Screening for Colorectal Cancer Using a Multitarget Stool DNA Test: Modeling the Effect of the Intertest Interval on Clinical Effectiveness

Detecting colorectal cancer using genetic and epigenetic biomarkers: screening and diagnosis

Colorectal cancer (CRC) is one of the most frequent types of cancer, with high incidence rates and mortality globally. The extended timeframe for developing CRC allows for the potential screening and early identification of the disease. Furthermore, studies have shown that survival rates for patients with cancer are increased when diagnoses are made at earlier stages. Recent research suggests that the development of CRC, including its precancerous lesion, is influenced not only by genetic factors but also by epigenetic variables. Studies suggest epigenetics plays a significant role in cancer development, particularly CRC. While this approach is still in its early stages and faces challenges due to the variability of CRC, it shows promise as a potential method for understanding and addressing the disease. This review examined the current evidence supporting genetic and epigenetic biomarkers for screening and diagnosis. In addition, we also discussed the feasibility of translating these methodologies into clinical settings. Several markers show promising potential, including the methylation of vimentin (VIM), syndecan-2 (SDC2), and septin 9 (SEPT9). However, their application as screening and diagnostic tools, particularly for early-stage CRC, has not been fully optimized, and their effectiveness needs validation in large, multi-center patient populations. Extensive trials and further investigation are required to translate genetic and epigenetic biomarkers into practical clinical use. biomarkers, diagnostic biomarkers.

Joint Asian Pacific Association of Gastroenterology (APAGE)-Asian Pacific Society of Digestive Endoscopy (APSDE) clinical practice guidelines on the use of non-invasive biomarkers for diagnosis of colorectal neoplasia

Screening for colorectal cancer (CRC) is effective in reducing CRC related mortality. Current screening methods include endoscopy based and biomarker based approaches. This guideline is a joint official statement of the Asian Pacific Association of Gastroenterology (APAGE) and the Asian Pacific Society of Digestive Endoscopy (APSDE), developed in response to the increasing use of, and accumulating supportive evidence for the role of, non-invasive biomarkers for the diagnosis of CRC and its precursor lesions. A systematic review of 678 publications and a two stage Delphi consensus process involving 16 clinicians in various disciplines was undertaken to develop 32 evidence based and expert opinion based recommendations for the use of faecal immunochemical tests, faecal based tumour biomarkers or microbial biomarkers, and blood based tumour biomarkers for the detection of CRC and adenoma. Comprehensive up-to-date guidance is provided on indications, patient selection and strengths and limitations of each screening tool. Future research to inform clinical applications are discussed alongside objective measurement of research priorities. This joint APAGE-APSDE practice guideline is intended to provide an up-to-date guide to assist clinicians worldwide in utilising non-invasive biomarkers for CRC screening; it has particular salience for clinicians in the Asia-Pacific region.

Analysis of blood markers for early colorectal cancer diagnosis

BACKGROUND

Colorectal cancer (CRC) is a very common tumor worldwide. Its mortality can be limited by early diagnosis through screening programs. These programs are based on fecal occult blood testing and colonoscopy. Our objective was to find a model based on the determination of blood biomarkers that was efficacious enough to become part of the early diagnosis of CRC.

METHODS

In a total of 221 patients who underwent a colonoscopy, two types of markers were identified (I) classic: carcinoembryonic antigen (CEA), CA19.9, α-fetoprotein, CA125, CA72.4, and ferritin; and (II) experimental: neutrophil gelatinase-associated lipocalin (NGAL), estimated glomerular filtration rate (EGFR), 8-hydroxydeoxyguanosine (8OHdG), calprotectin, and cysteine-rich 61 (Cyr61). We divided the patients into four groups according to colonoscopy results: a control group (n=83) with normal colonoscopy, a polyp group (n=56), a CRC group (n=45), and an inflammatory disease group (n=37). We built an algorithm based on multivariate logistic regression analysis.

RESULTS

A total of 51.6% were males, and the median age was 63 years. We designed an algorithm based on the combination of several markers that discriminated CRC patients from the rest of the patients with a performance of 94%, a sensitivity of 95.6%, and a specificity of 80.6%. Discriminating by sex also resulted in two powerful algorithms, although it performed better in males (97% vs. 91%).

CONCLUSIONS

Our study has devised a predictive model with high efficacy based on the determination of several biomarkers. We think that it could be incorporated into the set of methods used in CRC screening.

