As tests evolve and costs of cancer care rise: reappraising stool-based screening for colorectal neoplasia

Comparative Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening With Blood-Based Biomarkers (Liquid Biopsy) vs Fecal Tests or Colonoscopy

BACKGROUND & AIMS

Colorectal cancer (CRC) screening is highly effective but underused. Blood-based biomarkers (liquid biopsy) could improve screening participation.

METHODS

Using our established Markov model, screening every 3 years with a blood-based test that meets minimum Centers for Medicare & Medicaid Services' thresholds (CMSmin) (CRC sensitivity 74%, specificity 90%) was compared with established alternatives. Test attributes were varied in sensitivity analyses.

RESULTS

CMSmin reduced CRC incidence by 40% and CRC mortality by 52% vs no screening. These reductions were less profound than the 68%-79% and 73%-81%, respectively, achieved with multi-target stool DNA (Cologuard; Exact Sciences) every 3 years, annual fecal immunochemical testing (FIT), or colonoscopy every 10 years. Assuming the same cost as multi-target stool DNA, CMSmin cost $28,500/quality-adjusted life-year gained vs no screening, but FIT, colonoscopy, and multi-target stool DNA were less costly and more effective. CMSmin would match FIT's clinical outcomes if it achieved 1.4- to 1.8-fold FIT's participation rate. Advanced precancerous lesion (APL) sensitivity was a key determinant of a test's effectiveness. A paradigm-changing blood-based test (sensitivity >90% for CRC and 80% for APL; 90% specificity; cost ≤$120-$140) would be cost-effective vs FIT at comparable participation.

CONCLUSIONS

CMSmin could contribute to CRC control by achieving screening in those who will not use established methods. Substituting blood-based testing for established effective CRC screening methods will require higher CRC and APL sensitivities that deliver programmatic benefits matching those of FIT. High APL sensitivity, which can result in CRC prevention, should be a top priority for screening test developers. APL detection should not be penalized by a definition of test specificity that focuses on CRC only.

Colonoscopy vs the Fecal Immunochemical Test: Which is Best?

Although there is no debate around the effectiveness of colorectal cancer screening in reducing disease burden, there remains a question regarding the most effective and cost-effective screening modality. Current United States guidelines present a panel of options that include the 2 most commonly used modalities, colonoscopy and stool testing with the fecal immunochemical test (FIT). Large-scale comparative effectiveness trials comparing colonoscopy and FIT for colorectal cancer outcomes are underway, but results are not yet available. This review will separately state the "best case" for FIT and colonoscopy as the screening tool of first choice. In addition, the review will examine these modalities from a health economics perspective to provide the reader further context about the relative advantages of these commonly used tests.

The Use of a Non-Invasive Biomarker for Colorectal Cancer Screening: A Comparative Cost-Effectiveness Modeling Study

This study aimed to examine the cost-effectiveness of fecal biomarker M3 panel compared to fecal immunochemical test (FIT) and colonoscopy in an Asian population. In a hypothetical population of 100,000 persons aged 50 years who received FIT yearly, M3 biomarker yearly, or colonoscopy every 10 years until the age of 75 years. Participants with positive FOBT or a result of "high risk" identified using the M3 biomarker are offered colonoscopy. We assumed surveillance colonoscopy is repeated every 3 years, and examined the treatment cost. A comparison of various outcome measures was conducted using Markov modelling. The incremental cost-effectiveness ratio (ICER) of FIT, M3 biomarker, and colonoscopy was USD108,176, USD133,485 and USD159,596, respectively. Comparing with FIT, the use of M3 biomarker could lead to significantly smaller total loss of cancer-related life-years (2783 vs. 5279); a higher number of CRC cases prevented (1622 vs. 146), a higher proportion of CRC cases prevented (50.2% vs. 4.5%), more life-years saved (2852 vs. 339), and cheaper total costs per life-year saved (USD212,553 vs. 773,894). The total costs per life-year saved is more affordable than that achieved by colonoscopy as a primary screening tool (USD212,553 vs. USD236,909). The findings show that M3 biomarkers may be more cost-effective than colonoscopy.

Evaluating the quality of the economic evidence in colorectal cancer genomics studies

The increase in the use of genome-based screening and diagnostic tests adds to the overall costs of oncologic care for colorectal cancer. This, in turn, has resulted in an increase in published economic analyses. Aim: To perform a systematic literature review of the available economic evidence evaluating the value of genomic testing for colorectal cancer and appraise the quality of the economic studies conducted to date. Methods: A systematic review of the literature for economic studies of colorectal cancer genomics from January 2006 through October 2020, and evaluation of study quality using the Quality of Health Economic Studies (QHES) instrument was conducted. The validated QHES was then applied to a final set of articles that met eligibility criteria. Results: Our search of the literature initially yielded 12,859 records. A final set of 49 articles met our inclusion criteria. The QHES score ranged from 24 to 100, with an average score of 82. Most of the studies (n = 40, 82%) scored above 75 and were considered of good quality. Conclusion: Our analysis revealed that most of the economic analyses of colorectal cancer genomic molecular diagnostics in the literature may be of good quality. There is, however, some variation in methodological rigor between the articles.

Estimating cost-effectiveness of screening for colorectal cancer in Vietnam

Background:Presently, there are no national screening programs for cancer in Vietnam. This study aimed to analyze the cost-effectiveness of an annual colorectal cancer (CRC) screening program from the healthcare service provider's perspective for the Vietnamese population.Methods:The economic model consisted of adecision tree and aMarkov model. Adecision tree was constructed for comparing two strategies, including ascreening group with aguaiac-based fecal occult blood test (gFOBT) and ano-screening group in general populations, aged 50 years and above. The Markov model projected outcomes over a25-year horizon. The cost-effectiveness outcome was the incremental cost-effectiveness ratio (ICER) represented by costs per quality-adjusted life-years (QALYs).Results:When compared with no screening, ICER was $1,388per QALY with an increased cost of $ 43.98 and again of 0.032 QALY (Willingness to pay $2,590). The uptake rate of gFOBT, cost of colonoscopy, and the total cost of screening contributed to the largest impact on the ICER. PSA showed that results were robust to variation in parameter estimates, with annual screening remaining cost-effective compared with no screening.Conclusion:Our screening strategy could be considered cost-effective compared to ano screening strategy. Our findings could be potentially used to develop aCRC national screening program.

Improving Adenoma Detection Rates: The Role of the Fecal Immunochemical Test

Background

There is limited knowledge about adenoma detection rates (ADRs) in patients with a positive fecal immunochemical test (FIT). We hypothesized that colonoscopy performed after FIT would result in higher ADRs.

Methods

We reviewed ADRs for colonoscopies performed after a positive FIT test and compared them to ADR rates for routine colonoscopy performed without an initial FIT test between November 2014 and March 2017 at multiple endoscopy sites.

Results

A total of 979 patients underwent a FIT testing in the Texas panhandle, of whom 12.1% (n=119) tested positive. Also, 32.8% (n=39) were found to have one or more tubular adenomatous polyps on final pathological examination. Among these patients, the majority were female (64.1%; n=25). Of the patients, 15.9% (n=19) had a hyperplastic polyp, 1.7% (n=2) had findings consistent with ulcerative colitis, and 0.8% (n=1) were positive for an adenocarcinoma. In the control group of 2,603 patients in whom routine colonoscopy was performed as the initial tool for screening, 719 were found to have one or more tubular adenomas, with an ADR rate of 27.5%. In this group, the cancer rate was found to be 1%.

Conclusions

There was a significant increase in the ADR when colonoscopy is conducted after a positive FIT test. Recommending colonoscopies after a positive FIT test will not only improve ADRs significantly but also lower the overall healthcare cost for screening colon cancer in this era of escalating healthcare costs.

Cost-Effectiveness of Current Colorectal Cancer Screening Tests

Cost-effectiveness analysis compares benefits and costs of different interventions to inform decision makers. Alternatives are compared based on an incremental cost-effectiveness ratio reported in terms of cost per quality-adjusted life-year gained. Multiple cost-effectiveness analyses of colorectal cancer (CRC) screening have been performed. Although regional epidemiology of CRC, relevant screening strategies, regional health system, and applicable medical costs in local currencies differ by country and region, several overarching points emerge from literature on cost-effectiveness of CRC screening. Cost-effectiveness analysis informs decisions in ongoing debates, including preferred age to begin average-risk CRC screening, and implementation of CRC screening tailored to predicted CRC risk.

Efficacy and cost-effectiveness of fecal immunochemical test versus colonoscopy in colorectal cancer screening: a systematic review and meta-analysis

BACKGROUND AND AIMS

The fecal immunochemical test (FIT) and colonoscopy are the most commonly used strategies for colorectal cancer (CRC) screening worldwide. We aimed to compare their efficacy and cost-effectiveness in CRC screening in an average-risk population.

METHODS

PubMed, Embase, and National Health Services Economic Evaluation Database were searched. Risk ratio (RR) was used to evaluate the differences in detection rates of colorectal neoplasia between FIT and colonoscopy groups. A random-effects model was used to pool RRs. Incremental cost-effectiveness ratios (ICERs) were calculated to evaluate the cost-effectiveness of FIT versus colonoscopy.

