancer includes induction of activating mutations in the proto-oncogene K-ras. The mutations in K-ras appear early during tumorigenesis, at the intermediate adenoma stage, and thus can be used as a biomarker for early detection in about 40% of colonic tumors. A large yet unknown number of mutated cells are shed from the developing tumor during its progression. Indeed, K-ras mutations were detected in DNA isolated from stool obtained from symptomatic and asymptomatic patients with colorectal cancer, suggesting a novel approach for a noninvasive screening procedure. However, severe difficulties in obtaining reproducible yields of amplifiable DNA from stool, and usage of nonquantitative, time-consuming procedures, hampered further progress in the utilization of K-ras mutations for the early detection of colorectal cancer. Apparently a novel protocol is required that provides reproducible output of amplifiable DNA from small amounts of stool, detects if K-ras mutated DNA is present, and determines the quantity of K-ras mutated cells in the stool sample. In addition, this protocol should be simple, robotics compatible, and thus suitable for cost-effective, large-scale mutation screening. Molecular assays for detecting K-ras mutations and additional biomarkers in stool DNA promise to be highly sensitive, specific, and cost-effective. As such they should be very effective when used in chemoprevention studies and screening protocols for colorectal cancer.

Screening for colorectal cancer using the faecal occult blood test, hemoccult

BACKGROUND

Colorectal cancer is a leading cause of illness and death in the Western world. In Australia, the United Kingdom and the United States, it is the second commonest cancer for women after breast cancer (age-standardised incidence 22-33 per 100,000), and men after prostate or lung cancer (age-standardised incidence 31-47 per 100,000) (Jeffs et al, 1996; Parkin et al, 1992). Just under half of all persons affected will die from their disease (Jeffs et al, 1996; Parkin et al, 1992) The human and financial costs of this disease have prompted considerable research efforts to evaluate the ability of screening tests to detect the cancer at an early curable stage. Tests which have been considered for screening include faecal occult blood tests, sigmoidoscopy and colonoscopy.

OBJECTIVES

To determine whether screening for colorectal cancer using the faecal occult blood test, Hemoccult reduces colorectal cancer mortality and to consider the benefits and harms of screening.

SEARCH STRATEGY

Published and unpublished data for this review were identified by: * retrieving studies included in a systematic review conducted by some of the authors in 1995, * searches of MEDLINE, Current Contents and the Cochrane Controlled Trials Register, * writing to trial lists.

SELECTION CRITERIA

All controlled trials of screening for colorectal cancer using Hemoccult were eligible for inclusion in the review.

DATA COLLECTION AND ANALYSIS

Data from the trials were independently extracted by two authors. Data analysis was performed using the group subjects were randomised to ('intention to screen'), whether or not they were ever screened. To estimate the effect of Hemoccult screening on colorectal cancer mortality, we calculated relative risks and risk differences for each trial, and then overall, using fixed and random effects models and tested for heterogeneity of effects. We calculated summary measures of effect including all trials and also for just the randomised controlled trials. We also calculated a summary measure of effect, adjusted for attendance at screening in each trial (not shown in Meta-view).

MAIN RESULTS

Meta-analysis of mortality results from the randomised controlled trials shows that those allocated to screening had a reduction in colorectal cancer mortality of 16% (RR 0.84, CI: 0.77-0.93). When adjusted for screening attendance in the individual studies, the mortality reduction is 23% (RR 0.77, CI: 0.57-0.89). Overall, if 10 000 people were offered a biennial Hemoccult screening program and two-thirds attended for at least one Hemoccult test, there would be 8.5 deaths (CI: 3.6-13.5) from colorectal cancer prevented over 10 years. However, the screening program would also result in 2 800 participants having at least one colonoscopy, if screening harms from the Minnesota trial are considered, and there would be 3.4 colonoscopy complications (perforation or haemorrhage). If screening harms from the Gothenburg trial are considered, approximately 600 participants would need at least one sigmoidoscopy and double contrast barium enema, resulting in 1.8 perforations or haemorrhages.

