Global burden of young-onset gastric cancer: a systematic trend analysis of the global burden of disease study 2019

BACKGROUND

While gastric cancer is generally declining globally, the temporal trend of young-onset (< 40 years) gastric cancer remains uncertain. We performed this analysis to determine the temporal trends of young-onset gastric cancer compared to late-onset cancer (≥ 40 years).

METHODS

We extracted cross-sectional data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. The burden of gastric cancer from 1990 to 2019 was assessed through indicators including incidence and mortality rates, which were classified at global, national, and regional levels, and according to socio-demographic indexes (SDI) and age or sex groups. Joinpoint regression analysis was used to identify specific years with significant changes. The correlation between AAPC with countries' average SDI was tested by Pearson's Test.

RESULTS

The global incidence rate of young-onset gastric cancer decreased from 2.20 (per 100,000) in 1990 to 1.65 in 2019 (AAPC: - 0.95; 95% confidence interval [CI] - 1.25 to - 0.65; P < 0.001). Late-onset cancer incidence also decreased from 59.53 (per 100,000) in 1990 to 41.26 in 2019 (AAPC: - 1.23; 95% CI - 1.39 to - 1.06, P < 0.001). Despite an overall decreasing trend, the incidence rate of young-onset cancer demonstrated a significant increase from 2015 to 2019 (annual percentage change [APC]: 1.39; 95% CI 0.06 to 2.74; P = 0.041), whereas no upward trend was observed in late-onset cancer. Mortality rates of young- and late-onset cancer both exhibited a significant decline during this period (AAPC: - 1.82; 95% CI - 2.15 to - 1.56; P < 0.001 and AAPC: - 1.69, 95% CI - 1.79 to - 1.59; P < 0.001). The male-to-female rate ratio for incidence and mortality in both age groups have been increasing since 1990. While countries with high SDI have had a greater decline in the incidence of late-onset gastric cancer (slope of AAPC change: - 0.20, P = 0.004), it was not observed in young-onset cancer (slope of AAPC change: - 0.11, P = 0.13).

CONCLUSIONS

The global incidence and mortality rates of both young- and late-onset gastric cancer have decreased since 1990. However, the incidence rate of young-onset cancer has demonstrated a small but significant upward trend since 2015. There was disparity in the decline in young-onset gastric cancer among male and high SDI countries. These findings could help to inform future strategies in preventing gastric cancer in younger individuals.

Projected Colorectal Cancer Incidence and Mortality Based on Observed Adherence to Colonoscopy and Sequential Stool-Based Screening

INTRODUCTION

Modeling supporting recommendations for colonoscopy and stool-based colorectal cancer (CRC) screening tests assumes 100% sequential participant adherence. The impact of observed adherence on the long-term effectiveness of screening is unknown. We evaluated the effectiveness of a program of screening colonoscopy every 10 years vs annual high-sensitivity guaiac-based fecal occult blood testing (HSgFOBT) using observed sequential adherence data.

METHODS

The MIcrosimulation SCreening ANalysis (MISCAN) model used observed sequential screening adherence, HSgFOBT positivity, and diagnostic colonoscopy adherence in HSgFOBT-positive individuals from the National Colonoscopy Study (single-screening colonoscopy vs ≥4 HSgFOBT sequential rounds). We compared CRC incidence and mortality over 15 years with no screening or 10 yearly screening colonoscopy vs annual HSgFOBT with 100% and differential observed adherence from the trial.

RESULTS

Without screening, simulated incidence and mortality over 15 years were 20.9 (95% probability interval 15.8-26.9) and 6.9 (5.0-9.2) per 1,000 participants, respectively. In the case of 100% adherence, only screening colonoscopy was predicted to result in lower incidence; however, both tests lowered simulated mortality to a similar level (2.1 [1.6-2.9] for screening colonoscopy and 2.5 [1.8-3.4] for HSgFOBT). Observed adherence for screening colonoscopy (83.6%) was higher than observed sequential HSgFOBT adherence (73.1% first round; 49.1% by round 4), resulting in lower simulated incidence and mortality for screening colonoscopy (14.4 [10.8-18.5] and 2.9 [2.1-3.9], respectively) than HSgFOBT (20.8 [15.8-28.1] and 3.9 [2.9-5.4], respectively), despite a 91% adherence to diagnostic colonoscopy with FOBT positivity. The relative risk of CRC mortality for screening colonoscopy vs HSgFOBT was 0.75 (95% probability interval 0.68-0.80). Findings were similar in sensitivity analyses with alternative assumptions for repeat colonoscopy, test performance, risk, age, and projection horizon.

DISCUSSION

Where sequential adherence to stool-based screening is suboptimal and colonoscopy is accessible and acceptable-as observed in the national colonoscopy study, microsimulation, comparative effectiveness, screening recommendations.

Prevalence of Gastric Precursor Lesions in Countries With Differential Gastric Cancer Burden: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The prevalence of precursor lesions for gastric cancer (GC) and the differential burden between countries of varying GC risk is not well-understood. We conducted a systematic review and meta-analysis to estimate the global prevalence of precursor lesions.

METHODS

We estimated the prevalence of atrophic gastritis (AG), gastric intestinal metaplasia (IM), and dysplasia in regions with low, medium, and high GC incidence. Because IM is an advanced manifestation of AG, we assessed the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. Prevalence was sub-stratified by Helicobacter pylori infection, symptomatology, and period (<2000, 2000-2010, and >2010).

RESULTS

Among the 582 articles that underwent full-text review, 166 studies met inclusion criteria. The global prevalence estimates of AG, IM, and dysplasia were 25.4%, 16.2%, and 2.0%, respectively, on the basis of 126 studies that reported the prevalence of less advanced precursors, regardless of the presence of more advanced lesions. The prevalence of all precursor lesions was higher in high and medium compared with low GC incidence countries (P < .01). Prevalence of AG and IM was significantly higher among H pylori-infected individuals (P < .01) but not statistically different between symptomatic and asymptomatic individuals (P > .17). All precursors demonstrated a secular decrease in prevalence over time.

CONCLUSIONS

Gastric precursor lesions have differences in prevalence in regions with differential GC incidence and are associated with H pylori infection. Because of the substantial prevalence of precursor lesions in both symptomatic and asymptomatic individuals, symptomatic evaluation may not be sufficient to identify individuals at risk. These estimates provide important insights for tailoring GC prevention strategies.

Risk-Stratified Screening for Colorectal Cancer Using Genetic and Environmental Risk Factors: A Cost-Effectiveness Analysis Based on Real-World Data

BACKGROUND & AIMS

Previous studies on the cost-effectiveness of personalized colorectal cancer (CRC) screening were based on hypothetical performance of CRC risk prediction and did not consider the association with competing causes of death. In this study, we estimated the cost-effectiveness of risk-stratified screening using real-world data for CRC risk and competing causes of death.

METHODS

Risk predictions for CRC and competing causes of death from a large community-based cohort were used to stratify individuals into risk groups. A microsimulation model was used to optimize colonoscopy screening for each risk group by varying the start age (40-60 years), end age (70-85 years), and screening interval (5-15 years). The outcomes included personalized screening ages and intervals and cost-effectiveness compared with uniform colonoscopy screening (ages 45-75, every 10 years). Key assumptions were varied in sensitivity analyses.

RESULTS

Risk-stratified screening resulted in substantially different screening recommendations, ranging from a one-time colonoscopy at age 60 for low-risk individuals to a colonoscopy every 5 years from ages 40 to 85 for high-risk individuals. Nevertheless, on a population level, risk-stratified screening would increase net quality-adjusted life years gained (QALYG) by only 0.7% at equal costs to uniform screening or reduce average costs by 1.2% for equal QALYG. The benefit of risk-stratified screening improved when it was assumed to increase participation or costs less per genetic test.

CONCLUSIONS

Personalized screening for CRC, accounting for competing causes of death risk, could result in highly tailored individual screening programs. However, average improvements across the population in QALYG and cost-effectiveness compared with uniform screening are small.

Personalized Multilevel Intervention for Improving Appropriate Use of Colorectal Cancer Screening in Older Adults: A Cluster Randomized Clinical Trial

Importance

Despite guideline recommendations, clinicians do not systematically use prior screening or health history to guide colorectal cancer (CRC) screening decisions in older adults.

Objective

To evaluate the effect of a personalized multilevel intervention on screening orders in older adults due for average-risk CRC screening.

Design, Setting, and Participants

Interventional 2-group parallel unmasked cluster randomized clinical trial conducted from November 2015 to February 2019 at 2 US Department of Veterans Affairs (VA) facilities: 1 academic VA medical center and 1 of its connected outpatient clinics. Randomization at the primary care physician/clinician (PCP) level, stratified by study site and clinical full-time equivalency. Participants were 431 average-risk, screen-due US veterans aged 70 to 75 years attending a primary care visit. Data analysis was performed from August 2018 to August 2023.

Intervention

The intervention group received a multilevel intervention including a decision-aid booklet with detailed information on screening benefits and harms, personalized for each participant based on age, sex, prior screening, and comorbidity. The control group received a multilevel intervention including a screening informational booklet. All participants received PCP education and system-level modifications to support personalized screening.

Main Outcomes and Measures

The primary outcome was whether screening was ordered within 2 weeks of clinic visit. Secondary outcomes were concordance between screening orders and screening benefit and screening utilization within 6 months.