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.

Designing optimal allocations for cancer screening using queuing network models

Cancer is one of the leading causes of death, but mortality can be reduced by detecting tumors earlier so that treatment is initiated at a less aggressive stage. The tradeoff between costs associated with screening and its benefit makes the decision of whom to screen and when a challenge. To enable comparisons across screening strategies for any cancer type, we demonstrate a mathematical modeling platform based on the theory of queuing networks designed for quantifying the benefits of screening strategies. Our methodology can be used to design optimal screening protocols and to estimate their benefits for specific patient populations. Our method is amenable to exact analysis, thus circumventing the need for simulations, and is capable of exactly quantifying outcomes given variability in the age of diagnosis, rate of progression, and screening sensitivity and intervention outcomes. We demonstrate the power of this methodology by applying it to data from the Surveillance, Epidemiology and End Results (SEER) program. Our approach estimates the benefits that various novel screening programs would confer to different patient populations, thus enabling us to formulate an optimal screening allocation and quantify its potential effects for any cancer type and intervention.

We describe a mathematical modeling methodology that offers quantitative insights into the potential benefits of screening and other interventions on cancer mortality. Our queuing-theoretic approach represents a potentially useful alternative to more traditional modeling approaches, in that it can provide more detailed results and entirely circumvents the need for simulations. Our methodology can be widely applied to estimate costs and benefits of screening strategies. By providing a detailed example of our method applied to epidemiological data, we hope to encourage greater uptake of this methodology in the community.

High Positive Predictive Value of Multitarget Stool DNA After Aerodigestive Tract Radiotherapy

BACKGROUND AND AIMS:

Multitarget stool DNA (mt-sDNA) is approved for average-risk colorectal cancer screening; test performance in persons with prior radiation therapy (RT) has not been studied. RT can induce gastrointestinal bleeding and alter DNA methylation, which may affect mt-sDNA accuracy. Among patients previously treated with RT, we aimed to measure the positive predictive value (PPV) of mt-sDNA and compare these results to historical estimates of mt-sDNA PPV among average-risk patients.

METHODS:

After institutional review board approval, we conducted a retrospective cohort study of a multisite academic and community-based practice. Patients with RT and subsequent mt-sDNA use during the study period (2014–2016) were identified. The findings at diagnostic colonoscopy were compared with published reports among average-risk patients. Nominal P values were generated by 2-tailed Fisher’s exact testing in comparisons of colorectal neoplasia (CRN) rates between groups.

RESULTS:

There were 220 patients who had RT before mt-sDNA testing. RT was delivered along the aerodigestive tract in 108 patients. Mt-sDNA tests were positive in 45 of 220 patients (20%), and colonoscopy findings were available for 42; 31 of 42 patients (74%) had CRN. PPV by mt-sDNA was similar when stratified by site of prior RT (along vs outside the aerodigestive tract; P = 1.00). Detection of advanced CRN (36%) was nominally higher than previously published retrospective (27%) and prospective (20%) studies. The median time from the start of RT to mt-sDNA use was 7 (interquartile range, 3–14) years.

CONCLUSION:

With a test positivity rate and PPV for CRN similar to reports among average-risk patients, prior RT does not appear to adversely affect mt-sDNA performance.

Beyond liquid biopsy: Toward non-invasive assays for distanced cancer diagnostics in pandemics

Liquid biopsy technologies have seen a significant improvement in the last decade, offering the possibility of reliable analysis and diagnosis from several biological fluids. The use of these technologies can overcome the limits of standard clinical methods, related to invasiveness and poor patient compliance. Along with this there are now mature examples of lab-on-chips (LOC) which are available and could be an emerging and breakthrough technology for the present and near-future clinical demands that provide sample treatment, reagent addition and analysis in a sample-in/answer-out approach. The possibility of combining non-invasive liquid biopsy and LOC technologies could greatly assist in the current need for minimizing exposure and transmission risks. The recent and ongoing pandemic outbreak of SARS-CoV-2, indeed, has heavily influenced all aspects of life worldwide. Ordinary tasks have been forced to switch from “in presence” to “distanced”, limiting the possibilities for a large number of activities in all fields of life outside of the home. Unfortunately, one of the settings in which physical distancing has assumed noteworthy consequences is the screening, diagnosis and follow-up of diseases.

