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

Circulating RNA Markers Associated with Adenoma-Carcinoma Sequence in Colorectal Cancer

Colorectal cancer progresses through a well-defined adenoma-carcinoma sequence (ACS), which is pivotal for early detection and intervention. While ACS-based surveillance has been instrumental, its reliance on tissue sampling limits accurate staging. Liquid biopsies, including circulating tumor DNA (ctDNA) and extracellular RNA, have emerged as non-invasive alternatives, yet they primarily detect genetic alterations or passive RNA release rather than active biological processes. Thus, there is a need for biomarkers that reflect real-time immune responses and tumor-microenvironment interactions during ACS progression. This study aimed to identify circulating RNA biomarkers associated with ACS by analyzing blood samples from 160 individuals across five groups: colorectal cancer, advanced adenoma, non-advanced adenoma, symptomatic non-disease control, and healthy control. RNA sequencing coupled with gene ontology and protein-protein interaction analyses identified stage-specific circulating transcripts. Notably, IFI27 was linked to the symptomatic non-disease control group, DEFA4 to the non-advanced adenoma group, MPO to the advanced adenoma group, and CD177 to the colorectal cancer group. These findings suggest that colorectal-cancer-related circulating RNA markers reflect host immune responses during ACS progression, supporting their potential role in early detection and non-invasive diagnoses. By addressing critical gaps in early colorectal cancer detection, this study advances the utility of circulating RNA biomarkers and liquid biopsies in colorectal cancer screening and clinical management.

Risk factors, prevention and screening of colorectal cancer: A rising problem

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer death worldwide. The leading risk factors for CRC include male gender, age over 50, family history, obesity, tobacco smoking, alcohol consumption, and unhealthy diet. CRC screening methods vary considerably between countries and depend on incidence, economic resources and healthcare structure. Important aspects of screening include adherence, which can vary significantly across ethnic and socioeconomic groups. Basic concepts of CRC screening include pre-stratification of patients by identifying risk factors and then using fecal immunochemical test or guaiac-based fecal occult blood test and/or colonoscopy or radiologic imaging techniques. Technological capabilities for CRC screening are rapidly evolving and include stool DNA test, liquid biopsy, virtual colonography, and the use of artificial intelligence. A CRC prevention strategy should be comprehensive and include active patient education along with targeted implementation of screening.

Cost-effectiveness of blood-based colorectal cancer screening - a simulation model incorporating real-world longitudinal adherence

OBJECTIVES

Although U.S. Preventive Services Task Force (USPSTF) recommended CRC screenings are effective; patient reluctance reduces adherence. Most cost-effectiveness models assume perfect adherence, yet one-third of eligible individuals aren't current with CRC screening. Our study assesses the cost-effectiveness of Shield, an FDA-approved blood-based CRC screening test, using real-world adherence.

METHODS

The CAN-SCREEN (Colorectal cANcer SCReening Economics and adherENce) model, a validated discrete-event simulation, evaluated clinical and economic outcomes of CRC screening under real-world adherence scenarios. We compared the Shield blood-based test administered every 3 years to no screening, considering it cost-effective if the incremental cost-effectiveness ratio (ICER) was under $100,000 per quality-adjusted life-year (QALY) gained.

RESULTS

Shield increased QALYs by 154 and raised costs by $7.5 million per 1,000 individuals, with an ICER of $48,662 per QALY, meeting the $100,000/QALY threshold. Shield remained cost-effective up to a unit cost of $3,241 (at $100,000/QALY) and $4,942 (at $150,000/QALY). Sensitivity analyses confirmed cost-effectiveness with lower adherence to diagnostic colonoscopy (56.1%) and annual screenings.

CONCLUSION

The CAN-SCREEN model shows that Shield is cost-effective compared to no screening. Including real-world adherence improves accuracy in assessing screening strategies. Shield's noninvasive approach offers a promising, cost-effective way to increase adherence and reduce CRC mortality.

Patient Perspectives on Personalized Risk Communication Using Polygenic Risk Scores to Inform Colorectal Cancer Screening Decisions

Introduction

Colorectal cancer is increasingly diagnosed in people aged <50 years. New U.S. guidelines recommend screening initiation at age 45 years. Providing personalized risk for colorectal cancer using polygenic risk scores may be an opportunity to engage this younger population in colorectal cancer screening. There is limited research on patient understanding of polygenic risk scores results and use of polygenic risk scores to inform colorectal cancer screening decisions.

Methods

From May 2022 to June 2023, 20 Kaiser Permanente Colorado members aged 46-51 years who had been offered colorectal cancer screening but had never completed it signed consent to provide a saliva sample for colorectal cancer polygenic risk score analysis. After receiving personalized polygenic risk scores for colorectal cancer, participants completed a semistructured interview regarding the understanding of their polygenic risk scores, perceived colorectal cancer risk, and intention to screen. Thematic analysis was conducted using Atlas.ti, Version 8.

Results

Of the 19 participants who successfully completed polygenic risk score-related testing and a semistructured interview, 13 were female, 14 never smoked cigarettes, 6 were Hispanic, and 13 were non-Hispanic White. One participant had high risk for colorectal cancer on the basis of polygenic risk score results. Qualitative interviews showed participants' understanding of their results, trust in polygenic risk scores, perception of risk for colorectal cancer, plans to complete colorectal cancer screening, intent to share polygenic risk scores with healthcare providers, and concerns about genetic results impacting health care.

Conclusions

Qualitative analyses suggest that participants were interested in and understood their polygenic risk score results. Further study is needed to develop guidelines, effective calls to action, provider engagement, and health education materials on use of polygenic risk scores for health decision making.

A Comparison of International Modeling Methods for Evaluating Health Economics of Colorectal Cancer Screening: A Systematic Review

OBJECTIVES

Cost-effectiveness analysis (CEA) is an accepted approach to evaluate cancer screening programs. CEA estimates partially depend on modeling methods and assumptions used. Understanding common practice when modeling cancer relies on complete, accessible descriptions of prior work. This review's objective is to comprehensively examine published CEA modeling methods used to evaluate colorectal cancer (CRC) screening from an aspiring modeler's perspective. It compares existing models, highlighting the importance of precise modeling method descriptions and essential factors when modeling CRC progression.

METHODS

MEDLINE, EMBASE, Web of Science, and Scopus electronic databases were used. The Consolidated Health Economic Evaluation Reporting Standards statement and data items from previous systematic reviews formed a template to extract relevant data. Specific focus included model type, natural history, appropriate data sources, and survival analysis.

RESULTS

Seventy-eight studies, with 52 unique models were found. Twelve previously published models were reported in 39 studies, with 39 newly developed models. CRC progression from the onset was commonly modeled, with only 6 models not including it as a model component.

CONCLUSIONS

Modeling methods needed to simulate CRC progression depend on the natural history structure and research requirements. For aspiring modelers, accompanying models with clear overviews and extensive modeling assumption descriptions are beneficial. Open-source modeling would also allow model replicability and result in appropriate decisions suggested for CRC screening programs.

Epidemiological trends in gastrointestinal cancers and risk factors across U.S. states from 2000 to 2021: a systematic analysis for the global burden of disease study 2021

INTRODUCTION

Gastrointestinal (GI) cancers account for over a quarter of all cancer-related deaths in the United States; however, the latest trends in their prevalence remain unclear.

METHODS

Data on GI cancers were obtained from the Global Burden of Disease Study 2021. Age-standardized incidence rates (ASIR) and age-standardized mortality rates (ASMR) were estimated across various states, sexes, ages, and risk factors, and annual percentage changes were calculated.

RESULTS

From 2000 to 2021, liver cancer exhibited the greatest increase in both the ASIR and the ASMR, followed by pancreatic cancer. In contrast, stomach cancer showed the greatest decline, followed by colorectal cancer, esophageal cancer, and biliary tract cancer. Most GI cancers predominantly affect men and tend toward a younger age of onset. Geographic disparities exist in the burden of GI cancers and their risk factors. For esophageal, stomach, and colorectal cancers, mortality rates linked to diet and smoking decreased, whereas alcohol-related mortality increased in several states, especially West Virginia. Hepatitis C remains the leading cause of liver cancer, with intravenous drug use as the primary risk factor. Non-alcoholic steatohepatitis (NASH) is the fastest-growing cause of liver cancer, followed by excessive alcohol use. Mortality rates for pancreatic cancer due to high body-mass index and high fasting plasma glucose have increased across states and age groups.

DISCUSSION

The epidemiological trends of GI cancers in the U.S. have shifted substantially. States need to implement targeted policies that address specific populations and risk factors for each cancer type.

Potential for enhancing efficacy of screening colonoscopy by lowering starting ages and extending screening intervals: A modelling study for Germany

Studies aimed to evaluate the expected impact of alternative screening strategies are essential for optimizing colorectal cancer (CRC) screening offers, but such studies are lacking in Germany, where two screening colonoscopies (CS) 10 years apart are offered for men from age 50 and women from age 55. Our aim was to explore whether and to what extent the efficacy of utilizing two CS could be enhanced by alternative starting ages and screening intervals. We modeled the expected numbers of CRC cases, CRC deaths, years of potential life lost (YPLL), and disability-adjusted life years (DALYs) due to CRC in hypothetical cohorts of 100,000 men and women aged 45-85 using COSIMO, a validated Markov-based multi-state simulation model. Modeled strategies included combinations of starting ages (45/50/55/60) and CS (10/15/20 years). For men, CRC deaths could be slightly reduced by extending the interval to 15 years, with a second CS at 65. YPLL and DALYs would be reduced by decreasing starting age to 45 when combined with a 15-year screening interval. For women, use of two CS at ages 50 and 65 would reduce all CRC burden parameters compared to the current earliest-use offer at 55 and 65 years. Our results suggest that lowering the starting age of screening colonoscopy to 45 for men and 50 for women, combined with extending the CS screening interval to 15 years would have the potential to enable significant reductions in years of potential life lost, and disability-adjusted life years compared to current screening offers in Germany.