Results

A total of 436 patients were consented, and 431 were analyzed across 67 PCPs. Patients had a mean (SD) age of 71.5 (1.7) years; 424 were male (98.4%); 374 were White (86.8%); 89 were college graduates (21.5%); and 351 (81.4%) had undergone prior screening. A total of 258 (59.9%) were randomized to intervention, and 173 (40.1%) to control. Screening orders were placed for 162 of 258 intervention patients (62.8%) vs 114 of 173 control patients (65.9%) (adjusted difference, -4.0 percentage points [pp]; 95% CI, -15.4 to 7.4 pp). In a prespecified interaction analysis, the proportion receiving orders was lower in the intervention group than in the control group for those in the lowest benefit quartile (59.4% vs 71.1%). In contrast, the proportion receiving orders was higher in the intervention group than in the control group for those in the highest benefit quartile (67.6% vs 52.2%) (interaction P = .049). Fewer intervention patients (106 of 256 [41.4%]) utilized screening overall at 6 months than controls (96 of 173 [55.9%]) (adjusted difference, -13.4 pp; 95% CI, -25.3 to -1.6 pp).

Conclusions and Relevance

In this cluster randomized clinical trial, patients who were presented with personalized information about screening benefits and harms in the context of a multilevel intervention were more likely to receive screening orders concordant with benefit and were less likely to utilize screening.

Trial Registration

ClinicalTrials.gov Identifier: NCT02027545.

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.

Combining Asian and European genome-wide association studies of colorectal cancer improves risk prediction across racial and ethnic populations

Polygenic risk scores (PRS) have great potential to guide precision colorectal cancer (CRC) prevention by identifying those at higher risk to undertake targeted screening. However, current PRS using European ancestry data have sub-optimal performance in non-European ancestry populations, limiting their utility among these populations. Towards addressing this deficiency, we expand PRS development for CRC by incorporating Asian ancestry data (21,731 cases; 47,444 controls) into European ancestry training datasets (78,473 cases; 107,143 controls). The AUC estimates (95% CI) of PRS are 0.63(0.62-0.64), 0.59(0.57-0.61), 0.62(0.60-0.63), and 0.65(0.63-0.66) in independent datasets including 1681-3651 cases and 8696-115,105 controls of Asian, Black/African American, Latinx/Hispanic, and non-Hispanic White, respectively. They are significantly better than the European-centric PRS in all four major US racial and ethnic groups (p-values < 0.05). Further inclusion of non-European ancestry populations, especially Black/African American and Latinx/Hispanic, is needed to improve the risk prediction and enhance equity in applying PRS in clinical practice.

Factors associated with detection of hereditary diffuse gastric cancer on endoscopy in individuals with germline CDH1 mutations

BACKGROUND AND AIMS

Individuals with germline pathogenic CDH1 variants have a high risk of hereditary diffuse gastric cancer. The sensitivity of EGD in detecting signet ring cell carcinoma (SRCC) in this population is low. We aimed to identify endoscopic findings and biopsy practices associated with detection of SRCC.

METHODS

This retrospective cohort included individuals with a germline pathogenic/likely pathogenic CDH1 variant undergoing at least 1 EGD at Memorial Sloan Kettering Cancer Center between January 1, 2006, and March 25, 2022. The primary outcome was detection of SRCC on EGD. Findings on gastrectomy were also assessed. The study included periods before and after implementation of the Cambridge protocol for endoscopic surveillance, allowing for assessment of a spectrum of biopsy practices.

RESULTS

Ninety-eight CDH1 patients underwent at least 1 EGD at our institution. SRCC was detected in 20 (20%) individuals on EGD overall and in 50 (86%) of the 58 patients undergoing gastrectomy. Most SRCC foci were detected in the gastric cardia/fundus (EGD, 50%; gastrectomy, 62%) and body/transition zone (EGD, 60%; gastrectomy, 62%). Biopsy results of gastric pale mucosal areas were associated with detection of SRCC (P < .01). The total number of biopsy samples taken on EGD was associated with increased detection of SRCC (P = .01), with 43% detected when ≥40 samples were taken.

CONCLUSIONS

Targeted biopsy sampling of gastric pale mucosal areas and increasing number of biopsy samples taken on EGD were associated with detection of SRCC. SRCC foci were mostly detected in the proximal stomach, supporting updated endoscopic surveillance guidelines. Further studies are needed to refine endoscopic protocols to improve SRCC detection in this high-risk population.

Critical Appraisal of Decision Models Used for the Economic Evaluation of Bladder Cancer Screening and Diagnosis: A Systematic Review

BACKGROUND AND OBJECTIVE

Bladder cancer is common among current and former smokers. High bladder cancer mortality may be decreased through early diagnosis and screening. The aim of this study was to appraise decision models used for the economic evaluation of bladder cancer screening and diagnosis, and to summarise the main outcomes of these models.

METHODS

MEDLINE via PubMed, Embase, EconLit and Web of Science databases was systematically searched from January 2006 to May 2022 for modelling studies that assessed the cost effectiveness of bladder cancer screening and diagnostic interventions. Articles were appraised according to Patient, Intervention, Comparator and Outcome (PICO) characteristics, modelling methods, model structures and data sources. The quality of the studies was also appraised using the Philips checklist by two independent reviewers.

RESULTS

Searches identified 3082 potentially relevant studies, which resulted in 18 articles that met our inclusion criteria. Four of these articles were on bladder cancer screening, and the remaining 14 were diagnostic or surveillance interventions. Two of the four screening models were individual-level simulations. All screening models (n = 4, with three on a high-risk population and one on a general population) concluded that screening is either cost saving or cost effective with cost-effectiveness ratios lower than $53,000/life-years saved. Disease prevalence was a strong determinant of cost effectiveness. Diagnostic models (n = 14) assessed multiple interventions; white light cystoscopy was the most common intervention and was considered cost effective in all studies (n = 4). Screening models relied largely on published evidence generalised from other countries and did not report the validation of their predictions to external data. Almost all diagnostic models (n = 13 out of 14) had a time horizon of 5 years or less and most of the models (n = 11) did not incorporate health-related utilities. In both screening and diagnostic models, epidemiological inputs were based on expert elicitation, assumptions or international evidence of uncertain generalisability. In modelling disease, seven models did not use a standard classification system to define cancer states, others used risk-based, numerical or a Tumour, Node, Metastasis classification. Despite including certain components of disease onset or progression, no models included a complete and coherent model of the natural history of bladder cancer (i.e. simulating the progression of asymptomatic primary bladder cancer from cancer onset, i.e. in the absence of treatment).

CONCLUSIONS

The variation in natural history model structures and the lack of data for model parameterisation suggest that research in bladder cancer early detection and screening is at an early stage of development. Appropriate characterisation and analysis of uncertainty in bladder cancer models should be considered a priority.

Projected long-term effects of colorectal cancer screening disruptions following the COVID-19 pandemic

The aftermath of the initial phase of the COVID-19 pandemic may contribute to the widening of disparities in colorectal cancer (CRC) outcomes due to differential disruptions to CRC screening. This comparative microsimulation analysis uses two CISNET CRC models to simulate the impact of ongoing screening disruptions induced by the COVID-19 pandemic on long-term CRC outcomes. We evaluate three channels through which screening was disrupted: delays in screening, regimen switching, and screening discontinuation. The impact of these disruptions on long-term CRC outcomes was measured by the number of life-years lost due to CRC screening disruptions compared to a scenario without any disruptions. While short-term delays in screening of 3-18 months are predicted to result in minor life-years loss, discontinuing screening could result in much more significant reductions in the expected benefits of screening. These results demonstrate that unequal recovery of screening following the pandemic can widen disparities in CRC outcomes and emphasize the importance of ensuring equitable recovery to screening following the pandemic.

Young-onset colorectal cancer

In the past decades the incidence of colorectal cancer (CRC) in people under the age of 50 years has increased, which is referred to as early-onset CRC or young-onset CRC (YO-CRC). YO-CRC is expected to account for 11% of colon cancers and 23% of rectal cancers by 2030. This trend is observed in different parts of the world and in both men and women. In 20% of patients with YO-CRC, a hereditary cancer syndrome is found as the underlying cause; however, in the majority of patients no genetic predisposition is present. Beginning in the 1950s, major changes in lifestyle such as antibiotic use, low physical activity and obesity have affected the gut microbiome and may be an important factor in YO-CRC development. Owing to a lack of screening, patients with YO-CRC are often diagnosed with advanced-stage disease. Long-term treatment-related complications should be taken into account in these younger patients, making the more traditional sequential approaches of drug therapy not always the most appropriate option. To better understand the underlying mechanism and define relationships between environmental factors and YO-CRC development, long-term prospective studies are needed with lifestyle data collected from childhood.

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

BACKGROUND AND 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 to sequential HSgFOBT has not been reported. In this randomized clinical trial, we assessed adherence and pathology findings for a single screening-colonoscopy versus sequential and non-sequential HSgFOBT.

METHODS

Participants aged 40-69 were enrolled in three centers, which represented different clinical settings. Participants were randomized into a single screening-colonoscopy arm versus sequential HSgFOBT arm comprised 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-SER) were measured.