In this review, we analyse biological fluids that are easily collected without the intervention of specialized personnel and the possibility that they may be used -or not-for innovative diagnostic assays. We consider their advantages and limitations, mainly due to stability and storage and their integration into Point-of-Care diagnostics, demonstrating that technologies in some cases are mature enough to meet current clinical needs.

Detection of Postcolonoscopy Colorectal Neoplasia by Multi-target Stool DNA

INTRODUCTION

Significant variability between colonoscopy operators contributes to postcolonoscopy colorectal cancers (CRCs). We aimed to estimate postcolonoscopy colorectal neoplasia (CRN) detection by multi-target stool DNA (mt-sDNA), which has not previously been studied for this purpose.

METHODS

In a retrospective cohort of patients with +mt-sDNA and completed follow-up colonoscopy, positive predictive value (PPV) for endpoints of any CRN, advanced adenoma, right-sided neoplasia, sessile serrated polyps (SSP), and CRC were stratified by the time since previous colonoscopy (0-9, 10, and ≥11 years). mt-sDNA PPV at ≤9 years from previous average-risk screening colonoscopy was used to estimate CRN missed at previous screening colonoscopy.

RESULTS

Among the 850 studied patients with +mt-sDNA after a previous negative screening colonoscopy, any CRN was found in 535 (PPV 63%). Among 107 average-risk patients having +mt-sDNA ≤9 years after last negative colonoscopy, any CRN was found in 67 (PPV 63%), advanced neoplasia in 16 (PPV 15%), right-sided CRN in 48 (PPV 46%), and SSP in 20 (PPV 19%). These rates were similar to those in 47 additional average risk persons with previous incomplete colonoscopy and in an additional 68 persons at increased CRC risk. One CRC (stage I) was found in an average risk patient who was mt-sDNA positive 6 years after negative screening colonoscopy.

DISCUSSION

The high PPV of mt-sDNA 0-9 years after a negative screening colonoscopy suggests that lesions were likely missed on previous examination or may have arisen de novo. mt-sDNA as an interval test after negative screening colonoscopy warrants further study.

Cost-Effectiveness of Multitarget Stool DNA Testing vs Colonoscopy or Fecal Immunochemical Testing for Colorectal Cancer Screening in Alaska Native People

OBJECTIVE

To estimate the cost-effectiveness of multitarget stool DNA testing (MT-sDNA) compared with colonoscopy and fecal immunochemical testing (FIT) for Alaska Native adults.

PATIENTS AND METHODS

A Markov model was used to evaluate the 3 screening test effects over 40 years. Outcomes included colorectal cancer (CRC) incidence and mortality, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). The study incorporated updated evidence on screening test performance and adherence and was conducted from December 15, 2016, through November 6, 2019.

RESULTS

With perfect adherence, CRC incidence was reduced by 52% (95% CI, 46% to 56%) using colonoscopy, 61% (95% CI, 57% to 64%) using annual FIT, and 66% (95% CI, 63% to 68%) using MT-sDNA. Compared with no screening, perfect adherence screening extends life by 0.15, 0.17, and 0.19 QALYs per person with colonoscopy, FIT, and MT-sDNA, respectively. Colonoscopy is the most expensive strategy: approximately $110 million more than MT-sDNA and $127 million more than FIT. With imperfect adherence (best case), MT-sDNA resulted in 0.12 QALYs per person vs 0.05 and 0.06 QALYs per person by FIT and colonoscopy, respectively. Probabilistic sensitivity analyses supported the base-case analysis. Under varied adherence scenarios, MT-sDNA either dominates or is cost-effective (ICERs, $1740-$75,868 per QALY saved) compared with FIT and colonoscopy.

CONCLUSION

Each strategy reduced costs and increased QALYs compared with no screening. Screening by MT-sDNA results in the largest QALY savings. In Markov model analysis, screening by MT-sDNA in the Alaska Native population was cost-effective compared with screening by colonoscopy and FIT for a wide range of adherence scenarios.

Sensitive detection of colorectal cancer in peripheral blood by a novel methylation assay

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Early detection of CRC can significantly reduce its mortality rate. Current method of CRC diagnosis relies on the invasive endoscopy. Non-invasive assays including fecal occult blood testing (FOBT) and fecal immunological test (FIT) are compromised by low sensitivity and specificity, especially at early stages. Thus, a non-invasive and accurate approach for CRC screening would be highly desirable.