Cost-Effectiveness of Noninvasive Colorectal Cancer Screening in Community Clinics

Importance

Several noninvasive tests for colorectal cancer screening are available, but their effectiveness in settings with low adherence to screening and follow-up colonoscopy is not well documented.

Objective

To assess the cost-effectiveness of and outcomes associated with noninvasive colorectal cancer screening strategies, including new blood-based tests, in a population with low adherence to screening and ongoing surveillance colonoscopy.

Design, Setting, and Participants

The validated microsimulation model used for the decision analytical modeling study projected screening outcomes from 2025 to 2124 for a simulated cohort of 10 million individuals aged 50 years in 2025 and representative of a predominantly Hispanic or Latino patient population served by a Federally Qualified Health Center in Southern California. The simulated population had low adherence to first-step noninvasive testing (45%), second-step follow-up colonoscopy after an abnormal noninvasive test result (40%), and ongoing surveillance colonoscopy among patients with high-risk findings at follow-up colonoscopy (80%).

Exposures

Colorectal cancer screening strategies included no screening, an annual or biennial fecal immunochemical test, a triennial multitarget stool DNA test, and a triennial blood-based test. Using a blood-based test was assumed to increase first-step adherence by 17.5 percentage points.

Main Outcomes and Measures

Outcomes included colorectal cancer incidence and mortality, life-years gained and quality-adjusted life-years gained relative to no screening, costs, and net monetary benefit assuming a willingness to pay of $100 000 per quality-adjusted life-year gained.

Results

Under realistic adherence assumptions, a program of annual fecal immunochemical testing was the most effective and cost-effective strategy, yielding 121 life-years gained per 1000 screened individuals and a net monetary benefit of $5883 per person. Triennial blood testing was the least effective, yielding 23 life-years gained per 1000, and was not cost-effective, with a negative net monetary benefit. Annual fecal immunochemical testing with 45% first-step adherence and 80% adherence to follow-up and surveillance colonoscopy yielded greater benefit than triennial blood testing with perfect adherence (88 vs 77 life-years gained per 1000).

Conclusions and Relevance

This study suggests that in a federally qualified health care setting, prioritizing the convenience of blood tests over less costly and more effective existing stool-based tests could result in higher costs and worse population-level outcomes. Novel screening modalities should be carefully evaluated for performance in community settings before widespread adoption.

Multi-Cancer Early Detection Tests: State of the Art and Implications for Radiologists

Multi-cancer early detection (MCED) tests are already being marketed as noninvasive, convenient opportunities to test for multiple cancer types with a single blood sample. The technology varies-involving detection of circulating tumor DNA, fragments of DNA, RNA, or proteins unique to each targeted cancer. The priorities and tradeoffs of reaching diagnostic resolution in the setting of possible false positives and negatives remain under active study. Given the well-established role of imaging in lesion detection and characterization for most cancers, radiologists have an essential role to play in selecting diagnostic pathways, determining the validity of test results, resolving false-positive MCED test results, and evaluating tradeoffs for clinical policy. Appropriate access to and use of imaging tests will also factor into clinical guidelines. Thus, all clinicians potentially involved with MCED tests for cancer screening will need to weigh the benefits and harms of MCED testing, including consideration of how the tests will be used alongside or in place of other screening options, how diagnostic confirmation tests should be selected, and what the implications are for policy and reimbursement decisions. Further, patients will need regular support to make informed decisions about screening using MCED tests in the context of their personal cancer risks, health-related values, and access to care.

Colorectal cancer screening knowledge among community pharmacists: A national survey

BACKGROUND

Colorectal cancer (CRC) screening can reduce CRC morbidity and mortality. Community pharmacies could be a viable option for delivering home-based CRC screening tests such as fecal immunochemical tests (FITs). However, little is known about community pharmacists' knowledge about CRC screening guidelines.

OBJECTIVE

We assessed community pharmacists' knowledge about CRC screening to identify education and training needs for a pharmacy-based CRC screening program.

METHODS

Between September 2022 and January 2023, we conducted an online national survey of community pharmacists practicing in the United States. Responders were eligible if they were currently-licensed community pharmacists and currently practiced in the United States. The survey assessed knowledge of national CRC screening guidelines, including recommended starting age, frequency of screening, different screening modalities, and follow-up care. Using multiple linear regression, we evaluated correlates of community pharmacists' level of CRC screening knowledge, defined as the total number of knowledge questions answered correctly from "0" (no questions correct) to "5" (all questions correct).

RESULTS

A total of 578 eligible community pharmacists completed the survey, with a response rate of 59%. Most community pharmacists correctly answered the question about the next steps following a positive FIT (87%) and the question about where a FIT can be done (84%). A minority of community pharmacists responded correctly to questions about the age to start screening with FIT (34%) and how often a FIT should be repeated (28%). Only 5% of pharmacists answered all knowledge questions correctly. Community pharmacists answered more CRC screening knowledge questions correctly as their years in practice increased. Board-certified community pharmacists answered more CRC screening knowledge questions correctly compared to those who were not board-certified.

CONCLUSION

To ensure the successful implementation of a pharmacy-based CRC screening program, community pharmacists need to be educated about CRC screening and trained to ensure comprehensive patient counseling and preventive service delivery.

When Should Colon Cancer Screening Begin? The Impact of Early-Onset Colorectal Cancer and the Reality of an Unscreened Older Population

BACKGROUND

Recent increases in colorectal cancer (CRC) incidence and mortality under age 50 have led the US to recommend starting screening at age 45 years instead of 50. Several other countries are now also reconsidering the age to start CRC screening.

AIMS

To aid decision makers in making an informed decision about lowering the starting age of CRC screening in their jurisdictions.

METHODS

In this article, we present the clinical and modeling evidence for the optimal age to start CRC screening and provide a checklist of considerations for decisions on age to start CRC screening.

RESULTS

Two observational studies showed that detection of advanced neoplasia in those aged 45-49 years undergoing colonoscopy was at least as high as in those aged 50-54 years. One Taiwanese study reported a 22% reduction in CRC incidence and a 39% reduction in CRC mortality from FIT screening in those 40-49 years compared to those 50 years and older. Nine modeling studies concluded that lowering the age to start screening to age 45 was cost-effective. However, lowering the start age can have negative spill-off effects, such as increased wait times for diagnostic colonoscopy for symptomatic individuals and decreased screening participation. In an effort to support decision making and prevent negative spill-off, the National Colorectal Cancer Screening Network in Canada proposed a Worksheet to determine the resource impact of earlier screening initiation.

CONCLUSIONS

Lowering the age to start CRC screening to 45 years likely leads to a reduction in CRC incidence and mortality but requires additional healthcare resources. Policy makers can use the worksheet to assess the expected increase and assess the feasibility within their jurisdictions.

How Good Is Good Enough? What Should Be the Target for CRC Screening?

Colorectal Cancer (CRC) screening of average-risk individuals has been shown to reduce CRC mortality and incidence. Incidence is reduced by detection and removal of cancer precursor lesions (CPLs), resulting in cancer prevention. Mortality reduction is achieved with detection of curable CRC, as well as prevention by removing CPLs before cancer develops. Targets of screening include both curable CRC and CPLs. Non-invasive stool tests are a multi-step screening program which can detect curable cancers and less likely to detect CPLs than invasive screening. The non-invasive programs depend on completion of colonoscopy if the test is positive. Invasive screening with colonoscopy is a one-step test program, with excellent detection of both curable CRCs and CPLs, if performed with high-quality. Current evidence suggests that either program could be effective, despite different targets. Patient adherence and program quality are perhaps the important determinants of program effectiveness.

Does Colonoscopy as a First Screening Test Still Make Sense?-Counterpoint

Colonoscopy has been widely regarded as the gold standard for its high diagnostic accuracy and preventive potential. However, its invasive nature, high cost, and suboptimal participation rates limit its utility at the population level. Non-invasive screening tests, notably the fecal immunochemical test (FIT) and multitarget stool DNA tests, present promising alternatives that may improve screening participation and reduce barriers to participation. Among these, FIT has demonstrated a consistent advantage in enhancing participation, which subsequently contributes to better long-term outcomes in CRC prevention. FIT-based two-step screening offers several practical advantages, including cost-effectiveness, non-invasiveness, and greater flexibility. Moreover, the quantitative nature of FIT allows for adjustable sensitivity thresholds and the ability of risk stratification, making it adaptable across diverse populations and scenarios. Through serial testing, FIT can increase cumulative detection rates over time. This approach facilitates the identification of high-risk individuals, allowing for more judicious use of colonoscopy resources and reducing unnecessary invasive procedures, especially among low-risk populations. Notably, evidence indicates that participation to FIT-based screening is consistently higher than to colonoscopy, which enhances the detection of early-stage cancers and advanced adenomas in the long run. Given the constraints of limited endoscopic capacity, the aging population, and the recent lowering of the recommended screening age due to the rising incidence of early-onset CRC, FIT emerges as a practical, flexible solution. The role of two-step FIT screening in improving participation and enabling risk-stratified, personalized approaches to CRC prevention is pivotal, advocating for its expanded integration into future screening paradigms.

