Patient Navigation Plus Tailored Digital Video Disc Increases Colorectal Cancer Screening Among Low-Income and Minority Patients Who Did Not Attend a Scheduled Screening Colonoscopy: A Randomized Trial.

BACKGROUND: Up to 50% of people scheduled for screening colonoscopy do not complete this test and no studies have focused on minority and low-income populations. Interventions are needed to improve colorectal cancer (CRC) screening knowledge, reduce barriers, and provide alternative screening options. Patient navigation (PN) and tailored interventions increase CRC screening uptake, however there is limited information comparing their effectiveness or the effect of combining them. PURPOSE: Compare the effectiveness of two interventions to increase CRC screening among minority and low-income individuals who did not attend their screening colonoscopy appointment-a mailed tailored digital video disc (DVD) alone versus the mailed DVD plus telephone-based PN compared to usual care. METHODS: Patients (n = 371) aged 45-75 years at average risk for CRC who did not attend a screening colonoscopy appointment were enrolled and were randomized to: (i) a mailed tailored DVD; (ii) the mailed DVD plus phone-based PN; or (iii) usual care. CRC screening outcomes were from electronic medical records at 12 months. Multivariable logistic regression analyses were used to study intervention effects. RESULTS: Participants randomized to tailored DVD plus PN were four times more likely to complete CRC screening compared to usual care and almost two and a half times more likely than those who were sent the DVD alone. CONCLUSIONS: Combining telephone-based PN with a mailed, tailored DVD increased CRC screening among low-income and minority patients who did not attend their screening colonoscopy appointments and has potential for wide dissemination.

Up to half of people scheduled for a screening colonoscopy do not complete this test. There is a need for interventions to improve knowledge about colorectal cancer (CRC) screening, enhance access to screening by offering alternative test options, foster skills for completing screening, and mitigate barriers. The purpose of this study was to compare the effects of two interventions aimed at increasing CRC screening­a mailed tailored digital video disc (DVD) alone versus the mailed DVD plus telephone-based patient navigation (PN)­for patients who had not completed a scheduled screening colonoscopy. We enrolled 371 patients aged 45­75 years who had no CRC risk factors other than age, who were scheduled for a screening colonoscopy but did not attend their appointment. Participants were randomized to receive either: (i) a mailed tailored DVD; (ii) the mailed DVD plus phone-based PN; or (iii) usual care. Those who received the tailored DVD plus PN were four times more likely to complete CRC screening with stool test or colonoscopy compared to usual care. Combining telephone-based PN with a mailed, tailored DVD increased CRC screening among low-income and minority patients who did not attend a scheduled screening colonoscopy appointment.

Next-Generation Multitarget Stool DNA Test for Colorectal Cancer Screening.