RESULTS

A new qPCR-based assay combining the simultaneous detection of the DNA methylation status of ten candidate genes was used to examine plasma samples from 56 normal controls, 6 hyperplastic polys, 9 non-advanced adenomas (NAAs), 22 advanced adenomas (AAs) and 175 CRC patients, using 10 ng of cfDNA. We further built a logistic regression model for CRC diagnosis. We tested ten candidate methylation markers including twist1, vav3-as1, fbn1, c9orf50, sfmbt2, kcnq5, fam72c, itga4, kcnj12 and znf132. All markers showed moderate diagnostic performance with AUCs ranging from 0.726 to 0.815. Moreover, a 4-marker model, comprised of two previously reported markers (c9orf50 and twist1) and two novel ones (kcnj12 and znf132), demonstrated high performance for detecting colorectal cancer in an independent validation set (N = 69) with an overall AUC of 0.911 [95% confidence interval (CI) 0.834-0.988], sensitivity of 0.800 [95% CI 0.667-0.933] and specificity of 0.971 [95% CI 0.914-1.000]. The stage-stratified sensitivity of the model was 0.455 [95% CI 0.227-0.682], 0.667 [95% CI 0.289-1.000], 0.800 [95% CI 0.449-1.000], 0.800 [95% CI 0.449-1.000] and 0.842 [95% CI 0.678-1.000] for advanced adenoma and CRC stage I-IV, respectively.

CONCLUSION

kcnj12 and znf132 are two novel methylation biomarkers for CRC diagnosis. The 4-marker methylation model provides a new non-invasive choice for CRC screening and interception.

Specificity of the Multi-Target Stool DNA Test for Colorectal Cancer Screening in Average-Risk 45-49 Year-Olds: A Cross-Sectional Study

High-specificity colorectal cancer screening is desirable to triage patients <50 years for colonoscopy; however, most endorsed colorectal cancer screening tests have not been rigorously evaluated in younger populations. This prospective cross-sectional study determined the specificity of the multitarget stool DNA (mt-sDNA) test in an average-risk screening population of 45 to 49 year-olds. Specificity was the primary outcome and was measured in participants without colorectal cancer or advanced precancerous lesions [APL- advanced adenomas (AA), and sessile serrated lesions ≥10 mm], and in the subgroup of participants with negative colonoscopic findings. APL sensitivity was a secondary outcome. The evaluable cohort included those who completed the study without protocol deviations and had a usable mt-sDNA test. Of 983 enrolled participants, 816 formed the evaluable cohort, with a mean age of 47.8 (SD, 1.5) years; 47.7% were women. No participants had colorectal cancer, 49 had APL, 253 had nonadvanced adenomas (NAA), and 514 had negative colonoscopic findings. mt-sDNA test specificity was 95.2% (95% CI, 93.4-96.6) in participants with NAA or negative findings [96.3% (confidence interval (CI), 94.3%-97.8%)] in those with negative findings, and did not differ by sex (P = 0.75) or race (P = 0.36) in participants with NAA or negative findings. Sensitivity for APL was 32.7% (CI, 19.9-47.5%), with most APL (83.7%) measuring 10-19 mm and none having high-grade dysplasia. The area under the ROC curve for discriminating between APL and lesser findings was 0.72 (CI, 0.64-0.81). mt-sDNA's high specificity would help minimize risk from unnecessary diagnostic procedures in this age group. This study shows that mt-sDNA has high specificity among average-risk 45 to 49-year olds, supporting its use as a noninvasive option for colorectal cancer screening. PREVENTION RELEVANCE: This study shows that mt-sDNA has high specificity among average-risk 45-49 year olds, supporting its use as a non-invasive option for colorectal cancer screening.

