Colorectal cancer screening:20 years of development and recent progress

Colorectal cancer(CRC)is the second most common cancer in Europe and its incidence is steadily increasing.This trend could be reversed through timely secondary prevention(screening).In the last twenty years,CRC screening programs across Europe have experienced considerable improvements(fecal occult blood testing;transition from opportunistic to population based program settings).The Czech Republic is a typical example of a country with a long history of nationwide CRC screening programs in the face of very high CRC incidence and mortality rates.Each year,approximately 8000 people are diagnosed with CRC and some 4000 die from this malignancy.Twenty years ago,the first pilot studies on CRC screening led to the introduction of the opportunistic Czech National Colorectal Cancer Screening Program in 2000.Originally,this program was based on the guaiac fecal occult blood test(FOBT)offered by general practitioners,followed by colonoscopy in cases of FOBT positivity.The program has continuously evolved,namely with the implementation of immunochemical FOBTs and screening colonoscopy,as well as the involvement of gynecologists.Since the establishment of the Czech CRC Screening Registry in 2006,2405850 FOBTs have been performed and 104565 preventive colonoscopies recorded within the screening program.The overall program expanded to cover 25.0%of the target population by 2011.However,stagnation in the annual number of performed FOBTs lately has led to switching to the option of a population-based program with personal invitation,which is currently being prepared.     

The impact of colorectal cancer screening on life expectancy

METHODS: The purpose of this study was to assess the effect of screening for colorectal cancer on life expectancy and estimate the number of colonoscopies needed per life year saved. The declining exponential approximation of life expectancy was used to calculate the effect of colorectal cancer screening on expected remaining lifetime. The annual number of deaths from colorectal cancer and the size of the population were obtained from the vital statistics of the United States. Published reports were consulted to determine the decrease in mortality from colorectal cancer achieved by fecal occult blood testing, screening sigmoidoscopy or colonoscopy. A Markov chain analysis was used to determine the endoscopic resources required to screen and survey the entire population of U.S. residents age 50 years until death or age 85 years. RESULTS: Colorectal cancer decreases the life expectancy of U.S. residents aged 50 to 54 years by 292 days and those aged 70 to 74 years by 70 days. Screening with fecal occult blood tests extends expected lifetime of the 2 age groups by 51 and 12 days, respectively, whereas screening with sigmoidoscopy leads to increases of 86 and 21 days. Colonoscopic screening increases expected lifetime by 170 and 41 days, respectively. The number of colonoscopies needed to save 1 year of expected life ranges from 2.9 to 6.0, depending on the type of screening regimen used. CONCLUSIONS: The extension of life through screening colonoscopy is two or three times longer than the extension achieved through flexible sigmoidoscopy or fecal occult blood test, respectively. Although a large number of colonoscopies are required to screen the U.S. population, relatively few colonoscopies need to be invested per year of life expectancy saved.     

Fecal DNA testing compared with conventional colorectal cancer screening methods: a decision analysis

BACKGROUND & AIMS: Fecal DNA testing is an emerging tool to detect colorectal cancer (CRC). Our aims were to estimate the clinical and economic consequences of fecal DNA testing vs. conventional CRC screening. METHODS: Using a Markov model, we estimated CRC incidence, CRC mortality, and discounted cost/life-year gained for screening by fecal DNA testing (F-DNA), fecal occult blood testing (FOBT) and/or sigmoidoscopy, or colonoscopy (COLO) in persons at average CRC risk from age 50 to 80 years. RESULTS: Compared with no screening, F-DNA at a screening interval of 5 years decreased CRC incidence by 35% and CRC mortality by 54% and gained 4560 life-years per 100,000 persons at USD $47,700/life-year gained in the base case. However, F-DNA gained fewer life-years and was more costly than conventional screening. The average number of colonoscopies per person was 3.8 with COLO and 0.8 with F-DNA. In most 1-way sensitivity analyses and Monte Carlo simulation iterations, F-DNA remained reasonably cost-effective compared with no screening, but COLO and FOBT dominated F-DNA. Assuming fecal DNA testing sensitivities of 65% for CRC and 40% for large polyp, and 95% specificity, a screening interval of 2 years and a test cost of USD $195 would be required to make F-DNA comparable with COLO. CONCLUSIONS: Fecal DNA testing every 5 years appears effective and cost-effective compared with no screening, but inferior to other strategies such as FOBT and COLO. Fecal DNA testing could decrease the national CRC burden if it could improve adherence with screening, particularly where the capacity to perform screening colonoscopy is limited.     

