Colorectal Cancer Screening: Recommendations for Physicians and Patients From the U.S. Multi-Society Task Force on Colorectal Cancer

Thioredoxin system in colorectal cancer: Its role in carcinogenesis, disease progression, and response to treatment

The thioredoxin system is essential for many physiological processes, including the maintenance of redox signalling pathways. Alterations in the activity, expression and interactions with other signalling pathways can lead to protective or pathophysiological responses. Thioredoxin and thioredoxin reductase, the two main components of this system, are often overexpressed in cancer, including colorectal cancer. This overexpression is often linked with tumour progression and poor outcomes. This review discusses the role of the Trx system in driving colorectal carcinogenesis and disease progression, as well as the challenges of targeting this system. Additionally, the recent advancements in the development of novel and effective thioredoxin inhibitors for colorectal cancer are also explored.

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.

Personalized Decisional Algorithms for Soft Tissue Defect Reconstruction after Abdominoperineal Resection for Low-Lying Rectal Cancers

BACKGROUND

Abdominoperineal resection (APR)-the standard surgical procedure for low-lying rectal cancer (LRC)-leads to significant perineal defects, posing considerable reconstruction challenges that, in selected cases, necessitate the use of plastic surgery techniques (flaps).

PURPOSE

To develop valuable decision algorithms for choosing the appropriate surgical plan for the reconstruction of perineal defects.

METHODS

Our study included 245 LRC cases treated using APR. Guided by the few available publications in the field, we have designed several personalized decisional algorithms for managing perineal defects considering the following factors: preoperative radiotherapy, intraoperative position, surgical technique, perineal defect volume, and quality of tissues and perforators. The algorithms have been improved continuously during the entire period of our study based on the immediate and remote outcomes.

RESULTS

In 239 patients following APR, the direct closing procedure was performed versus 6 cases in which we used various types of flaps for perineal reconstruction. Perineal incisional hernia occurred in 12 patients (5.02%) with direct perineal wound closure versus in none of those reconstructed using flaps.

CONCLUSION

The reduced rate of postoperative complications suggests the efficiency of the proposed decisional algorithms; however, more extended studies are required to categorize them as evidence-based management guide tools.

Investigation of the relationship between colonoscopy insertion difficulty factors and endoscope shape using an endoscopic position detection unit

In this study, we investigated the relationship between the cecal intubation time (CIT) and the form and method used for passing through the sigmoid/descending colon junction (SDJ) and the hepatic flexure using an endoscopic position detection unit (UPD), with reference to various factors [age, sex, body mass index (BMI), history of abdominal and pelvic surgery, and diverticulum]. A total of 152 patients underwent colonoscopy with UPD. The mean age was 66.9 ± 12.4 years, and the male to female ratio was 3.6:1. The average CIT time was 14.3 ± 8.2 min. Age, number of experienced endoscopies, history of abdominal and pelvic surgery, BMI, and diverticulum were associated with prolonged CIT; SDJ passage pattern was straight: 8.6 ± 5.0, alpha loop: 11.8 ± 5.6, puzzle ring-like loop: 20.2 ± 5.0, reverse alpha loop: 22.4 ± 9.7, and other loop: 24.7 ± 10.5. The hepatic flexure passing method was in the following order: right rotation maneuver: 12.6 ± 6.6, push maneuver: 15.1 ± 5.9, and right rotation with positional change maneuver: 20.5 ± 7.2. In conclusion, colonoscopy with UPD revealed an association between CIT and SDJ passage pattern and hepatic flexure passing method.

Colonoscopy vs the Fecal Immunochemical Test: Which is Best?

Although there is no debate around the effectiveness of colorectal cancer screening in reducing disease burden, there remains a question regarding the most effective and cost-effective screening modality. Current United States guidelines present a panel of options that include the 2 most commonly used modalities, colonoscopy and stool testing with the fecal immunochemical test (FIT). Large-scale comparative effectiveness trials comparing colonoscopy and FIT for colorectal cancer outcomes are underway, but results are not yet available. This review will separately state the "best case" for FIT and colonoscopy as the screening tool of first choice. In addition, the review will examine these modalities from a health economics perspective to provide the reader further context about the relative advantages of these commonly used tests.

National Trends in the Incidence of Sporadic Malignant Colorectal Polyps in Young Patients (20-49 Years): An 18-Year SEER Database Analysis

Background and Objectives: Conflicting guidelines exist for initiating average-risk colorectal cancer screening at the age of 45 years. The United States Preventive Services Task Force (USPSTF) changed its guidelines in 2021 to recommend initiating screening at 45 years due to an increasing incidence of young-onset colorectal cancer. However, the American College of Physicians (ACP) recently recommended not screening average-risk individuals between 45 and 49 years old. We aim to study the national trends in the incidence of sporadic malignant polyps (SMP) in patients from 20 to 49 years old. Materials and Methods: We analyzed the Surveillance, Epidemiology, and End Results database (2000-2017) on patients aged 20-49 years who underwent diagnostic colonoscopy with at least a single malignant sporadic colorectal polyp. Results: Of the 10,742 patients diagnosed with SMP, 42.9% were female. The mean age of incidence was 43.07 years (42.91-43.23, 95% CI). Approximately 50% of malignant polyps were diagnosed between 45 and 49 years of age, followed by 25-30% between 40 and 45. There was an upward trend in malignant polyps, with a decreased incidence of malignant villous adenomas and a rise in malignant adenomas and tubulovillous adenomas. Conclusions: Our findings suggest that almost half of the SMPs under 50 years occurred in individuals under age 45, younger than the current screening threshold recommended by the ACP. There has been an upward trend in malignant polyps in the last two decades. This reflects changes in tumor biology, and necessitates further research and support in the USPSTF guidelines to start screening at the age of 45 years.

Screening for Colorectal Cancer

Colorectal cancer (CRC) is the second leading cause of cancer death. Screening has been proven to reduce both cancer incidence and cancer-related mortality. Various screening tests are available, each with their own advantages and disadvantages and varying levels of evidence to support their use. Clinicians should offer CRC screening to average-risk persons aged 50 to 75 years; starting screening at age 45 years remains controversial. Screening may be beneficial in select persons aged 76 to 85 years, based on their overall health and screening history. Offering a choice of screening tests or sequentially offering an alternate test for those who do not complete screening can significantly increase participation.