Optimal Stopping Ages for Colorectal Cancer Screening

Importance

Prior studies have shown that the benefits, harms, and costs of colorectal cancer (CRC) screening at older ages are associated with a patient's sex, health, and screening history. However, these studies were hypothetical exercises and not directly informed by data on CRC risk.

Objective

To identify the optimal stopping ages for CRC screening by sex, comorbidity, and screening history from a cost-effectiveness perspective.

Design, Setting, and Participants

This economic evaluation first validated the MISCAN-Colon (Microsimulation Screening Analysis-Colon) model against community-based CRC incidence and mortality rates for 2 subcohorts of the PRECISE (Optimizing Colorectal Cancer Screening Precision and Outcomes in Community-Based Populations) cohort. Subsequently, different CRC screening scenarios were simulated in older individuals. Cohorts of US adults aged 76 to 90 years varied by sex and comorbidity status (none, low, moderate, or severe). Statistical and sensitivity analyses were performed from March 2023 to May 2024.

Exposures

CRC screening histories including fecal immunochemical test (FIT) or colonoscopy, such as a negative colonoscopy result from 10, 15, 20, 25, or 30 years before the index age; 1 to 5 negative FIT results within 5 years of the index age, with different patterns of recency; or a combination of negative colonoscopy and negative FIT results.

Main Outcomes and Measures

The main outcomes included estimated lifetime clinical outcomes, incremental costs, and quality-adjusted life-years gained (QALYG) associated with 1 additional FIT or colonoscopy. Optimal stopping age for screening, defined as the oldest age for which the incremental cost-effectiveness ratio was still below the willingness-to-pay threshold of $100 000 per QALYG, was evaluated.

Results

The first of the 2 PRECISE subcohorts used in validating the simulation model included 25 974 adults (15 060 females [58.0%]; 54.7% aged 76 to 80 years) with a negative colonoscopy result 10 years before the index date. The second subcohort consisted of 118 269 adults (67 058 females [56.7%]; 90.5% aged 76 to 80 years) with a negative FIT result 1 year before the index date. Older age, male sex, higher comorbidity levels, and recent CRC screenings were associated with reduced incremental benefit and cost-effectiveness of additional screening. For the reference cohort of 76-year-old females without comorbidities and a negative colonoscopy result 10 years before the index age, 1 additional colonoscopy cost $38 226 per QALYG. For cohorts with otherwise equivalent characteristics, associated costs increased to $1 689 945 per QALYG for females at age 90 years without comorbidities and a negative colonoscopy results 10 years before the index age, $51 604 per QALYG for males at age 76 years without comorbidities and a negative colonoscopy result 10 years before the index age, and $108 480 per QALYG for females at age 76 years with severe comorbidities and a negative colonoscopy result 10 years before the index age and decreased to $16 870 per QALYG for females without comorbidities and a negative colonoscopy result 30 years before the index age. The optimal stopping ages across different cohorts ranged from younger than 76 to 86 years for colonoscopy and younger than 76 to 88 years for FIT.

Conclusions and Relevance

In this economic evaluation, age, sex, screening history, comorbidity, and future screening modality were associated with the clinical outcomes, cost-effectiveness, and optimal stopping age for CRC screening. These results can inform guideline development and patient-directed informed decision-making.

Early-onset Colorectal Cancer Patients Do Not Require Shorter Intervals for Post-surgical Surveillance Colonoscopy

BACKGROUND & AIMS

Early-onset colorectal cancer (EO-CRC), diagnosed before age 50, is rising in incidence worldwide. Although post-surgical colonoscopy surveillance strategies exist, appropriate intervals in EO-CRC remain elusive, as long-term surveillance outcomes remain scant. We sought to compare findings of surveillance colonoscopies of EO-CRC with patients with average onset colorectal cancer (AO-CRC) to help define surveillance outcomes in these groups.

METHODS

Single-institution retrospective chart review identified EO-CRC and AO-CRC patients with colonoscopy and no evidence of disease. Surveillance intervals and time to development of advanced neoplasia (CRC and advanced polyps [adenoma/sessile serrated]) were examined. For each group, 3 serial surveillance colonoscopies were evaluated. Statistical analyses were performed utilizing log-ranked Kaplan-Meier method and Cox proportional hazards.

RESULTS

A total of 1259 patients with CRC were identified, with 612 and 647 patients in the EO-CRC and AO-CRC groups, respectively. Compared with patients with AO-CRC, patients with EO-CRC had a 29% decreased risk of developing advanced neoplasia from time of initial surgery to first surveillance colonoscopy (hazard ratio, 0.71; 95% confidence interval, 0.52-1.0). Average follow-up time from surgical resection to first surveillance colonoscopy was 12.6 months for both cohorts. Overall surveillance findings differed between cohorts (P = .003), and patients with EO-CRC were found to have less advanced neoplasia compared with their counterparts with AO-CRC (12.4% vs 16.0%, respectively). Subsequent colonoscopies found that, while patients with EO-CRC returned for follow-up surveillance colonoscopy earlier than patients with AO-CRC, the EO-CRC cohort did not have more advanced neoplasia nor non-advanced adenomas.

CONCLUSIONS

Patients with EO-CRC do not have an increased risk of advanced neoplasia compared with patients with AO-CRC and therefore do not require more frequent colonoscopy surveillance than current guidelines recommend.

A Review on Calibration Methods of Cancer Simulation Models

Calibration, a critical step in the development of simulation models, involves adjusting unobservable parameters to ensure that the outcomes of the model closely align with observed target data. This process is particularly vital in cancer simulation models with a natural history component where direct data to inform natural history parameters are rarely available. This work reviews the literature of cancer simulation models with a natural history component and identifies the calibration approaches used in these models with respect to the following attributes: calibration target, goodness-of-fit (GOF) measure, parameter search algorithm, acceptance criteria, and stopping rules. After a comprehensive search of the PubMed database from 1981 to June 2023, 68 studies were included in the review. Nearly all (n=66) articles specified the calibration targets, and most articles (n=56) specified the parameter search algorithms they used, whereas goodness-of-fit metric (n=51) and acceptance criteria/stopping rule (n=45) were reported for fewer times. The most frequently used calibration targets were incidence, mortality, and prevalence, whose data sources primarily come from cancer registries and observational studies. The most used goodness-of-fit measure was weighted mean squared error. Random search has been the predominant method for parameter search, followed by grid search and Nelder-mead method. Machine learning-based algorithms, despite their fast advancement in the recent decade, has been underutilized in the cancer simulation models. More research is needed to compare different parameter search algorithms used for calibration.

Key points

This work reviewed the literature of cancer simulation models with a natural history component and identified the calibration approaches used in these models with respect to the following attributes: calibration target, goodness-of-fit (GOF) measure, parameter search algorithm, acceptance criteria, and stopping rules.Random search has been the predominant method for parameter search, followed by grid search and Nelder-mead method.Machine learning-based algorithms, despite their fast advancement in the recent decade, has been underutilized in the cancer simulation models. Furthermore, more research is needed to compare different parameter search algorithms used for calibration.

The Use of Blood-Based Biomarkers in the Prediction of Colorectal Neoplasia at the Time of Primary Screening Colonoscopy Among Average-Risk Patients: A Systematic Literature Review

BACKGROUND/OBJECTIVES

Risk prediction models (RPMs) for colorectal cancer (CRC) could facilitate risk-based screening. Models incorporating biomarkers may improve the utility of current RPMs. We performed a systematic review of studies reporting RPMs for CRC that evaluated the impact of blood-based biomarkers on clinical outcome prediction at the time of screening colonoscopy in average-risk populations.

METHODS

We conducted a search of MEDLINE, Web of Science, and PubMed databases from inception through April 2024. Studies that developed or validated a model to predict risk of CRC or its precursors were included. Studies were limited to those including patients undergoing average-risk CRC screening.

RESULTS

Sixteen studies published between 2015 and 2024 were included. Outcomes included CRC (16 studies) and high-risk adenomas (1 study). Using a complete blood count was the most common biomarker and was able to achieve an AUC of 0.82 and a specificity of 0.88. Other blood-based biomarkers included were various serum proteins/metabolites/enzymes, plasma metabolites, insulin-related factors, and anemia markers. The highest-performing model, with an AUC of 0.99, involved the use of a plasma metabolite panel.

CONCLUSIONS

The evidence base of RPMs for CRC screening is expanding and incorporating biomarkers, which remain a prominent aspect of model discovery. Most RPMs included a lack of internal/external validation or discussion as to how the model could be implemented clinically. As biomarkers improve the discriminatory potential of RPMs, more research is needed for the evaluation and implementation of RPMs within existing CRC screening frameworks.

How Do We Assess Controversies Using Evidence-Based Radiology?

