Emulator-Based Bayesian Calibration of the CISNET Colorectal Cancer Models.

PURPOSE: To calibrate Cancer Intervention and Surveillance Modeling Network (CISNET)'s SimCRC, MISCAN-Colon, and CRC-SPIN simulation models of the natural history colorectal cancer (CRC) with an emulator-based Bayesian algorithm and internally validate the model-predicted outcomes to calibration targets. METHODS: We used Latin hypercube sampling to sample up to 50,000 parameter sets for each CISNET-CRC model and generated the corresponding outputs. We trained multilayer perceptron artificial neural networks (ANNs) as emulators using the input and output samples for each CISNET-CRC model. We selected ANN structures with corresponding hyperparameters (i.e., number of hidden layers, nodes, activation functions, epochs, and optimizer) that minimize the predicted mean square error on the validation sample. We implemented the ANN emulators in a probabilistic programming language and calibrated the input parameters with Hamiltonian Monte Carlo-based algorithms to obtain the joint posterior distributions of the CISNET-CRC models' parameters. We internally validated each calibrated emulator by comparing the model-predicted posterior outputs against the calibration targets. RESULTS: The optimal ANN for SimCRC had 4 hidden layers and 360 hidden nodes, MISCAN-Colon had 4 hidden layers and 114 hidden nodes, and CRC-SPIN had 1 hidden layer and 140 hidden nodes. The total time for training and calibrating the emulators was 7.3, 4.0, and 0.66 h for SimCRC, MISCAN-Colon, and CRC-SPIN, respectively. The mean of the model-predicted outputs fell within the 95% confidence intervals of the calibration targets in 98 of 110 for SimCRC, 65 of 93 for MISCAN, and 31 of 41 targets for CRC-SPIN. CONCLUSIONS: Using ANN emulators is a practical solution to reduce the computational burden and complexity for Bayesian calibration of individual-level simulation models used for policy analysis, such as the CISNET CRC models. In this work, we present a step-by-step guide to constructing emulators for calibrating 3 realistic CRC individual-level models using a Bayesian approach. HIGHLIGHTS: We use artificial neural networks (ANNs) to build emulators that surrogate complex individual-based models to reduce the computational burden in the Bayesian calibration process.ANNs showed good performance in emulating the CISNET-CRC microsimulation models, despite having many input parameters and outputs.Using ANN emulators is a practical solution to reduce the computational burden and complexity for Bayesian calibration of individual-level simulation models used for policy analysis.This work aims to support health decision scientists who want to quantify the uncertainty of calibrated parameters of computationally intensive simulation models under a Bayesian framework.

Characteristics of a cost-effective blood test for colorectal cancer screening.

BACKGROUND: Blood-based biomarker tests can potentially change the landscape of colorectal cancer (CRC) screening. We characterize the conditions under which blood test screening would be as effective and cost-effective as annual fecal immunochemical testing (FIT) or decennial colonoscopy. METHODS: We used the three CISNET-Colon models to compare scenarios of no screening, annual FIT, decennial colonoscopy, and a blood test meeting CMS coverage criteria (74% CRC sensitivity and 90% specificity). We varied the sensitivity to detect CRC (74%-92%), advanced adenomas (AAs, 10%-50%), screening interval (1-3 years), and test cost ($25-$500). Primary outcomes included quality-adjusted life-years gained (QALYG) from screening and costs for an US average-risk 45-year-old cohort. RESULTS: Annual FIT yielded 125-163 QALYG per 1,000 at a cost of $3,811-5,384 per person, whereas colonoscopy yielded 132-177 QALYG at a cost of $5,375-7,031 per person. A blood test with 92% CRC sensitivity and 50% AA sensitivity yielded 117-162 QALYG if used every three years and 133-173 QALYG if used every year but would not be cost-effective if priced above $125 per test. If used every three years, a $500 blood test only meeting CMS coverage criteria yielded 83-116 QALYG, at a cost of $8,559-9,413 per person. CONCLUSION: Blood tests that only meet CMS coverage requirements should not be recommended to patients who would otherwise undergo screening by colonoscopy or FIT due to lower benefit. Blood tests need higher AA sensitivity (above 40%) and lower costs (below $125) to be cost-effective.

Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening With a Blood Test That Meets the Centers for Medicare & Medicaid Services Coverage Decision.

BACKGROUND & AIMS: A blood-based colorectal cancer (CRC) screening test may increase screening participation. However, blood tests may be less effective than current guideline-endorsed options. The Centers for Medicare & Medicaid Services (CMS) covers blood tests with sensitivity of at least 74% for detection of CRC and specificity of at least 90%. In this study, we investigate whether a blood test that meets these criteria is cost-effective. METHODS: Three microsimulation models for CRC (MISCAN-Colon, CRC-SPIN, and SimCRC) were used to estimate the effectiveness and cost-effectiveness of triennial blood-based screening (from ages 45 to 75 years) compared to no screening, annual fecal immunochemical testing (FIT), triennial stool DNA testing combined with an FIT assay, and colonoscopy screening every 10 years. The CMS coverage criteria were used as performance characteristics of the hypothetical blood test. We varied screening ages, test performance characteristics, and screening uptake in a sensitivity analysis. RESULTS: Without screening, the models predicted 77-88 CRC cases and 32-36 CRC deaths per 1000 individuals, costing $5.3-$5.8 million. Compared to no screening, blood-based screening was cost-effective, with an additional cost of $25,600-$43,700 per quality-adjusted life-year gained (QALYG). However, compared to FIT, triennial stool DNA testing combined with FIT, and colonoscopy, blood-based screening was not cost-effective, with both a decrease in QALYG and an increase in costs. FIT remained more effective (+5-24 QALYG) and less costly (-$3.2 to -$3.5 million) than blood-based screening even when uptake of blood-based screening was 20 percentage points higher than uptake of FIT. CONCLUSION: Even with higher screening uptake, triennial blood-based screening, with the CMS-specified minimum performance sensitivity of 74% and specificity of 90%, was not projected to be cost-effective compared with established strategies for colorectal cancer screening.

Emulator-based Bayesian calibration of the CISNET colorectal cancer models.

Purpose: To calibrate Cancer Intervention and Surveillance Modeling Network (CISNET) 's SimCRC, MISCAN-Colon, and CRC-SPIN simulation models of the natural history colorectal cancer (CRC) with an emulator-based Bayesian algorithm and internally validate the model-predicted outcomes to calibration targets. Methods: We used Latin hypercube sampling to sample up to 50,000 parameter sets for each CISNET-CRC model and generated the corresponding outputs. We trained multilayer perceptron artificial neural networks (ANN) as emulators using the input and output samples for each CISNET-CRC model. We selected ANN structures with corresponding hyperparameters (i.e., number of hidden layers, nodes, activation functions, epochs, and optimizer) that minimize the predicted mean square error on the validation sample. We implemented the ANN emulators in a probabilistic programming language and calibrated the input parameters with Hamiltonian Monte Carlo-based algorithms to obtain the joint posterior distributions of the CISNET-CRC models' parameters. We internally validated each calibrated emulator by comparing the model-predicted posterior outputs against the calibration targets. Results: The optimal ANN for SimCRC had four hidden layers and 360 hidden nodes, MISCAN-Colon had 4 hidden layers and 114 hidden nodes, and CRC-SPIN had one hidden layer and 140 hidden nodes. The total time for training and calibrating the emulators was 7.3, 4.0, and 0.66 hours for SimCRC, MISCAN-Colon, and CRC-SPIN, respectively. The mean of the model-predicted outputs fell within the 95% confidence intervals of the calibration targets in 98 of 110 for SimCRC, 65 of 93 for MISCAN, and 31 of 41 targets for CRC-SPIN. Conclusions: Using ANN emulators is a practical solution to reduce the computational burden and complexity for Bayesian calibration of individual-level simulation models used for policy analysis, like the CISNET CRC models. In this work, we present a step-by-step guide to constructing emulators for calibrating three realistic CRC individual-level models using a Bayesian approach.

Cost-Effectiveness Analysis of Screening for Pancreatic Cancer Among High-Risk Populations.