A Cell-free DNA Blood-Based Test for Colorectal Cancer Screening

BACKGROUND

Colorectal cancer is the third most diagnosed cancer in adults in the United States. Early detection could prevent more than 90% of colorectal cancer-related deaths, yet more than one third of the screening-eligible population is not up to date with screening despite multiple available tests. A blood-based test has the potential to improve screening adherence, detect colorectal cancer earlier, and reduce colorectal cancer-related mortality.

METHODS

We assessed the performance characteristics of a cell-free DNA (cfDNA) blood-based test in a population eligible for colorectal cancer screening. The coprimary outcomes were sensitivity for colorectal cancer and specificity for advanced neoplasia (colorectal cancer or advanced precancerous lesions) relative to screening colonoscopy. The secondary outcome was sensitivity to detect advanced precancerous lesions.

RESULTS

The clinical validation cohort included 10,258 persons, 7861 of whom met eligibility criteria and were evaluable. A total of 83.1% of the participants with colorectal cancer detected by colonoscopy had a positive cfDNA test and 16.9% had a negative test, which indicates a sensitivity of the cfDNA test for detection of colorectal cancer of 83.1% (95% confidence interval [CI], 72.2 to 90.3). Sensitivity for stage I, II, or III colorectal cancer was 87.5% (95% CI, 75.3 to 94.1), and sensitivity for advanced precancerous lesions was 13.2% (95% CI, 11.3 to 15.3). A total of 89.6% of the participants without any advanced colorectal neoplasia (colorectal cancer or advanced precancerous lesions) identified on colonoscopy had a negative cfDNA blood-based test, whereas 10.4% had a positive cfDNA blood-based test, which indicates a specificity for any advanced neoplasia of 89.6% (95% CI, 88.8 to 90.3). Specificity for negative colonoscopy (no colorectal cancer, advanced precancerous lesions, or nonadvanced precancerous lesions) was 89.9% (95% CI, 89.0 to 90.7).

CONCLUSIONS

In an average-risk screening population, this cfDNA blood-based test had 83% sensitivity for colorectal cancer, 90% specificity for advanced neoplasia, and 13% sensitivity for advanced precancerous lesions. (Funded by Guardant Health; ECLIPSE ClinicalTrials.gov number, NCT04136002.).

Machine learning-based identification of colorectal advanced adenoma using clinical and laboratory data: a phase I exploratory study in accordance with updated World Endoscopy Organization guidelines for noninvasive colorectal cancer screening tests

Objective

The recent World Endoscopy Organization (WEO) guidelines now recognize precursor lesions of colorectal cancer (CRC) as legitimate screening targets. However, an optimal screening method for detecting advanced adenoma (AA), a significant precursor lesion, remains elusive.

Methods

We employed five machine learning methods, using clinical and laboratory data, to develop and validate a diagnostic model for identifying patients with AA (569 AAs vs. 3228 controls with normal colonoscopy). The best-performing model was selected based on sensitivity and specificity assessments. Its performance in recognizing adenoma-carcinoma sequence was evaluated in line with guidelines, and adjustable thresholds were established. For comparison, the Fecal Occult Blood Test (FOBT) was also selected.

Results

The XGBoost model demonstrated superior performance in identifying AA, with a sensitivity of 70.8% and a specificity of 83.4%. It successfully detected 42.7% of non-advanced adenoma (NAA) and 80.1% of CRC. The model-transformed risk assessment scale provided diagnostic performance at different positivity thresholds. Compared to FOBT, the XGBoost model better identified AA and NAA, however, was less effective in CRC.

Conclusion

The XGBoost model, compared to FOBT, offers improved accuracy in identifying AA patients. While it may not meet the recommendations of some organizations, it provides value for individuals who are unable to use FOBT for various reasons.

Distinct clinical characteristics in stage III rectal cancer among different age groups and treatment outcomes after neoadjuvant chemoradiotherapy

Background

There is a rapidly increasing incidence of early-onset colorectal cancer (EO-CRC) which threatens the survival of young people, while aging also represents a challenging clinical problem.

Objectives

We aimed to investigate the differences in the clinical characteristics and prognosis in stage III rectal cancer (RC), to help optimize treatment strategies.

Design and methods

This study included 757 patients with stage III RC, all of whom received neoadjuvant chemoradiotherapy and total mesorectal excision. The whole cohort was categorized as very early onset (VEO, ⩽30 years old), early onset (EO, >30 years old, ⩽50 years old), intermediate onset (IO, >50 years, ⩽70 years), or late onset (LO, >70 years old).

Results

There were more female VEO patients than males, more mucinous adenocarcinoma, signet-ring cell carcinoma, pre-treatment cT4 stage, and higher pre-treatment serum carbohydrate antigen 19-9 compared with the other three groups. VEO patients had the worst survival with the highest RC-related mortality (34.5%), recurrence (13.8%), and metastasis (51.7%). LO patients had the highest non-RC-related mortality rate (16.6%). The Cox regression model showed VEO was a negative independent prognostic factor for disease-free survival [DFS, hazard ratio (HR): 2.830, 95% confidence interval (CI): 1.633-4.904, p < 0.001], distant metastasis-free survival (DMFS, HR: 2.969, 95% CI: 1.720-5.127, p < 0.001), overall survival (OS, HR: 2.164, 95% CI: 1.102-4.249, p = 0.025), and cancer-specific survival (CSS, HR: 2.321, 95% CI: 1.145-4.705, p = 0.020). LO was a negative independent factor on DFS (HR: 1.800, 95% CI: 1.113-2.911, p = 0.017), DMFS (HR: 1.903, 95% CI: 1.150-3.149, p = 0.012), OS (HR: 2.856, 95% CI: 1.745-4.583, p < 0.001), and CSS (HR: 2.248, 95% CI: 1.282-3.942, p = 0.005). VEO patients had better survival in the total neoadjuvant therapy-like (TNT-like) pattern on DFS (p = 0.039). IO patients receiving TNT-like patterns had better survival on DFS, OS, and CSS (p = 0.006, p = 0.018, p = 0.006, respectively).

Conclusion

In stage III RC, VEO patients exhibited unique clinicopathological characteristics, with VEO a negative independent prognostic factor for DFS, DMFS, OS, and CSS. VEO and IO patients may benefit from a TNT-like treatment pattern.