BACKGROUND: A next-generation multitarget stool DNA test, including assessments of DNA molecular markers and hemoglobin level, was developed to improve the performance of colorectal cancer screening, primarily with regard to specificity. METHODS: In a prospective study, we evaluated a next-generation multitarget stool DNA test in asymptomatic adults 40 years of age or older who were undergoing screening colonoscopy. The primary outcomes were sensitivity of the test for colorectal cancer and specificity for advanced neoplasia (colorectal cancer or advanced precancerous lesions). Advanced precancerous lesions included one or more adenomas or sessile serrated lesions measuring at least 1 cm in the longest dimension, lesions with villous histologic features, and high-grade dysplasia. Secondary objectives included the quantification of sensitivity for advanced precancerous lesions and specificity for nonneoplastic findings or negative colonoscopy and comparison of sensitivities for colorectal cancer and advanced precancerous lesions between the multitarget stool DNA test and a commercially available fecal immunochemical test (FIT). RESULTS: Of 20,176 participants, 98 had colorectal cancer, 2144 had advanced precancerous lesions, 6973 had nonadvanced adenomas, and 10,961 had nonneoplastic findings or negative colonoscopy. With the next-generation test, sensitivity for colorectal cancer was 93.9% (95% confidence interval [CI], 87.1 to 97.7), and specificity for advanced neoplasia was 90.6% (95% CI, 90.1 to 91.0). Sensitivity for advanced precancerous lesions was 43.4% (95% CI, 41.3 to 45.6), and specificity for nonneoplastic findings or negative colonoscopy was 92.7% (95% CI, 92.2 to 93.1). With the FIT, sensitivity was 67.3% (95% CI, 57.1 to 76.5) for colorectal cancer and 23.3% (95% CI, 21.5 to 25.2) for advanced precancerous lesions; specificity was 94.8% (95% CI, 94.4 to 95.1) for advanced neoplasia and 95.7% (95% CI, 95.3 to 96.1) for nonneoplastic findings or negative colonoscopy. As compared with FIT, the next-generation test had superior sensitivity for colorectal cancer (P<0.001) and for advanced precancerous lesions (P<0.001) but had lower specificity for advanced neoplasia (P<0.001). No adverse events occurred. CONCLUSIONS: The next-generation multitarget stool DNA test showed higher sensitivity for colorectal cancer and advanced precancerous lesions than FIT but also showed lower specificity. (Funded by Exact Sciences; BLUE-C ClinicalTrials.gov number, NCT04144738.).

Colorectal Cancer Screening Programs in Latin America: A Systematic Review and Meta-Analysis.

Importance: Colorectal cancer (CRC) is a leading cause of cancer-related mortality globally, with increasing incidence and mortality in Latin America. CRC screening programs can reduce disease burden, but information on screening programs in Latin America is limited. Objective: To describe characteristics (eg, type of program, uptake, neoplastic yield) of CRC screening programs in Latin America. Data Sources: PubMed, Ovid MEDLINE, EMBASE, Cochrane, PsycINFO, Web of Science Core Collection, LILACS, and SciELO were searched from inception to February 2023. Relevant references from bibliographies, conference proceedings, and gray literature were considered. The search strategy included English, Spanish, and Portuguese terms. Study Selection: Included were studies of CRC screening programs in Latin America using fecal immunochemical test (FIT) or colonoscopy as the primary screening method. Four reviewers independently assessed study eligibility based on titles, with review of abstracts and full texts as needed. Data Extraction and Synthesis: Guidelines from Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed for data abstraction and quality assessment. Descriptive information was extracted, and data were pooled using a random-effects model. Main outcomes and Measures: Program performance indicators included rates of participation and FIT positivity, adenoma detection rate (ADR), advanced adenoma detection rate (AADR), CRC detection rate, and colonoscopy quality indicators. Results: There were 17 studies included from upper middle-income and high-income countries in Latin America with a total of 123 929 participants. Thirteen studies used FIT as the initial screening method, whereas 4 used screening colonoscopy. The participation rate in FIT-based programs was 85.8% (95% CI, 78.5%-91.4%). FIT positivity rates were 15.2% (95% CI, 9.6%-21.8%) for the 50-ng/mL threshold and 9.7% (95% CI, 6.8%-13.0%) for the 100-ng/mL threshold. For FIT-based studies, the pooled ADR was 39.0% (95% CI, 29.3%-49.2%) and CRC detection rate was 4.9% (95% CI, 2.6%-7.9%); for screening colonoscopy-based studies, the pooled ADR was 19.9% (95% CI, 15.5%-24.8%) and CRC detection rate was 0.4% (95% CI, 0.1%-0.8%). Conclusions and Relevance: This systematic review and meta-analysis suggests that CRC screening in upper middle-income countries in Latin America is feasible, detecting rates of neoplasia comparable with those of high-income regions. Population-based screening programs should be developed or enhanced in these settings. There is a knowledge gap regarding feasibility and yield of screening programs in lower middle-income countries.

CRC screening with sigmoidoscopy extends life by 110 d; other cancer screening tests do not extend life.