Yellow-Gold Polarized Light Microscopy May Improve Accuracy of Pathological Staging of Colorectal Adenocarcinoma

Introduction Polarized light (PL) has been used in pathology for multiple reasons, including the demonstration of foreign bodies, the evaluation of crystals, and the demonstration of fibrosis. We incidentally found that yellow-gold polarization routinely occurs surrounding desmoplastic scar tissue abutting the invasive glands of colonic adenocarcinoma. We hypothesized that evaluating the use of polarized light over a series of invasive adenocarcinomas of the large intestine might produce evidence of its utility. Methods Large intestinal resections with invasive adenocarcinoma were reviewed with yellow-gold polarized light microscopy by two surgical pathologists postoperatively between January 2017 and March 2019. Specimens were examined under yellow-gold polarized light to evaluate invasion from the submucosa into the muscularis propria, from the muscularis propria into pericolic fat, and to the serosa. The diagnosed location, T stage, history of radiotherapy, mucinous features, and grade were recorded. Photographs were taken when images were deemed to be of value. The two-tailed Fisher's exact test was used to compare the invasion detection of the tumor into fat in scar tissue in colorectal cancer. Results A total of 75 large intestinal resections with invasive adenocarcinoma from 75 patients were accessioned. Concerning the initial stage, three (4%) were T1, nine (12%) were T2, 46 (61%) were T3, and 17 (22%) were T4. A history of previous radiation treatment was seen in 10 (13%). Two (2%) were poorly differentiated. Nine (12%) were mucinous carcinomas; mucinous areas were seen to pose difficulty in 12 (16%). Overall, one out of nine, initially staged as T2, was upstaged to T3 (11%), with the addition of yellow-gold polarized light microscopy. One tumor was downstaged from T2 to T1 (11%). For many T2 and T3 tumors, invasion into the muscularis propria was better defined by yellow-gold polarized light. Conclusion Yellow-gold polarized light microscopy may be a useful adjunct to conventional microscopy in more precisely staged pathological colorectal cancer specimens.

Stool-Based Tests for Colorectal Cancer Screening: Performance Benchmarks Lead to High Expected Efficacy

PURPOSE OF REVIEW

Participation goals for colorectal cancer (CRC) screening in the USA have not been met. Non-invasive screening strategies may improve CRC screening participation. We highlight recent literature on stool-based screening performance and expectations for emerging non-invasive screening tests.

RECENT FINDINGS

Stool-based CRC screening detects screen-relevant colorectal neoplasia and outperforms a currently available plasma assay. Though modestly sensitive for CRC, adherence to annual fecal immunochemical testing (FIT) is sub-optimal. Multi-target stool DNA (MT-sDNA) has greater adherence, superior sensitivity for screen-relevant lesions (including those in the proximal colon and sessile serrated architecture), and equivalent specificity to FIT over a 3-year period. Stool-based CRC screening tests are anticipated to reduce the incidence and mortality of CRC through detection of early-stage cancers and high-risk polyps. These endpoints in performance will need to be met by emerging blood sample-based tests in order have meaningful impact in clinical practice.

Analysis of the effectiveness of two noninvasive fecal tests used to screen for colorectal cancer in average-risk adults

OBJECTIVES

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Although a significant proportion of CRC cases and deaths are preventable by screening, the morbidity and mortality from CRC remains high and is attributed to suboptimal screening rates. Low levels of population CRC screening uptake may be due to reluctance toward invasiveness of some screening tests, embarrassment, exposure to anesthesia, and grueling preparation, especially for the invasive screening tests. Noninvasive tests overcome many of these barriers because they are more convenient and potentially more attractive to patients compared to invasive tests. This study uses Markov cohort simulation model developed with the help of TreeAge pro software to compare two noninvasive fecal CRC screens, fecal immunohistochemical test (FIT) and multitarget stool DNA test (Mt-sDNA) with no screening in order to identify the more effective noninvasive fecal test to screen for colorectal cancer in average-risk adults.

STUDY DESIGN

Simulation study developed with Markov model using TreeAge pro software, which included a hypothetical cohort at the average risk of developing colorectal cancer.

METHODS

Markov model was used to compare population-level CRC-related cases and deaths averted, life-years gained (LYG), and colonoscopies required for two noninvasive CRC screening strategies compared with no screening: annual fecal immunohistochemical testing (FIT) and 3-yearly multitarget stool DNA testing (Mt-sDNA). The model simulated the natural history of the adenoma-carcinoma sequence in average-risk persons starting at age 50 years, and natural history parameters were estimated from the literature and via verification to data on precancerous lesions (i.e. adenomas) and CRC incidence. Screening strategies were then superimposed on the natural history component of the model, allowing for precancerous lesions to be detected and removed, or CRC to be detected and treated at a potentially earlier stage. The sensitivity and specificity for each screen for precancerous lesions and CRC were the performance parameters used to estimate the effectiveness.