At its best, the practice of medicine involves careful integration of experience and evidence. Generating evidence to address controversies in radiology - and translating such evidence to practice - requires appropriate selection of methods, and an understanding of the strengths, shortcomings, and biases inherent to different research designs and analyses. Equipped with such knowledge, the radiologic community can ensure that both research and clinical practice in our discipline excels, and that those questions that will be the most critical to answer will be formulated for successful investigation in the years to come.

Impact of racial disparities in follow-up and quality of colonoscopy on colorectal cancer outcomes

BACKGROUND

The benefits of colorectal cancer (CRC) screening programs rely on completing follow-up colonoscopy when a noncolonoscopy test is abnormal and on quality of colonoscopy screening as measured by the endoscopists' adenoma detection rate. Existing data demonstrate substantially lower follow-up colonoscopy rates and adenoma detection rate for Black Americans than White Americans. However, the contributions of racial differences in follow-up colonoscopy and adenoma detection rate on CRC outcomes have not been rigorously evaluated.

METHODS

We used established and validated CRC-Adenoma Incidence and Mortality (CRC-AIM) model as our analysis platform, with inputs from published literature that report lower follow-up colonoscopy rates and adenoma detection rate in Black adults compared with White adults (15% and 10% lower, respectively). We simulated screening with annual fecal immunochemical test, triennial multitarget stool DNA, and colonoscopy every 10 years between ages 45 and 75 years using real-world utilization of the screening modalities vs no screening. We reported lifetime outcomes per 1000 Black adults.

RESULTS

Elimination of Black-White disparities in follow-up colonoscopy rates would reduce CRC incidence and mortality by 5.2% and 9.3%, respectively, and improve life-years gained with screening by 3.4%. Elimination of Black-White disparities in endoscopists' adenoma detection rate would reduce CRC incidence and mortality by 9.4% and improve life-years gained by 3.7%. Elimination of both disparities would reduce CRC incidence and mortality by 14.6% and 18.7%, respectively, and improve life-years gained by 7.1%.

CONCLUSIONS

This modeling study predicts eliminating racial differences in follow-up colonoscopy rates, and quality of screening colonoscopy would substantially reduce Black-White disparities in CRC incidence and mortality.

The Efficacy of Real-time Computer-aided Detection of Colonic Neoplasia in Community Practice: A Pragmatic Randomized Controlled Trial

BACKGROUND & AIMS

The use of computer-aided detection (CADe) has increased the adenoma detection rates (ADRs) during colorectal cancer (CRC) screening/surveillance in randomized controlled trials (RCTs) but has not shown benefit in real-world implementation studies. We performed a single-center pragmatic RCT to evaluate the impact of real-time CADe on ADRs in colonoscopy performed by community gastroenterologists.

METHODS

We enrolled 1100 patients undergoing colonoscopy for CRC screening, surveillance, positive fecal-immunohistochemical tests, and diagnostic indications at one community-based center from September 2022 to March 2023. Patients were randomly assigned (1:1) to traditional colonoscopy or real-time CADe. Blinded pathologists analyzed histopathologic findings. The primary outcome was ADR (the percentage of patients with at least 1 histologically proven adenoma or carcinoma). Secondary outcomes were adenomas detected per colonoscopy (APC), sessile-serrated lesion detection rate, and non-neoplastic resection rate.

RESULTS

The median age was 55.5 years (interquartile range, 50-62 years), 61% were female, 72.7% were of Hispanic ethnicity, and 9.1% had inadequate bowel preparation. The ADR for the CADe group was significantly higher than the traditional colonoscopy group (42.5% vs 34.4%; P = .005). The mean APC was significantly higher in the CADe group compared with the traditional colonoscopy group (0.89 ± 1.46 vs 0.60 ± 1.12; P < .001). The improvement in adenoma detection was driven by increased detection of <5 mm adenomas. CADe had a higher sessile-serrated lesion detection rate than traditional colonoscopy (4.7% vs 2.0%; P = .01). The improvement in ADR with CADe was significantly higher in the first half of the study (47.2% vs 33.7%; P = .002) compared with the second half (38.7% vs 34.9%; P = .33).

CONCLUSIONS

In a single-center pragmatic RCT, real-time CADe modestly improved ADR and APC in average-detector community endoscopists. (ClinicalTrials.gov number, NCT05963724).

Non-gastrointestinal symptom burden following colorectal cancer treatment-a systematic review

BACKGROUND

Colorectal cancer is one of the most common malignancies worldwide. Improvements in screening and treatment have allowed for earlier detection and longer survival. However, treatments, which may involve surgery, radiotherapy and/or chemotherapy, often lead to patients developing both gastrointestinal and non-gastrointestinal symptoms that can persist long term. This systematic review aims to understand better the non-gastrointestinal symptoms that patients develop after colorectal cancer treatment and how these are identified and assessed through the use of questionnaires.

METHOD

The review was conducted according to PRISMA guidelines. Scopus, PubMed, Web of Science, PsycINFO and Cochrane Library were searched. Eligible studies evaluated the non-gastrointestinal symptoms that patients had developed and continued to have at 12 months or longer after treatment. Studies that were performed on patients who were within 12 months of treatment, who had a recurrent or a secondary cancer, had stage 4 cancer/were palliative or that looked solely at gastro-intestinal symptoms were excluded. Articles were limited to studies on human subjects written in English published between February 2012 and July 2024.

RESULTS

The searches identified 3491 articles. Thirty-seven articles met the inclusion criteria, of which, 33 were quantitative, 2 were qualitative and 2 were mixed methods study designs. Nearly two-thirds (n = 22) were cross-sectional studies, whereas 14 were longitudinal. One study had both a cross-sectional and longitudinal component to it. Most studies were of medium to high quality based on the Newcastle Ottawa Scale (n = 23) and were conducted in 14 countries, the majority of which were performed in the Netherlands (n = 14). The majority of participants in the included studies (n = 30/37) were men. There were also three studies that were performed with only female participants and one study that was performed with male participants only. The age range of research participants across all the studies was 29 to 89 years. Forty-five different validated questionnaires containing 5-125 question items were used to collect information on the side effects and impact of colorectal cancer treatment. Completion rate for questionnaires varied from 30 to 100% (median 63.5%). These determined effects on quality of life, emotional/psychological distress, sexual and urinary dysfunction, neuropathy, fatigue and hip pain.

CONCLUSION

This systematic review highlighted a wide range of longer-term non-gastrointestinal symptoms that frequently adversely affect QoL following treatment. These studies included highlighting the importance of nutrition/diet, physical activity, spirituality and communication in managing these long-term side effects.

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

BACKGROUND

Blood-based biomarker tests can potentially change the landscape of colorectal cancer (CRC) screening. We characterize the conditions under which blood test screening would be as effective and cost-effective as annual fecal immunochemical testing or decennial colonoscopy.

METHODS

We used the 3 Cancer Information and Surveillance Modeling Network-Colon models to compare scenarios of no screening, annual fecal immunochemical testing, decennial colonoscopy, and a blood test meeting Centers for Medicare & Medicaid (CMS) coverage criteria (74% CRC sensitivity and 90% specificity). We varied the sensitivity to detect CRC (74%-92%), advanced adenomas (10%-50%), screening interval (1-3 years), and test cost ($25-$500). Primary outcomes included quality-adjusted life-years (QALY) gained from screening and costs for a US average-risk cohort of individuals aged 45 years.

RESULTS

Annual fecal immunochemical testing yielded 125-163 QALY gained per 1000 at a cost of $3811-$5384 per person, whereas colonoscopy yielded 132-177 QALY gained at a cost of $5375-$7031 per person. A blood test with 92% CRC sensitivity and 50% advanced adenoma sensitivity yielded 117-162 QALY gained if used every 3 years and 133-173 QALY gained if used every year but would not be cost-effective if priced above $125 per test. If used every 3 years, a $500 blood test only meeting CMS coverage criteria yielded 83-116 QALY gained at a cost of $8559-$9413 per person.

CONCLUSION

Blood tests that only meet CMS coverage requirements should not be recommended to patients who would otherwise undergo screening by colonoscopy or fecal immunochemical testing because of lower benefit. Blood tests need higher advanced adenoma sensitivity (above 40%) and lower costs (below $125) to be cost-effective.

Evaluation of long-term benefits and cost-effectiveness of nation-wide colorectal cancer screening strategies in China in 2020-2060: a modelling analysis

Background

Evidence on the long-term benefits and cost-effectiveness of colorectal cancer (CRC) screening strategies in China remains limited. This modelling study aims to address this issue for various CRC screening strategies in China between 2020 and 2060.

Methods

Using a previously developed microsimulation model (MIMIC-CRC) with Chinese epidemiological data, we evaluated four CRC screening strategies targeting population aged 45-74 years: no screening, colonoscopy every 10 years, biennial faecal immunochemical testing (FIT), and a roll-out FIT screening strategy. Screening coverage (invitation) rates from 5% to 100% were analysed. Single-cohort analysis of 100,000 individuals was conducted to estimate the relative cost-effectiveness of each strategy. A multiple-cohort analysis of 100,000 people aged 40+ over 2020-2060 was conducted to project nation-wide long-term benefits and cost-effectiveness.

