Randomised controlled trial of faecal-occult-blood screening for colorectal cancer

Willingness-to-pay for colorectal cancer screening

Willingness-to-pay (WTP) techniques are increasingly being used in economic evaluation, as a means of assessing the value of new health care technologies. This paper presents the results of a WTP investigation of two types of screening for colorectal cancer. A questionnaire was issued to a general population via general practitioners (GPs), yielding a sample of approximately 2000 cases for analysis. Regression models demonstrated that WTP was significantly influenced by factors such as gender, income, age, risk perceptions, illness experiences and health beliefs. The median WTP for screening emerged as being pound30 or pound50, depending on the method used to elicit WTP, but independent of the screening protocol. Combining the results with those from related research, it emerged, first, that WTP subjects offered higher values for flexible sigmoidoscopy screening than the costs actually incurred by revealed preference studies and, second, they offered WTP values similar to the likely resource costs of the screening procedures.

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.

Effect of dietary restriction on participation in faecal occult blood test screening for colorectal cancer

OBJECTIVES

To determine if participation in colorectal cancer screening using faecal occult blood testing (FOBT) is affected by a restrictive diet and if it is associated with certain demographic variables.

PARTICIPANTS AND SETTING

1,203 residents of South Australia aged 50-69 years, with no "currently active bowel disease", randomly selected from a database of people willing to be contacted about unspecified health issues.

DESIGN

Randomised controlled trial: participants were offered screening by immunochemical FOBT by mail in 1998. Half were randomly allocated to a group instructed to follow a low-peroxidase diet, as required for guaiac FOBT, while the other group was not so restricted.

MAIN OUTCOME MEASURES

Effect of diet restriction on participation (return of correctly completed FOBT sample cards within 15 weeks); time taken to return cards; relationships between participation and demographic variables.

RESULTS

Participation rates were 65.9% (no-diet group) and 53.3% (diet group) (difference, 12.6%; 95% CI, 7.1%-18.1%). In the first week, rates of return as a proportion of all tests returned were 13.1% (no-diet) and 1.6% (diet) (difference, 11.5%; 95% CI, 8.6%-14.4%), increasing to 54.3% and 44.5%, respectively, after five weeks (difference, 9.8%; 95% CI, 4.2%-15.4%). Participation was significantly associated with older age (odds ratio, 1.40; 95% CI, 1.10-1.78), but not sex, Index of Social Disadvantage or rural versus urban address.

CONCLUSIONS

Dietary restrictions create a barrier to FOBT-based screening for colorectal cancer. The use of immunochemical rather than guaiac FOBT removes this barrier.

Stage of extension and treatment for colorectal cancer after a negative test and among non-responders in mass screening with guaiac faecal occult blood test: a French experience

Despite its proven efficacy in three randomized trials, the relevance of mass screening for colorectal cancer using the guaiac faecal occult blood test is still debated. The low sensitivity of the test and the poor participation rate, especially in France, are major obstacles to its effectiveness. The aim of our study was to characterize cancers occurring after a negative test and among non-participants in the screening programme organized in the French department of Calvados. Cancers in the negative test group had a later stage of extension than subjects testing positively but an earlier stage of extension than cancers in the reference group, which were not different from those of non-responders. The proportion of resection for non-responders was significantly lower than that for participants, whatever the test result (P < 0.001), and lower than that for reference subjects (P < 0.05). There was no difference in treatment between negative and positive responders. Negative responders did not have a delayed cancer diagnosis or a worse condition of treatment than people who were not screened. Low sensitivity reduced the efficacy of colorectal cancer screening but did not seem to increase the potential to do harm.

Colorectal cancer-screening tests and associated health behaviors

BACKGROUND

Studies have shown that screening reduces colorectal cancer mortality. We analyzed national survey data to determine rates of use of fecal occult blood testing (FOBT) and sigmoidoscopy, and to determine if these rates differ by demographic factors and other health behaviors.

METHODS

A total of 52,754 respondents aged >or=50 years were questioned in the 1997 Behavioral Risk Factor Surveillance System (BRFSS) survey (a random-digit-dialing telephone survey of the non-institutionalized U.S. population) about their use of FOBT and sigmoidoscopy.