RESULTS

3,523 participants were included in the trial with 1761 and 1762 participants randomized to the screening-colonoscopy and HSgFOBT arms, respectively. Adherence was 1473 (83.6%) for the screening-colonoscopy arm versus 1288 (73.1%) for the HSgFOBT arm after one round (RR=1.14, [95% CI 1.10-1.19] P ≤0.001), but only 674 (38.3%) over four 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 in the HSgFOBT arm (84.7%) (RR=1.04, [95% CI 1.02-1.07]). 436 (24.7%) participants crossed over to screening-colonoscopy over the first four rounds. ADN-SER were detected in 121 (8.2%) of the 1473 participants in the colonoscopy arm who were adherent to protocol in the first 12 months of the study, whereas the detection of ADN-SER among those who were not sequentially adherent (N=709) to HSgFOBT was subpar (0.6%) (RR=14.72, [95% CI 5.46-39.67]) when compared to those who were sequentially adherent (3.3%) (N=647) (RR=2.52, [95% CI 1.61-3.98]) to HSgFOBT in the first four rounds. When including colonoscopies from HSgFOBT patients who were never positive yet crossed over (N=1483), 5.5% of ADN-SER were detected (RR=1.50, [95% CI 1.15-1.96]) in the first four rounds.

CONCLUSIONS

Observed adherence to sequential rounds of HSgFOBT was suboptimal when compared to a single screening-colonoscopy. The detection of ADN-SER was inferior when non-sequential HSgFOBT adherence was compared to sequential adherence. However, the greatest number of ADN-SER was detected among those who crossed over to colonoscopy and opted to receive a colonoscopy. The effectiveness of a HSgFOBT screening program may be enhanced if crossover to screening-colonoscopy is permitted.

Validation of a Genetic-Enhanced Risk Prediction Model for Colorectal Cancer in a Large Community-Based Cohort

BACKGROUND

Polygenic risk scores (PRS) which summarize individuals' genetic risk profile may enhance targeted colorectal cancer screening. A critical step towards clinical implementation is rigorous external validations in large community-based cohorts. This study externally validated a PRS-enhanced colorectal cancer risk model comprising 140 known colorectal cancer loci to provide a comprehensive assessment on prediction performance.

METHODS

The model was developed using 20,338 individuals and externally validated in a community-based cohort (n = 85,221). We validated predicted 5-year absolute colorectal cancer risk, including calibration using expected-to-observed case ratios (E/O) and calibration plots, and discriminatory accuracy using time-dependent AUC. The PRS-related improvement in AUC, sensitivity and specificity were assessed in individuals of age 45 to 74 years (screening-eligible age group) and 40 to 49 years with no endoscopy history (younger-age group).

RESULTS

In European-ancestral individuals, the predicted 5-year risk calibrated well [E/O = 1.01; 95% confidence interval (CI), 0.91-1.13] and had high discriminatory accuracy (AUC = 0.73; 95% CI, 0.71-0.76). Adding the PRS to a model with age, sex, family and endoscopy history improved the 5-year AUC by 0.06 (P < 0.001) and 0.14 (P = 0.05) in the screening-eligible age and younger-age groups, respectively. Using a risk-threshold of 5-year SEER colorectal cancer incidence rate at age 50 years, adding the PRS had a similar sensitivity but improved the specificity by 11% (P < 0.001) in the screening-eligible age group. In the younger-age group it improved the sensitivity by 27% (P = 0.04) with similar specificity.

CONCLUSIONS

The proposed PRS-enhanced model provides a well-calibrated 5-year colorectal cancer risk prediction and improves discriminatory accuracy in the external cohort.

IMPACT

The proposed model has potential utility in risk-stratified colorectal cancer prevention.

The Impacts of Computer-Aided Detection of Colorectal Polyps on Subsequent Colonoscopy Surveillance Intervals: Simulation Study

BACKGROUND

Computer-aided detection (CADe) of colorectal polyps has been shown to increase adenoma detection rates, which would potentially shorten subsequent surveillance intervals.

OBJECTIVE

The purpose of this study is to simulate the potential changes in subsequent colonoscopy surveillance intervals after the application of CADe in a large cohort of patients.

METHODS

We simulated the projected increase in polyp and adenoma detection by universal CADe application in our patients who had undergone colonoscopy with complete endoscopic and histological findings between 2016 and 2020. The simulation was based on bootstrapping the published performance of CADe. The corresponding changes in surveillance intervals for each patient, as recommended by the US Multi-Society Task Force on Colorectal Cancer (USMSTF) or the European Society of Gastrointestinal Endoscopy (ESGE), were determined after the CADe was determined.

RESULTS

A total of 3735 patients who had undergone colonoscopy were included. Based on the simulated CADe effect, the application of CADe would result in 19.1% (n=714) and 1.9% (n=71) of patients having shorter surveillance intervals, according to the USMSTF and ESGE guidelines, respectively. In particular, all (or 2.7% (n=101) of the total) patients who were originally scheduled to have 3-5 years of surveillance would have their surveillance intervals shortened to 3 years, following the USMSTF guidelines. The changes in this group of patients were largely attributed to an increase in the number of adenomas (n=75, 74%) rather than serrated lesions being detected.

CONCLUSIONS

Widespread adoption of CADe would inevitably increase the demand for surveillance colonoscopies with the shortening of original surveillance intervals, particularly following the current USMSTF guideline.

Elucidating the Drivers for the Rising Incidence of Early-Onset Colorectal Cancer: How Ecologic Studies Could Help and What Is Next

The incidence of colorectal cancer diagnosed before age 50, often referred to as early-onset colorectal cancer, has been increasing, whereas the overall colorectal cancer incidence has declined. Elucidating the drivers for the rising burden of early-onset colorectal cancer is a priority in cancer epidemiology and prevention. In this issue of Cancer Epidemiology, Biomarkers & Prevention, Chen and colleagues demonstrated that ecologic studies are a helpful method to reveal emerging risk factors at the population level and concluded that alcohol use might be a potential contributor to the rising incidence of early-onset colorectal cancer. Moving forward, because of the observed birth cohort effect in early-onset colorectal cancer, where younger generations have a steeper increase, hypothesis-driven investigations on emerging risk factors in recent generations, especially during early life, are warranted. Ultimately, the identified risk factors could be integrated with well-established microsimulation models of colorectal cancer, powerful tools that can simultaneously capture population-level secular changes in risk factors, relative risk estimates for each risk factor, and the natural history of colorectal cancer. This would allow us to quantitatively estimate the explained and unexplained portion of the rising incidence of early-onset colorectal cancer by calendar period and birth cohorts, and to help identify priorities in etiologic research, prevention, and early detection. See related article by Chen et al., p. 217.

Combining Asian-European Genome-Wide Association Studies of Colorectal Cancer Improves Risk Prediction Across Race and Ethnicity

Polygenic risk scores (PRS) have great potential to guide precision colorectal cancer (CRC) prevention by identifying those at higher risk to undertake targeted screening. However, current PRS using European ancestry data have sub-optimal performance in non-European ancestry populations, limiting their utility among these populations. Towards addressing this deficiency, we expanded PRS development for CRC by incorporating Asian ancestry data (21,731 cases; 47,444 controls) into European ancestry training datasets (78,473 cases; 107,143 controls). The AUC estimates (95% CI) of PRS were 0.63(0.62-0.64), 0.59(0.57-0.61), 0.62(0.60-0.63), and 0.65(0.63-0.66) in independent datasets including 1,681-3,651 cases and 8,696-115,105 controls of Asian, Black/African American, Latinx/Hispanic, and non-Hispanic White, respectively. They were significantly better than the European-centric PRS in all four major US racial and ethnic groups (p-values<0.05). Further inclusion of non-European ancestry populations, especially Black/African American and Latinx/Hispanic, is needed to improve the risk prediction and enhance equity in applying PRS in clinical practice.

Impact and Recovery from COVID-19-Related Disruptions in Colorectal Cancer Screening and Care in the US: A Scenario Analysis

BACKGROUND

Many colorectal cancer-related procedures were suspended during the COVID-19 pandemic. In this study, we predict the impact of resulting delays in screening (colonoscopy, FIT, and sigmoidoscopy) and diagnosis on colorectal cancer-related outcomes, and compare different recovery scenarios.

METHODS

Using the MISCAN-Colon model, we simulated the US population and evaluated different impact and recovery scenarios. Scenarios were defined by the duration and severity of the disruption (percentage of eligible adults affected), the length of delays, and the duration of the recovery. During recovery (6, 12 or 24 months), capacity was increased to catch up missed procedures. Primary outcomes were excess colorectal cancer cases and -related deaths, and additional colonoscopies required during recovery.

RESULTS

With a 24-month recovery, the model predicted that the US population would develop 7,210 (0.18%) excess colorectal cancer cases during 2020-2040, and 6,950 (0.65%) excess colorectal cancer-related deaths, and require 108,500 (8.6%) additional colonoscopies per recovery month, compared with a no-disruption scenario. Shorter recovery periods of 6 and 12 months, respectively, decreased excess colorectal cancer-related deaths to 4,190 (0.39%) and 4,580 (0.43%), at the expense of 260,200-590,100 (20.7%-47.0%) additional colonoscopies per month.

CONCLUSIONS

The COVID-19 pandemic will likely cause more than 4,000 excess colorectal cancer-related deaths in the US, which could increase to more than 7,000 if recovery periods are longer.