RESULTS

Annual FIT was more effective than three yearly Mt-sDNA in reducing CRC cases, averting CRC-related deaths, and increasing the LYG compared to no screening. On average, annual FIT resulted in 3.5 fewer CRC cases, and 2.9 fewer CRC deaths per 1000 persons screened compared to 3-yearly Mt-sDNA. Annual FIT usage resulted in a 0.18 LYG compared to Mt-sDNA, which allowed 0.16 LYG, and an annual FIT screening led to a total of 203 more colonoscopies performed compared to Mt-sDNA. One-way sensitivity analysis conducted over the sensitivity rates of each screen by type of lesion showed that FIT remained the more effective strategy for all ranges of sensitivity. Threshold analysis results identified the lowest FIT sensitivity value at which Mt-sDNA performed better for conventional high-risk adenomas and CRC detection to be 0.16 and 0.052, respectively.

CONCLUSION

Both the noninvasive screens were effective compared to no screening. Additionally, annual FIT as a first step noninvasive screening test for CRC appears to be more effective compared to three-yearly Mt-sDNA.

Cost-Effectiveness of Cancer Screening: Health and Costs in Life Years Gained

INTRODUCTION

Studies reporting on the cost-effectiveness of cancer screening usually account for quality of life losses and healthcare costs owing to cancer but do not account for future costs and quality of life losses related to competing risks. This study aims to demonstrate the impact of medical costs and quality of life losses of other diseases in the life years gained on the cost-effectiveness of U.S. cancer screening.

METHODS

Cost-effectiveness studies of breast, cervical, and colorectal cancer screening in the U.S. were identified using a systematic literature review. Incremental cost-effectiveness ratios of the eligible articles were updated by adding lifetime expenditures and health losses per quality-adjusted life year gained because of competing risks. This was accomplished using data on medical spending and quality of life by age and disease from the Medical Expenditure Panel Survey (2011-2015) combined with cause-deleted life tables. The study was conducted in 2018.

RESULTS

The impact of quality of life losses and healthcare expenditures of competing risks in life years gained incurred owing to screening were the highest for breast cancer and the lowest for cervical cancer. The updates suggest that incremental cost-effectiveness ratios are underestimated by $10,300-$13,700 per quality-adjusted life year gained if quality of life losses and healthcare expenditures of competing risks are omitted in economic evaluations. Furthermore, cancer screening programs that were considered cost saving, were found not to be so following the inclusion of medical expenditures of competing risks.

CONCLUSIONS

Practical difficulties in quantifying quality of life losses and healthcare expenditures owing to competing risks in life years gained can be overcome. Their inclusion can have a substantial impact on the cost-effectiveness of cancer screening programs.

Fecal DNA Testing for Colorectal Cancer Screening

Fecal (or stool) DNA examination is a noninvasive strategy recommended by several medical professional societies for colorectal cancer (CRC) screening in average-risk individuals. Fecal DNA tests assay stool for human DNA shed principally from the colon. Colonic lesions such as adenomatous and serrated polyps and cancers exfoliate cells containing neoplastically altered DNA that may be detected by sensitive assays that target specific genetic and epigenetic biomarkers to discriminate neoplastic lesions from non-neoplastic tissue. Cross-sectional validation studies confirmed initial case-control studies' assessment of performance of an optimized multitarget stool DNA (mt-sDNA) test, leading to approval by the US Food and Drug Administration in 2014. Compared to colonoscopy, mt-sDNA showed sensitivity of 92% for detection of CRC, much higher than the 74% sensitivity of another recommended noninvasive strategy, fecal immunochemical testing (FIT). Detections of advanced adenomas and sessile serrated polyps were higher with mt-sDNA than FIT (42% versus 24% and 42% versus 5%, respectively), but overall specificity for all lesions was lower (87% versus 95%). The mt-sDNA test increases patient life-years gained in CRC screening simulations, but its cost relative to other screening strategies needs to be reduced by 80-90% or its sensitivity for polyp detection enhanced to be cost effective. Noninvasive CRC screening strategies such as fecal DNA, however, have the potential to significantly increase national screening rates due to their noninvasive nature and convenience for patients.