RESULTS

The age-adjusted proportion of respondents who reported having had a colorectal cancer screening test during the recommended time interval (past year for FOBT and past 5 years for sigmoidoscopy) was 19.8% for FOBT, 30.5% for sigmoidoscopy, and 41.1% for either FOBT or sigmoidoscopy. Rates of use of colorectal cancer screening tests were higher for those who had other screening tests (mammography, Papanicolaou smear, and cholesterol check). There were also differences in rates of use of colorectal cancer screening tests according to other health behaviors (smoking, seat belt use, fruit and vegetable intake, and physical activity) and several demographic factors. However, none of the subgroups that we examined reported a rate of FOBT use above 29% within the past year or a rate of sigmoidoscopy use above 41% within the past 5 years.

CONCLUSIONS

While rates of use of FOBT and sigmoidoscopy were higher among people who practiced other healthy behaviors, rates of use were still quite low in all subgroups. There is a need for increased awareness of the importance of colorectal cancer screening.

CT colonography without cathartic preparation: feasibility study

PURPOSE

To evaluate methods for contrast material labeling of stool in the unprepared colon for computed tomographic (CT) colonography and to determine their sensitivity for polyp detection.

MATERIALS AND METHODS

Fifty-six patients with suspected or known polyps were assigned to five groups. Two to seven doses of 225 mL of dilute contrast material were orally administered during 24 or 48 hours. Transverse CT images were assessed for effectiveness of stool labeling. Colonoscopy was performed in all patients and was the standard. Two radiologists blinded to prior imaging and colonoscopic results assessed polyp detection.

RESULTS

For each group, average stool labeling scores and ranges were as follows: 24 hour two dose, 16% and 8%-21%; 24 hour five dose, 53% and 27%-66%; 48 hour four dose, 38% and 22%-48%; 48 hour six dose, 68% and 54%-77%; and 48 hour seven dose, 88% and 75%-98%. Sensitivity for the two radiologists for the identification of patients with polyps 1 cm or larger for each group was as follows: 24 hour two dose, 50% and 67%; 24 hour five dose, 100% and 100%; 48 hour four dose, 58% and 75%; 48 hour six dose, 56% and 67%; and 48 hour seven dose, 100% and 80%.

CONCLUSION

Ingestion of contrast material adequately labels stool for lesion identification; a 48-hour lead time and multiple doses of contrast material are required. Sensitivity for polyp detection in patients with adequate stool labeling approaches the sensitivity for polyp detection in prepared colons.

Fecal occult blood testing in a noncompliant inner city minority population: increased compliance and adherence to screening procedures without loss of test sensitivity using stool obtained at the time of in-office rectal examination

OBJECTIVES

Fecal occult blood screening is cost-effective, is easily administered to large groups of patients, and reduces mortality associated with colorectal cancer. Within our predominant African American and Latino inner city clinic populations, compliance with common screening procedures is suboptimal. A procedure with increased compliance is needed to adequately screen this population at high risk for colorectal cancer. The objective of this study was to compare the results of the 3-day at-home hemoccult test for occult blood to those of a hemoccult test performed from stool obtained at rectal examination in the office.

METHODS

A total of 350 consecutive patients referred to the GI clinic of University Hospital or Jersey City Medical Center for colorectal cancer screening had both the 3-day at-home hemoccult test and an in-office hemoccult examination performed, followed by either sigmoidoscopy (for negative results) or by colonoscopy (for positive results).

RESULTS

Patients were noncompliant with dietary restrictions, 3-day card return, follow-up appointments, and endoscopy with conventional screening methods. Decisions based on the in-office examination with direct scheduling of endoscopy significantly improved compliance with follow-up. There was no statistical difference between the two detection methods, suggesting that the in-office examination was the more effective screening test.

CONCLUSIONS

Endoscopy based on an in-office hemoccult examination is an acceptable alternative to using the 3-day at-home stool collection to govern endoscopic choices. In a noncompliant inner city population, use of the in-office examination increased compliance with follow up, potentially allowing more patients exposure to screening.