SOURCE CITATION: Bretthauer M, Wieszczy P, Løberg M, et al. Estimated lifetime gained with cancer screening tests: a meta-analysis of randomized clinical trials. JAMA Intern Med. 2023;183:1196-1203. 37639247.

Stool-Based Colorectal Cancer Screening Test Performance Characteristics in Those With and Without Hemorrhoids.

Objective: To evaluate the effect of hemorrhoids on noninvasive stool test performance for colorectal cancer (CRC) screening. Patients and Methods: We conducted a retrospective cohort study of test characteristics for the fecal immunochemical test (FIT) and the multitarget stool DNA (mt-sDNA) test, on the basis of hemorrhoid status, recorded at the time of colonoscopy, among patients enrolled in the pivotal prospective study for mt-sDNA that was conducted from June 2011, to May 2013. Test characteristics (sensitivity, specificity, positive, and negative predictive values) for FIT and mt-sDNA (performed < 90 days before colonoscopy) were stratified by the presence of hemorrhoids and compared. Results: Hemorrhoids were found in 51.7% (5163 of 9989) of the study cohort. Across all test characteristics, there were no statistically significant differences for FIT or mt-sDNA when stratified by hemorrhoid status. Analysis revealed mt-sDNA sensitivity of 44% and 41% for advanced precancerous lesions in nonhemorrhoidal and hemorrhoid patients, respectively (P=.41). The FIT sensitivity among the same lesion category was 24.9% in patients without hemorrhoids and 22.8% in those with hemorrhoids (P=.48). The mt-sDNA specificity was 86.4% in patients without hemorrhoids vs 87.7% in those with hemorrhoids (P=.67), although FIT specificity was 95.0% among patients without hemorrhoids vs 94.7% in those with hemorrhoids (P=.44). Conclusion: The presence of asymptomatic hemorrhoids did not adversely affect test performance in this large clinical study. These findings suggest that in the absence of overt gastrointestinal bleeding, FIT and mt-sDNA are options for CRC screening, irrespective of hemorrhoid status. Trial Registration: clinicaltrials.gov Identifier: NCT01397747.

Baseline Features and Reasons for Nonparticipation in the Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) Study, a Colorectal Cancer Screening Trial.

Importance: The Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) randomized clinical trial sought to recruit 50 000 adults into a study comparing colorectal cancer (CRC) mortality outcomes after randomization to either an annual fecal immunochemical test (FIT) or colonoscopy. Objective: To (1) describe study participant characteristics and (2) examine who declined participation because of a preference for colonoscopy or stool testing (ie, fecal occult blood test [FOBT]/FIT) and assess that preference's association with geographic and temporal factors. Design, Setting, and Participants: This cross-sectional study within CONFIRM, which completed enrollment through 46 Department of Veterans Affairs medical centers between May 22, 2012, and December 1, 2017, with follow-up planned through 2028, comprised veterans aged 50 to 75 years with an average CRC risk and due for screening. Data were analyzed between March 7 and December 5, 2022. Exposure: Case report forms were used to capture enrolled participant data and reasons for declining participation among otherwise eligible individuals. Main Outcomes and Measures: Descriptive statistics were used to characterize the cohort overall and by intervention. Among individuals declining participation, logistic regression was used to compare preference for FOBT/FIT or colonoscopy by recruitment region and year. Results: A total of 50 126 participants were recruited (mean [SD] age, 59.1 [6.9] years; 46 618 [93.0%] male and 3508 [7.0%] female). The cohort was racially and ethnically diverse, with 748 (1.5%) identifying as Asian, 12 021 (24.0%) as Black, 415 (0.8%) as Native American or Alaska Native, 34 629 (69.1%) as White, and 1877 (3.7%) as other race, including multiracial; and 5734 (11.4%) as having Hispanic ethnicity. Of the 11 109 eligible individuals who declined participation (18.0%), 4824 (43.4%) declined due to a stated preference for a specific screening test, with FOBT/FIT being the most preferred method (2820 [58.5%]) vs colonoscopy (1958 [40.6%]; P < .001) or other screening tests (46 [1.0%] P < .001). Preference for FOBT/FIT was strongest in the West (963 of 1472 [65.4%]) and modest elsewhere, ranging from 199 of 371 (53.6%) in the Northeast to 884 of 1543 (57.3%) in the Midwest (P = .001). Adjusting for region, the preference for FOBT/FIT increased by 19% per recruitment year (odds ratio, 1.19; 95% CI, 1.14-1.25). Conclusions and Relevance: In this cross-sectional analysis of veterans choosing nonenrollment in the CONFIRM study, those who declined participation more often preferred FOBT or FIT over colonoscopy. This preference increased over time and was strongest in the western US and may provide insight into trends in CRC screening preferences.