PURPOSE: We evaluated the potential cost-effectiveness of combined magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) screening for pancreatic ductal adenocarcinoma (PDAC) among populations at high risk for the disease. METHODS: We used a microsimulation model of the natural history of PDAC to estimate the lifetime health benefits, costs, and cost-effectiveness of PDAC screening among populations with specific genetic risk factors for PDAC, including BRCA1 and BRCA2, PALB2, ATM, Lynch syndrome, TP53, CDKN2A, and STK11. For each high-risk population, we simulated 29 screening strategies, defined by starting age and frequency. Screening included MRI with follow-up EUS in a subset of patients. Costs of tests were based on Medicare reimbursement for MRI, EUS, fine-needle aspiration biopsy, and pancreatectomy. Cancer-related cost by stage of disease and phase of treatment was based on the literature. For each high-risk population, we performed an incremental cost-effectiveness analysis, assuming a willingness-to-pay (WTP) threshold of $100,000 US dollars (USD) per quality-adjusted life year (QALY) gained. RESULTS: For men with relative risk (RR) 12.33 (CDKN2A) and RR 28 (STK11), annual screening was cost-effective, starting at age 55 and 40 years, respectively. For women, screening was only cost-effective for those with RR 28 (STK11), with annual screening starting at age 45 years. CONCLUSION: Combined MRI/EUS screening may be a cost-effective approach for the highest-risk populations (among mutations considered, those with RR >12). However, for those with moderate risk (RR, 5-12), screening would only be cost-effective at higher WTP thresholds (eg, $200K USD/QALY) or with once-only screening.

Estimated US Cancer Deaths Prevented With Increased Use of Lung, Colorectal, Breast, and Cervical Cancer Screening.

Importance: Increased use of recommended screening could help achieve the Cancer Moonshot goal of reducing US cancer deaths. Objective: To estimate the number of cancer deaths that could be prevented with a 10-percentage point increase in the use of US Preventive Services Task Force (USPSTF)-recommended screening. Design, Setting, and Participants: This decision analytical model study is an extension of previous studies conducted for the USPSTF from 2018 to 2023. This study simulated contemporary cohorts of US adults eligible for lung, colorectal, breast, and cervical cancer screening. Exposures: Annual low-dose computed lung tomography among eligible adults aged 50 to 80 years; colonoscopy every 10 years among adults aged 45 to 75 years; biennial mammography among female adults aged 40 to 74 years; and triennial cervical cytology screening among female adults aged 21 to 29 years, followed by human papillomavirus testing every 5 years from ages 30 to 65 years. Main Outcomes and Measures: Estimated number of cancer deaths prevented with a 10-percentage point increase in screening use, assuming screening commences at the USPSTF-recommended starting age and continues throughout the lifetime. Outcomes were presented 2 ways: (1) per 100 000 and (2) among US adults in 2021; and they were expressed among the target population at the age of screening initiation. For lung cancer, estimates were among those who will also meet the smoking eligibility criteria during their lifetime. Harms from increased uptake were also reported. Results: A 10-percentage point increase in screening use at the age that USPSTF recommended screening commences was estimated to prevent 226 lung cancer deaths (range across models within the cancer site, 133-332 deaths), 283 (range, 263-313) colorectal cancer deaths, 82 (range, 61-106) breast cancer deaths, and 81 (1 model; no range available) cervical cancer deaths over the lifetimes of 100 000 persons eligible for screening. These rates corresponded with an estimated 1010 (range, 590-1480) lung cancer deaths prevented, 11 070 (range, 10 280-12 250) colorectal cancer deaths prevented, 1790 (range, 1330-2310) breast cancer deaths prevented, and 1710 (no range available) cervical cancer deaths prevented over the lifetimes of eligible US residents at the recommended age to initiate screening in 2021. Increased uptake was also estimated to generate harms, including 100 000 (range, 45 000-159 000) false-positive lung scans, 6000 (range, 6000-7000) colonoscopy complications, 300 000 (range, 295 000-302 000) false-positive mammograms, and 348 000 (no range available) colposcopies over the lifetime. Conclusions and Relevance: In this decision analytical model study, a 10-percentage point increase in uptake of USPSTF-recommended lung, colorectal, breast, and cervical cancer screening at the recommended starting age was estimated to yield important reductions in cancer deaths. Achieving these reductions is predicated on ensuring equitable access to screening.

Ultrasound Surveillance of Small, Incidentally Detected Gallbladder Polyps: Projected Benefits by Sex, Age, and Comorbidity Level.