RESULTS

Six randomized controlled trials and 17 cost-effectiveness studies were included. The participation rate in the FIT group was higher than that in the colonoscopy group (41.6% vs 21.9%). In the intention-to-treat analysis, FIT had a detection rate of CRC comparable with colonoscopy (RR, .73; 95% confidence interval, .37-1.42) and lower detection rates of any adenoma and advanced adenoma than 1-time colonoscopy. Most included cost-effectiveness studies showed that annual (13/15) or biennial (5/6) FIT was cost-saving (ICER < $0) or very cost-effective ($0 < ICER ≤ $25000/quality-adjusted life-year) compared with colonoscopy every 10 years.

CONCLUSIONS

FIT may be similar to 1-time colonoscopy in the detection rate of CRC, although it has lower detection rates of any adenoma and advanced adenoma than 1-time colonoscopy. Furthermore, annual or biennial FIT appears to be very cost-effective or cost-saving compared with colonoscopy every 10 years. These findings indicate, at least partly, that FIT is noninferior to colonoscopy in CRC screening in an average-risk population. Our findings should be treated with caution and need to be further confirmed.

Strategies for Colorectal Cancer Screening

The incidence of colorectal cancer (CRC) is increasing worldwide. CRC has high mortality when detected at advanced stages, yet it is also highly preventable. Given the difficulties in implementing major lifestyle changes or widespread primary prevention strategies to decrease CRC risk, screening is the most powerful public health tool to reduce mortality. Screening methods are effective but have limitations. Furthermore, many screen-eligible people remain unscreened. We discuss established and emerging screening methods, and potential strategies to address current limitations in CRC screening. A quantum step in CRC prevention might come with the development of new screening strategies, but great gains can be made by deploying the available CRC screening modalities in ways that optimize outcomes while making judicious use of resources.

Cost-Effectiveness of Colorectal Cancer Screening Strategies-A Systematic Review

BACKGROUND & AIMS

Widespread screening for colorectal cancer (CRC) has reduced its incidence and mortality. Previous studies investigated the economic effects of CRC screening. We performed a systematic review to provide up-to-date evidence of the cost effectiveness of CRC screening strategies by answering 3 research questions.

METHODS

We searched PubMed, National Institute for Health Research Economic Evaluation Database, Social Sciences Citation Index (via the Web of Science), EconLit (American Economic Association) and 3 supplemental databases for original articles published in English from January 2010 through December 2017. All monetary values were converted to US dollars (year 2016). For all research questions, we extracted, or calculated (if necessary), per-person costs and life years (LYs) and/or quality-adjusted LYs, as well as the incremental costs per LY gained or quality-adjusted LY gained compared with the baseline strategy. A cost-saving strategy was defined as one that was less costly and equally or more effective than the baseline strategy. The net monetary benefit approach was used to answer research question 2.

RESULTS

Our review comprised 33 studies (17 from Europe, 11 from North America, 4 from Asia, and 1 from Australia). Annual and biennial guaiac-based fecal occult blood tests, annual and biennial fecal immunochemical tests, colonoscopy every 10 years, and flexible sigmoidoscopy every 5 years were cost effective (even cost saving in most US models) compared to no screening. In addition, colonoscopy every 10 years was less costly and/or more effective than other common strategies in the United States. Newer strategies such as computed tomographic colonography, every 5 or 10 years, was cost effective compared with no screening.

CONCLUSIONS

In an updated review, we found that common CRC screening strategies and computed tomographic colonography continued to be cost effective compared to no screening. There were discrepancies among studies from different regions, which could be associated with the model types or model assumptions.

Cost-effectiveness of High-performance Biomarker Tests vs Fecal Immunochemical Test for Noninvasive Colorectal Cancer Screening

BACKGROUND & AIMS

Biomarker assays could increase the accuracy of noninvasive detection of colorectal cancer (CRC); fecal immunochemical tests (FITs) are estimated to miss 27%-47% of CRCs and 70%-80% of advanced adenomas per round of screening. We investigated the conditions under which biomarker screens would be cost-effective compared with FIT screens of average-risk individuals.

METHODS

We used the MISCAN-Colon microsimulation model to estimate the effects of various CRC screening test characteristics on life-years gained (LYG) and; age-specific all-cause mortality was based on the 2010 Dutch life tables. Simulated CRC incidence rate and CRC stage distribution were calibrated to observed data in The Netherlands from 1999 through 2003 (before opportunities for screening). Survival rates after diagnosis of CRC at an age younger than 75 years were based on CRC relative survival data from 1985 through 2004; survival for individuals diagnosed at an age of 75 years or older was adjusted to fit the observed age-increasing mortality/incidence ratio. We modeled FIT along with hypothetical biomarker tests with different test performance levels. For each biomarker test we calculated the maximum unit cost for the test to be cost-effective compared with FIT, assuming a willingness-to-pay threshold of €50,000 ($56,000) per LYG.

RESULTS

Biennial FIT screening of subjects 55-75 years old provided 84.9 LYG at a cost of €122,000 ($137,000) per 1000 participants. Considering a unit cost of €7 ($8) for FIT (including kit and analysis only, excluding organizational costs), a biomarker test that detects CRC with higher levels of specificity and sensitivity (100%) and advanced adenomas at a proportionally higher level of sensitivity (53%) should never exceed a cost of €51 ($57). The threshold cost could increase to more than €200 ($224) for high-performing biomarker tests in cases of limited colonoscopy capacity or higher uptake of this test.

CONCLUSIONS

By using the MISCAN-Colon microsimulation model to estimate effects of CRC screening tests, we found that for a biomarker test with increased overall performance to be cost-effective, it should not exceed 7-fold the unit cost of FIT. This maximum would increase substantially if colonoscopy becomes more expensive or scarce, or if the new test has higher screening uptake. These values could be used to estimate the added value of new biomarkers compared with current FIT screening.

Antibody-sandwich ELISA analysis of a novel blood biomarker of CST4 in gastrointestinal cancers

Background

Members of the cystatin family have increasingly been proven to be involved in several tumors, including gastric cancer (GC) and colorectal cancer (CRC). Cystatin S (CST4) was found to be upregulated at the gene expression level in GC cells, making it a potential novel biomarker for the early diagnosis of gastrointestinal cancer.

Materials and methods

Quantitative real-time polymerase chain reaction and Western blotting analysis were used to explore CST4 expression in gastrointestinal cancer tissues and cell lines. We purified CST4 recombinant protein and generated anti-CST4 monoclonal antibodies to develop an antibody-sandwich enzyme-linked immunosorbent assay (ELISA) analysis system for blood CST4 detection. The performance and clinical efficacy of the detection method were evaluated using a training set and validation set, respectively.

Results

According to the quantitative real-time polymerase chain reaction and Western blotting results, CST4-mRNA expression and protein expression were upregulated in gastrointestinal cancer tissues and cell lines. The ELISA detection system for CST4 showed significantly better sensitivities of 69.0% and 69.0% and specificities of 85.6% and 83.6% for GC and CRC, respectively, than other common clinical biomarkers, carcinoembryonic antigen, CA19-9, CA125, and CA72-4. Clinical verification experiments using GC and CRC validation sets also found distinguishable CST4 median concentrations (177.7 pg·mL^-1 and 174.2 pg·mL^-1 respectively) and high positive detection rates (72.3% and 88.4% respectively), further confirming the specificity and sensitivity of this method.

Conclusion

We validated the overexpression of CST4 in gastrointestinal cancer tissues and cell lines and developed an antibody-sandwich ELISA analysis system for blood CST4 detection, which exhibited high specificity and sensitivity. Novel blood biomarkers of CST4 have enormous potential in terms of clinical diagnostic value in GC and CRC.

Timed colonoscopy withdrawal, a mandatory quality measure in the era of national screening?

BACKGROUND

A minimum recommended withdrawal time for screening colonoscopy is recommended for by both the US Multi-Society Task Force on Colorectal Cancer and European Society of Gastrointestinal Endoscopy.

AIM

To characterize the relationship between endoscopists withdrawal time at colonoscopy and polyp detection in a symptomatic cohort of patients as compared to previously untimed withdrawal.

METHODS

Three experienced medical endoscopists prospectively performed 1079 colonoscopies during a 24-month period in an Irish hospital. Mean withdrawal time and individual polyp detection rate were noted.

RESULTS

Introduction of mandatory withdrawal time which was monitored and documented was associated with higher polyp detection rate (33 versus 21%, p < 0.005) as compared to previously untimed withdrawal.

CONCLUSION

Our findings support a monitored colonoscopy withdrawal time of at least 6 min, which correlates with higher colon polyp detection rates in a symptomatic cohort.

Diagnostic Accuracy of Fecal Immunochemical Test in Patients at Increased Risk for Colorectal Cancer: A Meta-analysis

IMPORTANCE

The potential role of the fecal immunochemical test (FIT) for screening patients at increased risk for colorectal cancer (CRC) has not yet been elucidated.