Mortality After Postcolonoscopy Colorectal Cancer in the Veterans Affairs Health Care System.

Importance: Postcolonoscopy colorectal cancer (PCCRC) refers to colorectal cancer (CRC) diagnosed after a colonoscopy in which no cancer was found and is reflective of colonoscopy quality at the individual and system levels. Colonoscopy is widely performed in the Veterans Affairs (VA) health care system, but the prevalence of PCCRC and its associated mortality are unknown. Objective: To examine PCCRC prevalence and its all-cause mortality (ACM) and CRC-specific mortality (CSM) within the VA health care system. Design, Setting, and Participants: This retrospective cohort study used VA-Medicare administrative data to identify 29 877 veterans aged 50 to 85 years with newly diagnosed CRC between January 1, 2003, and December 31, 2013. Patients whose colonoscopy occurred less than 6 months before CRC diagnosis with no other colonoscopy within the previous 36 months were categorized as having detected CRC (DCRC). Those who had a colonoscopy that did not detect CRC between 6 and 36 months before CRC diagnosis were categorized as having postcolonoscopy CRC (PCCRC-3y). A third group included patients with CRC and no colonoscopy within the prior 36 months. The final analysis of the data was performed in September 2022. Exposures: Prior receipt of colonoscopy. Main Outcomes and Measures: Cox proportional hazards regression (with censoring, last follow-up December 31, 2018) analyses were conducted to compare PCCRC-3y and DCRC for 5-year ACM and CSM after CRC diagnosis. Results: Of 29 877 patients with CRC (median [IQR] age, 67 [60-75] years; 29 353 [98%] male; 5284 [18%] Black, 23 971 [80%] White, and 622 [2%] other), 1785 (6%) were classified as having PCCRC-3y and 21 811 (73%) as having DCRC. The 5-year ACM rates were 46% vs 42% for patients with PCCRC-3y vs patients with DCRC. The 5-year CSM rates were 26% vs 25% for patients with PCCRC-3y vs patients with DCRC. In multivariable Cox proportional hazards regression analysis, there was no significant difference in ACM and CSM between patients with PCCRC-3y (adjusted hazard ratio [aHR], 1.04; 95% CI, 0.98-1.11; P = .18) and patients with DCRC (aHR, 1.04; 95% CI, 0.95-1.13; P = .42). However, compared with patients with DCRC, patients with no prior colonoscopy had significantly higher ACM (aHR, 1.76; 95% CI, 1.70-1.82; P < .001) and CSM (aHR, 2.22; 95% CI, 2.12-2.32; P < .001). Compared with patients with DCRC, patients with PCCRC-3y had significantly lower odds of having undergone colonoscopy performed by a gastroenterologist (odds ratio, 0.48; 95% CI, 0.43-0.53; P < .001). Conclusions and Relevance: This study found that PCCRC-3y constituted 6% of CRCs in the VA system, which is similar to other settings. Compared with patients with CRC detected by colonoscopy, those with PCCRC-3y have comparable ACM and CSM.

Risk Factors for Early-onset Sporadic Colorectal Cancer in Male Veterans.