Potential impact of population-based colorectal cancer screening in Canada

Randomized controlled trials (RCT) have shown the efficacy of screening for colorectal cancer (CRC) using the faecal occult blood test (FOBT) with follow-up by colonoscopy. We evaluated the potential impact of population-based screening by FOBT followed by colonoscopy in Canada: mortality reduction, cost-effectiveness, and resource requirements. The microsimulation model POHEM was adapted to simulate CRC screening using Canadian data and RCT results about test sensitivity and specificity, participation, incidence, staging, progression, mortality and direct health care costs. In Canada, biennial screening of 67% of individuals aged 50-74 in the year 2000 resulted in an estimated 10-year CRC mortality reduction of 16.7%. The life expectancy of the cohort increased by 15 days on average and the demand for colonoscopy rose by 15% in the first year. The estimated cost of screening was $112 million per year or $11,907 per life-year gained (discounted at 5%). Potential effectiveness would depend on reaching target participation rates and finding resources to meet the demand for FOBT and colonoscopy. This work was conducted in support of the National Committee on Colorectal Cancer Screening.     

Reduction in colorectal cancer mortality by fecal occult blood screening in a French controlled study

BACKGROUND & AIMS: Several randomized population-based studies have shown that screening for colorectal cancer (CRC) by fecal occult blood tests (FOBTs) can reduce CRC mortality. The aim of this French population-based study was to assess whether a similar benefit could be obtained in countries characterized by high performances in the diagnosis and management of CRC. METHODS: Small-sized geographic areas, including 91,199 individuals aged 45-74 years, were allocated to either FOBT screening or no screening. Six screening rounds were performed. The FOBT was performed without diet restriction and was sent to a central analysis center and processed without rehydration. Screening group participants who had a positive test result were offered a full colonoscopy. The entire population was followed up for 11 years after study entry. RESULTS: Acceptability of the test was 52.8% at the first screening round and varied between 53.8% and 58.3% in the successive rounds. Positivity rates were 2.1% initially and 1.4% on average in the successive rounds. CRC mortality was significantly lower in the screening population compared with the control population (mortality ratio, 0.84; 95% confidence interval, 0.71-0.99). The reduction in CRC mortality was more pronounced in those who participated at least once (mortality ratio, 0.67; 95% confidence interval, 0.56-0.81). CONCLUSIONS: Our findings, together with the results of other trials, suggest that biennial screening by FOBTs can reduce CRC mortality regardless of the quality of the health system and support attempts to introduce large-scale screening programs into the general population.     

Cost-effectiveness of colorectal cancer screening: comparison of community-based flexible sigmoidoscopy with fecal occult blood testing and colonoscopy

BACKGROUND AND AIMS: To determine the cost-effectiveness of screening for colorectal cancer using flexible sigmoidoscopy once every 10 years, compared with annual and biennial rehydrated Hemoccult fecal occult blood testing and colonoscopy once every 10 years, or no screening. METHODS: A Markov model was developed in order to simulate the progression of a cohort of asymptomatic, average-risk individuals aged 55-64 years who were moving through a defined series of states towards death. The main outcome measures were: cases of colorectal cancer averted, colorectal cancer deaths averted, and cost per life-year saved. RESULTS: Colonoscopy averted the greatest number of cases of colorectal cancer (35%), followed by flexible sigmoidoscopy (25%), and annual (24%) and biennial (14%) fecal occult blood testing. Colonoscopy averted the greatest number of deaths from colorectal cancer (31%), followed by annual fecal occult blood testing (29%), flexible sigmoidoscopy (21%) and biennial fecal occult blood testing (19%). Flexible sigmoidoscopy was the most efficient in terms of cost per life-year saved (16,801 Australian dollars), followed by colonoscopy (19,285 Australian dollars), biennial (41,183 Australian dollars), and annual (46,900 Australian dollars) fecal occult blood testing. CONCLUSIONS: Flexible sigmoidoscopy and colonoscopy are cost-effective strategies for reducing the disease burden of colorectal cancer.     