OBJECTIVE: Incidentally detected gallbladder polyps are commonly encountered when performing upper abdominal ultrasound. Our purpose was to estimate the life expectancy (LE) benefit of ultrasound-based gallbladder surveillance in patients with small (6-7 to <10 mm), incidentally detected gallbladder polyps, accounting for patient sex, age, and comorbidity level. METHODS: We developed a decision-analytic Markov model to evaluate hypothetical cohorts of women and men with small gallbladder polyps, with varying age (66-80 years) and comorbidity level (none, mild, moderate, severe). Drawing from current evidence, in the base case, we assumed no increased risk of gallbladder cancer in patients with small gallbladder polyps. To estimate maximal possible LE gains from surveillance, we assumed perfect cancer control consequent to 5 years of surveillance. We varied key assumptions including cancer risk and test performance characteristics in sensitivity analysis. RESULTS: Projected LE gains from surveillance were <3 days across most cohorts and scenarios evaluated. For 66- and 80-year-olds with no comorbidities, LE gains were 1.46 and 1.45 days, respectively, for women, and 0.67 and 0.75 days for men. With 10 years of surveillance, LE gains increased to 2.94 days for 66-year-old women with no comorbidities (men: 1.35 days). If we assumed a 10% increase in gallbladder cancer risk among individuals with polyps, LE gains increased slightly to 1.60 days for 66-year-old women with no comorbidities (men: 0.74 days). Results were sensitive to test performance and surgical mortality. DISCUSSION: Even under unrealistic, optimistic assumptions of cancer control, ultrasound surveillance of incidentally detected small gallbladder polyps provided limited benefit.

Estimated Reductions in Opioid Overdose Deaths With Sustainment of Public Health Interventions in 4 US States.

Importance: In 2021, more than 80 000 US residents died from an opioid overdose. Public health intervention initiatives, such as the Helping to End Addiction Long-term (HEALing) Communities Study (HCS), are being launched with the goal of reducing opioid-related overdose deaths (OODs). Objective: To estimate the change in the projected number of OODs under different scenarios of the duration of sustainment of interventions, compared with the status quo. Design, Setting, and Participants: This decision analytical model simulated the opioid epidemic in the 4 states participating in the HCS (ie, Kentucky, Massachusetts, New York, and Ohio) from 2020 to 2026. Participants were a simulated population transitioning from opioid misuse to opioid use disorder (OUD), overdose, treatment, and relapse. The model was calibrated using 2015 to 2020 data from the National Survey on Drug Use and Health, the US Centers for Disease Control and Prevention, and other sources for each state. The model accounts for reduced initiation of medications for OUD (MOUDs) and increased OODs during the COVID-19 pandemic. Exposure: Increasing MOUD initiation by 2- or 5-fold, improving MOUD retention to the rates achieved in clinical trial settings, increasing naloxone distribution efforts, and furthering safe opioid prescribing. An initial 2-year duration of interventions was simulated, with potential sustainment for up to 3 additional years. Main Outcomes and Measures: Projected reduction in number of OODs under different combinations and durations of sustainment of interventions. Results: Compared with the status quo, the estimated annual reduction in OODs at the end of the second year of interventions was 13% to 17% in Kentucky, 17% to 27% in Massachusetts, 15% to 22% in New York, and 15% to 22% in Ohio. Sustaining all interventions for an additional 3 years was estimated to reduce the annual number of OODs at the end of the fifth year by 18% to 27% in Kentucky, 28% to 46% in Massachusetts, 22% to 34% in New York, and 25% to 41% in Ohio. The longer the interventions were sustained, the better the outcomes; however, these positive gains would be washed out if interventions were not sustained. Conclusions and Relevance: In this decision analytical model study of the opioid epidemic in 4 US states, sustained implementation of interventions, including increased delivery of MOUDs and naloxone supply, was found to be needed to reduce OODs and prevent deaths from increasing again.

Randomized Trial of Facilitated Adherence to Screening Colonoscopy vs Sequential Fecal-Based Blood Test.