Feasibility and Colonoscopy Yield Using the Fecal Immunochemical Test (FIT)-Based Colorectal Cancer Screening in a Latin America Country

BACKGROUND & AIMS

Organized colorectal cancer (CRC) screening is not widely practiced in Latin America and the results of regional studies may help overcome barriers for implementation of national screening programs. We aimed to describe the implementation and findings of a fecal immunochemical test (FIT)-based program in Brazil.

METHODS

In a prospective population-based study, asymptomatic individuals (50-75 years old) from Sao Paulo city were invited to undergo FIT for CRC screening. Participants with positive FIT (≥10 μg Hb/g feces) were referred for colonoscopy. Subjects were classified into groups according to the presence of CRC, precursor lesions, and other benign findings, possibly related to bleeding.

RESULTS

Of a total of 9881 subjects, 7.8% had positive FIT and colonoscopy compliance was 68.9% (n = 535). Boston scale was considered adequate in 99% and cecal intubation rate was 99.4%. CRC was diagnosed in 5.9% of the cases, adenoma in 63.2%, advanced adenoma in 31.4%, and advanced neoplasia in 33.0%. Age was positively associated with CRC (P = .03). Higher FIT concentrations were associated with increased detection of CRC (P < .008), advanced adenoma (P < .001), and advanced neoplasia (P < .001).

CONCLUSIONS

Implementation of a FIT-based CRC screening program was feasible in a low-resource setting, and there was a high yield for neoplasia in individuals with a positive FIT. This approach could be used as a model to plan and disseminate organized CRC screening more broadly in Brazil and Latin America.

Managing Colorectal Cancer from Ethology to Interdisciplinary Treatment: The Gains and Challenges of Modern Medicine

Colorectal cancer (CRC) is a common malignant tumor of the gastrointestinal tract, which has become a serious threat to human health worldwide. This article exhaustively reviews colorectal cancer's incidence and relevance, carcinogenesis molecular pathways, up-to-date treatment opportunities, prophylaxis, and screening program achievements, with attention paid to its regional variations and changes over time. This paper provides a concise overview of known CRC risk factors, including familial, hereditary, and environmental lifestyle-related risk factors. The authors take a closer look into CRC's molecular genetic pathways and the role of specific enzymes involved in carcinogenesis. Moreover, the role of the general practitioner and multidisciplinary approach in CRC treatment is summarized and highlighted based on recent recommendations and experience. This article gives a clear understanding and review of the gains and challenges of modern medicine towards CRC. The authors believe that understanding the current patterns of CRC and its revolution is imperative to the prospects of reducing its burden through cancer prevention and cancer-adjusted treatment.

Unsatisfactory Fecal Immunochemical Tests for Colorectal Cancer Screening: Prevalence, Reasons, and Subsequent Testing

BACKGROUND

Fecal immunochemical test (FIT) is an effective colorectal cancer screening modality. Little is known about prevalence, reasons, and testing after unsatisfactory FIT, or a FIT that cannot be processed by the laboratory due to inadequate stool specimen or incomplete labeling.

METHODS

Our retrospective cohort study examined unsatisfactory FIT among average-risk individuals aged 50-74 years in a large, integrated, safety-net health system who completed an index FIT from 2010 to 2019. We determined prevalence of unsatisfactory FIT and categorized reasons hierarchically. We used multivariable logistic regression models to identify factors associated with: (i) unsatisfactory FIT; and (ii) subsequent testing within 15 months of the unsatisfactory FIT.

RESULTS

Of 56,980 individuals completing an index FIT, 10.2% had an unsatisfactory FIT. Reasons included inadequate specimen (51%), incomplete labeling (27%), old specimen (13%), and broken/leaking container (8%). Unsatisfactory FIT was associated with being male [OR, 1.10; confidence interval (CI), 1.03-1.16], Black (OR, 1.46; CI, 1.33-1.61), Spanish speaking (OR, 1.12; CI, 1.01-1.24), on Medicaid (OR, 1.42; CI, 1.28-1.58), and received FIT by mail (OR, 2.66; CI, 2.35-3.01). Among those with an unsatisfactory FIT, fewer than half (41%) completed a subsequent test within 15 months (median, 4.4 months). Adults aged 50-54 years (OR, 1.16; CI, 1.01-1.39) and those who received FIT by mail (OR, 1.92; CI, 1.49-2.09) were more likely to complete a subsequent test.

CONCLUSIONS

One in ten returned a FIT that could not be processed, mostly due to patient-related reasons. Fewer than half completed a subsequent test after unsatisfactory FIT.

IMPACT

Screening programs should address these breakdowns such as specimen collection and labeling to improve real-world effectiveness. See related In the Spotlight, p. 183.

Reduction in colorectal cancer incidence by screening endoscopy

Colorectal cancer (CRC) incidence rates decreased by up to 50% in older age groups in the USA in the era of the widespread uptake of screening colonoscopy, despite adverse trends in CRC risk factors and increasing CRC incidence at younger ages. However, reported first results from a randomized trial, the NordICC study, suggested rather modest effects of screening colonoscopy. As outlined in this Perspective, the apparent discrepancy between real-world and trial evidence could be explained by strong attenuation of effect estimates from screening endoscopy trials by several factors, including limited screening adherence, widespread uptake of colonoscopy outside the screening offers and the inclusion of prevalent, non-preventable CRC cases in reported numbers of incident cases. Alternative interpretations of screening endoscopy trial results accounting for prevalence bias are in line with trends in CRC incidence reduction in countries offering CRC screening, and should encourage more widespread implementation and uptake of effective CRC screening.

Variation in Receipt of Cancer Screening and Immunizations by 10-year Life Expectancy among U.S. Adults aged 65 or Older in 2019

IMPORTANCE

The likelihood of benefit from a preventive intervention in an older adult depends on its time-to-benefit and the adult's life expectancy. For example, the time-to-benefit from cancer screening is >10 years, so adults with <10-year life expectancy are unlikely to benefit.

OBJECTIVE

To examine receipt of screening for breast, prostate, or colorectal cancer and receipt of immunizations by 10-year life expectancy.

DESIGN

Analysis of 2019 National Health Interview Survey.

PARTICIPANTS

8,329 non-institutionalized adults >65 years seen by a healthcare professional in the past year, representing 46.9 million US adults.

MAIN MEASURES

Proportions of breast, prostate, and colorectal cancer screenings, and immunizations, were stratified by 10-year life expectancy, estimated using a validated mortality index. We used logistic regression to examine receipt of cancer screening and immunizations by life expectancy and sociodemographic factors.