Findings

In single-cohort analysis, all strategies yielded reductions in CRC incidence and mortality compared to no screening, with colonoscopy outperforming FIT-based strategies at the same invitation rates. In multiple-cohort analysis, among people over 40 years of age in China over 2020-2060, compared to no screening, at invitation rate of 5%, screening by colonoscopy, biennial FIT and roll-out FIT-based approach were estimated to avert 1.2, 0.4, and 0.3 million incident CRCs and 0.2, 0.1, and 0.1 million CRC-related deaths, respectively, compared to no screening (25.4 million incident CRCs and 4.4 million CRC-related deaths), and this preventive effect enlarged as the screening coverage rate increased. At full coverage, colonoscopy achieved the largest reductions (38.2% lower incidence and 43.2% lower mortality) but required the most resources. Biennial FIT and roll-out FIT-based approach screening was slightly less effective but had significant reduced colonoscopy needs (reduction of 83.8% and 85.2%, respectively) and overall cost (reduction of 23.4% and 37.8%, respectively) compared to colonoscopy screening.

Interpretation

Nation-wide implementation of screening would be effective in reducing the burden of CRC in China. Biennial FIT and roll-out FIT-based screening strategies could prevent incident CRC cases and CRC-related deaths with considerably fewer resources than colonoscopy screening. Efforts should be made to increase the screening coverage in China.

Funding

Chinese Academy of Medical Science Innovation Fund for Medical Science (2022-I2M-1-0031); National Natural Science Foundation of China (82173606; 82273726); Beijing Nova Program of Science and Technology (20230484397).

Dissemination of colorectal cancer information among Hispanic patients and their social network

BACKGROUND

Colorectal cancer (CRC) screening decision aids can inform patients about CRC screening benefits, costs, and procedures. Patients who receive the decision aid report wanting to share the information with their families and friends. We evaluated a CRC screening decision aid on Hispanic patients' communication to their alters and whether patient-alter communication leads to alters' CRC screening intention.

METHODS

We conducted a one-arm pre/post study of Hispanic patients and their alters; patients (n = 42) and their alters (n = 19) were recruited from a clinic site in Yakima County, Washington State. Patients viewed a CRC screening decision aid at the clinic site. Survey data from patients and alters were collected via telephone including patients' communication with their alters about CRC screening after viewing the decision aid and alters' intention to be screened for CRC after talking to the patient.

RESULTS

Most participants reported sharing CRC information with their alters after viewing the decision aid, and most alters confirmed they had received CRC information from participants (68%). The decision aid was associated with participants' own intention to undergo CRC screening and with alters' intention to be screened for CRC using a fecal occult blood test (p = 0.014) and sigmoidoscopy (p = 0.011).

CONCLUSIONS

Patient decision aids have the potential to increase CRC screening behavior beyond the decision aid recipients to their social network.

TRIAL REGISTRATION

Trials Registration Number: NCT04444232 "Retrospectively registered."

Retrospective study evaluating association of colorectal tumors and hepatitis C virus

BACKGROUND

Chronic hepatitis C virus (HCV) has been associated with hepatic and extrahepatic malignancies. Limited studies have shown an association between colorectal adenomas and HCV populations.

AIM

To study the prevalence of colorectal adenomas in patients with HCV compared to the general population and to evaluate if it is an independent risk factor for colorectal adenomas.

METHODS

Patients were divided into HCV and non-HCV based on their HCV RNA titers. Patients with alcoholic liver disease, hepatitis B infection, and inflammatory bowel disease were excluded. Continuous variables were analyzed using the Mann-Whitney U test, and categorical variables using χ 2 with P < 0.05 were considered statistically significant. The significant covariates (independent variables) were matched in both groups by propensity score matching, followed by multivariate regression analysis.

RESULTS

Of the 415 patients screened, 109 HCV patients and 97 non-HCV patients with colonoscopy results were included in the study. HCV patients were older, had a smoking history, had less frequent aspirin use, and had a lower body mass index (BMI) (P < 0.05). The HCV cohort had a significantly increased number of patients with adenomas (adenoma detection rate of 53.2% vs 34%. P = 0.006). We performed a propensity-matched multivariate analysis where HCV infection was significantly associated with colorectal adenoma (OR: 2.070, P = 0.019).

CONCLUSION

Our study shows a significantly higher rate of adenomas in HCV patients compared to the general population. Prospective studies would help determine if the increase in adenoma detection lowers the risk for colorectal cancer.

Impact of the serrated pathway on the simulated comparative effectiveness of colorectal cancer screening tests

BACKGROUND

Colorectal cancers (CRCs) arise from adenomas, which can produce fecal occult blood and can be detected endoscopically, or sessile serrated lesions (SSLs), which rarely bleed and may be more challenging to detect. Models informing CRC screening policy should reflect both pathways, accounting for uncertainty.

METHODS

Novel decision-analytic model of the adenoma and serrated pathways for CRC (ANSER) to compare current and emerging screening strategies, accounting for differential test sensitivities for adenomas and SSLs, and uncertainty. Strategies included colonoscopy every 10 years, stool-DNA/FIT (sDNA-FIT) every 1-3 years, or fecal immunochemical testing (FIT) every year from age 45 to 75 years. Outcomes included CRC cases and deaths, cost-effectiveness (cost/quality-adjusted life-year [QALY] gained), and burden-benefit (colonoscopies/life-year gained), with 95% uncertainty intervals (UIs).

RESULTS

ANSER predicted 62.5 (95% UI = 58.8-66.3) lifetime CRC cases and 24.1 (95% UI = 22.5-25.7) CRC deaths/1000 45-year-olds without screening, and 78%-87% CRC mortality reductions with screening. The tests' outcome distributions overlapped for QALYs gained but separated for required colonoscopies and costs. All strategies cost less than $100 000/QALY gained vs no screening. Colonoscopy was the most effective and cost-effective, costing $9300/life-year gained (95% UI = $500-$21 900) vs FIT. sDNA-FIT cost more than $500 000/QALY gained vs FIT. As more CRCs arose from SSLs, colonoscopy remained preferred based on clinical benefit and cost-effectiveness, but cost-effectiveness improved for a next-generation sDNA-FIT.

CONCLUSION

When the serrated pathway is considered, modeling suggests that colonoscopy is cost-effective vs FIT. In contrast, modeling suggests that sDNA-FIT is not cost-effective vs FIT despite its greater sensitivity for SSLs, even if a substantial minority of CRCs arise from SSLs.

Utility of Stool-Based Tests for Colorectal Cancer Detection: A Comprehensive Review

Colorectal cancer (CRC) is a significant global health issue where early detection is crucial for improving treatment outcomes and survival rates. This comprehensive review assesses the utility of stool-based tests in CRC screening, including traditional fecal occult blood tests (FOBT), both chemical (gFOBT) and immunochemical techniques (FIT), as well as multitarget stool DNA (mt-sDNA) as a novel and promising biomarker. The advancements, limitations and the impact of false positives and negatives of these methods are examined. The review analyzed various studies on current screening methods, focusing on laboratory tests and biomarkers. Findings indicate that while FIT and mt-sDNA tests offer enhanced sensitivity and specificity over traditional guaiac-based FOBT, they also come with higher costs and potential for increased false positives. FIT shows better patient adherence due to its ease to use, but incorrect usage and interpretation of FOBT can lead to significant diagnostic errors. In conclusion, despite the improvements in FOBT methods like FIT in CRC detection, careful consideration of each method's benefits and drawbacks is essential. Effective CRC screening programs should combine various methods tailored to specific population needs, aiming for early detection and reduced mortality rates.

A novel dual-target Septin9 methylation assay for improved detection of early-stage colorectal cancer and high-grade intraepithelial neoplasia

BACKGROUND

Colorectal cancer (CRC) ranks as the third most common malignancies in the world, and periodic examination of the patient is advantageous in reducing the mortality of CRC. The first blood-based Septin9 gene methylation assay which recognized by the US FDA for CRC examination was Epi proColon. However, this assay was not broadly applied in the current clinical guideline because of its relatively lower sensitivity in the detection of early-stage CRC.

METHODS

This study aimed at developing a new multiplex Septin9 methylation assay (ColonUSK) which simultaneously evaluates two CpG-rich subregions in the promoter of the Septin9 gene and an internal control in a single reaction. ColonUSK proved increased sensitivity, with a detection limit as low as 12pg of the positive DNA compared with the Septin9 assay targeting one CpG-rich subregion. 1366 subjects were prospectively recruited from four comprehensive hospitals in China in an opportunistic screening study for assessing its value in CRC detection. Blind testing was developed to evaluate ColonUSK in comparison with clinical examination using clinical gold standard such as colonoscopy.

RESULTS

The assay demonstrates clinical sensitivity for diagnosing colorectal cancer (CRC) and advanced adenoma at rates of 77.34% and 25.26%, respectively. Furthermore, ColonUSK exhibits a high degree of specificity for non-CRC cases (95.95%) clinically. Significantly, the detection rate of cases in high-grade intraepithelial neoplasia increased to 54.29%. The value for the assay in the Kappa test was 0.76, showing a high degree of consistency between ColonUSK and clinical gold standard.

CONCLUSIONS

ColonUSK indicated moderate diagnostic value and could become a non-invasive detection way for CRC. The implementation of the ColonUSK assay has the capacity to markedly enhance CRC screening practices.