IMPACT

Our results highlight that catching-up colorectal cancer-related services within 12 months provides a good balance between required resources and mitigation of the impact of the disruption on colorectal cancer-related deaths.

Unequal Recovery in Colorectal Cancer Screening Following the COVID-19 Pandemic: A Comparative Microsimulation Analysis

The aftermath of the initial phase of the COVID-19 pandemic may contribute to the widening of disparities in access to colorectal cancer (CRC) screening due to differential disruptions to CRC screening. This comparative microsimulation analysis uses two CISNET CRC models to simulate the impact of ongoing screening disruptions induced by the COVID-19 pandemic on long-term CRC outcomes. We evaluate three channels through which screening was disrupted: delays in screening, regimen switching, and screening discontinuation. The impact of these disruptions on long-term colorectal cancer (CRC) outcomes was measured by the number of Life-years lost due to CRC screening disruptions compared to a scenario without any disruptions. While short-term delays in screening of 3-18 months are predicted to result in minor life-years loss, discontinuing screening could result in much more significant reductions in the expected benefits of screening. These results demonstrate that unequal recovery of screening following the pandemic can widen disparities in colorectal cancer outcomes and emphasize the importance of ensuring equitable recovery to screening following the pandemic.

Rates of repeated colonoscopies to clean the colon from low-risk and high-risk adenomas: results from the EPoS trials

OBJECTIVE

High-quality colonoscopy (adequate bowel preparation, whole-colon visualisation and removal of all neoplastic polyps) is a prerequisite to start polyp surveillance, and is ideally achieved in one colonoscopy. In a large multinational polyp surveillance trial, we aimed to investigate clinical practice variation in number of colonoscopies needed to enrol patients with low-risk and high-risk adenomas in polyp surveillance.

DESIGN

We retrieved data of all patients with low-risk adenomas (one or two tubular adenomas <10 mm with low-grade dysplasia) and high-risk adenomas (3-10 adenomas, ≥1 adenoma ≥10 mm, high-grade dysplasia or villous components) in the European Polyp Surveillance trials fulfilling certain logistic and methodologic criteria. We analysed variations in number of colonoscopies needed to achieve high-quality colonoscopy and enter polyp surveillance by endoscopy centre, and by endoscopists who enrolled ≥30 patients.

RESULTS

The study comprised 15 581 patients from 38 endoscopy centres in five European countries; 6794 patients had low-risk and 8787 had high-risk adenomas. 961 patients (6.2%, 95% CI 5.8% to 6.6%) underwent two or more colonoscopies before surveillance began; 101 (1.5%, 95% CI 1.2% to 1.8%) in the low-risk group and 860 (9.8%, 95% CI 9.2% to 10.4%) in the high-risk group. Main reasons were poor bowel preparation (21.3%) or incomplete colonoscopy/polypectomy (14.4%) or planned second procedure (27.8%). Need of repeat colonoscopy varied between study centres ranging from 0% to 11.8% in low-risk adenoma patients and from 0% to 63.9% in high-risk adenoma patients. On the second colonoscopy, the two most common reasons for a repeat (third) colonoscopy were piecemeal resection (26.5%) and unspecified reason (23.9%).

CONCLUSION

There is considerable practice variation in the number of colonoscopies performed to achieve complete polyp removal, indicating need for targeted quality improvement to reduce patient burden.

TRIAL REGISTRATION NUMBER

NCT02319928.

Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

BACKGROUND

Although colonoscopy is widely used as a screening test to detect colorectal cancer, its effect on the risks of colorectal cancer and related death is unclear.

METHODS

We performed a pragmatic, randomized trial involving presumptively healthy men and women 55 to 64 years of age drawn from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. The participants were randomly assigned in a 1:2 ratio either to receive an invitation to undergo a single screening colonoscopy (the invited group) or to receive no invitation or screening (the usual-care group). The primary end points were the risks of colorectal cancer and related death, and the secondary end point was death from any cause.

RESULTS

Follow-up data were available for 84,585 participants in Poland, Norway, and Sweden - 28,220 in the invited group, 11,843 of whom (42.0%) underwent screening, and 56,365 in the usual-care group. A total of 15 participants had major bleeding after polyp removal. No perforations or screening-related deaths occurred within 30 days after colonoscopy. During a median follow-up of 10 years, 259 cases of colorectal cancer were diagnosed in the invited group as compared with 622 cases in the usual-care group. In intention-to-screen analyses, the risk of colorectal cancer at 10 years was 0.98% in the invited group and 1.20% in the usual-care group, a risk reduction of 18% (risk ratio, 0.82; 95% confidence interval [CI], 0.70 to 0.93). The risk of death from colorectal cancer was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64 to 1.16). The number needed to invite to undergo screening to prevent one case of colorectal cancer was 455 (95% CI, 270 to 1429). The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual-care group (risk ratio, 0.99; 95% CI, 0.96 to 1.04).

CONCLUSIONS

In this randomized trial, the risk of colorectal cancer at 10 years was lower among participants who were invited to undergo screening colonoscopy than among those who were assigned to no screening. (Funded by the Research Council of Norway and others; NordICC ClinicalTrials.gov number, NCT00883792.).

Age-Stratified Prevalence and Predictors of Neoplasia Among U.S. Adults Undergoing Screening Colonoscopy in a National Endoscopy Registry

BACKGROUND & AIMS

Several U.S. organizations now recommend starting average-risk colorectal cancer screening at age 45 years, but the prevalence of colonic neoplasia in individuals younger than 50 years has not been well characterized. We used a national endoscopic registry to calculate age-stratified prevalence and predictors of colorectal neoplasia.

METHODS

Outpatient screening colonoscopies performed during 2010-2020 in the GI Quality Improvement Consortium registry were analyzed. We measured the prevalence of advanced neoplasia and adenomas by age, sex, and race/ethnicity, as well as the prevalence ratio of neoplasia compared with the reference group of 50- to 54-year-olds. Multivariable logistic regression models were used to identify predictors of neoplasia.

RESULTS

We identified 3,928,727 screening colonoscopies, of which 129,736 (3.3%) were performed on average-risk individuals younger than 50 years. The prevalence of advanced neoplasia was 6.2% for 50- to 54-year-olds and 5.0% (prevalence ratio, 0.81; 95% confidence interval, 0.78-0.83) for average-risk 45- to 49-year-olds. Men had higher prevalence of neoplasia than women for all age groups. White individuals had higher prevalence of advanced neoplasia than persons of other racial/ethnic groups in most age groups, which was partially driven by serrated lesions. On multivariable regression, White individuals had higher odds of advanced neoplasia than Black, Hispanic, and Asian individuals in both younger and older age groups.

CONCLUSIONS

In a large U.S. endoscopy registry, the prevalence of advanced neoplasia in 45- to 49-year-olds was substantial and supports beginning screening at age 45 years. White individuals had higher risk of advanced neoplasia than Black, Hispanic, and Asian individuals across the age spectrum. These findings may inform adenoma detection benchmarks and risk-based screening strategies.

Guaiac-based faecal occult blood tests versus faecal immunochemical tests for colorectal cancer screening in average-risk individuals

BACKGROUND

Worldwide, many countries have adopted colorectal cancer (CRC) screening programmes, often based on faecal occult blood tests (FOBTs). CRC screening aims to detect advanced neoplasia (AN), which is defined as CRC or advanced adenomas. FOBTs fall into two categories based on detection technique and the detected blood component: qualitative guaiac-based FOBTs (gFOBTs) and faecal immunochemical tests (FITs), which can be qualitative and quantitative. Screening with gFOBTs reduces CRC-related mortality.

OBJECTIVES

To compare the diagnostic test accuracy of gFOBT and FIT screening for detecting advanced colorectal neoplasia in average-risk individuals.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS Citation Index, Science Citation Index Expanded, and Google Scholar. We searched the reference lists and PubMed-related articles of included studies to identify additional studies.

SELECTION CRITERIA

We included prospective and retrospective studies that provided the number of true positives, false positives, false negatives, and true negatives for gFOBTs, FITs, or both, with colonoscopy as reference standard. We excluded case-control studies. We included studies in which all participants underwent both index test and reference standard ("reference standard: all"), and studies in which only participants with a positive index test underwent the reference standard while participants with a negative test were followed for at least one year for development of interval carcinomas ("reference standard: positive"). The target population consisted of asymptomatic, average-risk individuals undergoing CRC screening. The target conditions were CRC and advanced neoplasia (advanced adenomas and CRC combined).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and selected studies for inclusion. In case of disagreement, a third review author made the final decision. We used the Rutter and Gatsonis hierarchical summary receiver operating characteristic model to explore differences between tests and identify potential sources of heterogeneity, and the bivariate hierarchical model to estimate sensitivity and specificity at common thresholds: 10 µg haemoglobin (Hb)/g faeces and 20 µg Hb/g faeces. We performed indirect comparisons of the accuracy of the two tests and direct comparisons when both index tests were evaluated in the same population.