Dutch endoscopic capacity in the era of colorectal cancer screening

BACKGROUND: Future colorectal cancer (CRC) screening programmes should not (greatly) interfere with regular health care. Hence, we analysed the Dutch endoscopic practice to provide a clear insight into endoscopic workload and manpower with a special emphasis on the current ability to facilitate a successful implementation of a faecal occult blood test (FOBT)-based nationwide CRC screening programme. METHODS: A questionnaire was sent to all Dutch endoscopy units (n = 100) in the spring of 2005. The questionnaire included topics ranging from the numbers and specifications of endoscopies performed in 2004 and the numbers of endoscopists per unit to expected vacancies for gastroenterologists and waiting times. RESULTS: The response rate was 98%, representing a total of 49,253 hospital beds. overall, a 26% increase in the number of endoscopies from 325,000 in 1999 to almost 410,000 in 2004 was found, accompanied by a 25% increase in manpower. The total number of endoscopists was 598. regional differences were observed in the number of endoscopists, the total number of endoscopies and colonoscopies, and the number of endoscopies per endoscopist. A biannual FOBT-based screening programme would yield an additional workload of 25,385 colonoscopies a year amounting to a 22% increase in the total number of colonoscopies performed. However, the workload per unit would only have to increase by five extra colonoscopies a week. CONCLUSION: Whereas an FOBT-based CRC screening programme is currently feasible without strongly interfering with regular health care, future plans regarding the scale and preferred mode of screening should incorporate solid data on the (regional) endoscopic capacity and manpower needed for a successful implementation.     

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

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

Cost-Effectiveness of Colon Cancer Screening

The cost-effectiveness of two colon cancer-screening strategies was compared. The first strategy mirrors the recommendations of the American Cancer Society and includes sigmoidoscopy starting at age 50, and yearly fecal occult blood testing. The second strategy is screening with colonoscopy. The analysis revealed that the 10-yr cost of screening with sigmoidoscopy is nearly $1,700, compared with nearly $2,500 for colonoscopy, using prevailing procedure costs. This difference can be reduced by lowering the cost of normal colonoscopies. The cost of identifying one patient with an adenomatous polyp is $8,766 with sigmoidoscopy, compared to $5,988 with colonoscopy because of the higher detection rate with colonoscopy. The calculated cost of preventing one death from colon cancer is $444,133 with sigmoidoscopy versus $347,214 with colonoscopy. In conclusion, colon cancer prevention with current screening methods is very costly. Screening with sigmoidoscopy and fecal occult blood testing may not be cost-effective, compared to screening with colonoscopy.     

Switching from guaiac to immunochemical faecal occult blood test increases participation and diagnostic yield of colorectal cancer screening

BackgroundCompared with the guaiac-faecal occult blood test (gFOBT), faecal immunological tests (FIT) are considered to be more effective for colorectal cancer (CRC) screening. However, only scarce research has examined the outcomes of switching to FIT within a mature gFOBT-based CRC screening programme.MethodsWe reported a 15-year experience of biennial FOBT screening in a well-defined population of approximately one million inhabitants, including six gFOBT-based screening rounds and one round with FIT at the 30 μg Hb/g cut-off. The main outcome measures were screening participation, FOBT positivity and advanced neoplasia detection in each round.ResultsIn this study, 647 676 screenings were performed in 228 716 different individuals, leading to 17 819 positives and 16 580 follow-up colonoscopies. Compared with the last gFOBT round, switching to FIT led to an increased participation of nearly 20% points, and a fivefold increased detection of CRC and advanced adenoma among invitees (3-fold among attendees). The numbers needed to screen and scope to detect one advanced neoplasia declined from 221 to 66 and from 4.7 to 2.6, respectively.ConclusionsThe present population-based study demonstrated a dramatical increase in the diagnostic yield of advanced neoplasia by switching to FIT within a mature gFOBT-based CRC screening programme.     