Diagnostic Performance of Intestinal Fusobacterium nucleatum in Colorectal Cancer: A Meta-Analysis

Background:

Increasing evidence has supported the link of intestinal Fusobacterium nucleatum infection to colorectal cancer (CRC). However, the value of F. nucleatum as a biomarker in CRC detection has not been fully defined. In order to reduce the random error and bias of individual research, this meta-analysis aimed to evaluate the diagnostic performance of intestinal F. nucleatum in CRC patients and provide evidence-based data to clinical practice.

Methods:

An article search was performed from PubMed, Embase, Cochrane Library, and Web of Science databases up to December 2017, using the following key words: “Fusobacterium nucleatum”, ”Fusobacterium spp.”, ”Fn”, “colorectal cancer(s)”, “colorectal carcinoma(s)”, “colorectal neoplasm(s)”, and “colorectal tumor(s)”. Articles on relationships between F. nucleatum and CRC were selected according to the preestablished inclusion and exclusion criteria. This meta-analysis was performed using STATA 12.0 software, which included mapping of forest plots, heterogeneity tests, meta-regression, subgroup analysis, sensitivity analysis, and publication bias. The sensitivity, specificity, positive likelihood ratio (LR), negative LR, diagnostic odds ratio (DOR), and their corresponding 95% confidence interval (CI) of each eligible study were summarized.

Results:

Finally, data for 1198 participants (629 CRC and 569 healthy controls) in 10 controlled studies from seven articles were included. The summary receiver operator characteristic curve was mapped. The diagnostic performance of intestinal F. nucleatum infection on CRC was as follows: the area under the curve: 0.86 (95% CI: 0.83–0.89), the pooled sensitivity: 0.81 (95% CI: 0.64–0.91), specificity: 0.77 (95% CI: 0.59–0.89), and DOR: 14.00 (95% CI: 9.00–22.00).

Conclusion:

Intestinal F. nucleatum is a valuable marker for CRC diagnosis.

Colorectal cancer development and advances in screening

Most colon tumors develop via a multistep process involving a series of histological, morphological, and genetic changes that accumulate over time. This has allowed for screening and detection of early-stage precancerous polyps before they become cancerous in individuals at average risk for colorectal cancer (CRC), which may lead to substantial decreases in the incidence of CRC. Despite the known benefits of early screening, CRC remains the second leading cause of cancer-related deaths in the United States. Hence, it is important for health care providers to have an understanding of the risk factors for CRC and various stages of disease development in order to recommend appropriate screening strategies. This article provides an overview of the histological/molecular changes that characterize the development of CRC. It describes the available CRC screening methods and their advantages and limitations and highlights the stages of CRC development in which each screening method is most effective.

Multi-Target Stool DNA Test: Is the Future Here?

Colorectal cancer (CRC) screening reduces CRC incidence and mortality and is widely recommended. However, despite these demonstrated benefits, a large percentage of the population remains unscreened. The multi-target stool DNA (MT-sDNA) test is a new, non-invasive option for CRC screening that has a high accuracy rate in detection of colorectal neoplasia and offers great opportunity to enhance screening uptake. This review provides the current state of the art knowledge about the use of MT-sDNA in CRC screening.

Multitarget stool DNA for colorectal cancer screening: A review and commentary on the United States Preventive Services Draft Guidelines

Multitarget stool DNA (mt-sDNA) testing was approved for average risk colorectal cancer (CRC) screening by the United States Food and Drug Administration and thereafter reimbursed for use by the Medicare program (2014). The United States Preventive Services Task Force (USPSTF) October 2015 draft recommendation for CRC screening included mt-sDNA as an “alternative” screening test that “may be useful in select clinical circumstances”, despite its very high sensitivity for early stage CRC. The evidence supporting mt-sDNA for routine screening use is robust. The clinical efficacy of mt-sDNA as measured by sensitivity, specificity, life-years gained (LYG), and CRC deaths averted is similar to or exceeds that of the other more specifically recommended screening options included in the draft document, especially those requiring annual testing adherence. In a population with primarily irregular screening participation, tests with the highest point sensitivity and reasonable specificity are more likely to favorably impact CRC related morbidity and mortality than those depending on annual adherence. This paper reviews the evidence supporting mt-sDNA for routine screening and demonstrates, using USPSTF’s modeling data, that mt-sDNA at three-year intervals provides significant clinical net benefits and fewer complications per LYG than annual fecal immunochemical testing, high sensitivity guaiac based fecal occult blood testing and 10-year colonoscopy screening.