Identifying risk factors for early-onset colorectal cancer (EOCRC) could help reverse its rising incidence through risk factor reduction and/or early screening. We sought to identify EOCRC risk factors that could be used for decisions about early screening. Using electronic databases and medical record review, we compared male veterans ages 35 to 49 years diagnosed with sporadic EOCRC (2008-2015) matched 1:4 to clinic and colonoscopy controls without colorectal cancer, excluding those with established inflammatory bowel disease, high-risk polyposis, and nonpolyposis syndromes, prior bowel resection, and high-risk family history. We ascertained sociodemographic and lifestyle factors, family and personal medical history, physical measures, vital signs, medications, and laboratory values 6 to 18 months prior to case diagnosis. In the derivation cohort (75% of the total sample), univariate and multivariate logistic regression models were used to derive a full model and a more parsimonious model. Both models were tested using a validation cohort. Among 600 cases of sporadic EOCRC [mean (SD) age 45.2 (3.5) years; 66% White], 1,200 primary care clinic controls [43.4 (4.2) years; 68% White], and 1,200 colonoscopy controls [44.7 (3.8) years; 63% White], independent risk factors included age, cohabitation and employment status, body mass index (BMI), comorbidity, colorectal cancer, or other visceral cancer in a first- or second-degree relative (FDR or SDR), alcohol use, exercise, hyperlipidemia, use of statins, NSAIDs, and multivitamins. Validation c-statistics were 0.75-0.76 for the full model and 0.74-0.75 for the parsimonious model, respectively. These independent risk factors for EOCRC may identify veterans for whom colorectal cancer screening prior to age 45 or 50 years should be considered. PREVENTION RELEVANCE: Screening 45- to 49-year-olds for colorectal cancer is relatively new with uncertain uptake thus far. Furthermore, half of EOCRC occurs in persons < 45 years old. Using risk factors may help 45- to 49-year-olds accept screening and may identify younger persons for whom earlier screening should be considered. See related Spotlight, p. 479.

In adults, sigmoidoscopy screening invitation reduced CRC incidence and related mortality at 15 y.

SOURCE CITATION: Juul FE, Cross AJ, Schoen RE, et al. 15-year benefits of sigmoidoscopy screening on colorectal cancer incidence and mortality: a pooled analysis of randomized trials. Ann Intern Med. 2022;175:1525-33. 36215714.

In adults, a single colonoscopy screening invitation vs. no invitation reduced CRC incidence at 10 y.

SOURCE CITATION: Bretthauer M, Løberg M, Wieszczy P, et al. Effect of colonoscopy screening on risks of colorectal cancer and related death. N Engl J Med. 2022;387:1547-56. 36214590.

The Prevalence, Humanistic Burden, and Health Care Impact of Irritable Bowel Syndrome Among United States Veterans.

BACKGROUND & AIMS: Irritable bowel syndrome (IBS) in veterans is understudied. This study sought to investigate (1) prevalence of IBS; (2) phenotypic, environmental, and psychosocial factors associated with IBS; and (3) associations of IBS with health-related quality of life and health care use. METHODS: From June 2018 to April 2020, we invited veterans to complete the Rome IV IBS questionnaire; Short Form-12; posttraumatic stress disorder (PTSD) checklist; Hospital Anxiety and Depression Scale; and questionnaires on general health, antibiotic use, infectious enteritis (IE), and health care use. RESULTS: Among 858 veteran respondents, 244 (28.4%) met Rome IV IBS criteria (47.5% IBS with diarrhea, 16.8% IBS with constipation, 33.6% mixed IBS). IBS was associated with greater anxiety and depression and lower quality of life (all P < .001). Provisional PTSD, IE, and bowel problems after antibiotics were more common in IBS (all P < .001) as were multiple doctor visits (P < .01) and hospitalizations (P = .04). Comparisons across non-IBS and IBS subgroups revealed overall associations of psychological comorbidities (P < .01), multiple doctor visits (P < .01), hospitalizations (P = .03), IE (P < .01), and bowel problems after IE (P = .03) or antibiotics (P < .01) with subgroup. Highest anxiety and depression scores, PTSD, multiple doctor visits, hospitalizations, and bowel problems after IE were observed in IBS with constipation. In adjusted analyses, IBS was associated (all P < .001) with anxiety (odds ratio [OR], 3.47), depression (OR, 2.88), lower quality of life, PTSD (OR, 3.09), IE (OR, 4.44), bowel problems after antibiotics (OR, 1.84), multiple doctor visits (OR, 2.08), and hospitalizations (OR, 1.78). CONCLUSIONS: IBS is prevalent among veterans and has a measurable impact on individuals and health care resources. Veterans with IBS may experience significant psychological impairment.