KEY RESULTS

Overall, 54.7% of participants were female, 41.4% were >75 years, and 76.4% were non-Hispanic White. Overall, 71.5% reported being current with colorectal cancer screening, including 61.4% of those with <10-year life expectancy. Among women, 67.0% reported a screening mammogram in the past 2 years, including 42.8% with <10-year life expectancy. Among men, 56.8% reported prostate specific antigen screening in the past two years, including 48.3% with <10-year life expectancy. Reported receipt of immunizations varied from 72.0% for influenza, 68.8% for pneumococcus, 57.7% for tetanus, and 42.6% for shingles vaccination. Lower life expectancy was associated with decreased likelihood of cancer screening and shingles vaccination but with increased likelihood of pneumococcal vaccination.

CONCLUSIONS

Despite the long time-to-benefit from cancer screening, in 2019 many US adults age >65 with <10-year life expectancy reported undergoing cancer screening while many did not receive immunizations with a shorter time-to-benefit. Interventions to improve individualization of preventive care based on older adults' life expectancy may improve care of older adults.

Uncovering a dose-response relationship between positive fecal immunochemical test (FIT) and all-cause, cardiovascular and cancer-related mortality

BACKGROUND

Fecal immunochemical test (FIT) is for colorectal cancer (CRC) screening. Its association with non-CRC mortality has been overlooked. Given the quantitative FIT values, its dose-response relationships with different causes of deaths and years of life shortened were assessed.

METHODS

This retrospective study included 546,214 adults aged ≥ 20 who attended a health surveillance program from 1994 to 2017 and were followed up until the end of 2020. FIT ≥ 20 μg Hb/g was defined as positive. The Cox model was used to assess adjusted hazard ratios (aHR).

RESULTS

Positive FIT was associated with increased all-cause mortality (aHR: 1.34, 95 % CI: 1.25-1.44) and all-cancer mortality (aHR: 1.71, 95 % CI: 1.55-1.89), with a reduction of life expectancy by 4 years. The association remained even with CRC excluded. With each 10 μg Hb/g increase in FIT above 20 μg Hb/g, life expectancy was reduced by one year, and mortality increased by 4 %. About 18.6 % of deaths with positive FIT were attributed to cardiovascular disease (CVD), followed by CRC (13.5 %) and upper gastrointestinal (GI) cancers (4.5 %). The all-cause mortality rate after excluding CRC for positive FIT was 3.56/1,000 person-year, comparable to the all-cause mortality rate of 3.69/1,000 person-year for hypertension.

CONCLUSION

Positive FIT was associated with increased mortality in a dose-response manner and shortened life expectancy by 4 years, an overlooked risk comparable to hypertension, even with CRC excluded. After a negative colonoscopy, subjects with positive FIT should undergo a workup on CVD risk factors and look for other upper GI cancers.

Prevalence and predictors of colorectal cancer screening in the United States: evidence from the HINTS database 2018 to 2020

BACKGROUND

The incidence of colorectal cancer (CRC) and CRC-related mortality among young adults (< 50 years) has been on the rise. The American Cancer Society (ACS) reduced the CRC screening age to 45 in 2018. Few studies have examined the barriers to CRC screening among young adults.

METHODS

Analyses were conducted using data from 7,505 adults aged 45-75 years who completed the 2018 to 2020 Health Information National Trends Survey. We examined the sociodemographic characteristics associated with CRC screening overall and by age group using separate multivariable logistic regression models.

RESULTS

76% of eligible adults had received screening for CRC. Increasing age, Black racial group [OR 1.45; 95% CI (1.07, 1.97)], having some college experience, a college degree or higher [OR 1.69; 95% CI (1.24, 2.29)], health insurance coverage [OR 4.48; 95% CI (2.96, 6.76)], primary care provider access [OR 2.48; 95% CI (1.91, 3.22)] and presence of a comorbid illness [OR 1.39; 95% CI (1.12, 1.73)] were independent predictors of CRC screening. Current smokers were less likely to undergo CRC screening [OR 0.59; 95% CI (0.40, 0.87)]. Among adults aged 50-64 years, being of Hispanic origin [OR 0.60; 95% CI (0.39, 0.92)] was associated with a lower likelihood of CRC screening.

CONCLUSION

CRC screening rates among adults 45-49 years are low but are increasing steadily. Odds of CRC screening among Blacks is high which is encouraging while the odds among current smokers is low and concerning given their increased risk of developing CRC.

Identification of taxonomic changes in the fecal bacteriome associated with colorectal polyps and cancer: potential biomarkers for early diagnosis

Colorectal cancer (CRC) commonly arises in individuals with premalignant colon lesions known as polyps, with both conditions being influenced by gut microbiota. Host-related factors and inherent characteristics of polyps and tumors may contribute to microbiome variability, potentially acting as confounding factors in the discovery of taxonomic biomarkers for both conditions. In this study we employed shotgun metagenomics to analyze the taxonomic diversity of bacteria present in fecal samples of 90 clinical subjects (comprising 30 CRC patients, 30 with polyps and 30 controls). Our findings revealed a decrease in taxonomic richness among individuals with polyps and CRC, with significant dissimilarities observed among the study groups. We identified significant alterations in the abundance of specific taxa associated with polyps (Streptococcaceae, Lachnoclostridium, and Ralstonia) and CRC (Lactobacillales, Clostridiaceae, Desulfovibrio, SFB, Ruminococcus, and Faecalibacterium). Clostridiaceae exhibited significantly lower abundance in the early stages of CRC. Additionally, our study revealed a positive co-occurrence among underrepresented genera in CRC, while demonstrating a negative co-occurrence between Faecalibacterium and Desulfovibrio, suggesting potential antagonistic relationships. Moreover, we observed variations in taxonomic richness and/or abundance within the polyp and CRC bacteriome linked to polyp size, tumor stage, dyslipidemia, diabetes with metformin use, sex, age, and family history of CRC. These findings provide potential new biomarkers to enhance early CRC diagnosis while also demonstrating how intrinsic host factors contribute to establishing a heterogeneous microbiome in patients with CRC and polyps.