OBJECTIVE

To assess the diagnostic accuracy of FIT for CRC or advanced neoplasia (AN) in asymptomatic patients at above-average risk.

DATA SOURCES

MEDLINE, EMBASE, Cochrane Library, and gray literature sources through August 2016.

STUDY SELECTION

Diagnostic studies evaluating the accuracy of FIT for CRC or AN in patients with a personal or familial history of CRC using colonoscopy as the reference standard.

DATA EXTRACTION AND SYNTHESIS

Two authors (A.K. and P.P.) independently extracted data and evaluated study quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool, and evaluated the quality of the body of evidence by means of GRADE (Grading of Recommendations Assessment, Development, and Evaluation). Hierarchical models were used to synthesize available evidence.

MAIN OUTCOMES AND MEASURES

The primary outcome was the diagnostic performance of FIT for detecting CRC or AN.

RESULTS

We included 12 studies (6204 participants). Seven studies were deemed at high or unclear risk of bias. The average sensitivity of FIT for CRC was 93% (95% CI, 53%-99%), and the average specificity was 91% (95% CI, 89%-92%), yielding a positive likelihood ratio (LR+) of 10.30 (CI 7.7-13.9) and a negative likelihood ratio (LR-) of 0.08 (95% CI, 0.01-0.75) (GRADE: very low). The average sensitivity of FIT for AN was 48% (95% CI, 39%-57%); and the average specificity was 93% (95% CI, 91%-94%), yielding an LR+ of 6.55 (95% CI, 5.0-8.5) and an LR- of 0.57 (95% CI, 0.48-0.67) (GRADE: very low). Subgroup analyses indicated that FIT cutoff values between 15- and 25-μg/g feces provided the best combination of sensitivity and specificity for the diagnosis of CRC (93% and 94%, respectively). Quantitative and 1-sample FIT showed adequate test performance, but data on other FIT brands and multiple samples were insufficient.

CONCLUSIONS AND RELEVANCE

The FIT has high overall diagnostic accuracy for CRC but moderate accuracy for AN in patients at above-average personal or familial risk. Heterogeneity and wide confidence intervals limit the trustworthiness of our findings.

Cost-effectiveness of high-sensitivity faecal immunochemical test and colonoscopy screening for colorectal cancer

BACKGROUND

Colorectal cancer screening can decrease morbidity and mortality. However, there are widespread differences in the implementation of programmes and choice of strategy. The primary objective of this study was to estimate lifelong costs and health outcomes of two of the currently most preferred methods of screening for colorectal cancer: colonoscopy and sensitive faecal immunochemical test (FIT).

METHODS

A cost-effectiveness analysis of colorectal cancer screening in a Swedish population was performed using a decision analysis model, based on the design of the Screening of Swedish Colons (SCREESCO) study, and data from the published literature and registries. Lifelong cost and effects of colonoscopy once, colonoscopy every 10 years, FIT twice, FIT biennially and no screening were estimated using simulations.

RESULTS

For 1000 individuals invited to screening, it was estimated that screening once with colonoscopy yielded 49 more quality-adjusted life-years (QALYs) and a cost saving of €64 800 compared with no screening. Similarly, screening twice with FIT gave 26 more QALYs and a cost saving of €17 600. When the colonoscopic screening was repeated every tenth year, 7 additional QALYs were gained at a cost of €189 400 compared with a single colonoscopy. The additional gain with biennial FIT screening was 25 QALYs at a cost of €154 300 compared with two FITs.

CONCLUSION

All screening strategies were cost-effective compared with no screening. Repeated and single screening strategies with colonoscopy were more cost-effective than FIT when lifelong effects and costs were considered. However, other factors such as patient acceptability of the test and availability of human resources also have to be taken into account.

Comparative Effectiveness and Cost Effectiveness of a Multitarget Stool DNA Test to Screen for Colorectal Neoplasia

BACKGROUND & AIMS

We developed a model to determine whether a multitarget stool DNA (MT-sDNA) test that detects colorectal cancer (CRC) and polyps with higher sensitivity and lower specificity, but at a higher cost, than the fecal immunochemical test (FIT) can be used in screening.

METHODS

We used a Markov model of average-risk CRC screening to compare the effectiveness and cost effectiveness of screening with the MT-sDNA test vs FIT or colonoscopy. We accounted for the complex longitudinal participation patterns observed in organized programs vs opportunistic screening, as well as organized programs' patient support costs and differential payment rates by commercial insurers vs Medicare.

RESULTS

With optimal adherence, yearly FIT and colonoscopy every 10 years were dominant (more effective and less costly) than MT-sDNA every 3 years. Compared with successful organized FIT programs (50% consistent and 27% intermittent participation; patient support costs, $153/cycle), the patient support program for the MT-sDNA test would need 68% of subjects to participate consistently and 32% to participate intermittently every 3 years, or the MT-sDNA test would need to cost 60% less than in the base case ($260 commercial payment and $197 Medicare payment), for the MT-sDNA test to be preferred over FIT at a threshold of $100,000 per quality-adjusted life-year (QALY) gained. Compared with opportunistic yearly FIT screening (15% consistent and 30% intermittent participation), performing the MT-sDNA test every 3 years would cost less than $100,000 per QALY gained if the MT-sDNA test achieved a participation rate more than 1.7-fold that of FIT. The results were robust in sensitivity analyses. Assuming equal participation across strategies and a threshold of $100,000 per QALY gained, FIT was preferred in 99.3% of iterations in Monte Carlo simulation.

CONCLUSIONS

In a Markov model, we found FIT and colonoscopy to be more effective and less costly than the MT-sDNA test when participation rates were equal for all strategies. For the MT-sDNA test to be cost effective, the patient support program included in its cost would need to achieve substantially higher participation rates than those of FIT, whether in organized programs or under the opportunistic screening setting that is more common in the United States than in the rest of the world.

Cost Effectiveness of Colorectal Cancer Screening Strategies

BACKGROUND

Several screening tests are available to detect colorectal cancer (CRC) and reduce the incidence and mortality of CRC. The purpose of this review was to determine how current CRC screening strategies for CRC compare with no screening and whether agreement exists with regard to the cost effectiveness of different strategies.

METHODS

Databases were searched for cost-effectiveness analyses focused on CRC screening strategies in the United States and published between May 2007 and February 2014. We analyzed the uses of fecal occult blood, fecal immunochemistry, and stool DNA tests, as well as sigmoidoscopy, colonoscopy, and virtual colonoscopy. A paired comparison of each screening strategy with no screening across each of the studies reviewed was conducted. A series of paired comparisons of the results reported in each of the studies is also included.

RESULTS

When compared with no screening, all CRC screening strategies evaluated in this review were cost effective. There was disagreement as to which screening strategy was the most cost effective. However, sigmoidoscopy combined with fecal blood testing always dominated either strategy alone. Studies comparing colonoscopy with fecal blood testing, sigmoidoscopy, or both had mixed results.

CONCLUSIONS

Compared with no screening, all CRC screening strategies are more cost effective. Study results disagree as to which screening strategy should be the preferred method.

Stool Testing for Colorectal Cancer Screening

Colorectal cancer (CRC) screening has been shown to reduce CRC incidence and mortality and is widely recommended. However, despite the demonstrated benefits of screening and ongoing efforts to improve screening rates, a large percentage of the population remains unscreened. Noninvasive stool based tests offer great opportunity to enhance screening uptake. The evidence supporting the use of both fecal immunochemical testing (FIT) and stool DNA (sDNA) has been growing rapidly and both tests are now commercially available for use. Other stool biomarkers (eg, RNA and protein based) are also actively under study both for use independently and as adjuncts to the currently available tests. This mini review provides current, state of the art knowledge about noninvasive stool based screening. It includes a more detailed examination of those tests currently in use (ie, FIT and sDNA) but also provides an overview of stool testing options under development (ie, protein and RNA).

Derivation and Validation of a Scoring System to Stratify Risk for Advanced Colorectal Neoplasia in Asymptomatic Adults: A Cross-sectional Study

BACKGROUND

Several methods are recommended equally strongly for colorectal cancer screening in average-risk persons. Risk stratification would enable tailoring of screening within this group, with less invasive tests (sigmoidoscopy or occult blood tests) for lower-risk persons and colonoscopy for higher-risk persons.

OBJECTIVE

To create a risk index for advanced neoplasia (colorectal cancer and adenomas or serrated polyps ≥1.0 cm, villous histology, or high-grade dysplasia) anywhere in the colorectum, using the most common risk factors for colorectal neoplasia.

DESIGN

Cross-sectional study.

SETTING

Multiple endoscopy units, primarily in the Midwest.

PATIENTS

Persons aged 50 to 80 years undergoing initial screening colonoscopy (December 2004 to September 2011).

MEASUREMENTS

Derivation and validation of a risk index based on points from regression coefficients for age, sex, waist circumference, cigarette smoking, and family history of colorectal cancer.