REVIEWER'S CONCLUSIONS

Screening benefits include reduction in colorectal cancer mortality, possible reduction in cancer incidence through detection and removal of colorectal adenomas and potentially, treatment of early colorectal cancers may involve less invasive surgery. Harmful effects of screening include the physical complications of colonoscopy, disruption to lifestyle, stress and discomfort of testing and investigations, and the anxiety caused by falsely positive screening tests. Although screening benefits are likely to outweigh harms for populations at increased risk of colorectal cancer, we need more information about the harmful effects of screening, the community's responses to screening and screening costs for different health care systems before widespread screening can be recommended.

A comparison of virtual and conventional colonoscopy for the detection of colorectal polyps

BACKGROUND

Virtual colonoscopy is a new method of imaging the colon in which thin-section, helical computed tomography (CT) is used to generate high-resolution, two-dimensional axial images. Three-dimensional images of the colon simulating those obtained with conventional colonoscopy are then reconstructed off-line. We compared the performance of virtual and conventional colonoscopy for the detection of colorectal polyps.

METHODS

We prospectively studied 100 patients at high risk for colorectal neoplasia (60 men and 40 women; mean age, 62 years). We performed virtual colonoscopy immediately before conventional colonoscopy. We inserted a rectal tube and insufflated the colon with air to the maximal level that the patient could tolerate. We administered 1 mg of glucagon intravenously immediately before CT scanning to minimize the degree of smooth-muscle spasm and peristalsis and to reduce the patient's discomfort.

RESULTS

The entire colon was clearly seen by virtual colonoscopy in 87 patients and by conventional colonoscopy in 89. Fifty-one patients had normal findings on conventional colonoscopy. In the other 49, we identified a total of 115 polyps and 3 carcinomas. Virtual colonoscopy identified all 3 cancers, 20 of 22 polyps that were 10 mm or more in diameter (91 percent), 33 of 40 that were 6 to 9 mm (82 percent), and 29 of 53 that were 5 mm or smaller (55 percent). There were 19 false positive findings of polyps and no false positive findings of cancer. Of the 69 adenomatous polyps, 46 of the 51 that were 6 mm or more in diameter (90 percent) and 12 of the 18 that were 5 mm or smaller (67 percent) were correctly identified by virtual colonoscopy. Although discomfort was not specifically recorded, none of the patients requested that virtual colonoscopy be stopped because of discomfort or pain.

CONCLUSIONS

In a group of patients at high risk for colorectal neoplasia, virtual and conventional colonoscopy had similar efficacy for the detection of polyps that were 6 mm or more in diameter.

Colorectal cancer screening

Colorectal cancer is an important problem in the United States, with over 130,000 new cases and 55,000 deaths each year. There is now strong evidence that screening for colorectal cancer with fecal occult blood testing can decrease mortality, and additional evidence that removing benign adenomas can decrease cancer incidence. Evidence-based screening guidelines depend on colorectal cancer risk. Individuals at higher risk because of a personal or family history deserve more intensive screening than asymptomatic individuals over age 50.

Flexible sigmoidoscopy by nurses: state of the art 1999

Although screening flexible sigmoidoscopy is associated with a significant decrease in colorectal cancer mortality, less than 50% of eligible Americans have had a sigmoidoscopy. As the United States population ages, over 50 million Americans will be eligible for colorectal cancer screening with flexible sigmoidoscopy. The projected increase in a population eligible for screening is expected to increase demand for this procedure and may result in overwhelming currently available endoscopic resources. Gastroenterology nurses should actively seek training to perform flexible sigmoidoscopy to accommodate this increased demand. Current barriers to nurse-performed sigmoidoscopy are prohibitions by state Boards of Nursing and lack of procedural reimbursement for nurse endoscopists performing flexible sigmoidoscopy. The lack of research about the effectiveness of this practice is a contributing factor to the hindrances in the development of this nursing role. This review outlines research about the effectiveness of flexible sigmoidoscopy by nurses, legal and reimbursement issues, and details the scope of training programs used by institutions with nurse endoscopists.