BACKGROUND & AIMS: Colorectal cancer (CRC) screening guidelines include screening colonoscopy and sequential high-sensitivity fecal occult blood testing (HSgFOBT), with expectation of similar effectiveness based on the assumption of similar high adherence. However, adherence to screening colonoscopy compared with sequential HSgFOBT has not been reported. In this randomized clinical trial, we assessed adherence and pathology findings for a single screening colonoscopy vs sequential and nonsequential HSgFOBTs. METHODS: Participants aged 40-69 years were enrolled at 3 centers representing different clinical settings. Participants were randomized into a single screening colonoscopy arm vs sequential HSgFOBT arm composed of 4-7 rounds. Initial adherence to screening colonoscopy and sequential adherence to HSgFOBT, follow-up colonoscopy for positive HSgFOBT tests, crossover to colonoscopy, and detection of advanced neoplasia or large serrated lesions (ADN-SERs) were measured. RESULTS: There were 3523 participants included in the trial; 1761 and 1762 participants were randomized to the screening colonoscopy and HSgFOBT arms, respectively. Adherence was 1473 (83.6%) for the screening colonoscopy arm vs 1288 (73.1%) for the HSgFOBT arm after 1 round (relative risk [RR], 1.14; 95% CI, 1.10-1.19; P ≤ .001), but only 674 (38.3%) over 4 sequential HSgFOBT rounds (RR, 2.19; 95% CI, 2.05-2.33). Overall adherence to any screening increased to 1558 (88.5%) in the screening colonoscopy arm during the entire study period and 1493 (84.7%) in the HSgFOBT arm (RR, 1.04; 95% CI, 1.02-1.07). Four hundred thirty-six participants (24.7%) crossed over to screening colonoscopy during the first 4 rounds. ADN-SERs were detected in 121 of the 1473 participants (8.2%) in the colonoscopy arm who were adherent to protocol in the first 12 months of the study, whereas detection of ADN-SERs among those who were not sequentially adherent (n = 709) to HSgFOBT was subpar (0.6%) (RR, 14.72; 95% CI, 5.46-39.67) compared with those who were sequentially adherent (3.3%) (n = 647) (RR, 2.52; 95% CI, 1.61-3.98) to HSgFOBT in the first 4 rounds. When including colonoscopies from HSgFOBT patients who were never positive yet crossed over (n = 1483), 5.5% of ADN-SERs were detected (RR, 1.50; 95% CI, 1.15-1.96) in the first 4 rounds. CONCLUSIONS: Observed adherence to sequential rounds of HSgFOBT was suboptimal compared with a single screening colonoscopy. Detection of ADN-SERs was inferior when nonsequential HSgFOBT adherence was compared with sequential adherence. However, the greatest number of ADN-SERs was detected among those who crossed over to colonoscopy and opted to receive a colonoscopy. The effectiveness of an HSgFOBT screening program may be enhanced if crossover to screening colonoscopy is permitted. CLINICALTRIALS: gov, Number: NCT00102011.

Characterization and Valuation of the Uncertainty of Calibrated Parameters in Microsimulation Decision Models.

Background: We evaluated the implications of different approaches to characterize the uncertainty of calibrated parameters of microsimulation decision models (DMs) and quantified the value of such uncertainty in decision making. Methods: We calibrated the natural history model of CRC to simulated epidemiological data with different degrees of uncertainty and obtained the joint posterior distribution of the parameters using a Bayesian approach. We conducted a probabilistic sensitivity analysis (PSA) on all the model parameters with different characterizations of the uncertainty of the calibrated parameters. We estimated the value of uncertainty of the various characterizations with a value of information analysis. We conducted all analyses using high-performance computing resources running the Extreme-scale Model Exploration with Swift (EMEWS) framework. Results: The posterior distribution had a high correlation among some parameters. The parameters of the Weibull hazard function for the age of onset of adenomas had the highest posterior correlation of -0.958. When comparing full posterior distributions and the maximum-a-posteriori estimate of the calibrated parameters, there is little difference in the spread of the distribution of the CEA outcomes with a similar expected value of perfect information (EVPI) of $653 and $685, respectively, at a willingness-to-pay (WTP) threshold of $66,000 per quality-adjusted life year (QALY). Ignoring correlation on the calibrated parameters' posterior distribution produced the broadest distribution of CEA outcomes and the highest EVPI of $809 at the same WTP threshold. Conclusion: Different characterizations of the uncertainty of calibrated parameters affect the expected value of eliminating parametric uncertainty on the CEA. Ignoring inherent correlation among calibrated parameters on a PSA overestimates the value of uncertainty.