RESULTS

Among 2993 persons in the derivation set, prevalence of advanced neoplasia was 9.4%. Risks for advanced neoplasia in persons at very low, low, intermediate, and high risk were 1.92% (95% CI, 0.63% to 4.43%), 4.88% (CI, 3.79% to 6.18%), 9.93% (CI, 8.09% to 12.0%), and 24.9% (CI, 21.1% to 29.1%), respectively (P < 0.001). Sigmoidoscopy to the descending colon in the low-risk groups would have detected 51 of 70 (73% [CI, 61% to 83%]) advanced neoplasms. Among 1467 persons in the validation set, corresponding risks for advanced neoplasia were 1.65% (CI, 0.20% to 5.84%), 3.31% (CI, 2.08% to 4.97%), 10.9% (CI, 8.26% to 14.1%), and 22.3% (CI, 16.9% to 28.5%), respectively (P < 0.001). Sigmoidoscopy would have detected 21 of 24 (87.5% [CI, 68% to 97%]) advanced neoplasms.

LIMITATIONS

Split-sample validation; results apply to first-time screening.

CONCLUSION

This index stratifies risk for advanced neoplasia among average-risk persons by identifying lower-risk groups for which noncolonoscopy strategies may be effective and efficient and a higher-risk group for which colonoscopy may be preferred.

PRIMARY FUNDING SOURCE

National Cancer Institute, Walther Cancer Institute, Indiana University Simon Cancer Center, and Indiana Clinical and Translational Sciences Institute.

Faecal immunochemical tests versus guaiac faecal occult blood tests: what clinicians and colorectal cancer screening programme organisers need to know

Although colorectal cancer (CRC) is a common cause of cancer-related death, it is fortunately amenable to screening with faecal tests for occult blood and endoscopic tests. Despite the evidence for the efficacy of guaiac-based faecal occult blood tests (gFOBT), they have not been popular with primary care providers in many jurisdictions, in part because of poor sensitivity for advanced colorectal neoplasms (advanced adenomas and CRC). In order to address this issue, high sensitivity gFOBT have been recommended, however, these tests are limited by a reduction in specificity compared with the traditional gFOBT. Where colonoscopy is available, some providers have opted to recommend screening colonoscopy to their patients instead of faecal testing, as they believe it to be a better test. Newer methods for detecting occult human blood in faeces have been developed. These tests, called faecal immunochemical tests (FIT), are immunoassays specific for human haemoglobin. FIT hold considerable promise over the traditional guaiac methods including improved analytical and clinical sensitivity for CRC, better detection of advanced adenomas, and greater screenee participation. In addition, the quantitative FIT are more flexible than gFOBT as a numerical result is reported, allowing customisation of the positivity threshold. When compared with endoscopy, FIT are less sensitive for the detection of advanced colorectal neoplasms when only one time testing is applied to a screening population; however, this is offset by improved participation in a programme of annual or biennial screens and a better safety profile. This review will describe how gFOBT and FIT work and will present the evidence that supports the use of FIT over gFOBT, including the cost-effectiveness of FIT relative to gFOBT. Finally, specific issues related to FIT implementation will be discussed, particularly with respect to organised CRC screening programmes.

Comparing the effectiveness of competing tests for reducing colorectal cancer mortality: a network meta-analysis

BACKGROUND

Comparative effectiveness data pertaining to competing colorectal cancer (CRC) screening tests do not exist but are necessary to guide clinical decision making and policy.

OBJECTIVE

To perform a comparative synthesis of clinical outcomes studies evaluating the effects of competing tests on CRC-related mortality.

DESIGN

Traditional and network meta-analyses. Two reviewers identified studies evaluating the effect of guaiac-based fecal occult blood testing (gFOBT), flexible sigmoidoscopy (FS), or colonoscopy on CRC-related mortality.

INTERVENTIONS

gFOBT, FS, colonoscopy.

MAIN OUTCOME MEASUREMENTS

Traditional meta-analysis was performed to produce pooled estimates of the effect of each modality on CRC mortality. Bayesian network meta-analysis (NMA) was performed to indirectly compare the effectiveness of screening modalities. Multiple sensitivity analyses were performed.

RESULTS

Traditional meta-analysis revealed that, compared with no intervention, colonoscopy reduced CRC-related mortality by 57% (relative risk [RR] 0.43; 95% confidence interval [CI], 0.33-0.58), whereas FS reduced CRC-related mortality by 40% (RR 0.60; 95% CI, 0.45-0.78), and gFOBT reduced CRC-related mortality by 18% (RR 0.82; 95% CI, 0.76-0.88). NMA demonstrated nonsignificant trends favoring colonoscopy over FS (RR 0.71; 95% CI, 0.45-1.11) and FS over gFOBT (RR 0.74; 95% CI, 0.51-1.09) for reducing CRC-related deaths. NMA-based simulations, however, revealed that colonoscopy has a 94% probability of being the most effective test for reducing CRC mortality and a 99% probability of being most effective when the analysis is restricted to screening studies.

LIMITATIONS

Randomized trials and observational studies were combined within the same analysis.

CONCLUSION

Clinical outcomes studies demonstrate that gFOBT, FS, and colonoscopy are all effective in reducing CRC-related mortality. Network meta-analysis suggests that colonoscopy is the most effective test.

Personalizing colorectal cancer screening: a systematic review of models to predict risk of colorectal neoplasia

BACKGROUND & AIMS

A valid risk prediction model for colorectal neoplasia would allow patients to be screened for colorectal cancer (CRC) on the basis of risk. We performed a systematic review of studies reporting risk prediction models for colorectal neoplasia.

METHODS

We conducted a systematic search of MEDLINE, Scopus, and Cochrane Library databases from January 1990 through March 2013 and of references in identified studies. Case-control, cohort, and cross-sectional studies that developed or attempted to validate a model to predict risk of colorectal neoplasia were included. Two reviewers independently extracted data and assessed model quality. Model quality was considered to be good for studies that included external validation, fair for studies that included internal validation, and poor for studies with neither.

RESULTS

Nine studies developed a new prediction model, and 2 tested existing models. The models varied with regard to population, predictors, risk tiers, outcomes (CRC or advanced neoplasia), and range of predicted risk. Several included age, sex, smoking, a measure of obesity, and/or family history of CRC among the predictors. Quality was good for 6 models, fair for 2 models, and poor for 1 model. The tier with the largest population fraction (low, intermediate, or high risk) depended on the model. For most models that defined risk tiers, the risk difference between the highest and lowest tier ranged from 2-fold to 4-fold. Two models reached the 0.70 threshold for the C statistic, typically considered to indicate good discriminatory power.

CONCLUSIONS

Most current colorectal neoplasia risk prediction models have relatively weak discriminatory power and have not demonstrated generalizability. It remains to be determined how risk prediction models could inform CRC screening strategies.

Fecal-based colorectal cancer screening among the uninsured in northern Manhattan

BACKGROUND

Colorectal cancer (CRC) screening reduces CRC mortality; however, for many reasons, uninsured individuals are less likely to utilize CRC screening tests.

PURPOSE

To compare CRC screening behaviors and outcomes with guaiac fecal occult blood testing (gFOBT) from 1998 to 2006 and fecal immunochemical testing (FIT) from 2006 to 2010 in a community-based program serving uninsured patients in northern Manhattan.

METHODS

In 2013, we conducted a retrospective record review of individuals aged ≥50 years who received fecal-based CRC screening at the Northern Manhattan Cancer Screening Partnership between 1998 and 2010. Included were those with household income ≤250% of the federal poverty level, no medical insurance coverage, and who were not up to date with CRC screening. We assessed screening positivity rate, positive predictive value, differences in the use of diagnostic colonoscopy, colonoscopic findings, and adenoma detection rates for gFOBT versus FIT.

RESULTS

In total, 7,710 patients completed CRC screenings (4,951 gFOBT and 2,759 FIT). The majority were female, Hispanic, foreign born, and young at age of first screening. Compared to gFOBT, FIT detected twice as many positive tests (3.2% vs 1.5%, p≤0.001) and had a higher adenoma detection rate (18.2 vs 11.8, p=0.002).

CONCLUSIONS

The improved positivity and adenoma detection rates with greater number of screening tests over time favor the use of FIT over gFOBT for colorectal screening among uninsured populations in northern Manhattan.

Genetic pathways, prevention, and treatment of sporadic colorectal cancer

Epithelial cancer of the colon and rectum, also known as colorectal cancer (CRC), results from a progressive accumulation of genetic and epigenetic alterations that lead to uncontrolled growth of colonocytes, the cells lining the colon and rectum. CRC is the second leading cause of cancer-related deaths and the third most common cancer in men and in women in the U.S. Of all the patients diagnosed with CRC every year, it is estimated that the vast majority of CRCs are non-hereditary “sporadic cancers” with no apparent evidence of an inherited component. Sporadic CRC results from the cumulative effects of multiple genetic and epigenetic alterations caused by somatic mutations, which may themselves be the indirect result of several environmental factors. This review examines our current understanding of the major genetic alterations leading to colon cancer, options for prevention and early detection of CRC, and the currently available treatment approaches that may target these different genetic alterations.