Provider communication contributes to colorectal cancer screening intention through improving screening outcome expectancies and perceived behavioral control

Colorectal cancer (CRC) screening continues to be underutilized in the US despite the availability of multiple effective, guideline-recommended screening options. Provider recommendation has been consistently shown to improve screening completion. Yet, available literature provides little information as to how specific information providers communicate influence patient decision-making about CRC screening. We tested the pathways through which information communicated by providers about the "Why" and "How" of CRC screening using the mt-sDNA test contributes to intention to complete the test. Data came from a behavioral theory-informed survey that we developed to identify psychosocial factors associated with mt-sDNA screening. RTI International administered the survey between 03/2022-06/2022 to a sample of US adults ages 45-75 who received a valid order for mt-sDNA screening with a shipping date between 5/2021-9/2021. Participants completed an electronic or paper survey. We tested the proposed relationships using structural equation modeling and tested indirect effects using Monte Carlo method. A total of 2,973 participants completed the survey (response rate: 21.7%) and 81.6% (n = 2,427) reported have had a conversation with their health care provider about mt-sDNA screening before the test was ordered. We found that "Why" information from providers was positively associated with perceived effectiveness of mt-sDNA screening, while "How" information was positively associated with perceived ease of use. "Why" information contributed to screening intention through perceived effectiveness while "How" information contributed to screening intention through perceived ease of use. These findings emphasize the critical role of provider communication in shaping patient decision-making regarding CRC screening. CRC screening interventions could consider implementing provider-patient communication strategies focusing on improving patient understanding of the rationale for CRC screening and the effectiveness of available screening options as well as addressing barriers and enhancing patients' self-efficacy in completing their preferred screening option.

Focusing on colorectal cancer in young adults (Review)

Colorectal cancer (CRC) ranks as the third leading cause of cancer-related mortality worldwide. Recent years have witnessed an increase in the incidence of CRC among adults <50 years old on a global scale. The increased incidence is associated with several modifiable risk factors, including obesity, type II diabetes, physical inactivity and frequent antibiotic use. In younger individuals, haematochezia and abdominal pain are the most common symptoms, predominantly affecting the left-side colon. While certain cases of early-onset CRC (eoCRC) are associated with a genetic predisposition, the majority result from sporadic mutations in the genes APC, KRAS, BRAF and TP53, which trigger uncontrolled cell proliferation and tumour formation. Colorectal carcinogenesis involves three major pathways: The chromosomal instability (CIN), microsatellite instability and CpG island methylator phenotype pathways. Dysregulation of the CIN pathway accounts for 85% of sporadic cases of eoCRC. Notably, eoCRC exhibits a distinctive molecular profile, characterized by a decreased prevalence of BRAF mutations, an increased prevalence of KRAS mutations and LINE-1 hypomethylation, and involvement of the Microsatellite and Chromosomal Stable pathway. Prevention strategies for eoCRC primarily centre on lifestyle modifications and the development of screening programs targeting younger populations. Further exploration into the molecular mechanisms involved in the identification of novel risk factors associated with eoCRC is imperative. These efforts, in conjunction with the development of specific screening strategies, hold the potential to reduce morbidity and mortality in the future.

Enhanced family history-based algorithms increase the identification of individuals meeting criteria for genetic testing of hereditary cancer syndromes but would not reduce disparities on their own

OBJECTIVE

This study aimed to 1) investigate algorithm enhancements for identifying patients eligible for genetic testing of hereditary cancer syndromes using family history data from electronic health records (EHRs); and 2) assess their impact on relative differences across sex, race, ethnicity, and language preference.

MATERIALS AND METHODS

The study used EHR data from a tertiary academic medical center. A baseline rule-base algorithm, relying on structured family history data (structured data; SD), was enhanced using a natural language processing (NLP) component and a relaxed criteria algorithm (partial match [PM]). The identification rates and differences were analyzed considering sex, race, ethnicity, and language preference.

RESULTS

Among 120,007 patients aged 25-60, detection rate differences were found across all groups using the SD (all P < 0.001). Both enhancements increased identification rates; NLP led to a 1.9 % increase and the relaxed criteria algorithm (PM) led to an 18.5 % increase (both P < 0.001). Combining SD with NLP and PM yielded a 20.4 % increase (P < 0.001). Similar increases were observed within subgroups. Relative differences persisted across most categories for the enhanced algorithms, with disproportionately higher identification of patients who are White, Female, non-Hispanic, and whose preferred language is English.

CONCLUSION

Algorithm enhancements increased identification rates for patients eligible for genetic testing of hereditary cancer syndromes, regardless of sex, race, ethnicity, and language preference. However, differences in identification rates persisted, emphasizing the need for additional strategies to reduce disparities such as addressing underlying biases in EHR family health information and selectively applying algorithm enhancements for disadvantaged populations. Systematic assessment of differences in algorithm performance across population subgroups should be incorporated into algorithm development processes.

Advancing Colorectal Cancer Diagnosis with AI-Powered Breathomics: Navigating Challenges and Future Directions

Early detection of colorectal cancer is crucial for improving outcomes and reducing mortality. While there is strong evidence of effectiveness, currently adopted screening methods present several shortcomings which negatively impact the detection of early stage carcinogenesis, including low uptake due to patient discomfort. As a result, developing novel, non-invasive alternatives is an important research priority. Recent advancements in the field of breathomics, the study of breath composition and analysis, have paved the way for new avenues for non-invasive cancer detection and effective monitoring. Harnessing the utility of Volatile Organic Compounds in exhaled breath, breathomics has the potential to disrupt colorectal cancer screening practices. Our goal is to outline key research efforts in this area focusing on machine learning methods used for the analysis of breathomics data, highlight challenges involved in artificial intelligence application in this context, and suggest possible future directions which are currently considered within the framework of the European project ONCOSCREEN.

Attitudes and Experiential Factors Associated with Completion of mt-sDNA Test Kit for Colorectal Cancer Screening

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Despite the availability of multiple screening options, CRC screening is underutilized. We conducted a survey of patients (n = 2973) who were prescribed the multi-target stool DNA (mt-sDNA) screening test (commercialized as Cologuard® and manufactured by Exact Sciences Corporation) to understand attitudes and experiences that influence test completion and likelihood of future test completion. Using exploratory factor analyses, we developed three scales: Perceived Effectiveness, Perceived Ease of Use, and Perceived Comfort.