Colorectal Cancer Screening: An Updated Modeling Study for the US Preventive Services Task Force.

Importance: The US Preventive Services Task Force (USPSTF) is updating its 2016 colorectal cancer screening recommendations. Objective: To provide updated model-based estimates of the benefits, burden, and harms of colorectal cancer screening strategies and to identify strategies that may provide an efficient balance of life-years gained (LYG) from screening and colonoscopy burden to inform the USPSTF. Design, Setting, and Participants: Comparative modeling study using 3 microsimulation models of colorectal cancer screening in a hypothetical cohort of 40-year-old US individuals at average risk of colorectal cancer. Exposures: Screening from ages 45, 50, or 55 years to ages 70, 75, 80, or 85 years with fecal immunochemical testing (FIT), multitarget stool DNA testing, flexible sigmoidoscopy alone or with FIT, computed tomography colonography, or colonoscopy. All persons with an abnormal noncolonoscopy screening test result were assumed to undergo follow-up colonoscopy. Screening intervals varied by test. Full adherence with all procedures was assumed. Main Outcome and Measures: Estimated LYG relative to no screening (benefit), lifetime number of colonoscopies (burden), number of complications from screening (harms), and balance of incremental burden and benefit (efficiency ratios). Efficient strategies were those estimated to require fewer additional colonoscopies per additional LYG relative to other strategies. Results: Estimated LYG from screening strategies ranged from 171 to 381 per 1000 40-year-olds. Lifetime colonoscopy burden ranged from 624 to 6817 per 1000 individuals, and screening complications ranged from 5 to 22 per 1000 individuals. Among the 49 strategies that were efficient options with all 3 models, 41 specified screening beginning at age 45. No single age to end screening was predominant among the efficient strategies, although the additional LYG from continuing screening after age 75 were generally small. With the exception of a 5-year interval for computed tomography colonography, no screening interval predominated among the efficient strategies for each modality. Among the strategies highlighted in the 2016 USPSTF recommendation, lowering the age to begin screening from 50 to 45 years was estimated to result in 22 to 27 additional LYG, 161 to 784 additional colonoscopies, and 0.1 to 2 additional complications per 1000 persons (ranges are across screening strategies, based on mean estimates across models). Assuming full adherence, screening outcomes and efficient strategies were similar by sex and race and across 3 scenarios for population risk of colorectal cancer. Conclusions and Relevance: This microsimulation modeling analysis suggests that screening for colorectal cancer with stool tests, endoscopic tests, or computed tomography colonography starting at age 45 years provides an efficient balance of colonoscopy burden and life-years gained.

Comparing the Cost-Effectiveness of Innovative Colorectal Cancer Screening Tests.

BACKGROUND: Colorectal cancer (CRC) screening with colonoscopy and the fecal immunochemical test (FIT) is underused. Innovative tests could increase screening acceptance. This study determined which of the available alternatives is most promising from a cost-effectiveness perspective. METHODS: The previously validated Microsimulation Screening Analysis-Colon model was used to evaluate the cost-effectiveness of screening with capsule endoscopy every 5 or 10 years, computed tomographic colonography every 5 years, the multi-target stool DNA test every 1 or 3 years, and the methylated SEPT9 DNA plasma assay (mSEPT9) every 1 or 2 years. We also compared these strategies with annual FIT screening and colonoscopy screening every 10 years. Quality-adjusted life-years gained (QALYG), number of colonoscopies, and incremental cost-effectiveness ratios were projected. We assumed a willingness-to-pay threshold of $100 000 per QALYG. RESULTS: Among the alternative tests, computed tomographic colonography every 5 years, annual mSEPT9, and annual multi-target stool DNA screening had incremental cost-effectiveness ratios of $1092, $63 253, and $214 974 per QALYG, respectively. Other screening strategies were more costly and less effective than (a combination of) these 3. Under the assumption of perfect adherence, annual mSEPT9 screening resulted in more QALYG, CRC cases averted, and CRC deaths averted than annual FIT screening but led to a high rate of colonoscopy referral (51% after 3 years, 69% after 5 years). The alternative tests were not cost-effective compared with FIT and colonoscopy. CONCLUSIONS: This study suggests that for individuals not willing to participate in FIT or colonoscopy screening, mSEPT9 is the test of choice if the high colonoscopy referral rate is acceptable to them.