Duration of risk reduction in colorectal cancer incidence and mortality after a complete colonoscopy in Ontario, Canada: a population-based cohort study

BACKGROUND

Colorectal cancer guidelines recommend screening colonoscopy every 10 years after a negative procedure. If risk reduction extends past 10 years, the recommended interval could be extended, reducing the burden on the individual and health-care system. We aimed to estimate the duration that patients remain at reduced risk of colorectal cancer incidence and mortality after a complete colonoscopy.

METHODS

We did a population-based cohort study of individuals aged 50-65 years between Jan 1, 1994, to Dec 31, 2017. We excluded individuals with previous exposure to colonoscopy or colorectal surgery, those previously diagnosed with colorectal cancer, or a history of hereditary or other bowel disorders. We followed up participants until Dec 31, 2018, and identified all colonoscopies performed in this time period. We used a 9-level time-varying measure of exposure, capturing time since last complete colonoscopy (no complete colonoscopy, ≤5 years, >5-10 years, >10-15 years, and >15 years) and whether an intervention was performed (biopsy or polypectomy). A Cox proportional hazards regression model adjusting for age, sex, comorbidity, residential income quintile, and immigration status was used to estimate the association between exposure to a complete colonoscopy and colorectal cancer incidence and mortality.

FINDINGS

5 298 033 individuals (2 609 060 [49·2%] female and 2 688 973 [50·8%] male; no data on ethnicity were available) were included in the cohort, with a median follow-up of 12·56 years (IQR 6·26-20·13). 90 532 (1·7%) individuals were diagnosed with colorectal cancer and 44 088 (0·8%) died from colorectal cancer. Compared with those who did not have a colonoscopy, the risk of colorectal cancer in those who had a complete negative colonoscopy was reduced at all timepoints, including when the procedure occurred more than 15 years earlier (hazard ratio [HR] 0·62 [95% CI 0·51-0·77] for female individuals and 0·57 [0·46-0·70] for male individuals. A similar finding was observed for colorectal cancer mortality, with lower risk at all timepoints, including when the procedure occurred more than 15 years earlier (HR 0·64 [95% CI 0·49-0·83] for female participants and 0·65 [0·50-0·83] for male participants). Those who had a colonoscopy with intervention had a significantly lower colorectal cancer incidence than those who did not undergo colonoscopy if the procedure occurred within 10 years for females (HR 0·70 [95% CI 0·63-0·77]) and up to 15 years for males (0·62 [(0·53-0·72]).

INTERPRETATION

Compared with those who do not receive colonoscopy, individuals who have a negative colonoscopy result remain at lower risk for colorectal cancer incidence and mortality more than 15 years after the procedure. The current recommendation of repeat screening at 10 years in these individuals should be reassessed.

FUNDING

Canadian Institutes of Health Research.

Emulator-Based Bayesian Calibration of the CISNET Colorectal Cancer Models

PURPOSE

To calibrate Cancer Intervention and Surveillance Modeling Network (CISNET)'s SimCRC, MISCAN-Colon, and CRC-SPIN simulation models of the natural history colorectal cancer (CRC) with an emulator-based Bayesian algorithm and internally validate the model-predicted outcomes to calibration targets.

METHODS

We used Latin hypercube sampling to sample up to 50,000 parameter sets for each CISNET-CRC model and generated the corresponding outputs. We trained multilayer perceptron artificial neural networks (ANNs) as emulators using the input and output samples for each CISNET-CRC model. We selected ANN structures with corresponding hyperparameters (i.e., number of hidden layers, nodes, activation functions, epochs, and optimizer) that minimize the predicted mean square error on the validation sample. We implemented the ANN emulators in a probabilistic programming language and calibrated the input parameters with Hamiltonian Monte Carlo-based algorithms to obtain the joint posterior distributions of the CISNET-CRC models' parameters. We internally validated each calibrated emulator by comparing the model-predicted posterior outputs against the calibration targets.

RESULTS

The optimal ANN for SimCRC had 4 hidden layers and 360 hidden nodes, MISCAN-Colon had 4 hidden layers and 114 hidden nodes, and CRC-SPIN had 1 hidden layer and 140 hidden nodes. The total time for training and calibrating the emulators was 7.3, 4.0, and 0.66 h for SimCRC, MISCAN-Colon, and CRC-SPIN, respectively. The mean of the model-predicted outputs fell within the 95% confidence intervals of the calibration targets in 98 of 110 for SimCRC, 65 of 93 for MISCAN, and 31 of 41 targets for CRC-SPIN.

CONCLUSIONS

Using ANN emulators is a practical solution to reduce the computational burden and complexity for Bayesian calibration of individual-level simulation models used for policy analysis, such as the CISNET CRC models. In this work, we present a step-by-step guide to constructing emulators for calibrating 3 realistic CRC individual-level models using a Bayesian approach.

HIGHLIGHTS

We use artificial neural networks (ANNs) to build emulators that surrogate complex individual-based models to reduce the computational burden in the Bayesian calibration process.ANNs showed good performance in emulating the CISNET-CRC microsimulation models, despite having many input parameters and outputs.Using ANN emulators is a practical solution to reduce the computational burden and complexity for Bayesian calibration of individual-level simulation models used for policy analysis.This work aims to support health decision scientists who want to quantify the uncertainty of calibrated parameters of computationally intensive simulation models under a Bayesian framework.

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.

Longer Interval Between First Colonoscopy With Negative Findings for Colorectal Cancer and Repeat Colonoscopy

Importance

For individuals without a family history of colorectal cancer (CRC), colonoscopy screening every 10 years is recommended to reduce CRC incidence and mortality. However, debate exists about whether and for how long this 10-year interval could be safely expanded.

Objective

To assess how many years after a first colonoscopy with findings negative for CRC a second colonoscopy can be performed.

Design, Setting, and Participants

This cohort study leveraged Swedish nationwide register-based data to examine CRC diagnoses and CRC-specific mortality among individuals without a family history of CRC. The exposed group included individuals who had a first colonoscopy with findings negative for CRC at age 45 to 69 years between 1990 and 2016. The control group included individuals matched by sex, birth year, and baseline age (ie, the age of their matched exposed individual when the exposed individual's first colonoscopy with findings negative for CRC was performed). Individuals in the control group either did not have a colonoscopy during the follow-up or underwent colonoscopy that resulted in a CRC diagnosis. Up to 18 controls were matched with each exposed individual. Individuals were followed up from 1990 to 2018, and data were analyzed from November 2022 to November 2023.

Exposure

A first colonoscopy with findings negative for CRC, defined as a first colonoscopy without a diagnosis of colorectal polyp, adenoma, carcinoma in situ, or CRC before or within 6 months after screening.

Main Outcomes and Measures

The primary outcomes were CRC diagnosis and CRC-specific death. The 10-year standardized incidence ratio and standardized mortality ratio were calculated to compare risks of CRC and CRC-specific death in the exposed and control groups based on different follow-up screening intervals.

Results

The sample included 110 074 individuals (65 147 females [59.2%]) in the exposed group and 1 981 332 (1 172 646 females [59.2%]) in the control group. The median (IQR) age for individuals in both groups was 59 (52-64) years. During up to 29 years of follow-up of individuals with a first colonoscopy with findings negative for CRC, 484 incident CRCs and 112 CRC-specific deaths occurred. After a first colonoscopy with findings negative for CRC, the risks of CRC and CRC-specific death in the exposed group were significantly lower than those in their matched controls for 15 years. At 15 years after a first colonoscopy with findings negative for CRC, the 10-year standardized incidence ratio was 0.72 (95% CI, 0.54-0.94) and the 10-year standardized mortality ratio was 0.55 (95% CI, 0.29-0.94). In other words, the 10-year cumulative risk of CRC in year 15 in the exposed group was 72% that of the 10-year cumulative risk of CRC in the control group. Extending the colonoscopy screening interval from 10 to 15 years in individuals with a first colonoscopy with findings negative for CRC could miss the early detection of only 2 CRC cases and the prevention of 1 CRC-specific death per 1000 individuals, while potentially avoiding 1000 colonoscopies.

Conclusions and Relevance

This cohort study found that for the population without a family history of CRC, the 10-year interval between colonoscopy screenings for individuals with a first colonoscopy with findings negative for CRC could potentially be extended to 15 years. A longer interval between colonoscopy screenings could be beneficial in avoiding unnecessary invasive examinations.

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

BACKGROUND & AIMS

A blood-based colorectal cancer (CRC) screening test may increase screening participation. However, blood tests may be less effective than current guideline-endorsed options. The Centers for Medicare & Medicaid Services (CMS) covers blood tests with sensitivity of at least 74% for detection of CRC and specificity of at least 90%. In this study, we investigate whether a blood test that meets these criteria is cost-effective.

METHODS

Three microsimulation models for CRC (MISCAN-Colon, CRC-SPIN, and SimCRC) were used to estimate the effectiveness and cost-effectiveness of triennial blood-based screening (from ages 45 to 75 years) compared to no screening, annual fecal immunochemical testing (FIT), triennial stool DNA testing combined with an FIT assay, and colonoscopy screening every 10 years. The CMS coverage criteria were used as performance characteristics of the hypothetical blood test. We varied screening ages, test performance characteristics, and screening uptake in a sensitivity analysis.