Optimization of colonoscopy quality: Comprehensive review of the literature and future perspectives

Colonoscopy is crucial in preventing colorectal cancer (CRC) and reducing associated mortality. This comprehensive review examines the importance of high-quality colonoscopy and associated quality indicators, including bowel preparation, cecal intubation rate, withdrawal time, adenoma detection rate (ADR), complete resection, specimen retrieval, complication rates, and patient satisfaction, while also discussing other ADR-related metrics. Additionally, the review draws attention to often overlooked quality aspects, such as nonpolypoid lesion detection, as well as insertion and withdrawal skills. Moreover, it explores the potential of artificial intelligence in enhancing colonoscopy quality and highlights specific considerations for organized screening programs. The review also emphasizes the implications of organized screening programs and the need for continuous quality improvement. A high-quality colonoscopy is crucial for preventing postcolonoscopy CRC- and CRC-related deaths. Health-care professionals must develop a thorough understanding of colonoscopy quality components, including technical quality, patient safety, and patient experience. By prioritizing ongoing evaluation and refinement of these quality indicators, health-care providers can contribute to improved patient outcomes and develop more effective CRC screening programs.

AGA Clinical Practice Update on Risk Stratification for Colorectal Cancer Screening and Post-Polypectomy Surveillance: Expert Review

DESCRIPTION

Since the early 2000s, there has been a rapid decline in colorectal cancer (CRC) mortality, due in large part to screening and removal of precancerous polyps. Despite these improvements, CRC remains the second leading cause of cancer deaths in the United States, with approximately 53,000 deaths projected in 2023. The aim of this American Gastroenterological Association (AGA) Clinical Practice Update Expert Review was to describe how individuals should be risk-stratified for CRC screening and post-polypectomy surveillance and to highlight opportunities for future research to fill gaps in the existing literature.

METHODS

This Expert Review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. These Best Practice Advice statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these Best Practice Advice statements do not carry formal ratings regarding the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: All individuals with a first-degree relative (defined as a parent, sibling, or child) who was diagnosed with CRC, particularly before the age of 50 years, should be considered at increased risk for CRC. BEST PRACTICE ADVICE 2: All individuals without a personal history of CRC, inflammatory bowel disease, hereditary CRC syndromes, other CRC predisposing conditions, or a family history of CRC should be considered at average risk for CRC. BEST PRACTICE ADVICE 3: Individuals at average risk for CRC should initiate screening at age 45 years and individuals at increased risk for CRC due to having a first-degree relative with CRC should initiate screening 10 years before the age at diagnosis of the youngest affected relative or age 40 years, whichever is earlier. BEST PRACTICE ADVICE 4: Risk stratification for initiation of CRC screening should be based on an individual's age, a known or suspected predisposing hereditary CRC syndrome, and/or a family history of CRC. BEST PRACTICE ADVICE 5: The decision to continue CRC screening in individuals older than 75 years should be individualized, based on an assessment of risks, benefits, screening history, and comorbidities. BEST PRACTICE ADVICE 6: Screening options for individuals at average risk for CRC should include colonoscopy, fecal immunochemical test, flexible sigmoidoscopy plus fecal immunochemical test, multitarget stool DNA fecal immunochemical test, and computed tomography colonography, based on availability and individual preference. BEST PRACTICE ADVICE 7: Colonoscopy should be the screening strategy used for individuals at increased CRC risk. BEST PRACTICE ADVICE 8: The decision to continue post-polypectomy surveillance for individuals older than 75 years should be individualized, based on an assessment of risks, benefits, and comorbidities. BEST PRACTICE ADVICE 9: Risk-stratification tools for CRC screening and post-polypectomy surveillance that emerge from research should be examined for real-world effectiveness and cost-effectiveness in diverse populations (eg, by race, ethnicity, sex, and other sociodemographic factors associated with disparities in CRC outcomes) before widespread implementation.

Association between antibiotic use during early life and early-onset colorectal cancer risk overall and according to polygenic risk and FUT2 genotypes

Early-onset colorectal cancer (EOCRC) has been increasing worldwide. Potential risk factors may have occurred in childhood or adolescence. We investigated the associations between early-life factors and EOCRC risk, with a particular focus on long-term or recurrent antibiotic use (LRAU) and its interaction with genetic factors. Data on the UK Biobank participants recruited between 2006 and 2010 and followed up to February 2022 were used. We used logistic regression to estimate adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) of the associations between LRAU during early life and EOCRC risk overall and by polygenic risk score (constructed by 127 CRC-related genetic variants) and Fucosyltransferase 2 (FUT2), a gut microbiota regulatory gene. We also assessed the associations for early-onset colorectal adenomas, as precursor lesion of CRC, to examine the effect of LRAU during early-life and genetic factors on colorectal carcinogenesis. A total of 113 256 participants were included in the analysis, with 165 EOCRC cases and 719 EOCRA cases. LRAU was nominally associated with increased risk of early-onset CRC (OR = 1.48, 95% CI = 1.01-2.17, P = .046) and adenomas (OR = 1.40, 95% CI = 1.17-1.68, P < .001). When stratified by genetic polymorphisms of FUT2, LRAU appeared to confer a comparatively greater risk for early-onset adenomas among participants with rs281377 TT genotype (OR = 1.10, 95% CI = 0.79-1.52, P = .587, for CC genotype; OR = 1.75, 95% CI = 1.16-2.64, P = .008, for TT genotype; Pinteraction  = .089). Our study suggested that LRAU during early life is associated with increased risk of early-onset CRC and adenomas, and the association for adenomas is predominant among individuals with rs281377 TT/CT genotype. Further studies investigating how LRAU contributes together with genetic factors to modify EOCRC risk, particularly concerning the microbiome-related pathway underlying colorectal carcinogenesis, are warranted.

Personalized Initial Screening Age for Colorectal Cancer in Individuals at Average Risk

Importance

Colorectal cancer (CRC) risk varies widely in the population at average risk without a family history, but there are no established routines for translating this variation into personalized starting ages of screening.

Objective

To illustrate derivation of risk-adapted starting ages of CRC screening based on the concept of risk advancement period (RAP) using sex and a polygenic risk score (PRS) as an example.

Design, Setting, and Participants

This cohort study included participants in the UK Biobank study recruited in England, Wales, and Scotland between March 13, 2006, and October 1, 2010. Participants were aged 40 to 69 years, with no previous bowel cancer screening and no family history of CRC. Follow-up of cancer data was completed February 29, 2020, for England and Wales and January 31, 2021, for Scotland. The censoring date for death data was September 30, 2021, for England and Wales and October 31, 2021, for Scotland.

Exposures

Data on age, sex, and family history were collected at the baseline interview. A PRS was calculated based on 139 CRC-related risk loci.