Tests and investigations for colorectal cancer screening

Worldwide, colorectal (CRC) is the third most common form of cancer, after lung and breast cancer, and the fourth most common cause of cancer death, although in developed countries CRC incidence is higher and it accounts for an even higher proportion of cancer deaths. Successful treatment of early-stage CRC confers substantial survival advantage, and there is now overwhelming evidence that screening average-risk individuals for CRC reduces the incidence and disease-specific mortality. In spite of considerable research for new biomarkers for CRC, the detection of blood in faeces remains the most effective screening tool. The best evidence to date for population-based CRC screening comes from randomised-controlled trials that used a guaiac-based faecal occult blood test (gFOBt) as the first-line screening modality, whereby test-positive individuals are referred for follow-up investigations, usually colonoscopy. A major innovation in the last ten years or so has been the development of other more analytically sensitive and specific screening techniques for blood in faeces. The faecal immunochemical test for haemoglobin (FIT) confers substantial benefits over gFOBt in terms of analytical sensitivity, specificity and practicality and FIT are now recommended for CRC screening by the European guidelines for quality assurance in colorectal cancer screening and diagnosis. The challenge internationally is to develop high quality CRC screening programmes for which uptake is high. This is especially important for developing countries witnessing an increase in the incidence of CRC as populations adopt more westernised lifestyles. This review describes the tests available for CRC screening and how they are being used worldwide. The reader will gain an understanding of developments in CRC screening and issues that arise in choosing the most appropriate screening test (or tests) for organised population-based screening internationally and optimising the performance of the chosen test (or tests). Whilst a wide range of literature has been cited, this is not a systematic review. The authors provide FOBT CRC screening for a population of 14.6 million in the south of England and the senior author (SPH) was the lead author of the European guidelines for quality assurance in colorectal cancer screening and diagnosis and leads the World Endoscopy Organization Colorectal Cancer Committee's Expert Working Group on 'FIT for Screening'.

Multitarget stool DNA testing for colorectal-cancer screening

BACKGROUND

An accurate, noninvasive test could improve the effectiveness of colorectal-cancer screening.

METHODS

We compared a noninvasive, multitarget stool DNA test with a fecal immunochemical test (FIT) in persons at average risk for colorectal cancer. The DNA test includes quantitative molecular assays for KRAS mutations, aberrant NDRG4 and BMP3 methylation, and β-actin, plus a hemoglobin immunoassay. Results were generated with the use of a logistic-regression algorithm, with values of 183 or more considered to be positive. FIT values of more than 100 ng of hemoglobin per milliliter of buffer were considered to be positive. Tests were processed independently of colonoscopic findings.

RESULTS

Of the 9989 participants who could be evaluated, 65 (0.7%) had colorectal cancer and 757 (7.6%) had advanced precancerous lesions (advanced adenomas or sessile serrated polyps measuring ≥1 cm in the greatest dimension) on colonoscopy. The sensitivity for detecting colorectal cancer was 92.3% with DNA testing and 73.8% with FIT (P=0.002). The sensitivity for detecting advanced precancerous lesions was 42.4% with DNA testing and 23.8% with FIT (P<0.001). The rate of detection of polyps with high-grade dysplasia was 69.2% with DNA testing and 46.2% with FIT (P=0.004); the rates of detection of serrated sessile polyps measuring 1 cm or more were 42.4% and 5.1%, respectively (P<0.001). Specificities with DNA testing and FIT were 86.6% and 94.9%, respectively, among participants with nonadvanced or negative findings (P<0.001) and 89.8% and 96.4%, respectively, among those with negative results on colonoscopy (P<0.001). The numbers of persons who would need to be screened to detect one cancer were 154 with colonoscopy, 166 with DNA testing, and 208 with FIT.

CONCLUSIONS

In asymptomatic persons at average risk for colorectal cancer, multitarget stool DNA testing detected significantly more cancers than did FIT but had more false positive results. (Funded by Exact Sciences; ClinicalTrials.gov number, NCT01397747.).

Challenges and possible solutions to colorectal cancer screening for the underserved

Colorectal cancer (CRC) is a leading cause of cancer mortality worldwide. CRC incidence and mortality can be reduced through screening. However, in the United States, screening participation remains suboptimal, particularly among underserved populations such as the uninsured, recent immigrants, and racial/ethnic minority groups. Increasing screening rates among underserved populations will reduce the US burden of CRC. In this commentary focusing on underserved populations, we highlight the public health impact of CRC screening, list key challenges to screening the underserved, and review promising approaches to boost screening rates. We identify four key policy and research priorities to increase screening among underserved populations: 1) actively promote the message, "the best test is the one that gets done"; 2) develop and implement methods to identify unscreened individuals within underserved population groups for screening interventions; 3) develop and implement approaches for organized screening delivery; and 4) fund and enhance programs and policies that provide access to screening, diagnostic follow-up, and CRC treatment for underserved populations. This commentary represents the consensus of a diverse group of experts in cancer control and prevention, epidemiology, gastroenterology, and primary care from across the country who formed the Coalition to Boost Screening among the Underserved in the United States. The group was organized and held its first annual working group meeting in conjunction with the World Endoscopy Organization's annual Colorectal Cancer Screening Committee meeting during Digestive Disease Week 2012 in San Diego, California.

Review of economic evidence in the prevention and early detection of colorectal cancer

This paper aims to systematically review the cost-effectiveness evidence, and to provide a critical appraisal of the methods used in the model-based economic evaluation of CRC screening and subsequent surveillance. A search strategy was developed to capture relevant evidence published 1999-November 2012. Databases searched were MEDLINE, EMBASE, National Health Service Economic Evaluation (NHS EED), EconLit, and HTA. Full economic evaluations that considered costs and health outcomes of relevant intervention were included. Sixty-eight studies which used either cohort simulation or individual-level simulation were included. Follow-up strategies were mostly embedded in the screening model. Approximately 195 comparisons were made across different modalities; however, strategies modelled were often simplified due to insufficient evidence and comparators chosen insufficiently reflected current practice/recommendations. Studies used up-to-date evidence on the diagnostic test performance combined with outdated information on CRC treatments. Quality of life relating to follow-up surveillance is rare. Quality of life relating to CRC disease states was largely taken from a single study. Some studies omitted to say how identified adenomas or CRC were managed. Besides deterministic sensitivity analysis, probabilistic sensitivity analysis (PSA) was undertaken in some studies, but the distributions used for PSA were rarely reported or justified. The cost-effectiveness of follow-up strategies among people with confirmed adenomas are warranted in aiding evidence-informed decision making in response to the rapidly evolving technologies and rising expectations.

Health benefits and cost-effectiveness of a hybrid screening strategy for colorectal cancer

BACKGROUND & AIMS

Colorectal cancer (CRC) screening guidelines recommend screening schedules for each single type of test except for concurrent sigmoidoscopy and fecal occult blood test (FOBT). We investigated the cost-effectiveness of a hybrid screening strategy that was based on a fecal immunological test (FIT) and colonoscopy.

METHODS

We conducted a cost-effectiveness analysis by using the Archimedes Model to evaluate the effects of different CRC screening strategies on health outcomes and costs related to CRC in a population that represents members of Kaiser Permanente Northern California. The Archimedes Model is a large-scale simulation of human physiology, diseases, interventions, and health care systems. The CRC submodel in the Archimedes Model was derived from public databases, published epidemiologic studies, and clinical trials.

RESULTS

A hybrid screening strategy led to substantial reductions in CRC incidence and mortality, gains in quality-adjusted life years (QALYs), and reductions in costs, comparable with those of the best single-test strategies. Screening by annual FIT of patients 50-65 years old and then a single colonoscopy when they were 66 years old (FIT/COLOx1) reduced CRC incidence by 72% and gained 110 QALYs for every 1000 people during a period of 30 years, compared with no screening. Compared with annual FIT, FIT/COLOx1 gained 1400 QALYs/100,000 persons at an incremental cost of $9700/QALY gained and required 55% fewer FITs. Compared with FIT/COLOx1, colonoscopy at 10-year intervals gained 500 QALYs/100,000 at an incremental cost of $35,100/QALY gained but required 37% more colonoscopies. Over the ranges of parameters examined, the cost-effectiveness of hybrid screening strategies was slightly more sensitive to the adherence rate with colonoscopy than the adherence rate with yearly FIT. Uncertainties associated with estimates of FIT performance within a program setting and sensitivities for flat and right-sided lesions are expected to have significant impacts on the cost-effectiveness results.

CONCLUSIONS

In our simulation model, a strategy of annual or biennial FIT, beginning when patients are 50 years old, with a single colonoscopy when they are 66 years old, delivers clinical and economic outcomes similar to those of CRC screening by single-modality strategies, with a favorable impact on resources demand.

Colorectal cancer screening with blood-based biomarkers: cost-effectiveness of methylated septin 9 DNA versus current strategies

BACKGROUND

Screening reduces colorectal cancer mortality, but many persons remain unscreened. Screening with a blood test could improve screening rates. We estimated the comparative effectiveness and cost-effectiveness of colorectal cancer screening with emerging biomarkers, illustrated by a methylated Septin 9 DNA plasma assay ((m)SEPT9), versus established strategies.