MAIN RESULTS

We ran the initial search on 25 June 2019, which yielded 63 studies for inclusion. We ran a top-up search on 14 September 2021, which yielded one potentially eligible study, currently awaiting classification. We included a total of 33 "reference standard: all" published articles involving 104,640 participants. Six studies evaluated only gFOBTs, 23 studies evaluated only FITs, and four studies included both gFOBTs and FITs. The cut-off for positivity of FITs varied between 2.4 μg and 50 µg Hb/g faeces. For each Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability than gFOBTs for AN (P < 0.001) and CRC (P = 0.004). For the detection of AN, the summary sensitivity of gFOBTs was 15% (95% confidence interval (CI) 12% to 20%), which was significantly lower than FITs at both 10 μg and 20 μg Hb/g cut-offs with summary sensitivities of 33% (95% CI 27% to 40%; P < 0.001) and 26% (95% CI 21% to 31%, P = 0.002), respectively. Results were simulated in a hypothetical cohort of 10,000 screening participants with 1% CRC prevalence and 10% AN prevalence. Out of 1000 participants with AN, gFOBTs missed 850, while FITs missed 670 (10 μg Hb/g cut-off) and 740 (20 μg Hb/g cut-off). No significant differences in summary specificity for AN detection were found between gFOBTs (94%; 95% CI 92% to 96%), and FITs at 10 μg Hb/g cut-off (93%; 95% CI 90% to 95%) and at 20 μg Hb/g cut-off (97%; 95% CI 95% to 98%). So, among 9000 participants without AN, 540 were offered (unnecessary) colonoscopy with gFOBTs compared to 630 (10 μg Hb/g) and 270 (20 μg Hb/g) with FITs. Similarly, for the detection of CRC, the summary sensitivity of gFOBTs, 39% (95% CI 25% to 55%), was significantly lower than FITs at 10 μg and 20 μg Hb/g cut-offs: 76% (95% CI 57% to 88%: P = 0.001) and 65% (95% CI 46% to 80%; P = 0.035), respectively. So, out of 100 participants with CRC, gFOBTs missed 61, and FITs missed 24 (10 μg Hb/g) and 35 (20 μg Hb/g). No significant differences in summary specificity for CRC were found between gFOBTs (94%; 95% CI 91% to 96%), and FITs at the 10 μg Hb/g cut-off (94%; 95% CI 87% to 97%) and 20 μg Hb/g cut-off (96%; 95% CI 91% to 98%). So, out of 9900 participants without CRC, 594 were offered (unnecessary) colonoscopy with gFOBTs versus 594 (10 μg Hb/g) and 396 (20 μg Hb/g) with FITs. In five studies that compared FITs and gFOBTs in the same population, FITs showed a higher discriminative ability for AN than gFOBTs (P = 0.003). We included a total of 30 "reference standard: positive" studies involving 3,664,934 participants. Of these, eight were gFOBT-only studies, 18 were FIT-only studies, and four studies combined both gFOBTs and FITs. The cut-off for positivity of FITs varied between 5 µg to 250 µg Hb/g faeces. For each QUADAS-2 domain, we assessed risk of bias as high in less than 20% of studies. The summary curve showed that FITs had a higher discriminative ability for detecting CRC than gFOBTs (P < 0.001). The summary sensitivity for CRC of gFOBTs, 59% (95% CI 55% to 64%), was significantly lower than FITs at the 10 μg Hb/g cut-off, 89% (95% CI 80% to 95%; P < 0.001) and the 20 μg Hb/g cut-off, 89% (95% CI 85% to 92%; P < 0.001). So, in the hypothetical cohort with 100 participants with CRC, gFOBTs missed 41, while FITs missed 11 (10 μg Hb/g) and 11 (20 μg Hb/g). The summary specificity of gFOBTs was 98% (95% CI 98% to 99%), which was higher than FITs at both 10 μg and 20 μg Hb/g cut-offs: 94% (95% CI 92% to 95%; P < 0.001) and 95% (95% CI 94% to 96%; P < 0.001), respectively. So, out of 9900 participants without CRC, 198 were offered (unnecessary) colonoscopy with gFOBTs compared to 594 (10 μg Hb/g) and 495 (20 μg Hb/g) with FITs. At a specificity of 90% and 95%, FITs had a higher sensitivity than gFOBTs.

AUTHORS' CONCLUSIONS

FITs are superior to gFOBTs in detecting AN and CRC in average-risk individuals. Specificity of both tests was similar in "reference standard: all" studies, whereas specificity was significantly higher for gFOBTs than FITs in "reference standard: positive" studies. However, at pre-specified specificities, the sensitivity of FITs was significantly higher than gFOBTs.

Colorectal Cancer Screening within Colonoscopy Capacity Constraints: Can FIT-Based Programs Save More Lives by Trading off More Sensitive Test Cutoffs against Longer Screening Intervals?

Introduction. Colorectal cancer (CRC) prevention programs using fecal immunochemical testing (FIT) in screening rely on colonoscopy for secondary and surveillance testing. Colonoscopy capacity is an important constraint. Some European programs lack sufficient capacity to provide optimal screening intensity regarding age ranges, intervals, and FIT cutoffs. It is currently unclear how to optimize programs within colonoscopy capacity constraints. Design. Microsimulation modeling, using the MISCAN-Colon model, was used to determine if more effective CRC screening programs can be identified within constrained colonoscopy capacity. A total of 525 strategies were modeled and compared, varying 3 key screening parameters: screening intervals, age ranges, and FIT cutoffs, including previously unevaluated 4- and 5-year screening intervals (using a lifetime horizon and 100% adherence). Results were compared with the policy decisions taken in Ireland to provide CRC screening within available colonoscopy capacity. Outcomes estimated net costs, quality-adjusted life-years (QALYs), and required colonoscopies. The optimal strategies within finite colonoscopy capacity constraints were identified. Results. Combining a reduced FIT cutoff of 10 µg Hb/g, an extended screening interval of 4 y and an age range of 60–72 y requires 6% fewer colonoscopies, reduces net costs by 23% while preventing 15% more CRC deaths and saving 16% more QALYs relative to a strategy (FIT 40 µg Hb/g, 2-yearly, 60–70 year) approximating current policy. Conclusion. Previously overlooked longer screening intervals may optimize cancer prevention with finite colonoscopy capacity constraints. Changes could save lives, reduce costs, and relieve colonoscopy capacity pressures. These findings are relevant to CRC screening programs across Europe that employ FIT-based testing, which face colonoscopy capacity constraints.

Cost-effectiveness of prophylactic hysterectomy in first-degree female relatives with Lynch syndrome of patients diagnosed with colorectal cancer in the United States: a microsimulation study

Background

To evaluate the cost‐effectiveness of prophylactic hysterectomy (PH) in women with Lynch syndrome (LS).

Methods

We developed a microsimulation model incorporating the natural history for the development of hyperplasia with and without atypia into endometrial cancer (EC) based on the MISCAN‐framework. We simulated women identified as first‐degree relatives (FDR) with LS of colorectal cancer patients after universal testing for LS. We estimated costs and benefits of offering this cohort PH, accounting for reduced quality of life after PH and for having EC. Three minimum ages (30/35/40) and three maximum ages (70/75/80) were compared to no PH.

Results

In the absence of PH, the estimated number of EC cases was 300 per 1,000 women with LS. Total associated costs for treatment of EC were $5.9 million. Offering PH to FDRs aged 40–80 years was considered optimal. This strategy reduced the number of endometrial cancer cases to 5.4 (−98%), resulting in 516 quality‐adjusted life years (QALY) gained and increasing the costs (treatment of endometrial cancer and PH) to $15.0 million (+154%) per 1,000 women. PH from earlier ages was more costly and resulted in fewer QALYs, although this finding was sensitive to disutility for PH.

Conclusions

Offering PH to 40‐ to 80‐year‐old women with LS is expected to add 0.5 QALY per person at acceptable costs. Women may decide to have PH at a younger age, depending on their individual disutility for PH and premature menopause.

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.

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.

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.

Evaluating Screening Participation, Follow-up, and Outcomes for Breast, Cervical, and Colorectal Cancer in the PROSPR Consortium

BACKGROUND

Cancer screening is a complex process encompassing risk assessment, the initial screening examination, diagnostic evaluation, and treatment of cancer precursors or early cancers. Metrics that enable comparisons across different screening targets are needed. We present population-based screening metrics for breast, cervical, and colorectal cancers for nine sites participating in the Population-based Research Optimizing Screening through Personalized Regimens consortium.

METHODS

We describe how selected metrics map to a trans-organ conceptual model of the screening process. For each cancer type, we calculated calendar year 2013 metrics for the screen-eligible target population (breast: ages 40-74 years; cervical: ages 21-64 years; colorectal: ages 50-75 years). Metrics for screening participation, timely diagnostic evaluation, and diagnosed cancers in the screened and total populations are presented for the total eligible population and stratified by age group and cancer type.

RESULTS

The overall screening-eligible populations in 2013 were 305 568 participants for breast, 3 160 128 for cervical, and 2 363 922 for colorectal cancer screening. Being up-to-date for testing was common for all three cancer types: breast (63.5%), cervical (84.6%), and colorectal (77.5%). The percentage of abnormal screens ranged from 10.7% for breast, 4.4% for cervical, and 4.5% for colorectal cancer screening. Abnormal breast screens were followed up diagnostically in almost all (96.8%) cases, and cervical and colorectal were similar (76.2% and 76.3%, respectively). Cancer rates per 1000 screens were 5.66, 0.17, and 1.46 for breast, cervical, and colorectal cancer, respectively.