Projected national impact of colorectal cancer screening on clinical and economic outcomes and health services demand

BACKGROUND & AIMS: Colorectal cancer (CRC) screening is effective and cost-effective, but the potential national impact of widespread screening is uncertain. It is controversial whether screening colonoscopy can be offered widely and how emerging tests may impact health services demand. Our aim was to produce integrated, comprehensive estimates of the impact of widespread screening on national clinical and economic outcomes and health services demand. METHODS: We used a Markov model and census data to estimate the national consequences of screening 75% of the US population with conventional and emerging strategies. RESULTS: Screening decreased CRC incidence by 17%-54% to as few as 66,000 cases per year and CRC mortality by 28%-60% to as few as 23,000 deaths per year. With no screening, total annual national CRC-related expenditures were 8.4 US billion dollars. With screening, expenditures for CRC care decreased by 1.5-4.4 US billion dollars but total expenditures increased to 9.2-15.4 US billion dollars. Screening colonoscopy every 10 years required 8.1 million colonoscopies per year including surveillance, with other strategies requiring 17%-58% as many colonoscopies. With improved screening uptake, total colonoscopy demand increased in general, even assuming substantial use of virtual colonoscopy. CONCLUSIONS: Despite savings in CRC care, widespread screening is unlikely to be cost saving and may increase national expenditures by 0.8-2.8 US billion dollars per year with conventional tests. The current national endoscopic capacity, as recently estimated, may be adequate to support widespread use of screening colonoscopy in the steady state. The impact of emerging tests on colonoscopy demand will depend on the extent to which they replace screening colonoscopy or increase screening uptake in the population.     

A population-based estimate of the extent of colorectal cancer screening in Ontario

BACKGROUND/OBJECTIVE: The incidence and mortality rates for colorectal cancer (CRC) in Canada are among the highest in the world. For individuals >/=50 yr, CRC screening is effective in reducing both CRC incidence and mortality. The goal of this research was to conduct a Canadian population-based study of the use of tests and procedures to evaluate the large bowel to estimate the extent of CRC screening. METHODS: We identified an inception cohort of all residents of Ontario aged 50-59 on January 1, 1995, without a previous history of CRC or large-bowel evaluation by five tests or procedures: fecal occult blood test (FOBT), barium enema, rigid sigmoidoscopy, flexible sigmoidoscopy, and colonoscopy. We followed these individuals to December 31, 2000, identified all tests received, and determined the proportion that received one or more tests or procedures of each type. Data were obtained from three sources: the Ontario Health Insurance Plan (OHIP) database, the Canadian Institute for Health Information-Discharge Abstract Database (CIHI-DAD), and the Registered Persons Database (RPDB). RESULTS: We identified 982,443 individuals in our inception cohort without prior CRC or large bowel evaluation. The proportion that had at least one test or procedure was less than 10% for each type. The largest proportion (9.3%) had one or more FOBTs. Classified according to the initial test received, 14.5% had a non-endoscopic test (FOBT, barium enema) and 6% had an endoscopic test (rigid sigmoidoscopy, flexible sigmoidoscopy, colonoscopy). The majority (79.5%) had no test or procedure to evaluate the large bowel. CONCLUSION: An extraordinarily low proportion (<20.5%) of screen-eligible 50-59-yr-old men and women in Ontario were screened for CRC during a 6-yr follow-up. Given the high burden of CRC in Canada a major opportunity exists to improve the health of Canadians by increasing our screening efforts.     

Cost-effectiveness of a mailed educational reminder to increase colorectal cancer screening

Background

Colorectal cancer (CRC) screening rates are low in many areas and cost-effective interventions to promote CRC screening are needed. Recently in a randomized controlled trial, a mailed educational reminder increased CRC screening rates by 16.2% among U.S. Veterans. The aim of our study was to assess the costs and cost-effectiveness of a mailed educational reminder on fecal occult blood test (FOBT) adherence.

Methods

In a blinded, randomized, controlled trial, 769 patients were randomly assigned to the usual care group (FOBT alone, n = 382) or the intervention group (FOBT plus a mailed reminder, n = 387). Ten days after picking up the FOBT cards, a 1-page reminder with information related to CRC screening was mailed to the intervention group. Primary outcome was number of returned FOBT cards after 6 months. The costs and incremental cost-effectiveness ratio (ICER) of the intervention were assessed and calculated respectively. Sensitivity analyses were based on varying costs of labor and supplies.

Results

At 6 months after card distribution, 64.6% patients in the intervention group returned FOBT cards compared with 48.4% in the control group (P < 0.001). The total cost of the intervention was $962 or $2.49 per patient, and the ICER was $15 per additional person screened for CRC. Sensitivity analysis based on a 10% cost variation was $13.50 to $16.50 per additional patient screened for CRC.