Estimation of screening test (Hemoccult) sensitivity in colorectal cancer mass screening

3 controlled cohorts of mass-screening for colorectal cancer using a biennial faecal occult blood (HemoccultII test on well-defined European populations have demonstrated a 14% to 18% reduction in specific mortality. We aimed to estimate the sensitivity (S) of this HemoccultII test and and also mean sojourn time (MST) from French colorectal mass-screening programme data. 6 biennial screening rounds were performed from 1988 to 1998 in 45 603 individuals aged 45-74 years in Saône-et-Loire (Burgundy, France). The prevalent/incidence ratio was calculated in order to obtain a direct estimate of the product S.MST. The analysis of the proportional incidence and its modelling was used to derive an indirect estimate of S and MST. The product S.MST was higher for males than females and higher for left colon than either the right colon or rectum. The analysis of the proportional incidence confirmed the result for subsites but no other significant differences were found. The sensitivity was estimated at 0.57 and the MST at 2.56 years. This study confirms that the sensitivity of the Hemoccult test is relatively low and that the relatively short sojourn time is in favour of annual screening.

Observations from the CDC: CDC's Screen for Life: a National Colorectal Cancer Action Campaign

Colorectal cancer is the second leading cause of cancer-related deaths in the United States. Despite the availability of several different screening tests for colorectal cancer, screening rates remain low. To raise awareness about colorectal cancer and encourage men and women aged 50 and older to speak with their physicians about being screened for colorectal cancer, the Centers for Disease Control and Prevention and the Health Care Financing Administration launched Screen for Life: A National Colorectal Cancer Action Campaign in 1999. The purpose of this paper is to outline the development of this multiyear, multimedia campaign, from conducting formative research to developing campaign messages and materials. Limited process evaluation results are presented.

The diagnosis of cancer in the "roar" of potential cancer symptoms of patients in primary health care. Research by means of the computerised journal

OBJECTIVE

To describe the diagnostic work-up pattern in primary health care, aiming, with as few diagnostic activities as possible, to identify a number of malignancies among patients presenting with various symptoms, where a malignancy may be a differential diagnosis.

DESIGN

Survey of computerised journals. Diagnostic codes (ICD-9 system in primary health care) relating to signs, symptoms or diagnosis were selected where colorectal, pulmonary, breast and prostate malignancies might be differential diagnoses. All diagnostic actions were analysed.

SUBJECTS

6812 patients over 30 years of age from four health centres who were recorded for a total of 14455 selected diagnostic codes.

RESULTS

The diagnostic actions resulted in 1426 X-ray or sonographic investigations, 340 endoscopies, 16203 haematology, clinical chemistry or microbiology tests and 667 referrals to specialists. Forty-nine malignancies were diagnosed at the primary health care centres, while 10 malignancies were classified as "missed". The frequency of faecal-occult blood tests performed was low while that of ESR and pulmonary X-ray examinations was high.

CONCLUSION

The task for a GP identifying one or two undiagnosed malignancies per year of the four most common types among all the non-neoplastic ailments, and with as little diagnostic activity as possible, is a professional challenge to be scrutinised continuously.

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.

WHO antenatal care randomised trial for the evaluation of a new model of routine antenatal care

BACKGROUND

We undertook a multicentre randomised controlled trial that compared the standard model of antenatal care with a new model that emphasises actions known to be effective in improving maternal or neonatal outcomes and has fewer clinic visits.

METHODS

Clinics in Argentina, Cuba, Saudi Arabia, and Thailand were randomly allocated to provide either the new model (27 clinics) or the standard model currently in use (26 clinics). All women presenting for antenatal care at these clinics over an average of 18 months were enrolled. Women enrolled in clinics offering the new model were classified on the basis of history of obstetric and clinical conditions. Those who did not require further specific assessment or treatment were offered the basic component of the new model, and those deemed at higher risk received the usual care for their conditions; however, all were included in the new-model group for the analyses, which were by intention to treat. The primary outcomes were low birthweight (<2500 g), pre-eclampsia/eclampsia, severe postpartum anaemia (<90 g/L haemoglobin), and treated urinary-tract infection. There was an assessment of quality of care and an economic evaluation.