Colon cancer treatment in rural North and South Carolina

The purpose of this study was to determine the degree to which colon cancer treatment in rural North and South Carolina in 1991 and 1996 conformed to national treatment recommendations. Data came from medical records of colon cancer patients residing in rural North and South Carolina. The National Cancer Institute's Physician Data Query (PDQ) database was used to define state-of-the-art care and to categorize receipt of primary and/or adjuvant treatment. Changes in treatment over time, location, and stage and bivariate relationships between treatment and selected covariates were assessed with chi-square and Fisher's exact tests. Regression was used to control for possible interactions between patient and/or disease characteristics and treatment. The majority of colon cancer cases received primary therapy as suggested by the PDQ which was not significantly related to other factors examined. There was variation in provision of adjuvant therapy. Stage III patients received adjuvant therapy significantly more often than did stage II patients (p </= 0.01). Receipt of appropriate adjuvant therapy among stage III patients was significantly associated with younger patient age and white race (p </= 0.05). Rural colon cancer patients are likely to receive primary therapy as recommended by the PDQ, but may be less likely to receive suggested adjuvant therapy. Further understanding of variations in the rate of adjuvant therapy for colon cancer is needed to ensure appropriate treatment regimens are obtained for rural colon cancer patients.

Survival and treatment for colorectal cancer Medicare patients in two group/staff health maintenance organizations and the fee-for-service setting

The current study compares treatment use and long-term survival in colorectal cancer patients between Medicare beneficiaries enrolled in two large prepaid group/staff health maintenance organizations (HMOs) and the fee-for-service (FFS) setting. The study is based on 15,352 colorectal cancer cases diagnosed between 1985 and 1992 and followed through 1995. Survival differences between the HMO and FFS cases were assessed using Cox regression. Treatment differences were evaluated using logistic regression. HMO cases had a lower overall mortality than did FFS cases but not a significantly lower colorectal cancer-specific mortality. Use of surgical resection was similar between HMO and FFS cases. However, rectal cancer cases in the HMOs were more likely to receive postsurgical radiation therapy than FFS cases. Superior overall survival in the HMOs may be the result of increased colorectal cancer screening, greater use of adjuvant therapies, and selection of healthier individuals.

Reducing colorectal cancer mortality by repeated faecal occult blood test: a nested case-control study

Randomised trials have shown the efficacy of faecal occult blood testing (FOBT) in reducing colorectal cancer mortality, but observational studies are needed to monitor such efficacy in population programmes. We conducted a nested case-control study on a cohort of 21,879 subjects who participated in a colorectal screening programme from 1978 to 1995, undergoing at least one FOBT test. 95 fatal cases of colorectal cancer were eligible for the study. For each fatal case, 5 non-fatal matched controls were randomly selected from the cohort. FOBT screening history was less common among cases than controls. The odds ratio of colorectal cancer mortality among 'attenders' (defined as those who underwent a second FOBT within 2 years of study entry) with respect to 'non-attenders' was 0.64 (95% confidence interval 0.36-1.15). We also computed odds ratios defining exposure as one or more tests in the detectable preclinical period, hypothesising various lengths for the latter, which, however, yielded an efficacy estimate biased towards the null. A strong inverse relationship was observed between mortality and the number of tests, but this phenomenon is interpretable as 'healthy screenee bias'. The results suggest that the potential efficacy in preventing colorectal cancer mortality through annual FOBT screening may be of the order of one third.

Frequency of advanced neoplasia in the proximal colon without an index polyp in the rectosigmoid

PURPOSE

Screening endoscopy has the potential to reduce colorectal cancer mortality. However, the efficacy of screening flexible sigmoidoscopy compared with colonoscopy strongly depends on the frequency of advanced proximal neoplasms without an index polyp in the rectosigmoid. We have therefore determined this frequency in our endoscopy population.

METHODS

Endoscopic and histologic data were analyzed from all patients on whom integral colonoscopy was performed between 1980 and 1995. Advanced neoplasia was defined as cancer or adenomas >10 mm in diameter, adenomas with a villous component, or severe dysplasia. Patients with polyposis syndrome or inflammatory bowel disease were excluded.

RESULTS

Colonoscopy was performed on 11,760 patients. 2,272 (19.3 percent) had at least one colorectal neoplasm, of which 39 percent had the neoplasm above the rectosigmoid. Twenty-two percent of all patients with neoplasia had no index polyp in the rectosigmoid and 16 percent of these had no index polyp, but at least one advanced proximal neoplasm.

CONCLUSIONS

Although 39 percent of patients had neoplasms above the rectosigmoid, only 16 percent had an advanced proximal neoplasm without an index polyp in the rectosigmoid. This gives a figure on which to base the evaluation of screening sigmoidoscopy programs against those of screening colonoscopy.