METHODS

We conducted a cost-utility analysis using a validated decision analytic model comparing (m)SEPT9, fecal occult blood testing (FOBT), fecal immunochemical testing (FIT), sigmoidoscopy, and colonoscopy, projecting lifetime benefits and costs.

RESULTS

In the base case, (m)SEPT9 decreased colorectal cancer incidence by 35% to 41% and colorectal cancer mortality by 53% to 61% at costs of $8,400 to $11,500/quality-adjusted life year gained versus no screening. All established screening strategies were more effective than (m)SEPT9. FIT was cost saving, dominated (m)SEPT9, and was preferred among all the alternatives. Screening uptake and longitudinal adherence rates over time strongly influenced the comparisons between strategies. At the population level, (m)SEPT9 yielded incremental benefit at acceptable costs when it increased the fraction of the population screened more than it was substituted for other strategies.

CONCLUSIONS

(m)SEPT9 seems to be effective and cost-effective compared with no screening. To be cost-effective compared with established strategies, (m)SEPT9 or blood-based biomarkers with similar test performance characteristics would need to achieve substantially higher uptake and adherence rates than the alternatives. It remains to be proven whether colorectal cancer screening with a blood test can improve screening uptake or long-term adherence compared with established strategies.

IMPACT

Our study offers insights into the potential role of colorectal cancer screening with blood-based biomarkers.

Cost effectiveness of fecal DNA screening for colorectal cancer: a systematic review and quality appraisal of the literature

BACKGROUND

Fecal DNA (fDNA) testing is a noninvasive potential alternative to current colorectal cancer screening tests.

OBJECTIVE

We conducted a systematic review and quality assessment of studies of cost-effectiveness of fDNA as a colorectal cancer screening tool (compared with no screening and other screening modalities), and identified key variables that impinged on cost-effectiveness.

DATA SOURCES

We searched MEDLINE, Embase, and the Centre for Reviews and Dissemination for cost-effectiveness studies of fDNA-based screening, published in English by September 2011.

STUDY SELECTION

Studies that undertook an economic evaluation of fDNA, using either a cost-effectiveness or cost-utility analysis, compared with other relevant screening modalities and/or no screening were included. Additional inclusion criteria related to the presentation of data pertaining to model variables including time horizon, costs, fDNA performance characteristics, screening uptake, and comparators. A total of 369 articles were initially identified for review. After removing duplicates and applying inclusion and exclusion criteria, seven articles were included in the final review.

STUDY APPRAISAL

Data was abstracted on key descriptor variables including screening scenarios, time horizon, costs, test performance characteristics, screening uptake, comparators, and incremental cost-effectiveness ratios. Quality assessment was undertaken using a standard checklist for economic evaluations. Studies cited by cost-effectiveness articles as the source of data on fDNA test performance characteristics were also reviewed.

RESULTS

Seven cost-effectiveness studies were included, from the USA (4), Canada (1), Israel (1), and Taiwan (1). Markov models (5), a partially observable Markov decision process model (1) and MISCAN and SimCRC (1) microsimulation models were used. All studies took a third-party payer perspective and one included, in addition, a societal perspective. Comparator screening tests, screening intervals, and specific fDNA tests varied between studies. fDNA sensitivity and specificity parameters were derived from 12 research studies and one meta-analysis. Outcomes assessed were life-years gained and quality-adjusted life-years gained. fDNA was cost-effective when compared with no screening in six studies. Compared with other screening modalities, fDNA was not considered cost-effective in any of the base-case analyses: in five studies it was dominated by all alternatives considered. Sensitivity analyses identified cost, compliance, and test parameters as key influential parameters. In general, poor presentation of "study design" and "data collection" details lowered the quality of included articles.

LIMITATIONS

Although the literature searches were designed for high sensitivity, the possibility cannot be excluded that some eligible studies may have been missed. Reports (such as Health Technology Assessments produced by government agencies) and other forms of grey literature were excluded because they are difficult to identify systematically and/or may not report methods and results in sufficient detail for assessment.

CONCLUSION

On the basis of the available (albeit limited) evidence, while fDNA is cost-effective when compared with no screening, it is currently dominated by most of the other available screening options. Cost and test performance appear to be the main influences on cost-effectiveness.

Comparative effectiveness and cost-effectiveness of screening colonoscopy vs. sigmoidoscopy and alternative strategies

OBJECTIVES

Fecal occult blood testing (FOBT) and sigmoidoscopy are proven to decrease colorectal cancer (CRC) incidence and mortality. Sigmoidoscopy's benefit is limited to the distal colon. Observational data are conflicting regarding the degree to which colonoscopy affords protection against proximal CRC. Our aim was to explore the comparative effectiveness and cost-effectiveness of colonoscopy vs. sigmoidoscopy and alternative CRC screening strategies in light of the latest published data.

METHODS

We performed a contemporary cost-utility analysis using a Markov model validated against data from randomized controlled trials of FOBT and sigmoidoscopy. Persons at average CRC risk within the general US population were modeled. Screening strategies included those recommended by the United States (US) Preventive Services Task Force, including colonoscopy every 10 years (COLO), flexible sigmoidoscopy every 5 years (FS), annual fecal occult blood testing, annual fecal immunochemical testing (FIT), and the combination FS/FIT. The main outcome measures were quality-adjusted life-years (QALYs) and costs.

RESULTS

In the base case, FIT dominated other strategies. The advantage of FIT over FS and COLO was contingent on rates of uptake and adherence that are well above current US rates. Compared with FIT, FS and COLO both cost <$50,000/QALY gained when FIT per-cycle adherence was <50%. COLO cost $56,800/QALY gained vs. FS in the base case. COLO cost <$100,000/QALY gained vs. FS when COLO yielded a relative risk of proximal CRC of <0.5 vs. no screening. In probabilistic analyses, COLO was cost-effective vs. FS at a willingness-to-pay threshold of $100,000/QALY gained in 84% of iterations.

CONCLUSIONS

Screening colonoscopy may be cost-effective compared with FIT and sigmoidoscopy, depending on the relative rates of screening uptake and adherence and the protective benefit of colonoscopy in the proximal colon. Colonoscopy's cost-effectiveness compared with sigmoidoscopy is contingent on the ability to deliver ~50% protection against CRC in the proximal colon.

Noninvasive screening tests for colorectal cancer

BACKGROUND

Identifying an accurate, reliable, affordable, and acceptable noninvasive screening test for colorectal cancer (CRC) would greatly facilitate population screening.

METHODS

Published literature from 2000 through February 2012 on noninvasive CRC screening tests was identified, reviewed, and summarized.

RESULTS

The highest quality evidence for noninvasive screening exists for guaiac-based fecal occult blood tests (gFOBTs), for which the CRC-specific incidence and mortality reductions are modest. Fecal immunochemical tests (FITs) offer better sensitivity and comparable specificity. Cross-sectional studies comparing gFOBTs and FITs suggest that FITs provide higher detection of advanced neoplasia. Modeling studies favor FITs over gFOBTs with respect to effectiveness and cost-effectiveness. A myriad of studies report the performance of fecal-based and blood-based genetic and protein-based biomarkers; the studies differ in patient population assembled, marker selection, and assay methods. Several markers and panels of markers are promising, although nearly all studies focus on new markers and/or assay methods on small sets of referred patients rather than validating markers using optimal assays in a screening setting.

CONCLUSION

In the absence of long-term randomized trials, adoption of the noninvasive tests will require cross-sectional data on test characteristics obtained from the screening setting, where CRC prevalence is low and the full spectrum of colorectal findings exists, along with estimates of cumulative risks, benefits, and cost-effectiveness. Test adoption will ultimately depend on test characteristics, availability, affordability, and user appeal. There is no noninvasive substitute for the currently recommended screening tests. FITs should replace gFOBTs wherever gFOBTs are used for screening.

Inclusion of compliance and persistence in economic models: past, present and future

Economic models are developed to provide decision makers with information related to the real-world effectiveness of therapeutics, screening and diagnostic regimens. Although compliance with these regimens often has a significant impact on real-world clinical outcomes and costs, compliance and persistence have historically been addressed in a relatively superficial fashion in economic models. In this review, we present a discussion of the current state of economic modelling as it relates to the consideration of compliance and persistence. We discuss the challenges associated with the inclusion of compliance and persistence in economic models and provide an in-depth review of recent modelling literature that considers compliance or persistence, including a brief summary of previous reviews on this topic and a survey of published models from 2005 to 2012. We review the recent literature in detail, providing a therapeutic-area-specific discussion of the approaches and conclusions drawn from the inclusion of compliance or persistence in economic models. In virtually all publications, variation of model parameters related to compliance and persistence was shown to have a significant impact on predictions of economic outcomes. Growing recognition of the importance of compliance and persistence in the context of economic evaluations has led to an increasing number of economic models that consider these factors, as well as the use of more sophisticated modelling techniques such as individual simulations that provide an avenue for more rigorous consideration of compliance and persistence than is possible with more traditional methods. However, we note areas of continuing concern cited by previous reviews, including inconsistent definitions, documentation and tenuous assumptions required to estimate the effect of compliance and persistence. Finally, we discuss potential means to surmount these challenges via more focused efforts to collect compliance and persistence data.