FINDINGS

Women attending clinics assigned the new model (n=12568) had a median of five visits compared with eight within the standard model (n=11958). More women in the new model than in the standard model were referred to higher levels of care (13.4% vs 7.3%), but rates of hospital admission, diagnosis, and length of stay were similar. The groups had similar rates of low birthweight (new model 7.68% vs standard model 7.14%; stratified rate difference 0.96 [95% CI -0.01 to 1.92]), postpartum anaemia (7.59% vs 8.67%; 0.32), and urinary-tract infection (5.95% vs 7.41%; -0.42 [-1.65 to 0.80]). For pre-eclampsia/eclampsia the rate was slightly higher in the new model (1.69% vs 1.38%; 0.21 [-0.25 to 0.67]). Adjustment by several confounding variables did not modify this pattern. There were negligible differences between groups for several secondary outcomes. Women and providers in both groups were, in general, satisfied with the care received, although some women assigned the new model expressed concern about the timing of visits. There was no cost increase, and in some settings the new model decreased cost.

INTERPRETATIONS

Provision of routine antenatal care by the new model seems not to affect maternal and perinatal outcomes. It could be implemented without major resistance from women and providers and may reduce cost.

The role of inadequate health literacy skills in colorectal cancer screening

Colorectal cancer is ideally suited for early detection strategies that are likely to improve survival rates. Screening with either a fecal occult blood test (FOBT) or flexible sigmoidoscopy has been shown to identify precancerous polyps or cancers in early stages. However, persons with limited education and of lower socioeconomic status infrequently participate in screening programs in general and have very low rates of colorectal screening. Low literacy, which is common among persons with limited education and low income, may be an overlooked factor in understanding patients' decision making about colorectal cancer screening. This article provides information from focus groups about colorectal cancer screening, which we examine in the context of relevant literature on cancer screening and literacy. Using the health belief model, we examine the association between inadequate health literacy skills and low rates of colorectal cancer screening. The theoretical model also provides insights into strategies for improving knowledge, attitudes, and beliefs and screening rates for this challenging patient population.

Impact of systematic false-negative test results on the performance of faecal occult blood screening

The impact of systematic false-negative test results on mortality reduction and on programme sensitivity of annual faecal occult blood testing in ages 50-84 years is explored using a microsimulation model. We made calculations for test sensitivities of 80, 50 and 30%. In order to reproduce a cancer detection rate of 2.2 per 1000 at the first screening, the corresponding mean preclinical sojourn times had to be 1.42, 2.30 and 3.84 years, respectively. The fraction systematic results among the false-negative results is varied between 0 and 100%. With 80% test sensitivity, the reduction in mortality due to screening decreases from 25% without systematic results to 23% when all false-negative results are systematic and the programme sensitivity decreases from 63 to 58%. With 30% test sensitivity, mortality reduction decreases from 21 to 11% and programme sensitivity decreases from 52 to 27%. The impact of systematic false-negative test results is important if annual FOBT screening is considered.

Do undesirable effects of screening affect all-cause mortality in flexible sigmoidoscopy programmes? Experience from the Telemark Polyp Study 1983-1996

There is substantial evidence for the beneficial effect of screening programmes aimed at reducing mortality from colorectal cancer (CRC). The effect on all-cause mortality, however, may not necessarily be beneficial. In the present study we used the follow-up results 13 years after a flexible sigmoidoscopy screening to evaluate the long-term effects of informing participants about findings at flexible sigmoidoscopy (FS) screening. There were no severe complications and there was no long-term difference in deaths related to whether there had been any mucosal rupture (biopsy or snare resection) or not. As a group, those who attended in 1983 and were informed that they had polyps tended to improve their smoking habits more than those informed that they had no polyps. Similarly, and in spite of more people giving up smoking, the group with polyps had a trend towards a smaller increase in BMI (+0.7 (95% CI 0.2-1.1)) than the polyp-free group (+1.2 (95% CI 0.9-1.6)) (P = 0.07). The observations suggest that flexible sigmoidoscopy screening may face an educational challenge to avoid unfavourable changes in the lifestyle of screenees, an effect that may more than outweigh the beneficial effect of screening.