Main Outcomes and Measures

Hazard ratios (HRs) of sex and PRS with CRC risk and mortality were estimated using Cox proportional hazards regression models and were translated to RAPs to quantify how many years of age earlier or later men and individuals in higher or lower PRS deciles would reach risks comparable with those of the reference group (ie, women or those in the 5th and 6th PRS deciles).

Results

Among 242 779 participants (median age, 55 [IQR, 48-61] years; 55.7% women), 2714 incident CRC cases were identified during a median follow-up of 11.2 (IQR, 10.5-11.8) years and 758 deaths during a median follow-up of 12.8 (IQR, 12.0-13.4) years. The HRs of CRC risk were 1.57 (95% CI, 1.46-1.70) for men vs women and ranged from 0.51 (95% CI, 0.41-0.62) to 2.29 (95% CI, 2.01-2.62) across PRS deciles compared with the reference. The RAPs were 5.6 (95% CI, 4.6-6.6) years for men vs women and ranged from -8.4 (95% CI, -11.0 to -5.9) to 10.3 (95% CI, 8.5-12.1) years across PRS deciles compared with the reference deciles. Risk-adapted starting ages of screening would vary by 24 years between men in the highest PRS decile and women in the lowest PRS decile. Similar results were obtained regarding CRC mortality.

Conclusions and Relevance

In this large cohort study including women and men at average risk of CRC, risk-adapted starting ages of screening strongly varied by sex and a PRS. The RAP concept could easily accommodate additional factors for defining personalized starting ages of screening.

Narrow Band Imaging versus White Light for the Detection of Sessile Serrated Colorectal Lesions: A Randomized Clinical Trial

Background

Colorectal cancer (CRC) is a leading cause of cancer. The detection of pre-malignant lesions by colonoscopy is associated with reduced CRC incidence and mortality. Narrow band imaging has shown promising but conflicting results for the detection of serrated lesions.

Methods

We performed a randomized clinical trial to compare the mean detection of serrated lesions and hyperplastic polyps ≥10 mm with NBI or high-definition white light (HD-WL) withdrawal. We also compared all sessile serrated lesions (SSLs), adenoma, and polyp prevalence and rates.

Results

Overall, 782 patients were randomized (WL group 392 patients; NBI group 390 patients). The average number of serrated lesions and hyperplastic polyps ≥10 mm detected per colonoscopy (primary endpoint) was similar between the HD-WL and NBI group (0.118 vs. 0.156, p = 0.44). Likewise, the adenoma detection rate (55.2% vs. 53.2%, p = 0.58) and SSL detection rate (6.8% vs. 7.5%, p = 0.502) were not different between the two study groups. Withdrawal time was higher in the NBI group (10.88 vs. 9.47 min, p = 0.004), with a statistically nonsignificant higher total procedure time (20.97 vs. 19.30 min, p = 0.052).

Conclusions

The routine utilization of narrow band imaging does not improve the detection of serrated class lesions or any pre-malignant lesion and increases the withdrawal time.

Comparison of a Novel, Flavor-optimized, Polyethylene Glycol and Sulfate Bowel Preparation With Oral Sulfate Solution in Adults Undergoing Colonoscopy

INTRODUCTION

A new bowel preparation for colonoscopy has been developed containing poorly absorbed sulfate salts and polyethylene glycol 3350, which retain water within the intestinal lumen resulting in copious diarrhea, thereby cleansing the bowel. The product was formulated to be safe and effective with a sports drink-like flavor. This study evaluated the new flavored polyethylene glycol and sulfate solution (FPSS) compared with a Food and Drug Administration-approved bowel preparation containing sulfate salts only [oral sulfate solution (OSS)].

METHODS

Five hundred adults were enrolled in this multicenter, noninferiority study. Subjects were assigned FPSS or OSS administered in split-dose regimens (PM/AM). FPSS subjects took 2 L of the flavored osmotic solution (1 L at night and 1 L in the morning). OSS was taken according to its approved labeling. Colonoscopies were graded globally and segmentally by blinded local investigators using a 4-point scale (excellent, good, fair, and poor), with "good" and "excellent" considered successful. Safety was assessed by adverse events (AEs) and laboratory testing.

RESULTS

A high rate of cleansing success was seen with FPSS (94%), which was noninferior to OSS (94%). This conclusion was confirmed by blinded central readers. Segmental success rates were >90% for both preparations, including the right colon. Questionnaire ratings indicated the FPSS experience was preferred over OSS with 87% of FPSS subjects noting their preparation was "tolerable" to "very easy" to consume versus 74% for OSS. The majority of FPSS subjects agreed their preparation tasted like a sports drink. Gastrointestinal symptoms were the most common AEs. There was no difference between preparations for any AE and no clinically significant differences in laboratory parameters.

CONCLUSIONS

The new sports drink-like flavored preparation achieved a high level of cleansing in the study, demonstrating noninferiority to OSS. FPSS was well-tolerated with low rates of expected gastrointestinal symptoms. The optimized flavor of FPSS resulted in significantly better acceptance ratings.

Automated Diagnosis for Colon Cancer Diseases Using Stacking Transformer Models and Explainable Artificial Intelligence

Colon cancer is the third most common cancer type worldwide in 2020, almost two million cases were diagnosed. As a result, providing new, highly accurate techniques in detecting colon cancer leads to early and successful treatment of this disease. This paper aims to propose a heterogenic stacking deep learning model to predict colon cancer. Stacking deep learning is integrated with pretrained convolutional neural network (CNN) models with a metalearner to enhance colon cancer prediction performance. The proposed model is compared with VGG16, InceptionV3, Resnet50, and DenseNet121 using different evaluation metrics. Furthermore, the proposed models are evaluated using the LC25000 and WCE binary and muticlassified colon cancer image datasets. The results show that the stacking models recorded the highest performance for the two datasets. For the LC25000 dataset, the stacked model recorded the highest performance accuracy, recall, precision, and F1 score (100). For the WCE colon image dataset, the stacked model recorded the highest performance accuracy, recall, precision, and F1 score (98). Stacking-SVM achieved the highest performed compared to existing models (VGG16, InceptionV3, Resnet50, and DenseNet121) because it combines the output of multiple single models and trains and evaluates a metalearner using the output to produce better predictive results than any single model. Black-box deep learning models are represented using explainable AI (XAI).