CONCLUSIONS

Comprehensive assessment of metrics by the Population-based Research Optimizing Screening through Personalized Regimens consortium enabled systematic identification of screening process steps in need of improvement. We encourage widespread use of common metrics to allow interventions to be tested across cancer types and health-care settings.

Cost-effectiveness of surveillance with CT colonography after resection of colorectal cancer

OBJECTIVE

Surveillance following colorectal cancer (CRC) resection uses optical colonoscopy (OC) to detect intraluminal disease and CT to detect extracolonic recurrence. CT colonography (CTC) might be an efficient use of resources in this situation because it allows for intraluminal and extraluminal evaluations with one test.

DESIGN

We developed a simulation model to compare lifetime costs and benefits for a cohort of patients with resected CRC. Standard of care involved annual CT for 3 years and OC for years 1, 4 and every 5 years thereafter. For the CTC-based strategy, we replace CT+OC at year 1 with CTC. Patients with lesions greater than 6 mm detected by CTC underwent OC. Detection of an adenoma 10 mm or larger was followed by OC at 1 year, then every 3 years thereafter. Test characteristics and costs for CTC were derived from a clinical study. Medicare costs were used for cancer care costs as well as alternative test costs. We discounted costs and effects at 3% per year.

RESULTS

For persons with resected stage III CRC, the standard-of-care strategy was more costly (US$293) and effective (2.6 averted CRC cases and 1.1 averted cancer deaths per 1000) than the CTC-based strategy, with an incremental cost-effectiveness ratio of US$55 500 per quality-adjusted life-year gained. Our analysis was most sensitive to the sensitivity of CTC for detecting polyps 10 mm or larger and assumptions about disease progression.

CONCLUSION

In a simulation model, we found that replacing the standard-of-care approach to postdiagnostic surveillance with a CTC-based strategy is not an efficient use of resources in most situations.

The effect of using fecal testing after a negative sigmoidoscopy on the risk of death from colorectal cancer

OBJECTIVE

To examine whether receiving a fecal occult blood test after a negative sigmoidoscopy reduced mortality from colorectal cancer.

METHODS

We used a nested case-control design with incidence-density matching in historical cohorts of 1,877,740 50-90-year-old persons during 2006-2012, in an integrated health-system setting. We selected 1758 average risk patients who died from colorectal cancer and 3503 matched colorectal cancer-free persons. Colorectal cancer-specific death was ascertained from cancer and mortality registries. Screening histories were determined from electronic and chart-audit clinical data in the 5- to 10-year period prior to the reference date. We evaluated receipt of subsequent fecal occult blood test within five years of the reference date among patients with negative sigmoidoscopy two to six years before the reference date.

RESULTS

Of the 5261 patients, 831 patients (204 colorectal cancer deaths/627 controls) had either negative sigmoidoscopy only (n = 592) or negative sigmoidoscopy with subsequent screening fecal occult blood test (n = 239). Fifty-six (27.5%) of the 204 patients dying of colorectal cancer and 183 (29.2%) of the 627 colorectal cancer-free patients received fecal occult blood test following a negative sigmoidoscopy. Conditional regressions found no significant association between fecal occult blood test receipt and colorectal cancer death risk, overall (adjusted odds ratio = 0.93, confidence interval: 0.65-1.33), or for right (odds ratio = 1.02, confidence interval: 0.65-1.60) or left-colon/rectum (odds ratio = 0.77, confidence interval: 0.39-1.52) cancers. Similar results were obtained in sensitivity analyses with alternative exposure ascertainment windows or timing of fecal occult blood test.

CONCLUSIONS

Our results suggest that receipt of at least one fecal occult blood test during the several years after a negative sigmoidoscopy did not substantially reduce mortality from colorectal cancer.

Cumulative Burden of Colorectal Cancer-Associated Genetic Variants Is More Strongly Associated With Early-Onset vs Late-Onset Cancer

BACKGROUND & AIMS

Early-onset colorectal cancer (CRC, in persons younger than 50 years old) is increasing in incidence; yet, in the absence of a family history of CRC, this population lacks harmonized recommendations for prevention. We aimed to determine whether a polygenic risk score (PRS) developed from 95 CRC-associated common genetic risk variants was associated with risk for early-onset CRC.

METHODS

We studied risk for CRC associated with a weighted PRS in 12,197 participants younger than 50 years old vs 95,865 participants 50 years or older. PRS was calculated based on single nucleotide polymorphisms associated with CRC in a large-scale genome-wide association study as of January 2019. Participants were pooled from 3 large consortia that provided clinical and genotyping data: the Colon Cancer Family Registry, the Colorectal Transdisciplinary Study, and the Genetics and Epidemiology of Colorectal Cancer Consortium and were all of genetically defined European descent. Findings were replicated in an independent cohort of 72,573 participants.

RESULTS

Overall associations with CRC per standard deviation of PRS were significant for early-onset cancer, and were stronger compared with late-onset cancer (P for interaction = .01); when we compared the highest PRS quartile with the lowest, risk increased 3.7-fold for early-onset CRC (95% CI 3.28-4.24) vs 2.9-fold for late-onset CRC (95% CI 2.80-3.04). This association was strongest for participants without a first-degree family history of CRC (P for interaction = 5.61 × 10-5). When we compared the highest with the lowest quartiles in this group, risk increased 4.3-fold for early-onset CRC (95% CI 3.61-5.01) vs 2.9-fold for late-onset CRC (95% CI 2.70-3.00). Sensitivity analyses were consistent with these findings.

CONCLUSIONS

In an analysis of associations with CRC per standard deviation of PRS, we found the cumulative burden of CRC-associated common genetic variants to associate with early-onset cancer, and to be more strongly associated with early-onset than late-onset cancer, particularly in the absence of CRC family history. Analyses of PRS, along with environmental and lifestyle risk factors, might identify younger individuals who would benefit from preventive measures.

Long-term Risk of Colorectal Cancer and Related Death After Adenoma Removal in a Large, Community-based Population

BACKGROUND & AIMS

The long-term risks of colorectal cancer (CRC) and CRC-related death following adenoma removal are uncertain. Data are needed to inform evidence-based surveillance guidelines, which vary in follow-up recommendations for some polyp types. Using data from a large, community-based integrated health care setting, we examined the risks of CRC and related death by baseline colonoscopy adenoma findings.

METHODS

Participants at 21 medical centers underwent baseline colonoscopies from 2004 through 2010; findings were categorized as no-adenoma, low-risk adenoma, or high-risk adenoma. Participants were followed until the earliest of CRC diagnosis, death, health plan disenrollment, or December 31, 2017. Risks of CRC and related deaths among the high- and low-risk adenoma groups were compared with the no-adenoma group using Cox regression adjusting for confounders.

RESULTS

Among 186,046 patients, 64,422 met eligibility criteria (54.3% female; mean age, 61.6 ± 7.1 years; median follow-up time, 8.1 years from the baseline colonoscopy). Compared with the no-adenoma group (45,881 patients), the high-risk adenoma group (7563 patients) had a higher risk of CRC (hazard ratio [HR] 2.61; 95% confidence interval [CI] 1.87-3.63) and related death (HR 3.94; 95% CI 1.90-6.56), whereas the low-risk adenoma group (10,978 patients) did not have a significant increase in risk of CRC (HR 1.29; 95% CI 0.89-1.88) or related death (HR 0.65; 95% CI 0.19-2.18).

CONCLUSIONS

With up to 14 years of follow-up, high-risk adenomas were associated with an increased risk of CRC and related death, supporting early colonoscopy surveillance. Low-risk adenomas were not associated with a significantly increased risk of CRC or related deaths. These results can inform current surveillance guidelines for high- and low-risk adenomas.

Promoting colonoscopy screening among low-income Latinos at average risk of colorectal cancer: A randomized clinical trial

BACKGROUND

Screening colonoscopy (SC) for colorectal cancer (CRC) is underused by Latino individuals. The current randomized clinical trial examined the impact of 3 interventions: 1) patient navigation; 2) patient navigation plus standard Centers for Disease Control and Prevention print materials; and 3) patient navigation plus culturally targeted print materials for Latinos referred for SC. Demographic, personal and health history, and psychometric factors associated with SC also were examined.

METHODS

A total of 344 urban Latino individuals aged 50 to 85 years with no personal and/or immediate family history of CRC diagnosed before age 60 years, no personal history of a gastrointestinal disorder, no colonoscopy within the past 5 years, with insurance coverage, and with a referral for SC were consented. Participants were randomized to patient navigation (20%), patient navigation plus standard Centers for Disease Control and Prevention print materials (40%), and patient navigation plus culturally targeted print materials (40%). The completion of SC was assessed at 12 months.

RESULTS

The interventions had an overall SC rate of 82%. Counterintuitively, patients with an average income of <$10,000 were found to have higher SC rates (87%) than those with a greater income (75%).

CONCLUSIONS

The addition of standard or culturally targeted print materials did not appear to increase SC rates above those for patient navigation. Indeed, after controlling for other variables, culturally targeted print materials were found to be associated with lower SC rates among Puerto Rican individuals.

Association of Obesity With Risk of Early-Onset Colorectal Cancer Among Women

Importance

Colorectal cancer (CRC) incidence and mortality among individuals younger than 50 years (early-onset CRC) are increasing. The reasons for such increases are largely unknown, although the increasing prevalence of obesity may be partially responsible.