RESULTS

Without screening, the models predicted 77-88 CRC cases and 32-36 CRC deaths per 1000 individuals, costing $5.3-$5.8 million. Compared to no screening, blood-based screening was cost-effective, with an additional cost of $25,600-$43,700 per quality-adjusted life-year gained (QALYG). However, compared to FIT, triennial stool DNA testing combined with FIT, and colonoscopy, blood-based screening was not cost-effective, with both a decrease in QALYG and an increase in costs. FIT remained more effective (+5-24 QALYG) and less costly (-$3.2 to -$3.5 million) than blood-based screening even when uptake of blood-based screening was 20 percentage points higher than uptake of FIT.

CONCLUSION

Even with higher screening uptake, triennial blood-based screening, with the CMS-specified minimum performance sensitivity of 74% and specificity of 90%, was not projected to be cost-effective compared with established strategies for colorectal cancer screening.

Antibiotic prophylaxis prior to colonoscopy with biopsy does not decrease risk of prosthetic joint infection in total knee arthroplasty recipients

Introduction

Prosthetic joint infection (PJI) risk continues to receive much attention given its associated morbidity and costs to patients and healthcare systems. It has been hypothesized that invasive colonoscopies may increase the risk of PJI. However, the decision to administer antibiotic prophylaxis lacks clinical guidance. In this study we aimed to compare PJI rates in patients undergoing colonoscopies with and without antibiotic prophylaxis against a control group, analyzing PJI occurrences at 90 days, 6 months, 9 months, and 1-year post-procedure and (2) assess the impact of antibiotic prophylaxis on PJI rates to inform clinical guidelines.

Methods

We queried a national, all-payer database to identify all primary total knee arthroplasty procedures without prior history of PJI between January 2010 and October 2020 (n = 1.9 million). All patients who had a diagnosis of PJI within one year of index procedure were excluded. There were three cohorts identified: colonoscopy with biopsy without antibiotic prophylaxis; colonoscopy with biopsy with antibiotic prophylaxis; and a control of no prior colonoscopy. Both colonoscopy cohorts were slightly younger and had higher comorbidities than the controls. The PJI diagnoses were identified at four separate time intervals within one-year after colonoscopy: 90-days; 6-months; 9-months; and 1-year. Chi-square analyses with odds ratios (ORs) and 95% confidence intervals were conducted for PJI rates between groups at all time-points.

Results

Among all cohorts, no significant differences in PJI rates were found at 90-days (P = 0.459), 6-months (P = 0.608), 9-months (P = 0.598), and 1-year (P = 0.330). Similarly, direct comparison of both colonoscopy groups, with and without antibiotic prophylaxis, demonstrated no PJI rate differences at 90-day (P = 0.540), 6-months (P = 0.812), 9-months (P = 0.958), and 1-year (P = 0.207). Ranges of ORs between the colonoscopy cohorts were 1.07-1.43.

Conclusion

Invasive colonoscopy does not increase the risk of PJI in patients who have pre-existing knee implants. Furthermore, antibiotic prophylaxis may not be warranted in patients undergoing colonoscopy who have a planned biopsy.

Does a "Western Lifestyle" Confer a Higher Burden of Colorectal Cancer? A Comparison of EU15+ Countries versus Global Trends between 1990 and 2019

The incidence of colorectal cancer (CRC) in the U.S. is declining in adults 50 years and older; however, recent studies suggest an increasing disease burden among adults under age 50. This study aims to compare the incidence, mortality, and mortality-to-incidence ratios (MIRs) of CRC in EU15+ countries to determine if similar age-stratified occurrences are observed across these countries with similar "Western lifestyle"-related risk factors. Incidence and mortality rates for CRC between 1990 and 2019 were extracted using the Global Burden of Disease database. The data were age-stratified into groups between ages 25-49, 50-69, and greater than 69 years. We observed that the incidence of CRC increased globally for all age groups, with the highest increase observed for males (75.9%) and females (27.7%) aged 25-49. A similar trend was observed in 15 of the 19 EU15+ countries for males and 16 of the 19 EU15+ countries for females aged 25-49. Global mortality rates decreased for all age groups in females but increased for males in all age groups. This raises concerns regarding potentially modifiable risk factors contributing to increased CRC development and underscores the importance of implementing standardized screening at an earlier stage to ensure adequate detection in the younger population.

Bias due to coarsening of time intervals in the inference for the effectiveness of colorectal cancer screening

BACKGROUND

Observational studies are frequently used to estimate the comparative effectiveness of different colorectal cancer (CRC) screening methods due to the practical limitations and time needed to conduct large clinical trials. However, time-varying confounders, e.g. polyp detection in the last screening, can bias statistical results. Recently, generalized methods, or G-methods, have been used for the analysis of observational studies of CRC screening, given their ability to account for such time-varying confounders. Discretization, or the process of converting continuous functions into discrete counterparts, is required for G-methods when the treatment and outcomes are assessed at a continuous scale.

DEVELOPMENT

This paper evaluates the interplay between time-varying confounding and discretization, which can induce bias in assessing screening effectiveness. We investigate this bias in evaluating the effect of different CRC screening methods that differ from each other in typical screening frequency.

APPLICATION

First, using theory, we establish the direction of the bias. Then, we use simulations of hypothetical settings to study the bias magnitude for varying levels of discretization, frequency of screening and length of the study period. We develop a method to assess possible bias due to coarsening in simulated situations.

CONCLUSIONS

The proposed method can inform future studies of screening effectiveness, especially for CRC, by determining the choice of interval lengths where data are discretized to minimize bias due to coarsening while balancing computational costs.

Collaborative Modeling to Compare Different Breast Cancer Screening Strategies: A Decision Analysis for the US Preventive Services Task Force

Importance

The effects of breast cancer incidence changes and advances in screening and treatment on outcomes of different screening strategies are not well known.

Objective

To estimate outcomes of various mammography screening strategies.

Design, Setting, and Population

Comparison of outcomes using 6 Cancer Intervention and Surveillance Modeling Network (CISNET) models and national data on breast cancer incidence, mammography performance, treatment effects, and other-cause mortality in US women without previous cancer diagnoses.

Exposures

Thirty-six screening strategies with varying start ages (40, 45, 50 years) and stop ages (74, 79 years) with digital mammography or digital breast tomosynthesis (DBT) annually, biennially, or a combination of intervals. Strategies were evaluated for all women and for Black women, assuming 100% screening adherence and "real-world" treatment.

Main Outcomes and Measures

Estimated lifetime benefits (breast cancer deaths averted, percent reduction in breast cancer mortality, life-years gained), harms (false-positive recalls, benign biopsies, overdiagnosis), and number of mammograms per 1000 women.

Results

Biennial screening with DBT starting at age 40, 45, or 50 years until age 74 years averted a median of 8.2, 7.5, or 6.7 breast cancer deaths per 1000 women screened, respectively, vs no screening. Biennial DBT screening at age 40 to 74 years (vs no screening) was associated with a 30.0% breast cancer mortality reduction, 1376 false-positive recalls, and 14 overdiagnosed cases per 1000 women screened. Digital mammography screening benefits were similar to those for DBT but had more false-positive recalls. Annual screening increased benefits but resulted in more false-positive recalls and overdiagnosed cases. Benefit-to-harm ratios of continuing screening until age 79 years were similar or superior to stopping at age 74. In all strategies, women with higher-than-average breast cancer risk, higher breast density, and lower comorbidity level experienced greater screening benefits than other groups. Annual screening of Black women from age 40 to 49 years with biennial screening thereafter reduced breast cancer mortality disparities while maintaining similar benefit-to-harm trade-offs as for all women.

Conclusions

This modeling analysis suggests that biennial mammography screening starting at age 40 years reduces breast cancer mortality and increases life-years gained per mammogram. More intensive screening for women with greater risk of breast cancer diagnosis or death can maintain similar benefit-to-harm trade-offs and reduce mortality disparities.

Trends in Colorectal Cancer Screening from the National Health Interview Survey: Analysis of the Impact of Different Modalities on Overall Screening Rates

Colorectal cancer is the second leading cause of cancer-related mortality in adults in the United States. Despite compelling evidence of improved outcomes in colorectal cancer, screening rates are not optimal. This study aimed to characterize colorectal cancer screening trends over the last two decades and assess the impact of various screening modalities on overall colorectal cancer screening rates. Using National Health Interview Survey data from 2005 to 2021, we examined colorectal cancer screening [colonoscopy, multitarget stool DNA (mt-sDNA), fecal occult blood test (FOBT)/fecal immunochemical test, sigmoidoscopy, CT colonography] rates among adults ages 50-75 years (n = 85,571). A pseudo-time-series cross-sectional (pseudo-TSCS) analysis was conducted including a random effects generalized least squares regression model to estimate the relative impact of each modality on changes in colorectal cancer screening rates. Among 50 to 75 year olds, the estimated colorectal cancer screening rate increased from 47.7% in 2005 to 69.9% in 2021, with the largest increase between 2005 and 2010 (47.7%-60.7%). Rates subsequently plateaued until 2015 but increased from 63.5% in 2015 to 69.9% in 2018. This was primarily driven by the increased use of mt-sDNA (2.5% in 2018 to 6.6% in 2021). Pseudo-TSCS analysis results showed that mt-sDNA contributed substantially to the increase in overall screening rates (77.3%; P < 0.0001) between 2018 and 2021. While colorectal cancer screening rates increased from 2005 to 2021, they remain below the 80% goal. The introduction of mt-sDNA, a noninvasive screening test may have improved overall rates. Sustained efforts are required to further increase screening rates to improve patient outcomes and offering a range of screening options is likely to contribute to achieving this goal.