Using Online Colorectal Cancer Risk Calculators to Guide Screening Decision-Making.

BACKGROUND: Several online calculators estimate colorectal cancer risk, but their consistency is unknown. Our objectives were to quantify the variation in predicted risk and to determine which calculators are best used in the clinical setting. METHODS: We used the Google search engine to identify online colorectal cancer risk calculators and assessed the output of each for 3 hypothetical screening scenarios (low-, average-, and high-risk), varied by age (50, 62, 75 years), sex, and race (Black, White), with risk levels based on risk-appropriate values for variables in each model. Estimated risks for models within a given scenario were rated as consistent or inconsistent based on comparison with either the absolute magnitude of difference or average lifetime risk of colorectal cancer. Summary statistics for consistent and inconsistent estimates were compared using chi-square and Fisher's exact tests. RESULTS: We identified 5 online colorectal cancer risk calculators. Inconsistencies were found in none of 5-year, 19% of 10-year, and 81% of lifetime colorectal cancer risk estimate comparisons (P < .001). For a 50-year-old, 22% of risk estimate comparisons were inconsistent, vs 33% for a 62-year-old, and 36% for a 75-year-old (P = 0.14). CONCLUSIONS: Online colorectal cancer risk models are more consistent in predicting colorectal cancer risk for 5- and 10-year time frames compared with lifetime. For a US population, the National Cancer Institute's Colorectal Cancer Risk Assessment Tool is a rigorously developed calculator that can be used in the clinical setting to provide 5-year and lifetime risk estimates.

Three-Year Interval for the Multi-Target Stool DNA Test for Colorectal Cancer Screening: A Longitudinal Study.

Data supporting the clinical utility of multi-target stool DNA (mt-sDNA) at the guideline-recommended 3-year interval have not been reported.Between April 2015 and July 2016, candidates for colorectal cancer screening whose providers prescribed the mt-sDNA test were enrolled. Participants with a positive baseline test were recommended for colonoscopy and completed the study. Those with a negative baseline test were followed annually for 3 years. In year 3, the mt-sDNA test was repeated and colonoscopy was recommended independent of results. Data were analyzed using the Predictive Summary Index (PSI), a measure of the gain in certainty for dichotomous diagnostic tests (where a positive value indicates a net gain), and by comparing observed versus expected colorectal cancers and advanced precancerous lesions.Of 2,404 enrolled subjects, 2,044 (85%) had a valid baseline mt-sDNA result [284 (13.9%) positive and 1,760 (86.1%) negative]. Following participant attrition, the year 3 intention to screen cohort included 591 of 1,760 (33.6%) subjects with valid mt-sDNA and colonoscopy results, with no colorectal cancers and 63 advanced precancerous lesions [22 (34.9%) detected by mt-sDNA] and respective PSI values of 0% (P = 1) and 9.3% (P = 0.01). The observed 3-year colorectal cancer yield was lower than expected (one-sided P = 0.09), while that for advanced precancerous lesions was higher than expected (two-sided P = 0.009).Repeat mt-sDNA screening at a 3-year interval resulted in a statistically significant gain in detection of advanced precancerous lesions. Due to absence of year 3 colorectal cancers, the PSI estimate for colorectal cancer was underpowered and could not be reliably quantified. Larger studies are required to assess the colorectal cancer study findings. PREVENTION RELEVANCE: Understanding the 3-year yield of mt-sDNA for colorectal cancer and advanced precancerous polyps is required to ensure the clinical appropriateness of the 3-year interval and to optimize mt-sDNA's screening effectiveness.