Black and White Differences in Colorectal Cancer Screening and Screening Outcomes: A Narrative Review.

Racial disparities in colorectal cancer incidence are widely documented. There are two potential mechanisms for these disparities: differences in access to screening, including screening follow-up, and differences in underlying risk of colorectal cancer. We reviewed the literature for evidence of these two mechanisms. We show that higher colorectal cancer incidence in blacks relative to whites emerged only after the dissemination of screening and describe evidence of racial disparities in screening rates. In contrast to the strong evidence for differences in colorectal cancer screening utilization, there is limited evidence for racial differences in adenoma prevalence. In general, black and white patients who are screened have similar adenoma prevalence, though there is some evidence that advanced adenomas and adenomas in the proximal colon are somewhat more likely in black than white patients. We conclude that higher rates of colorectal cancer incidence among black patients are primarily driven by lower rates of colorectal cancer screening. Our findings highlight the need to increase black patients' access to quality screening to reduce colorectal cancer incidence and mortality.

Surveillance in Older Women With Incidental Ovarian Cysts: Maximal Projected Benefits by Age and Comorbidity Level.

PURPOSE: The aim of this study was to estimate effects on life expectancy (LE) of imaging-based ovarian surveillance after detection of incidental postmenopausal ovarian cysts, under different assumptions of patient age, comorbidity level, and cancer risk and detection. METHODS: A decision-analytic Markov model was developed to estimate LE benefits. Hypothetical cohorts of postmenopausal women with simple ovarian cysts were evaluated, with varied age (66-80 years) and comorbidity level (none, mild, moderate, severe). For each cohort, imaging "follow-up" (2 years) and "no-follow-up" strategies were compared. Consistent with current evidence, increased cancer risk in patients with cysts was not assumed; however, incident ovarian cancers could be detected during follow-up. To estimate theoretical maximal LE gains from follow-up, perfect ovarian cancer detection and treatment during follow-up were assumed. This and other key assumptions were varied in sensitivity analysis. RESULTS: Projected LE gains from follow-up were limited. For 66-, 70-, 75-, and 80-year-old women with no comorbidities, LE gains were 5.1, 5.1, 4.5, and 3.7 days; with severe comorbidities, they were 3.5, 3.2, 2.7, and 2.1 days. With sensitivity of 50% for cancer detection, they were 3.7 days for 66-year-old women with no comorbidities and 1.3 days for 80-year-old women with severe comorbidities. When cancer risk for women with cysts was assumed to be elevated (1.1 times average risk), LE gains increased only modestly (5.6 and 2.3 days for analogous cohorts). CONCLUSIONS: Even in the circumstance of perfect ovarian cancer detection and treatment, surveillance of postmenopausal women (≥66 years of age) with simple cysts affords limited benefits, particularly in women with advanced age and comorbidities.

Validation of Colorectal Cancer Models on Long-term Outcomes from a Randomized Controlled Trial.

Microsimulation models are often used to predict long-term outcomes and guide policy decisions regarding cancer screening. The United Kingdom Flexible Sigmoidoscopy Screening (UKFSS) Trial examines a one-time intervention of flexible sigmoidoscopy that was implemented before a colorectal cancer (CRC) screening program was established. Long-term study outcomes, now a full 17 y following randomization, have been published. We use the outcomes from this trial to validate 3 microsimulation models for CRC to long-term study outcomes. We find that 2 of 3 models accurately predict the relative effect of screening (the hazard ratios) on CRC-specific incidence 17 y after screening. We find that all 3 models yield predictions of the relative effect of screening on CRC incidence and mortality (i.e., the hazard ratios) that are reasonably close to the UKFSS results. Two of the 3 models accurately predict the relative reduction in CRC incidence 17 y after screening. One model accurately predicted the absolute incidence and mortality rates in the screened group. The models differ in their estimates related to adenoma detection at screening. Although high-quality screening results help to inform models, trials are expensive, last many years, and can be complicated by ethical issues and technological changes across the duration of the trial. Thus, well-calibrated and validated models are necessary to predict outcomes for which data are not available. The results from this validation demonstrate the utility of models in predicting long-term outcomes and in collaborative modeling to account for uncertainty.