Objective

To investigate prospectively the association between obesity and weight gain since early adulthood with the risk of early-onset CRC.

Design, Setting, and Participants

The Nurses' Health Study II is a prospective, ongoing cohort study of US female nurses aged 25 to 42 years at study enrollment (1989). A total of 85 256 women free of cancer and inflammatory bowel disease at enrollment were included in this analysis, with follow-up through December 31, 2011. Validated anthropomorphic measures and lifestyle information were self-reported biennially. Statistical analysis was performed from June 12, 2017, to June 28, 2018.

Exposures

Current body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared), BMI at 18 years of age, and weight gain since 18 years of age.

Main Outcomes and Measures

Relative risk (RR) for incident early-onset CRC.

Results

Among the 85 256 women studied, 114 cases of early-onset CRC were documented (median age at diagnosis, 45 years; interquartile range, 41-47 years) during 1 196 452 person-years of follow-up. Compared with women with a BMI of 18.5 to 22.9, the multivariable RR was 1.37 (95% CI, 0.81-2.30) for overweight women (BMI, 25.0-29.9) and 1.93 (95% CI, 1.15-3.25) for obese women (BMI, ≥30.0). The RR for each 5-unit increment in BMI was 1.20 (95% CI, 1.05-1.38; P = .01 for trend). Similar associations were observed among women without a family history of CRC and without lower endoscopy within the past 10 years. Both BMI at 18 years of age and weight gain since 18 years of age contributed to this observation. Compared with women with a BMI of 18.5 to 20.9 at 18 years of age, the RR of early-onset CRC was 1.32 (95% CI, 0.80-2.16) for women with a BMI of 21.0 to 22.9 and 1.63 (95% CI, 1.01-2.61) for women with a BMI of 23.0 or greater at 18 years of age (P = .66 for trend). Compared with women who had gained less than 5.0 kg or had lost weight, the RR of early-onset CRC was 1.65 (95% CI, 0.96-2.81) for women gaining 20.0 to 39.9 kg and 2.15 (95% CI, 1.01-4.55) for women gaining 40.0 kg or more (P = .007 for trend).

Conclusions and Relevance

Obesity was associated with an increased risk of early-onset CRC among women. Further investigations among men and to elucidate the underlying biological mechanisms are warranted.

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.

Cost-Effectiveness of Risk-Stratified Colorectal Cancer Screening Based on Polygenic Risk: Current Status and Future Potential

Background

Although uniform colonoscopy screening reduces colorectal cancer (CRC) mortality, risk-based screening may be more efficient. We investigated whether CRC screening based on polygenic risk is a cost-effective alternative to current uniform screening, and if not, under what conditions it would be.

Methods

The MISCAN-Colon model was used to simulate a hypothetical cohort of US 40-year-olds. Uniform screening was modeled as colonoscopy screening at ages 50, 60, and 70 years. For risk-stratified screening, individuals underwent polygenic testing with current and potential future discriminatory performance (area under the receiver-operating curve [AUC] of 0.60 and 0.65–0.80, respectively). Polygenic testing results were used to create risk groups, for which colonoscopy screening was optimized by varying the start age (40–60 years), end age (70–85 years), and interval (1–20 years).

Results

With current discriminatory performance, optimal screening ranged from once-only colonoscopy at age 60 years for the lowest-risk group to six colonoscopies at ages 40–80 years for the highest-risk group. While maintaining the same health benefits, risk-stratified screening increased costs by $59 per person. Risk-stratified screening could become cost-effective if the AUC value would increase beyond 0.65, the price per polygenic test would drop to less than $141, or risk-stratified screening would lead to a 5% increase in screening participation.

Conclusions

Currently, CRC screening based on polygenic risk is unlikely to be cost-effective compared with uniform screening. This is expected to change with a greater than 0.05 increase in AUC value, a greater than 30% reduction in polygenic testing costs, or a greater than 5% increase in adherence with screening.

Cost-effectiveness of a multitarget stool DNA test for colorectal cancer screening of Medicare beneficiaries

BACKGROUND

In 2014, the Centers for Medicare and Medicaid Services (CMS) began covering a multitarget stool DNA (mtSDNA) test for colorectal cancer (CRC) screening of Medicare beneficiaries. In this study, we evaluated whether mtSDNA testing is a cost-effective alternative to other CRC screening strategies reimbursed by CMS, and if not, under what conditions it could be.

METHODS

We use three independently-developed microsimulation models to simulate a cohort of previously unscreened US 65-year-olds who are screened with triennial mtSDNA testing, or one of six other reimbursed screening strategies. Main outcome measures are discounted life-years gained (LYG) and lifetime costs (CMS perspective), threshold reimbursement rates, and threshold adherence rates. Outcomes are expressed as the median and range across models.

RESULTS

Compared to no screening, triennial mtSDNA screening resulted in 82 (range: 79-88) LYG per 1,000 simulated individuals. This was more than for five-yearly sigmoidoscopy (80 (range: 71-89) LYG), but fewer than for every other simulated strategy. At its 2017 reimbursement rate of $512, mtSDNA was the most costly strategy, and even if adherence were 30% higher than with other strategies, it would not be a cost-effective alternative. At a substantially reduced reimbursement rate ($6-18), two models found that triennial mtSDNA testing was an efficient and potentially cost-effective screening option.

CONCLUSIONS

Compared to no screening, triennial mtSDNA screening reduces CRC incidence and mortality at acceptable costs. However, compared to nearly all other CRC screening strategies reimbursed by CMS it is less effective and considerably more costly, making it an inefficient screening option.

Long-term Risk of Colorectal Cancer and Related Deaths After a Colonoscopy With Normal Findings

Importance

Guidelines recommend a 10-year rescreening interval after a colonoscopy with normal findings (negative colonoscopy results), but evidence supporting this recommendation is limited.

Objective

To examine the long-term risks of colorectal cancer and colorectal cancer deaths after a negative colonoscopy result, in comparison with individuals unscreened, in a large, community-based setting.

Design, Setting, and Participants

A retrospective cohort study was conducted in an integrated health care delivery organization serving more than 4 million members across Northern California. A total of 1 251 318 average-risk screening-eligible patients (age 50-75 years) between January 1, 1998, and December 31, 2015, were included. The study was concluded on December 31, 2016.

Exposures

Screening was examined as a time-varying exposure; all participants contributed person-time unscreened until they were either screened or censored. If the screening received was a negative colonoscopy result, the participants contributed person-time in the negative colonoscopy results group until they were censored.

Main Outcomes and Measures

Using Cox proportional hazards regression models, the hazard ratios (HRs) for colorectal cancer and related deaths were calculated according to time since negative colonoscopy result (or since cohort entry for those unscreened). Hazard ratios were adjusted for age, sex, race/ethnicity, Charlson comorbidity score, and body mass index.

Results

Of the 1 251 318 patients, 613 692 were men (49.0%); mean age was 55.6 (7.0) years. Compared with the unscreened participants, those with a negative colonoscopy result had a reduced risk of colorectal cancer and related deaths throughout the more than 12-year follow-up period, and although reductions in risk were attenuated with increasing years of follow-up, there was a 46% lower risk of colorectal cancer (hazard ratio, 0.54; 95% CI, 0.31-0.94) and 88% lower risk of related deaths (hazard ratio, 0.12; 95% CI, 0.02-0.82) at the current guideline-recommended 10-year rescreening interval.

Conclusions and Relevance

A negative colonoscopy result in average-risk patients was associated with a lower risk of colorectal cancer and related deaths for more than 12 years after examination, compared with unscreened patients. Our study findings may be able to inform guidelines for rescreening after a negative colonoscopy result and future studies to evaluate the costs and benefits of earlier vs later rescreening intervals.

Modifiable Failures in the Colorectal Cancer Screening Process and Their Association With Risk of Death

BACKGROUND & AIMS

Colorectal cancer (CRC) deaths occur when patients do not receive screening or have inadequate follow-up of abnormal results or when the screening test fails. We have few data on the contribution of each to CRC-associated deaths or factors associated with these events.

METHODS

We performed a retrospective cohort study of patients in the Kaiser Permanente Northern and Southern California systems (55-90 years old) who died of CRC from 2006 through 2012 and had ≥5 years of enrollment before diagnosis. We compared data from patients with those from a matched cohort of cancer-free patients in the same system. Receipt, results, indications, and follow-up of CRC tests in the 10-year period before diagnosis were obtained from electronic databases and chart audits.

RESULTS

Of 1750 CRC deaths, 75.9% (n = 1328) occurred in patients who were not up to date in screening and 24.1% (n = 422) occurred in patients who were up to date. Failure to screen was associated with fewer visits to primary care physicians. Of 3486 cancer-free patients, 44.6% were up to date in their screening. Patients who were up to date in their screening had a lower risk of CRC death (odds ratio, 0.38; 95% confidence interval, 0.33-0.44). Failure to screen, or failure to screen at appropriate intervals, occurred in a 67.8% of patients who died of CRC vs 53.2% of cancer-free patients; failure to follow-up on abnormal results occurred in 8.1% of patients who died of CRC vs 2.2% of cancer-free patients. CRC death was associated with higher odds of failure to screen or failure to screen at appropriate intervals (odds ratio, 2.40; 95% confidence interval, 2.07-2.77) and failure to follow-up on abnormal results (odds ratio, 7.26; 95% confidence interval, 5.26-10.03).