Canadian guidelines for colorectal cancer screening

Decisions regarding colorectal cancer screening will continue to depend on local resources, which in some jurisdictions includes programmatic screening and individual patient preferences. I encourage gastroenterologists to participate in programmatic screening and assist in developing the colonoscopy quality assurance and improvement programs. Our involvement would ensure that we remain leaders in this area and that our expertise in quality in endoscopy is recognized. Finally, participation in programmatic screening should benefit endoscopic services by increasing resources to support higher colonoscopy volumes, shorter wait lists and continuing quality assurance.

Screening for colorectal cancer: established and emerging modalities

It has been estimated that >95% of cases of colorectal cancer (CRC) would benefit from curative surgery if diagnosis was made at an early or premalignant polyp stage of disease. Over the past 10 years, most developed nation states have implemented mass population screening programs, which are typically targeted at the older (at-risk) age group (>50-60 years old). Conventional screening largely relies on periodic patient-centric investigation, particularly involving colonoscopy and flexible sigmoidoscopy, or else on the fecal occult blood test. These methods are compromised by either low cost-effectiveness or limited diagnostic accuracy. Advances in the development of diagnostic molecular markers for CRC have yielded an expanding list of potential new screening modalities based on investigations of patient stool (for colonocyte DNA mutations, epigenetic changes or microRNA expression) or blood specimens (for plasma DNA mutations, epigenetic changes, heteroplasmic mitochondrial DNA mutations, leukocyte transcriptome profile, plasma microRNA expression or protein and autoantibody expression). In this Review, we present a critical evaluation of the performance data and relative merits of these various new potential methods. None of these molecular diagnostic methods have yet been evaluated beyond the proof-of-principle and pilot-scale study stage and it could be some years before they replace existing methods for population screening in CRC.

Molecular tests for colorectal cancer screening

Detecting and removing high-risk adenomas and early colorectal cancer (CRC) can reduce mortality of this disease. The noninvasive fecal occult blood test (FOBT; guaiac-based or immunochemical) is widely used in screening programs and although effective, it leaves room for improvement in terms of test accuracy. Molecular tests are expected to be more sensitive, specific and informative than current detection tests, and are promising future tools for CRC screening. This review provides an overview of the performances of DNA, RNA, and protein markers for CRC detection in stool and blood. Most emphasis currently is on DNA and protein markers. Among DNA markers there is trend to move away from mutation markers in favor of methylation markers. The recent boost in proteomics research leads to many new candidate protein markers. Usually in small series, some markers show better performance than the present FOBT. Evaluation in large well-controlled randomized trials is the next step needed to take molecular markers for CRC screening to the next level and warrant implementation in a screening setting.

Cost-effectiveness of colorectal cancer screening

Colorectal cancer is an important public health problem. Several screening methods have been shown to be effective in reducing colorectal cancer mortality. The objective of this review was to assess the cost-effectiveness of the different colorectal cancer screening methods and to determine the preferred method from a cost-effectiveness point of view. Five databases (MEDLINE, EMBASE, the Cost-Effectiveness Analysis Registry, the British National Health Service Economic Evaluation Database, and the lists of technology assessments of the Centers for Medicare and Medicaid Services) were searched for cost-effectiveness analyses published in English between January 1993 and December 2009. Fifty-five publications relating to 32 unique cost-effectiveness models were identified. All studies found that colorectal cancer screening was cost-effective or even cost-saving compared with no screening. However, the studies disagreed as to which screening method was most effective or had the best incremental cost-effectiveness ratio for a given willingness to pay per life-year gained. There was agreement among studies that the newly developed screening tests of stool DNA testing, computed tomographic colonography, and capsule endoscopy were not yet cost-effective compared with the established screening options.

Immunochemical faecal occult blood tests have superior stability and analytical performance characteristics over guaiac-based tests in a controlled in vitro study

Aims

The aims of this study were (1) to determine the measurement accuracy of a widely used guaiac faecal occult blood test (gFOBT) compared with an immunochemical faecal occult blood test (iFOBT) during in vitro studies, including their analytical stability over time at ambient temperature and at 4°C; and (2) to compare analytical imprecision and other characteristics between two commercially available iFOBT methods.

Methods

Faecal specimens from healthy volunteers negative for occult blood were spiked with red cell lysate to give concentrations of 0 (A), 2.5 (B) and 4.5 (C) mg Hb/g faeces respectively. Samples from each pool were then tested by nine blinded assessors in order to determine the measurement accuracy. Sample stability for the gFOBT at ambient temperature (18°C) was determined by repeating the gFOBT analysis on faecal samples (A, B and C) consecutively for 7 days. Stability for the iFOBT was tested on spiked faecal samples stored at 4°C and also at ambient temperature (18°C). Testing for other analytical performance characteristics including sample carryover and imprecision was performed for both iFOBT methods.

Results

Nine blinded assessors using gFOBT achieved correct readings for eight of nine samples from Pool A, five of nine from Pool B and seven of nine from Pool C. Overall, the sensitivity and specificity of gFOBT were 67% and 89% respectively. No discrepant results were detected with iFOBT. Faecal samples applied to gFOBT cards immediately postcollection gave positive results for the next 7 days only for pool C. In contrast, the results of iFOBT remained stable up to 14 days at 18°C. The within-run imprecision and sample carryover showed robust results with both iFOBT methods.

Conclusions

The superior analytical stability and measurement accuracy demonstrated by the iFOBT in this in vitro study confers advantages over traditional qualitative gFOBTs and supports their suitability for more widespread use in population-based colorectal-cancer screening programmes.

Colorectal cancer screening comparing no screening, immunochemical and guaiac fecal occult blood tests: a cost-effectiveness analysis

Comparability of cost-effectiveness of colorectal cancer (CRC) screening strategies is limited if heterogeneous study data are combined. We analyzed prospective empirical data from a randomized-controlled trial to compare cost-effectiveness of screening with either one round of immunochemical fecal occult blood testing (I-FOBT; OC-Sensor®), one round of guaiac FOBT (G-FOBT; Hemoccult-II®) or no screening in Dutch aged 50 to 75 years, completed with cancer registry and literature data, from a third-party payer perspective in a Markov model with first- and second-order Monte Carlo simulation. Costs were measured in Euros (€), effects in life-years gained, and both were discounted with 3%. Uncertainty surrounding important parameters was analyzed. I-FOBT dominated the alternatives: after one round of I-FOBT screening, a hypothetical person would on average gain 0.003 life-years and save the health care system €27 compared with G-FOBT and 0.003 life years and €72 compared with no screening. Overall, in 4,460,265 Dutch aged 50-75 years, after one round I-FOBT screening, 13,400 life-years and €320 million would have been saved compared with no screening. I-FOBT also dominated in sensitivity analyses, varying uncertainty surrounding important effect and cost parameters. CRC screening with I-FOBT dominated G-FOBT and no screening with or without accounting for uncertainty.

Colorectal cancer screening for average-risk North Americans: an economic evaluation

BACKGROUND

Colorectal cancer (CRC) fulfills the World Health Organization criteria for mass screening, but screening uptake is low in most countries. CRC screening is resource intensive, and it is unclear if an optimal strategy exists. The objective of this study was to perform an economic evaluation of CRC screening in average risk North American individuals considering all relevant screening modalities and current CRC treatment costs.

METHODS AND FINDINGS

An incremental cost-utility analysis using a Markov model was performed comparing guaiac-based fecal occult blood test (FOBT) or fecal immunochemical test (FIT) annually, fecal DNA every 3 years, flexible sigmoidoscopy or computed tomographic colonography every 5 years, and colonoscopy every 10 years. All strategies were also compared to a no screening natural history arm. Given that different FIT assays and collection methods have been previously tested, three distinct FIT testing strategies were considered, on the basis of studies that have reported "low," "mid," and "high" test performance characteristics for detecting adenomas and CRC. Adenoma and CRC prevalence rates were based on a recent systematic review whereas screening adherence, test performance, and CRC treatment costs were based on publicly available data. The outcome measures included lifetime costs, number of cancers, cancer-related deaths, quality-adjusted life-years gained, and incremental cost-utility ratios. Sensitivity and scenario analyses were performed. Annual FIT, assuming mid-range testing characteristics, was more effective and less costly compared to all strategies (including no screening) except FIT-high. Among the lifetimes of 100,000 average-risk patients, the number of cancers could be reduced from 4,857 to 1,393 [corrected] and the number of CRC deaths from 1,782 [corrected] to 457, while saving CAN$68 per person. Although screening patients with FIT became more expensive than a strategy of no screening when the test performance of FIT was reduced, or the cost of managing CRC was lowered (e.g., for jurisdictions that do not fund expensive biologic chemotherapeutic regimens), CRC screening with FIT remained economically attractive.