The recognition and endoscopic treatment of early gastric and colonic cancer

As the prognosis of both gastric and colonic cancer remains poor, the challenge is to detect lesions at an early and treatable stage. The benefit of early detection is not only improved survival, but also that patients may be treated with endoscopic mucosal resection, a low-cost, low-morbidity and low-mortality alternative to surgery. In spite of the increasing use of endoscopy in the West, we are not detecting as many early cancers as in Japan. This chapter will discuss the possible reasons for this discrepancy and give a practical guide to 'Japanese endoscopy techniques'. Finally, we have compiled a comprehensive review of the indications, techniques and complications of endoscopic mucosal resection. Throughout the chapter, controversies have been highlighted to give an insight into the limits of our knowledge and stimulate future research.

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.

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.

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.

Screening for colorectal cancer: what is the most cost-effective approach?

In Western countries, including Australia, colorectal cancer is the leading cause of cancer mortality in nonsmokers. Development of most colorectal cancers can be prevented by adenoma removal. The current screening strategies of faecal occult blood testing (FOBT), flexible sigmoidoscopy combined with FOBT and colonoscopy are all cost effective. In clinical practice, a range of options should be offered to allow for individual patients' preferences. A public education program is essential to the success of any screening strategy.

Antioxidants enhance the susceptibility of colon carcinoma cells to 5-fluorouracil by augmenting the induction of the bax protein

5 Fluorouracil (5 FU), the most effective systemic chemotherapeutic agent in the management of advanced colorectal carcinoma acts by inducing apoptosis. Response rates, approximately 20% is improved by folinic acid. This study investigates similar modulation of 5 FU-induced apoptosis by oxidant quenching. A five-fold reduction of intracellular oxidant levels by antioxidants N-acetylcysteine and vitamin E did not induce apoptosis, it however augmented pro-apoptotic bax protein expression, and apoptotic response to a non-toxic dose of 5 FU in the colorectal cancer cell lines colo 201 and colo 205. This suggests that reduction of intracellular levels of reactive oxygen species enhance susceptibility to 5 FU (apoptotic stimuli) by augmentation of bax expression.

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.

Review article: the prevention of colorectal cancer

Colorectal cancer is a leading cause of cancer mortality in the industrialized world. Survival remains poor because most cases are diagnosed at an advanced stage. It is a preventable disease as colorectal cancers usually develop slowly from an identifiable precursor lesion, the adenoma. The existing strategies for colorectal cancer prevention include dietary prevention, chemoprevention and endoscopic intervention. The exact relationship between diet, particularly fibre, and colorectal cancer remains unclear, with the most recent studies suggesting that dietary fibre may not decrease colorectal cancer risk as previously thought. Non-steroidal anti-inflammatory drugs have been shown to have a protective effect against colorectal cancer, but the adverse effect profile of the non COX-2 selective drugs, particularly the risk of gastrointestinal haemorrhage, precludes their widespread use. There is increasing evidence that colorectal cancer incidence and mortality can be decreased from endoscopic polypectomy and early detection of cancer. Faecal occult blood testing in the general population ('average-risk') has been shown in randomized trials to decrease mortality from colorectal cancer by 15--33%. Long-term results of randomized trials of the effectiveness of flexible sigmoidoscopy and colonoscopy screening in the general population are awaited. Targeting high risk individuals may also be an effective and efficient way to decrease the colorectal cancer burden. As many as 15--30% of colorectal cases may be due to hereditary factors. Individuals with one or two direct relatives affected are at moderate risk for colorectal cancer (empirical lifetime mortality from colorectal cancer approximately 10%) and approximately 2--3% of cases arise in individuals harbouring highly penetrant autosomal dominant mutations, which puts them at high-risk for colorectal cancer. Surveillance colonoscopy is offered to individuals at moderate and high risk for colorectal cancer.