PREVENTION RELEVANCE

This retrospective study highlights the importance of convenient stool-based colorectal cancer screening options to achieve the national goal of 80% for overall colorectal cancer screening rates. Empowering screening-eligible individuals with a choice for their colorectal cancer screening tests is imperative.

Early-Onset Colorectal Cancer-A Retrospective Study from a Tertiary Referral Hospital in Romania

Early-onset colorectal cancer emerges as a distinctive clinical and biological entity and is generally defined as the onset of colon or rectal neoplasia before the age of 50. Several reports describe an increasing incidence worldwide of colorectal cancers occurring in individuals younger than 50 years, along with particular histologic and molecular features. Although heredity may be an explanation in some cases with young-onset colorectal cancer, other driving factors remain partially unknown. The present study explores demographic, clinical, and pathological features within a group of patients diagnosed with colorectal cancer before the age of 50. It is a retrospective survey based on data collected between 2017 and 2023 within three surgical departments from a tertiary Romanian hospital. The clinical and pathological features we identified (later-stage disease, distal colon tumor localization, mucinous histology) are mainly superimposed with the existing data in the literature regarding this pathology. In order to lower the burden that colorectal neoplasia diagnosed in the young implies, a change of paradigm should be made in terms of establishing effective and targeted screening programs but also in the direction of enhancing complex clinical, pathological, and molecular diagnosis.

Population-level impact of the BMJ Rapid Recommendation for colorectal cancer screening: a microsimulation analysis

OBJECTIVE

In 2019, a BMJ Rapid Recommendation advised against colorectal cancer (CRC) screening for adults with a predicted 15-year CRC risk below 3%. Using Switzerland as a case study, we estimated the population-level impact of this recommendation.

DESIGN

We predicted the CRC risk of all respondents to the population-based Swiss Health Survey. We derived the distribution of risk-based screening start age, assuming predicted risk was calculated every 5 years between ages 25 and 70 and screening started when this risk exceeded 3%. Next, the MISCAN-Colon microsimulation model evaluated biennial faecal immunochemical test (FIT) screening with this risk-based start age. As a comparison, we simulated screening initiation based on age and sex.

RESULTS

Starting screening only when predicted risk exceeded 3% meant 82% of women and 90% of men would not start screening before age 65 and 60, respectively. This would require 43%-57% fewer tests, result in 8%-16% fewer CRC deaths prevented and yield 19%-33% fewer lifeyears gained compared with screening from age 50. Screening women from age 65 and men from age 60 had a similar impact as screening only when predicted risk exceeded 3%.

CONCLUSION

With the recommended risk prediction tool, the population impact of the BMJ Rapid Recommendation would be similar to screening initiation based on age and sex only. It would delay screening initiation by 10-15 years. Although halving the screening burdens, screening benefits would be reduced substantially compared with screening initiation at age 50. This suggests that the 3% risk threshold to start CRC screening might be too high.

Maximizing scarce colonoscopy resources: the crucial role of stool-based tests

During the COVID-19 pandemic, health systems, including federally qualified health centers, experienced disruptions in colorectal cancer (CRC) screening. National organizations called for greater use of at-home stool-based testing followed by colonoscopy for those with abnormal test results to limit (in-person) colonoscopy exams to people with acute symptoms or who were high risk. This stool-test-first strategy may also be useful for adults with low-risk adenomas who are due for surveillance colonoscopy. We argue that colonoscopy is overused as a first-line screening method in low- and average-risk adults and as a surveillance tool among adults with small adenomas. Yet, simultaneously, many people do not receive much-needed colonoscopies. Delivering the right screening tests at intervals that reduce the risk of CRC, while minimizing patient inconvenience and procedural risks, can strengthen health-care systems. Risk stratification could improve efficiency of CRC screening, but because models that adequately predict risk are years away from clinical use, we need to optimize use of currently available technology-that is, low-cost fecal testing followed by colonoscopy for those with abnormal test results. The COVID-19 pandemic highlighted the urgent need to adapt to resource constraints around colonoscopies and showed that increased use of stool-based testing was possible. Learning how to adapt to such constraints without sacrificing patients' health, particularly for patients who receive care at federally qualified health centers, should be a priority for CRC prevention research.

Costs and Projected Effect of a Federally Qualified Health Center-Based Mailed Colorectal Cancer Screening Program in Texas

Introduction

Mailed stool testing for colorectal cancer (CRC) may improve screening uptake and reduce the incidence and mortality of CRC, especially among patients at federally qualified health centers (FQHCs). To expand screening programs it is important to identify cost-effective approaches.

Methods

We developed a decision-analytic model to estimate the cost, effects on screening and patient outcomes (CRCs detected, CRCs prevented, CRC deaths prevented), and cost-effectiveness of implementing a state-wide mailed stool testing program over 5 years among unscreened, age-eligible (aged 50-75 y) patients at FQHCs in Texas. We compared various outreach strategies and organizational structures (centralized, regional, or a hybrid). We used data from our existing regional mailed stool testing program and recent systematic reviews to set parameters for the model. Costs included start-up and ongoing activities and were estimated in 2022 US dollars from the perspective of a hypothetical third-party payer. Cost-effectiveness was assessed by using both incremental and average cost-effectiveness ratios.

Results

Using either a statewide centralized or hybrid organizational configuration to mail stool tests to newly eligible FQHC patients and patients who have responded at least once since program inception is likely to result in the best use of resources over 5 years, enabling more than 110,000 additional screens, detecting an incremental 181 to 194 CRCs, preventing 91 to 98 CRCs, and averting 46 to 50 CRC deaths, at a cost of $10 million to $11 million compared with no program.

Conclusions

A statewide mailed stool testing program for FQHC patients can be implemented at reasonable cost with considerable effects on CRC screening outcomes, especially when its structure maximizes program efficiency while maintaining effectiveness.

Geographical Variations in Early Onset Colorectal Cancer in the United States between 2001 and 2020

BACKGROUND

Colorectal cancer remains the second leading cause of cancer-related death in the US. As early-onset colorectal cancer (EO-CRC) becomes more prevalent in the US, research attention has shifted towards identifying at-risk populations. Previous studies have highlighted the rising rate of early-onset adenocarcinoma (ADC) and neuroendocrine tumors (NET) in the US. However, data on geographical variations of EO-CRC are scarce. Hence, our study aims to analyze time trends in EO-CRC incidence rates across various US regions and to assess these trends by sex and histopathological subtypes (ADC and NET).

METHODS

We analyze data spanning from 2001 to 2020 from the United States Cancer Statistics (USCS) database, covering nearly 98% of the US population. Using SEER*Stat software version (8.4.2, NCI), we calculated EO-CRC incidence rates among adults aged 20-54 years, adjusting for the age standard 2000 US population. The rates were categorized by sex and US geographical regions into west, midwest, northeast, and south. Time trends, reported as annual percentage change (APC) and average APC (AAPC), were generated via Joinpoint Regression software (v.5.0.2, NCI) utilizing the weighted Bayesian Information Criteria "BIC" method to generate the best-fit trends with a two-sided p-value cutoff at 0.05. The rates were also stratified by histopathology into ADC and NET.

RESULTS

Between 2001 and 2020, a total of 514,875 individuals were diagnosed with early-onset CRC in the US, with 54.78% being men. Incidence rates and trends varied across geographical regions. In the western region (comprising 106,685 patients, 54.85% men), incidence rates significantly increased in both women (AAPC = 1.37, p < 0.001) and men (AAPC = 1.34, p < 0.001). Similarly, in the midwestern region (with 110,380 patients, 55.46% men), there were significant increases in incidence rates among women (AAPC = 1.06, p < 0.001) and men (AAPC = 1.35, p < 0.001). The northeastern region (with 94,758 patients, 54.53% men) also witnessed significant increases in incidence rates for both women (AAPC = 0.71, p < 0.001) and men (AAPC = 0.84, p < 0.001). In contrast, the southern region (with 203,052 patients, 54.48% men) experienced slower increases in incidence rates among both women and men (AAPC = 0.25, p < 0.05 in women; AAPC = 0.66, p < 0.05 in men). When stratified by histopathology, incidence rates for adenocarcinomas (ADC) increased in all regions, most notably in the west (AAPC = 1.45, p < 0.05), and least in the south (AAPC = 0.46, p < 0.05). Conversely, for neuroendocrine tumors (NET), while incidence rates increased similarly across all regions, the pace was notably faster compared to ADC, particularly in the west (AAPC = 3.26, p < 0.05) and slower in the south (AAPC = 2.24, p < 0.05) Discussion: Our analysis of nationwide US data spanning two decades and encompassing over half a million early-onset CRC patients, representing nearly 98% of the US population, highlights significant temporal variation in incidence rates across various geographical regions. The most substantial increases in incidence rates were observed in the west, while the least pronounced changes were noted in the south, affecting both men and women. These trends persisted across the main CRC histopathological subtypes, with NET exhibiting a notably swifter pace of increase compared with ADC. These findings hold important implications for public health strategies and underscore the need for targeted interventions to address the rising burden of early-onset CRC across different regions in the US.