Identification of colorectal cancer using structured and free text clinical data.

Colorectal cancer incidence has continually fallen among those 50 years old and over. However, the incidence has increased in those under 50. Even with the recent screening guidelines recommending that screening begins at age 45, nearly half of all early-onset colorectal cancer will be missed. Methods are needed to identify high-risk individuals in this age group for targeted screening. Colorectal cancer studies, as with other clinical studies, have required labor intensive chart review for the identification of those affected and risk factors. Natural language processing and machine learning can be used to automate the process and enable the screening of large numbers of patients. This study developed and compared four machine learning and statistical models: logistic regression, support vector machine, random forest, and deep neural network, in their performance in classifying colorectal cancer patients. Excellent classification performance is achieved with AUCs over 97%.

A two-phase approach to re-calibrating expensive computer simulation for sex-specific colorectal neoplasia development modeling.

BACKGROUND: Medical evidence from more recent observational studies may significantly alter our understanding of disease incidence and progression, and would require recalibration of existing computational and predictive disease models. However, it is often challenging to perform recalibration when there are a large number of model parameters to be estimated. Moreover, comparing the fitting performances of candidate parameter designs can be difficult due to significant variation in simulated outcomes under limited computational budget and long runtime, even for one simulation replication. METHODS: We developed a two-phase recalibration procedure. As a proof-of-the-concept study, we verified the procedure in the context of sex-specific colorectal neoplasia development. We considered two individual-based state-transition stochastic simulation models, estimating model parameters that govern colorectal adenoma occurrence and its growth through three preclinical states: non-advanced precancerous polyp, advanced precancerous polyp, and cancerous polyp. For the calibration, we used a weighted-sum-squared error between three prevalence values reported in the literature and the corresponding simulation outcomes. In phase 1 of the calibration procedure, we first extracted the baseline parameter design from relevant studies on the same model. We then performed sampling-based searches within a proper range around the baseline design to identify the initial set of good candidate designs. In phase 2, we performed local search (e.g., the Nelder-Mead algorithm), starting from the candidate designs identified at the end of phase 1. Further, we investigated the efficiency of exploring dimensions of the parameter space sequentially based on our prior knowledge of the system dynamics. RESULTS: The efficiency of our two-phase re-calibration procedure was first investigated with CMOST, a relatively inexpensive computational model. It was then further verified with the V/NCS model, which is much more expensive. Overall, our two-phase procedure showed a better goodness-of-fit than the straightforward employment of the Nelder-Mead algorithm, when only a limited number of simulation replications were allowed. In addition, in phase 2, performing local search along parameter space dimensions sequentially was more efficient than performing the search over all dimensions concurrently. CONCLUSION: The proposed two-phase re-calibration procedure is efficient at estimating parameters of computationally expensive stochastic dynamic disease models.

AGA White Paper: Challenges and Gaps in Innovation for the Performance of Colonoscopy for Screening and Surveillance of Colorectal Cancer.

In 2018, the American Gastroenterological Association's Center for GI Innovation and Technology convened a consensus conference, entitled "Colorectal Cancer Screening and Surveillance: Role of Emerging Technology and Innovation to Improve Outcomes." The conference participants, which included more than 60 experts in colorectal cancer, considered recent improvements in colorectal cancer screening rates and polyp detection, persistent barriers to colonoscopy uptake, and opportunities for performance improvement and innovation. This white paper originates from that conference. It aims to summarize current patient- and physician-centered gaps and challenges in colonoscopy, diagnostic and therapeutic challenges affecting colonoscopy uptake, and the potential use of emerging technologies and quality metrics to improve patient outcomes.