Fecal occult blood testing for iron deficiency: a reappraisal

Fecal occult blood (FOB) tests have been evaluated primarily for the application of colorectal cancer screening. Less is known about the performance characteristics of FOB tests for the evaluation of iron deficiency, the most common other application. As most clinically important occult gastrointestinal bleeding arises from the proximal gut, it is critical that FOB tests target analytes that are stable during the enteric transit. Available data indicate that guaiac-type and immunochemical tests are insensitive for the detection of proximal gut bleeding, and their use may confound the evaluation of iron deficiency. In contrast, the heme porphyrin test is sensitive for both proximal and distal sources of occult gastrointestinal bleeding, and this FOB test would appear to be the most rational selection for use in patients with iron deficiency or anemia. Outcome data are needed to better assess the impact of FOB testing on algorithms for evaluation of iron deficiency.

Therapeutic nursing or unblocking beds? A randomised controlled trial of a post-acute intermediate care unit

OBJECTIVES

To compare post-acute intermediate care in an inpatient nurse-led unit with conventional post-acute care on general medical wards of an acute hospital and to examine the model of care in a nurse-led unit.

DESIGN

Randomised controlled trial with six month follow up.

SETTING

Urban teaching hospital and surrounding area, including nine community hospitals.

PARTICIPANTS

238 patients accepted for admission to nurse-led unit.

INTERVENTIONS

Care in nurse-led unit or usual post-acute care.

MAIN OUTCOME MEASURES

Patients' length of stay, functional status, subsequent move to more dependent living arrangement.

RESULTS

Inpatient length of stay was significantly longer in the nurse-led unit than in general medical wards (14.3 days longer (95% confidence interval 7.8 to 20.7)), but this difference became non-significant when transfers to community hospitals were included in the measure of initial length of stay (4.5 days longer (-3.6 to 12.5)). No differences were observed in mortality, functional status, or living arrangements at any time. Patients in the nurse-led unit received significantly fewer minor medical investigations and, after controlling for length of stay, significantly fewer major reviews, tests, or drug changes.

CONCLUSIONS

The nurse-led unit seemed to be a safe alternative to conventional management, but a full accounting of such units' place in the local continuum of care and the costs associated with acute hospitals managing post-acute patients is needed if nurse-led units are to become an effective part of the government's recent commitment to intermediate care.

Methodological considerations on the design and analysis of an equivalence stratified cluster randomization trial

The World Health Organization and collaborating institutions in four developing countries have conducted a multi-centre randomized controlled trial, in which clinics were allocated at random to two antenatal care (ANC) models. These were the standard 'Western' ANC model and a 'new' ANC model consisting of tests, clinical procedures and follow-up actions scientifically demonstrated to be effective in improving maternal and newborn outcomes. The two models were compared using the equivalence approach. This paper discusses the implications of the equivalence approach in the sample size calculation, analysis and interpretation of results of this cluster randomized trial. It reviews the ethical aspects regarding informed consent, concluding that the Zelen design has a place in cluster randomization trials. It describes the estimation of the intracluster correlation coefficient (ICC) in a stratified cluster randomized trial using two methods and reports estimates of the ICC obtained for many maternal, newborn and perinatal outcomes. Finally, it discusses analytical problems that arose: issues encountered using a composite index, heterogeneity of the intervention effect across sites, the choice of the method of analysis and the importance of efficacy analyses. The choice of the clustered Woolf estimator and the generalized estimating equations (GEE) as the methods of analysis applied is discussed.

Evaluation of the optimum cut-off point in immunochemical occult blood testing in screening for colorectal cancer