The Next Step Trial: impact of a worksite colorectal cancer screening promotion program

BACKGROUND

The Next Step Trial was a randomized trial of worksite colorectal cancer screening promotion and nutrition interventions for automobile industry employees at increased risk of colorectal cancer. Interventions were tested at 28 worksites with 5,042 employees. This report describes results of the screening promotion intervention.

METHODS

Worksites randomized to the control group received a standard program including rectal examination, fecal occult blood testing, and flexible sigmoidoscopy. Intervention worksites received an enhanced program (i.e., standard program plus an educational booklet/telephone call). Compliance (i.e., completion of all recommended screening examinations) and coverage (i.e., completion of at least one screening examination), the primary and secondary outcomes, were measured over 2 years.

RESULTS

In the 2 years prior to baseline, 61% of employees had been screened. After random assignment, baseline differences in several employee characteristics and worksite screening procedures were detected, including more past history of screening in control worksites. After adjusting for differences, we found modest, but higher, compliance and coverage in intervention compared with control worksites (odds ratio [95% confidence limits] = 1.46 [1.1-2.0] and 1.33 [1.1, 1.6], respectively).

CONCLUSIONS

Adding a personally tailored behavioral intervention to a standard colorectal cancer screening program can promote continued employee participation in screening as measured by compliance. Further research is needed to assess intervention effects in other populations.

Screening guidelines for colorectal cancer

Evidence-based guidelines recommend that all asymptomatic, average-risk U.S. citizens >50 years of age be encouraged to undergo screening for colorectal cancer. Those at higher risk should be offered more intensive screening and follow-up surveillance. It is estimated that widespread adoption of these recommendations could reduce mortality from colorectal cancer by >50%. The only screening methods that have been evaluated directly are the fecal occult blood test and flexible sigmoidoscopy. Current guidelines now recommend annual screening for fecal occult blood plus flexible sigmoidoscopy every 5 years for asymptomatic, average-risk men and women >50 years of age. Indirect evidence supports the options of colonoscopy or barium enema x-ray screening for highly motivated individuals, but these methods have not yet been tested in prospective trials. In the future, gene-based screening tests may be developed, and computed tomography of the colon ("virtual colonoscopy") may prove effective and feasible.

Colorectal cancer screening and follow-up

Cancer of the colon and rectum is a significant health problem in the United States. Nearly 50% of the 186,000 patients diagnosed annually with colorectal cancer will eventually die of their disease. Because development of a colorectal carcinoma is most frequently preceded by the development of a well-recognized pre-malignant lesion, screening modalities can significantly impact the incidence and mortality rate of this disease. Population screening employing digital rectal examination, fecal occult blood testing and endoscopic examination of the rectum and colon has been demonstrated to reduce the risk of death from colorectal cancer. Screening regimens should be instituted at an earlier age and with increased frequency for patients in the highest risk categories. Patients who have been treated for a cancer of the colon or rectum should undergo surveillance at regular intervals in an attempt to identify recurrences of disease both in the residual colon and rectum and at distant sites. Most physicians and patients believe that intensive follow-up strategies will afford improved survival and quality of life, however few randomized studies examining the utility of intensive follow-up programs have been performed and the quality of cancer-related follow-up literature is generally poor. Good-quality clinical trials are needed to sort out which tests make a difference in the patient's long-term outcome. The algorithm for surveillance for recurrence in the future may be altered as newer testing modalities are developed.

Effectiveness and cost-effectiveness of colorectal cancer screening: Selecting the ideal strategy

Colorectal cancer is the second most common cancer killer of Americans. Recently developed and tested methods of screening and surveillance can effectively diagnose and treat the disease in most patients before symptoms develop when the chance of cure is high. It is also possible to prevent colorectal cancer by detecting and resecting premalignant adenomatous polyps. Evidence-based guidelines recommend that the average-risk population greater than age 50 be screened with annual faecal occult blood tests plus periodic flexible sigmoidoscopy. This approach is feasible, efficacious, affordable and cost-effective in a high-risk country such as the US. Widespread compliance with these recommendations could reduce the mortality from this malignancy by more than 50%.