Conclusions

A simple mailed educational reminder increases FOBT card return rate at a cost many health care systems can afford. Compared to other patient-directed interventions (telephone, letters from physicians, mailed reminders) for CRC screening, our intervention was more effective and cost-effective.

     

Colonoscopy and flexible sigmoidoscopy practice patterns in Ontario: a population-based study.

OBJECTIVE: To conduct a population-based study on the provision of large bowel endoscopic services in Ontario. METHODS: Data from the following databases were analyzed: the Ontario Health Insurance Plan, the Institute for Clinical Evaluative Sciences Physicians Database and Statistics Canada. The flexible sigmoidoscopy and colonoscopy rates per 10,000 persons (50 to 74 years of age) by region between April 1, 2001, and March 31, 2002, were calculated, as well as the numbers and types of physicians who performed each procedure. RESULTS: In 2001/2002, a total of 172,108 colonoscopies and 43,400 flexible sigmoidoscopies were performed in Ontario for all age groups. The colonoscopy rate was approximately five times that of flexible sigmoidoscopy; rates varied from 463.1 colonoscopies per 10,000 people in the north to 286.8 colonoscopies per 10,000 people in the east. Gastroenterologists in all regions tended to perform more procedures per physician, but because of the large number of general surgeons, the total number of procedures performed by each group was almost the same. CONCLUSION: Population-based rates of colonoscopies and flexible sigmoidoscopies are low in Ontario, as are the procedure volumes of approximately one-quarter of physicians.     

Noninvasive testing for colorectal cancer: a review

OBJECTIVES: Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Endoscopic screening is now in favor and its use is increasing, but overall participation rates are poor. A substantial percentage of the population will likely continue to resist endoscopic screening. As such, a noninvasive biomarker for the early detection of CRC remains a priority. Herein, we (i) review the currently available noninvasive screening markers for the early detection of CRC, (ii) discuss newer markers that have undergone preliminary testing, and (iii) introduce and explain potentially promising markers of the future. METHODS: The published literature on markers for early detection of CRC was identified using a MEDLINE/PubMed search with secondary review of cited publications. RESULTS: Noninvasive testing for CRC is most advanced in testing for stool fecal occult blood, globin, or DNA mutations. Study of abnormal mucins has also been explored. Research for serum-based markers is just beginning and includes serum proteomics, nuclear matrix proteins, and serum DNA testing. CONCLUSIONS: Serial guaiac-based fecal occult blood testing (FOBT) is simple, inexpensive, and proven effective at reducing mortality from CRC. Immunochemical fecal occult blood tests facilitate compliance and offer improved specificity, but at increased cost in comparison to FOBT. Fecal DNA testing may provide enhanced sensitivity for detection of CRC in comparison with FOBT, but its high cost limits its use for generalized screening. Rectal mucin testing requires additional evaluation to determine its sensitivity and specificity in comparison with guaiac-based FOBT. Serum tests, such as proteomics, nuclear matrix proteins, and serum DNA, are still in their infancy, but remain a hope for the future.     

What is the most cost-effective strategy to screen for second primary colorectal cancers in male cancer survivors in Korea？

AIM： To identify a cost-effective strategy of second primary colorectal cancer （CRC） screening for cancer survivors in Korea using a decision-analytic model. METHODS： A Markov model estimated the clinical and economic consequences of a simulated 50-year- old male cancer survivors＇ cohort, and we compared the results of eight screening strategies： no screening, fecal occult blood test （FOBT） annually, FOBT every 2 years, sigmoidoscopy every 5 years, double contrast barium enema every 5 years, and colonoscopy every 10 years （COL10）, every 5 years （COL5）, and every 3 years （COL3）. We included only direct medical costs, and our main outcome measures were discounted lifetime costs, life expectancy, and incremental cost- effectiveness ratio （ICER）. RESULTS： In the base-case analysis, the non-dominat- ed strategies in cancer survivors were COL5, and COL3. The ICER for COL3 in cancer survivors was $5593/life- year saved （LYS）, and did not exceed $10000/LYS in one-way sensitivity analyses. If the risk of CRC in can- cer survivors is at least two times higher than that in the general population, COL5 had an ICER of less than $10500/LYS among both good and poor prognosis of index cancer. If the age of cancer survivors starting CRC screening was decreased to 40 years, the ICER of COL5 was tess than $7400/LYS regardless of screening compliance. CONCLUSION： Our study suggests that more strict and frequent recommendations for colonoscopy such as COL5 and COL3 could be considered as economically reasonable second primary CRC screening strategies for Korean male cancer survivors.     