CONCLUSIONS

CRC screening with FIT reduces the risk of CRC and CRC-related deaths, and lowers health care costs in comparison to no screening and to other existing screening strategies. Health policy decision makers should consider prioritizing funding for CRC screening using FIT.

A resect and discard strategy would improve cost-effectiveness of colorectal cancer screening

BACKGROUND & AIMS

A "resect and discard" policy has been proposed for diminutive polyps detected by screening colonoscopy, because hyperplastic and adenomatous polyps can be distinguished, in vivo, by using narrow-band imaging (NBI). We modeled the cost-effectiveness of this policy.

METHODS

Markov modeling was used to compare the cost-effectiveness of universal pathology evaluations with a resect and discard policy for colonoscopy screening. In a resect and discard approach, diminutive lesions (≤5 mm), classified by endoscopy with high confidence, were not analyzed by a pathologist. Base case assumptions of an 84% rate of high-confidence classification, with a sensitivity and specificity for adenomas of 94% and 89%, respectively, were used. Census data were used to project outputs of the model onto the US population, assuming 23% as the current rate of adherence to a colonoscopy screening.

RESULTS

With universal referral of resected polyps to pathology, colonoscopy screening costs an estimated $3222/person, with a gain of 51 days/person. Endoscopic polypectomy accounted for $179/person, of which $46/person was related to pathology examination. Adoption of a resect and discard policy for eligible diminutive polyps resulted in a savings of $25/person, without any meaningful effect on screening efficacy. Projected onto the US population, this approach would result in an undiscounted annual savings of $33 million. In the sensitivity analysis, the rate of high-confidence diagnosis and the accuracy for endoscopic polyp determination were the most meaningful variables.

CONCLUSIONS

In a simulation model, a resect and discard strategy for diminutive polyps detected by screening colonoscopy resulted in a substantial economic benefit without an impact on efficacy.

Cost-effectiveness of colorectal cancer screening in high-risk Spanish patients: use of a validated model to inform public policy

BACKGROUND

The European Community has made a commitment to colorectal cancer (CRC) screening, but regional considerations may affect the design of national screening programs. We developed a decision analytic model tailored to a pilot screening program for high-risk persons in Spain with the aim of informing public policy decisions.

MATERIALS AND METHODS

We constructed a decision analytic Markov model based on our validated model of CRC screening that reflected CRC epidemiology and costs in persons with first-degree relatives with CRC in Aragón, Spain, and superimposed colonoscopy every 5 or 10 years from ages 40 to 80 years. The pilot program's preliminary clinical results and our modeling results were presented to regional health authorities.

RESULTS

In the model, without screening, 88 CRC cases occurred per 1,000 persons from age 40 to 85 years. In the base case, screening reduced this by 72% to 77% and gained 0.12 discounted life years per person. Screening every 10 years was cost saving, and screening every 5 years versus every 10 years cost 7,250 euros per life year gained. Based on these savings, 36 to 39 euros per person per year could go toward operating costs while maintaining a neutral budget. If screening costs doubled, screening remained highly cost-effective but no longer cost saving. These results contributed to the health authorities' decision to expand the pilot program to the entire region in 2009.

CONCLUSIONS

Colonoscopic screening of first-degree relatives of persons with CRC may be cost saving in public systems like that of Spain. Decision analytic modeling tailored to regional considerations can inform public policy decisions.

IMPACT

Tailored decision analytic modeling can inform regional policy decisions on cancer screening.

Cost-effectiveness of colorectal cancer screening - an overview

There are several modalities available for a colorectal cancer (CRC) screening program. When determining which CRC screening program to implement, the costs of such programs should be considered in comparison to the health benefits they are expected to provide. Cost-effectiveness analysis provides a tool to do this. In this paper we review the evidence on the cost-effectiveness of CRC screening. Published studies universally indicate that when compared with no CRC screening, all screening modalities provide additional years of life at a cost that is deemed acceptable by most industrialized nations. Many recent studies even find CRC screening to be cost-saving. However, when the alternative CRC screening strategies are compared against each other in an incremental cost-effectiveness analysis, no single optimal strategy emerges across the studies. There is consensus that the new technologies of stool DNA testing, computed tomographic colonography and capsule endoscopy are not yet cost-effective compared with the established CRC screening tests.

Mailed fecal-immunochemical test for colon cancer screening

Various interventions have been implemented to increase the rate of colon cancer screening. The purpose of this study was to determine if persons who are regular patients of a clinic, ages 50-64 years, and not up-to-date with colon cancer screening will complete the at-home fecal-immunochemical test (FIT) if it is mailed to them. This intervention was designed to have the subject avoid the signing of an informed consent and having to ask for the screening test; and, only one stool specimen was needed. Three hundred and fifty potential subjects were randomly selected from an electronic medical record database after meeting inclusion criteria. Eighty-seven fecal immunochemical tests were returned. Seven of the FIT kit results were positive for occult blood. Each respondent was sent a letter giving them their results. A minimal cue CRC screening intervention, a FIT kit sent in the mail without prerequisite of a signed informed consent, was offered to the study subjects. Twenty-six percent of the eligible persons were screened for colon cancer by this method. A mailed FIT kit or one handed to the patient at an office visit has minimal cost which can be recovered through insurance coverage. Commitment by health care providers is necessary for prevention. This method is one of several that could reach the hard to screen population.

The cost-effectiveness of screening for colorectal cancer

BACKGROUND

Published decision analyses show that screening for colorectal cancer is cost-effective. However, because of the number of tests available, the optimal screening strategy in Canada is unknown. We estimated the incremental cost-effectiveness of 10 strategies for colorectal cancer screening, as well as no screening, incorporating quality of life, noncompliance and data on the costs and benefits of chemotherapy.

METHODS

We used a probabilistic Markov model to estimate the costs and quality-adjusted life expectancy of 50-year-old average-risk Canadians without screening and with screening by each test. We populated the model with data from the published literature. We calculated costs from the perspective of a third-party payer, with inflation to 2007 Canadian dollars.

RESULTS

Of the 10 strategies considered, we focused on three tests currently being used for population screening in some Canadian provinces: low-sensitivity guaiac fecal occult blood test, performed annually; fecal immunochemical test, performed annually; and colonoscopy, performed every 10 years. These strategies reduced the incidence of colorectal cancer by 44%, 65% and 81%, and mortality by 55%, 74% and 83%, respectively, compared with no screening. These strategies generated incremental cost-effectiveness ratios of $9159, $611 and $6133 per quality-adjusted life year, respectively. The findings were robust to probabilistic sensitivity analysis. Colonoscopy every 10 years yielded the greatest net health benefit.

INTERPRETATION

Screening for colorectal cancer is cost-effective over conventional levels of willingness to pay. Annual high-sensitivity fecal occult blood testing, such as a fecal immunochemical test, or colonoscopy every 10 years offer the best value for the money in Canada.

A comparison of the acceptance of immunochemical faecal occult blood test and colonoscopy in colorectal cancer screening: a prospective study among Chinese

BACKGROUND

Preferences to choose immunochemical faecal occult blood test (FIT) and colonoscopy as colorectal cancer (CRC) screening modalities among asymptomatic Chinese subjects remain unknown.

AIM

To evaluate the preference of choosing colonoscopy vs. FIT among CRC screening participants.

METHODS

From a community-based CRC screening programme for asymptomatic Hong Kong Chinese aged 50-70 years, participants attended standardized educational sessions and chose the options of annual FIT for 5 years or direct colonoscopy once. Factors associated with choosing colonoscopy were evaluated by multivariate regression analysis.

RESULTS

Among 3430 participants [mean age 56.8 years (s.d. 5.0); female 55.1%, male 44.9%], 51.3% chose colonoscopy and 48.7% chose FIT. Older participants (65-70 years) were less likely to choose colonoscopy [adjusted odds ratio (aOR) 0.731, P = 0.041]. Subjects who chose colonoscopy were those disagreed screening would lead to discomfort (aOR 1.356, P < 0.001), had relatives or friends who had CRC (first degree relatives aOR 1.679, P < 0.001; second degree relatives aOR 1.304, P = 0.019; friends or others aOR 1.252, P = 0.026) and those who self-perceived their health as poor (aOR 1.529, P = 0.025).

CONCLUSIONS

Faecal occult blood test and direct colonoscopy were equally preferable to Chinese. Colonoscopy was preferred among the younger subjects, those with positive family history of CRC and self-perceived poor health status.

Molecular detection of colorectal neoplasia

A variety of noninvasive molecular approaches to colorectal cancer screening are emerging with potential to improve screening effectiveness and user-friendliness. These approaches are based on the sensitive assay of molecular markers in stool, blood, and urine samples. New methods, especially next generation stool-based tests, have been shown to detect both colorectal cancers and precancerous lesions with high accuracy. Validation of these technologies in average-risk populations are needed to establish their role for general colorectal cancer screening. This review addresses the biological rationale, technical advances, recent clinical performance data, and remaining issues with molecular screening for colorectal cancer.