This study was carried out to assess, from the aspects of cost-effectiveness and diagnostic validity, the optimum cut-off point for immunochemical occult blood testing using a 2-day method as a means of screening for colorectal cancer. Four thousand, two hundred and sixty asymptomatic individuals were subjects of this study. They gave samples for an immunochemical fecal occult blood test, and colonoscopy was carried out during a medical check-up. For evaluation of the optimum cut-off point, three cut-off levels of fecal haemoglobin, 50, 150 and 300 ng/ml, were used. A total of 27 patients with colorectal cancer were diagnosed. The average costs to detect one patient with colorectal cancer and the sensitivity and specificity of these three cut-off points of fecal haemoglobin were evaluated. The average costs for the detection of one cancer case were calculated as $2870.45 for cut-off level of 50 ng/ml, $2492.98 for that of 150 ng/ml and $3329.09 for that of 300 ng/ml, respectively. The sensitivity and specificity were calculated as 89 and 94% for the 50 ng/ml cut-off level, 81% and 96% for the 150 ng/ml cut-off level and 56 and 97% for the 300 ng/ml cut-off level, respectively, indicating a significant difference in the sensitivity between the 50 and 300 ng/ml levels (P<0.05), as well as between the 150 and 300 ng/ml levels (P<0.05), and a significant difference in the specificity between the 50 and 300 ng/ml levels (P<0.05). However, no significant difference was observed in the specificity between the 50 and 150 ng/ml levels. The findings show that 150 ng/ml of fecal haemoglobin is the optimal cut-off point when carrying out the OC-Hemodia test as a means of screening for colorectal cancer.

Factors that influence the decision to do an adequate evaluation of a patient with a positive stool for occult blood

OBJECTIVE

The factors that influence the decision to do an adequate evaluation for a positive test for fecal occult blood in a middle-aged or elderly patient are largely unknown. Our study was undertaken to determine whether factors such as the number of positive Hemoccult II card windows, age, gender, family history of colon cancer, the patient's concern that he or she might have colon cancer, or history of rectal bleeding influence the evaluation performed.

METHOD

A mass screening program for colon cancer was performed using unrehydrated Hemoccult II cards in the Boston area.

RESULTS

Among the 23,593 Hemoccult II cards returned to Beth Israel Deaconess Medical Center, cards from 1,112 patients (4.7%) were found to be positive for one or more of the six possible card windows. Ninety percent, or 940 patients, over 40 yr of age had follow-up information available. As the number of positive windows increased from one to four, there was a significant trend (p < 0.001) for the adequacy of the evaluation to increase. Family history (p = 0.044) and a patient's worry that he or she might have colon cancer (p = 0.003) significantly improved a patient's chance for an adequate evaluation.

CONCLUSIONS

Hemoccult testing is not followed by an adequate evaluation in a significant proportion of patients. Our study points out for the first time that the number of positive Hemoccult windows significantly influences the decision-making.

Promoting health in older adults: a four-year analysis

PURPOSE

The purpose of this study was to consider the influence of selected health promotion and disease prevention interventions in elderly residents of a continuing care retirement community (CCRC) over a four-year period by comparing actual health promotion practices of the residents.

DATA SOURCES

Original research using a descriptive design, face-to-face interviews of residents (N = 176-200), chart reviews, and administration of a mini-mental state exam (MMSE) and health survey administered annually.

CONCLUSIONS

In each year the mean age of the residents was at least 85, the majority were female, Caucasian, and unmarried. With the exception of checking stools for occult blood, there was a statistically significant change in all health promotion behaviors over the four-year period. The most significant change was in the area of exercise behavior, which increased from 24% of the residents participating in regular exercise in year one to 61% by year four.

IMPLICATIONS FOR PRACTICE

The purpose of health promotion and disease prevention in older adults is to reduce the potential years of life lost in premature mortality and ensure better quality of remaining life. In addition to regularly scheduled interventions (group education, on-site administration of pneumonia and flu vaccines, on-site exercise room and walking group), individualized counseling regarding the pros and cons of health-promotion activities was provided to help residents make an educated decision about engaging in these activities. These interventions can be used to help facilitate participation in health promotion activities as appropriate and desired for each older adult.

Lung cancer screening: improved survival but no reduction in deaths--the role of "overdiagnosis"

BACKGROUND

Randomized controlled trials (RCTs) of lung cancer screening consistently show an excess number of cancer cases and longer survival in screened groups, but no difference in mortality between screened and control populations.

METHODS

The current study reviewed the various types of biases that confuse comparisons based on intermediate endpoints such as stage distribution and survival and the reasons for basing evaluations in RCTs of screening for early cancers on mortality from a specific cancer.