Potential survival benefits from optimized chemotherapy implementation in advanced ovarian cancer: Projections from a microsimulation model.

BACKGROUND: Ovarian cancer is often diagnosed in advanced stages, when survival is poor. Treatment advances have been made, but are inconsistently implemented. Our purpose was to project the maximum life expectancy gains that could be achieved in women with stage IIIC epithelial ovarian cancer if the implementation of available chemotherapy regimens could be optimized. METHODS: We used a microsimulation model to estimate life expectancy benefits associated with "optimized" implementation of four post-operative chemotherapy options: standard intravenous chemotherapy; intraperitoneal + intravenous chemotherapy; bevacizumab + intravenous chemotherapy; and hyperthermic intraperitoneal chemotherapy + intravenous chemotherapy. Optimized implementation was defined as follows. Patients triaged to primary cytoreductive surgery received intraperitoneal + intravenous chemotherapy if optimally or completely cytoreduced, and bevacizumab + intravenous chemotherapy if suboptimally cytoreduced. Patients triaged to neoadjuvant chemotherapy received hyperthermic intraperitoneal chemotherapy at interval cytoreductive surgery if optimally or completely cytoreduced, and standard IV chemotherapy if suboptimally cytoreduced. Life expectancy associated with optimized implementation was compared with that of current utilization practices, estimated using published literature and the National Cancer Database. Effects of model uncertainty were evaluated in sensitivity analyses. RESULTS: Life expectancy associated with optimized implementation vs. current practice was 76.7 vs. 64.5 months (life expectancy gain = 12.2 months). Providing intraperitoneal + intravenous chemotherapy to all eligible patients was the largest driver of life expectancy gains, due to both the potential benefit conferred by intraperitoneal + intravenous chemotherapy and the proportion of eligible women who do not receive intraperitoneal + intravenous chemotherapy in current practice. CONCLUSION: Population-level life expectancy in stage IIIC epithelial ovarian cancer could be substantially improved through greater uptake of available chemotherapy regimens.

High-Intensity Versus Low-Intensity Surveillance for Patients With Colorectal Adenomas: A Cost-Effectiveness Analysis.

Background: Surveillance of patients with colorectal adenomas has limited long-term evidence to support current practice. Objective: To compare the lifetime benefits and costs of high- versus low-intensity surveillance. Design: Microsimulation model. Data Sources: U.S. cancer registry, cost data, and published literature. Target Population: U.S. patients aged 50, 60, or 70 years with low-risk adenomas (LRAs) (1 to 2 small adenomas) or high-risk adenomas (HRAs) (3 to 10 small adenomas or ≥1 large adenoma) removed after screening with colonoscopy or fecal immunochemical testing (FIT). Time Horizon: Lifetime. Perspective: Societal. Intervention: No further screening or surveillance, routine screening after 10 years, low-intensity surveillance (10 years after LRA removal and 5 years after HRA removal), and high-intensity surveillance (5 years after LRA removal and 3 years after HRA removal). Outcome Measures: Colorectal cancer (CRC) incidence and incremental cost-effectiveness. Results of Base-Case Analysis: Without surveillance or screening, lifetime CRC incidence for patients aged 50 years was 10.9% after LRA removal and 17.2% after HRA removal at screening colonoscopy. Subsequent colonoscopic screening, low-intensity surveillance, or high-intensity surveillance decreased incidence by 39%, 46% to 48%, and 55% to 56%, respectively. Incidence of CRC and surveillance benefits were higher for adenomas detected at FIT screening and lower for older patients. High-intensity surveillance cost less than $30 000 per quality-adjusted life-year (QALY) gained compared with low-intensity surveillance. Results of Sensitivity Analysis: High-intensity surveillance cost less than $100 000 per QALY gained in most alternative scenarios for adenoma recurrence, CRC incidence, longevity, quality of life, screening ages, surveillance ages, test performance, disutilities, and cost. Limitation: Few surveillance outcome data exist. Conclusion: The model suggests that high-intensity surveillance as recommended in the United States provides modest but clinically relevant benefits over low-intensity surveillance at acceptable cost. Primary Funding Source: National Cancer Institute.