The way to reduce the prevalence of colorectal cancer in Moscow: from the pilot study to screening

Were made calculations of the Moscow population that needs screening for colorectal cancer (CRC). In screening will be needed about 2.7 million people--with high risk of colorectal cancer--300 thousand, and at average risk--2.4 million. It is expected that during screening for colorectal cancer would be detected at 1%, i.e. approximately 26 700 people, and 10% (267 000)--adenomatous polyps that can be removed. Since the organization and conduct screening of the adult population of Moscow to the CRC requires large additional economic costs, endoscopic equipment and expertise, this program can be divided into different stages. The first stage should be to conduct a population-based study of MUSE (see, L.B. Lazebnik, et al. in this issue) in all administrative districts of Moscow. The next stage should be planned implementation of annual preventive endoscopic examinations of the population in accordance with formed risk groups. This program will significantly reduce the incidence of and mortality from colorectal cancer in Moscow.     

Cost-effectiveness of colonoscopy in screening for colorectal cancer

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

Clinical usefulness of fecal occult blood test as a screening method for asymptomatic patients with colon polyps]

BACKGROUND/AIMS: Detection of asymptomatic benign colon polyp is increasing because colonoscopy is widely used as a screening and diagnostic method. Fecal occult blood test is usually performed for the selection of patients requiring colonoscopy as well as mass screening for colon cancer. The aim of this study was to investigate the usefulness of fecal occult blood test performed prior to colonoscopy as a screening method of benign colon polyps. METHODS: Clinical characteristics of patients with polyps were evaluated according to the fecal occult blood test results in patients who underwent one-day fecal occult blood test and colonoscopic polypectomies from May 2003 to October 2004, retrospectively. RESULTS: A total of 942 colonoscopic polypectomies in 288 patients were evaluated. Fecal occult blood tests were positive only in 32 patients (11.1%). In univariate analysis, there was a significant difference in polyp size (p=0.02) and location (p=0.03) according to the presence of positive fecal occult blood tests. In addition, age of the patient (p=0.046), polyp size (mean, p=0.04; largest, p<0.01) and the number of polyps (p=0.045) were significantly different. However, in multivariate analysis, only polyp size larger than 20 mm was significantly related with positive fecal occult blood test with estimated odds ratio of 4.71. CONCLUSIONS: Fecal occult blood test has limitations as a screening test in asymptomatic patients with colon polyps, except for colon polyps larger than 20 mm in size.     

Colorectal cancer screening in Italy: feasibility and cost-effectiveness in a model area.

OBJECTIVE: To evaluate the feasibility and cost-effectiveness of screening programmes for colorectal cancer in Italy. DESIGN; We compared five types of programmes: annual faecal occult blood testing, sigmoidoscopy (every 5 years), faecal occult blood testing plus sigmoidoscopy (every 1 and 5 years), colonoscopy (every 10 years) (all in the age group 55-69 years, last examination at 70 years) and 'filter' colonoscopy. The latter had to be performed in persons at 50 years of age and repeated every 10 years until the age of 70. Costs for the tests and colon cancer care were paid by the Regional Health Office to the hospitals performing the procedures/treatments. SETTING: Data were applied to a small model area in northern Italy (Gemona, 80,000 inhabitants) with well-known demographic (age distribution) and epidemiological (colon cancer incidence) features. RESULTS: All-inclusive 10-year costs per screenee and per death prevented (in US dollars) were: 965 and 77,200 for faecal occult blood testing; 436 and 15,500 for sigmoidoscopy; 1521 and 35,000 for sigmoidoscopy plus faecal occult blood testing; 510 and 15,100 for colonoscopy; 510 and 14,000 for 'filter' colonoscopy. With 'filter' colonoscopy the programme required 870 colonoscopies per year, while with colonoscopy 13,700 colonoscopies were needed at time zero. CONCLUSIONS: In Italy, screening programmes based on sigmoidoscopy/colonoscopy are more cost effective than those based on faecal occult blood testing. 'Filter' colonoscopy at age 50 appears superior to the other types of endoscopy-based screening programmes because it utilizes, at any point in time, a much smaller fraction of available resources.