RESULTS

Four RCTs all showed improved stage of disease and survival in screened subjects, but there was no difference in mortality between screened and unscreened populations. The possible explanations for the higher incidence are chance (failed randomization) or "overdiagnosis" (detection of cases by screening that otherwise would never have surfaced). Analysis of the trial results confirmed that chance alone was a very unlikely explanation. Evidence suggests that some overdiagnosis of lung cancer is likely in screened subjects. This is a consistent observation in all other programs of screening for early cancers (breast, prostate, and neuroblastoma).

CONCLUSIONS

Overdiagnosis of cancer cases resulting from the screening process itself will give rise to excess cases of disease, and may, at least in part, explain the observations in the randomized trials.

Socio-demographic correlates of screening intention for colorectal cancer

OBJECTIVE

To assess the relationship between socio-demographic factors and screening intention for colorectal cancer (CRC).

METHODS

A cross-sectional survey of a random sample of 884 Queenslanders aged 40-80 years was conducted using a computer-assisted telephone interviewing system. The factors measured included socio-demographic characteristics, personal history of CRC, knowledge of others with CRC and perceived symptom status. Chi-squared and Monte Carlo estimates of Fisher Exact Tests were performed to determine the associations between socio-demographic factors and screening intention. In multivariate analyses, multinomial logistic regression (MNLR) was utilised to examine potential determinants of screening intention.

RESULTS

77.5% (95% CI 74.0%-80.7%) of the respondents indicated their intention to participate in CRC screening if it were recommended by their doctor or health authorities. The likelihood ratio chi-squared tests in the MNLR analyses show that age (chi(df = 6)2 = 15.0; p = 0.02), education (chi(df = 8)2 = 19.4; p = 0.01), perceived symptom status (chi(df = 4)2 = 22.9; p = 0.00), sex (chi(df = 2)2 = 4.5; p = 0.11), income (chi(df = 14)2 = 19.6; p = 0.14) and personal history of CRC (chi(df = 2)2 = 4.3; p = 0.12) were potential determinants of screening intention. Other socio-demographic factors, including country of birth, private health insurance status, Socio-economic Index for Areas, and Rural and Remote Areas Classification codes, were not associated with screening intention.

CONCLUSIONS AND IMPLICATIONS

The results indicate that a variety of socio-demographic factors are associated with screening intention and need to be considered in the future development of a population-based screening program for CRC.

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.

Flexible sigmoidoscopy screening for colorectal cancer in average-risk people: update of a community-based project

OBJECTIVES

To analyse results of a screening program for colorectal cancer using flexible sigmoidoscopy.

DESIGN

Survey of results of screening program and follow-up colonoscopies and identification of missed cases from State cancer registry data.

PARTICIPANTS

Asymptomatic, average-risk people aged 55-64 years who were either mailed invitations after random selection from the electoral roll or volunteered after hearing about the program.

SETTING

Fremantle Hospital, Western Australia (a public teaching hospital), July 1995 to November 1999 (first 4.5 years of the screening program).

MAIN OUTCOME MEASURES

Participation rates; lesions detected; stage of colorectal cancers diagnosed at the hospital before and after the screening program began (1989-1995 versus 1996-1999); and diagnoses of colorectal cancer in previously screened individuals (from State cancer registry data).

RESULTS

6446 people were mailed invitations, and 1483 were screened (23% participation rate). Another 1122 people volunteered, giving 2605 people screened overall. Flexible sigmoidoscopy showed adenomatous polyps in 352 people (14%), and colonoscopy was recommended in 399 (15%) on the basis of clinically suspicious lesions. Colonoscopy was performed in 302 (76% participation rate). Screening and follow-up colonoscopy detected 14 colorectal cancers (10 invasive, with eight of these Dukes stage A). One participant was diagnosed with colorectal cancer 12 months after sigmoidoscopy gave normal results. Incidence of colorectal cancer was 119 per 100000 per year, and prevalence was 0.5%. Before the screening program, 12% of cancers diagnosed at our hospital were Dukes stage A, compared with 28% after (P<0.001).

CONCLUSIONS

Flexible sigmoidoscopy screening is an acceptable strategy in asymptomatic, average-risk people which detects colorectal cancer and adenomatous polyps. Screening has been associated with a trend to earlier presentation of cancer in our institution.