CONCLUSIONS

Being up to date on screening substantially decreases the risk of CRC death. In 2 health care systems with high rates of screening, most people who died of CRC had failures in the screening process that could be rectified, such as failure to follow-up on abnormal findings; these significantly increased the risk for CRC death.

Yield and Cost-effectiveness of Computed Tomography Colonography Versus Colonoscopy for Post Colorectal Cancer Surveillance

Purpose. As part of a clinical trial comparing the utility of computed tomographic colonography (CTC) and optical colonoscopy (OC) for post colorectal cancer resection surveillance, we explored the diagnostic yield and costs of a strategy of CTC followed by OC if a polyp is observed (abbreviated CTC_S), versus OC 1 year following curative bowel resection, using the detection of actionable polyps on OC as the criterion. Methods. Using data from 231 patients who underwent same-day CTC followed by OC, we created a decision tree that outlined the choices and outcomes at 1-year clinical follow-up. Colorectal polyp prevalence, sensitivity, and specificity of CTC were compared with five exemplary studies and meta-analyses. Detection criteria were derived for ≥6 mm or ≥10 mm polyps. OC was the gold standard. Costs were gleaned from cataloging components of the cases at the principal investigator’s institution. Analyses included marginal cost of the OC strategy to detect additional actionable polyps and number of polyps missed per 10,000 patients. Results. At our prevalence of 0.156 for ≥6 mm (0.043 ≥10 mm), CTC_S would miss 779 ≥6 mm actionable polyps per 10,000 patients (≥10 mm: 173 per 10,000). Cost to detect an additional ≥6 mm polyp in this cohort is $5,700 (≥10 mm: $28,000). Sensitivity analyses demonstrate that any improvement in performance characteristics would raise the cost of OC to detect more actionable polyps. Similar results were seen using Medicare costs, or when literature values were used for performance characteristics. Conclusion. At an action threshold of ≥6 mm, OC costs at least $5,700 per extra polyp detected relative to CTC_S in patients undergoing surveillance after colorectal cancer surgery, on the order of incremental cost-effectiveness ratios found for other clinical problems involving short-term events.

Receipt of Colonoscopy Following Diagnosis of Advanced Adenomas: An Analysis within Integrated Healthcare Delivery Systems

BACKGROUND

To reduce colorectal cancer incidence and mortality, experts recommend surveillance colonoscopy 3 years after advanced adenoma removal. Little is known about adherence to that interval.

METHODS

We describe patterns of and factors associated with subsequent colonoscopy among persons with ≥3 adenomas and/or ≥1 adenoma with villous/tubulovillous histology in four U.S. integrated healthcare delivery systems. We report Kaplan-Meier estimators of the cumulative percentage of patients undergoing colonoscopy 6 months to 3.5 years after an index colonoscopy with high-risk findings. Combining data from three healthcare systems, we used multivariable logistic regression with inverse probability of censoring weights to estimate ORs and 95% confidence intervals (CI) for associations between patient characteristics and receipt of subsequent colonoscopy.

RESULTS

Among 6,909 persons with advanced adenomas, the percent receiving a subsequent colonoscopy 6 months to 3.5 years later ranged from 18.3% (95% CI: 11.7%-27.8%) to 59.5% (95% CI: 53.8%-65.2%) across healthcare systems. Differences remained significant in the multivariable model. Patients with ≥3 adenomas were more likely than those with 1 to 2 villous/tubulovillous adenomas to undergo subsequent colonoscopy. Subsequent colonoscopy was also more common for patients ages 60-74 and less common for patients ages 80 to 89 compared with those ages 50 to 54 years at their index colonoscopy. Sex, race/ethnicity, and comorbidity index score were generally not associated with subsequent colonoscopy receipt.

CONCLUSIONS

Colonoscopy within the recommended interval following advanced adenoma was underutilized and varied by healthcare system, age, and number of adenomas.

IMPACT

Strategies to improve adherence to surveillance colonoscopy following advanced adenomas are needed.

Effects of Organized Colorectal Cancer Screening on Cancer Incidence and Mortality in a Large Community-Based Population

BACKGROUND & AIMS

Little information is available on the effectiveness of organized colorectal cancer (CRC) screening on screening uptake, incidence, and mortality in community-based populations.

METHODS

We contrasted screening rates, age-adjusted annual CRC incidence, and incidence-based mortality rates before (baseline year 2000) and after (through 2015) implementation of organized screening outreach, from 2007 through 2008 (primarily annual fecal immunochemical testing and colonoscopy), in a large community-based population. Among screening-eligible individuals 51-75 years old, we calculated annual up-to-date status for cancer screening (by fecal test, sigmoidoscopy, or colonoscopy), CRC incidence, cancer stage distributions, and incidence-based mortality.

RESULTS

Initiation of organized CRC screening significantly increased the up-to-date status of screening, from 38.9% in 2000 to 82.7% in 2015 (P < .01). Higher rates of screening were associated with a 25.5% reduction in annual CRC incidence between 2000 and 2015, from 95.8 to 71.4 cases/100,000 (P < .01), and a 52.4% reduction in cancer mortality, from 30.9 to 14.7 deaths/100,000 (P < .01). Increased screening was initially associated with increased CRC incidence, due largely to greater detection of early-stage cancers, followed by decreases in cancer incidence. Advanced-stage CRC incidence rates decreased 36.2%, from 45.9 to 29.3 cases/100,000 (P < .01), and early-stage CRC incidence rates decreased 14.5%, from 48.2 to 41.2 cases/100,000 (P < .04).

CONCLUSIONS

Implementing an organized CRC screening program in a large community-based population rapidly increased screening participation to the ≥80% target set by national organizations. Screening rates were sustainable and associated with substantial decreases in CRC incidence and mortality within short time intervals, consistent with early detection and cancer prevention.

Colorectal Cancer Screening Participation Among Asian Americans Overall and Subgroups in an Integrated Health Care Setting with Organized Screening

Background

Screening reduces colorectal cancer deaths, but <50% of Asian Americans are screening up-to-date according to surveys, with variability across Asian subgroups. We examined colorectal cancer screening participation among Asian Americans overall and Asian subgroups in a large integrated health care system with organized screening.

Methods

Data were electronically accessed to characterize screening in 2016 for Asians overall and subgroups relative to the National Colorectal Cancer Roundtable target of ≥80% screening and compared with non-Hispanic whites. Screening up-to-date was defined as a colonoscopy with 10 years, a sigmoidoscopy within 5 years, or a fecal immunochemical test (FIT) completed in 2016.

Results

Among 436,398 patients, 69,826 (16.0%) were Asian, of whom 79.8% were screening up-to-date vs. 77.6% of non-Hispanic whites (p < 0.001). Almost all subgroups met the 80% target: Chinese (83.3%), Vietnamese (82.4%), Korean (82.1%), other Asian (80.3%), Filipino (78.7%), Asian Indian (79.6%), and Japanese (79.0%). Among Asians overall and non-Hispanic whites, 50.6% and 48.4% of members were up-to-date with screening by colonoscopy, and 28.0% and 28.2% were up-to-date by FIT, respectively. Across Asian subgroups, colonoscopy most frequently accounting for being screening up-to-date (range: 47.4–59.7%), followed by FIT (range: 21.6–31.5%).

Conclusions

In an organized screening setting, there were minimal differences in screening participation among Asian subgroups and almost all met the 80% screening target, despite differences in language preference. Screening test type differences across subgroups suggest possible preferences in screening modality, which can inform future research into tailored education or outreach.

Optimizing colorectal cancer screening by race and sex: Microsimulation analysis II to inform the American Cancer Society colorectal cancer screening guideline

BACKGROUND

Colorectal cancer (CRC) risk varies by race and sex. This study, 1 of 2 microsimulation analyses to inform the 2018 American Cancer Society CRC screening guideline, explored the influence of race and sex on optimal CRC screening strategies.

METHODS

Two Cancer Intervention and Surveillance Modeling Network microsimulation models, informed by US incidence data, were used to evaluate a variety of screening methods, ages to start and stop, and intervals for 4 demographic subgroups (black and white males and females) under 2 scenarios for the projected lifetime CRC risk for 40-year-olds: 1) assuming that risk had remained stable since the early screening era and 2) assuming that risk had increased proportionally to observed incidence trends under the age of 40 years. Model-based screening recommendations were based on the predicted level of benefit (life-years gained) and burden (required number of colonoscopies), the incremental burden-to-benefit ratio, and the relative efficiency in comparison with strategies with similar burdens.

RESULTS

When lifetime CRC risk was assumed to be stable over time, the models differed in the recommended age to start screening for whites (45 vs 50 years) but consistently recommended screening from the age of 45 years for blacks. When CRC risk was assumed to be increased, the models recommended starting at the age of 45 years, regardless of race and sex. Strategies recommended under both scenarios included colonoscopy every 10 or 15 years, annual fecal immunochemical testing, and computed tomographic colonography every 5 years through the age of 75 years.

CONCLUSIONS

Microsimulation modeling suggests that CRC screening should be considered from the age of 45 years for blacks and for whites if the lifetime risk has increased proportionally to the incidence for younger adults. Cancer 2018;124:2974-85. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.