Methods for Using Race and Ethnicity in Prediction Models for Lung Cancer Screening Eligibility

Importance

Using race and ethnicity in clinical prediction models can reduce or inadvertently increase racial and ethnic disparities in medical decisions.

Objective

To compare eligibility for lung cancer screening in a contemporary representative US population by refitting the life-years gained from screening-computed tomography (LYFS-CT) model to exclude race and ethnicity vs a counterfactual eligibility approach that recalculates life expectancy for racial and ethnic minority individuals using the same covariates but substitutes White race and uses the higher predicted life expectancy, ensuring that historically underserved groups are not penalized.

Design, Setting, and Participants

The 2 submodels composing LYFS-CT NoRace were refit and externally validated without race and ethnicity: the lung cancer death submodel in participants of a large clinical trial (recruited 1993-2001; followed up until December 31, 2009) who ever smoked (n = 39 180) and the all-cause mortality submodel in the National Health Interview Survey (NHIS) 1997-2001 participants aged 40 to 80 years who ever smoked (n = 74 842, followed up until December 31, 2006). Screening eligibility was examined in NHIS 2015-2018 participants aged 50 to 80 years who ever smoked. Data were analyzed from June 2021 to September 2022.

Exposure

Including and removing race and ethnicity (African American, Asian American, Hispanic American, White) in each LYFS-CT submodel.

Main Outcomes and Measures

By race and ethnicity: calibration of the LYFS-CT NoRace model and the counterfactual approach (ratio of expected to observed [E/O] outcomes), US individuals eligible for screening, predicted days of life gained from screening by LYFS-CT.

Results

The NHIS 2015-2018 included 25 601 individuals aged 50 to 80 years who ever smoked (2769 African American, 649 Asian American, 1855 Hispanic American, and 20 328 White individuals). Removing race and ethnicity from the submodels underestimated lung cancer death risk (expected/observed [E/O], 0.72; 95% CI, 0.52-1.00) and all-cause mortality (E/O, 0.90; 95% CI, 0.86-0.94) in African American individuals. It also overestimated mortality in Hispanic American (E/O, 1.08, 95% CI, 1.00-1.16) and Asian American individuals (E/O, 1.14, 95% CI, 1.01-1.30). Consequently, the LYFS-CT NoRace model increased Hispanic American and Asian American eligibility by 108% and 73%, respectively, while reducing African American eligibility by 39%. Using LYFS-CT with the counterfactual all-cause mortality model better maintained calibration across groups and increased African American eligibility by 13% without reducing eligibility for Hispanic American and Asian American individuals.

Conclusions and Relevance

In this study, removing race and ethnicity miscalibrated LYFS-CT submodels and substantially reduced African American eligibility for lung cancer screening. Under counterfactual eligibility, no one became ineligible, and African American eligibility increased, demonstrating the potential for maintaining model accuracy while reducing disparities.

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

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

PREVENTION RELEVANCE

Screening 45- to 49-year-olds for colorectal cancer is relatively new with uncertain uptake thus far. Furthermore, half of EOCRC occurs in persons < 45 years old. Using risk factors may help 45- to 49-year-olds accept screening and may identify younger persons for whom earlier screening should be considered. See related Spotlight, p. 479.

When should electronic medical records reminders for cancer screening stop?-Results from a national physician survey

BACKGROUND

Many older adults are screened for breast and colorectal cancers beyond guideline recommended thresholds. Electronic medical record (EMR) reminders are commonly used to prompt cancer screening. Behavioral economics theory suggests that changing the default settings for these reminders can be effective to reduce over-screening. We examined physician perspectives about acceptable thresholds for stopping EMR cancer screening reminders.

METHODS

In a national survey of 1200 primary care physicians (PCP) and 600 gynecologists randomly selected from the AMA Masterfile, we asked physicians to choose whether EMR reminders for cancer screening should stop based on a list of criteria that included age, life expectancy, specific serious illnesses, and functional limitations. Physicians could choose multiple responses. PCPs were randomized to questions about breast or colorectal cancer screening.

RESULTS

A total of 592 physicians participated (adjusted response rate 54.1%). 54.6% chose age and 71.8% chose life expectancy as criteria for stopping EMR reminders; only 30.6% chose functional limitations. Regarding age thresholds, 52.4% chose ages ≤75, 42.0% chose a threshold between 75 and 85, 5.6% would not stop reminders even at age 85. Regarding life expectancy thresholds, 32.0% chose ≥10 years, 53.1% chose a threshold between 5 and 9 years, 14.9% would not stop reminders even when life expectancy is <5 years.

CONCLUSIONS

We found that many physicians would continue EMR reminders for cancer screening even in light of older age, limited life expectancy, and functional limitations. This may reflect reluctance to stop cancer screening and/or reluctance to stop EMR reminders so that physicians can retain control to decide for individual patients, for example, to assess patient preference and ability to tolerate treatment. There was consensus for stopping EMR reminders at ages 85+ and <5-year life expectancy. Interventions that seek to reduce over-screening by suppressing EMR reminders may be important for these groups but may have limited physician buy-in outside these thresholds.

Trends in colorectal cancer screening in the United States, 2012 to 2020

OBJECTIVES

Despite recommendations to increase the uptake of colorectal cancer (CRC) screening, trends in CRC screening vary with sociodemographic status. We aimed to evaluate trends in CRC screening in the US population and subpopulations.

METHODS

A total of 1,082,924 participants aged 50 to 75 from five cycles (2012, 2014, 2016, 2018, and 2020) of the Behavioral Risk Factor Surveillance System were involved. Multivariable logistic regression models were performed to evaluate linear trends in CRC screening utilization from 2012 to 2018. Rao-Scott chi-square tests were used to assess the differences in CRC screening utilization between 2018 and 2020.

RESULTS

The estimated percentage reporting up-to-date with CRC screening increased significantly (P for trend <0.001), from 62.8% (95% CI, 62.4%-63.2%) in 2012 to 66.7% (95% CI, 66.3%-67.2%) in 2018 and 70.4% (95% CI, 69.8%-71.0%) in 2020, in accordance with 2008 US Preventive Services Task Force recommendations. Trends followed similar patterns in most subgroups, although with different magnitudes in several subgroups, primarily those underweight showed a stable percentage over time (P for trend  =  0.170). In 2020, 72.4% of participants reported they were up to date with CRC screening, including the utilization of stool DNA tests and virtual colonoscopy. Colonoscopy was the most commonly used test in 2020 (64.5%), followed by FOBT (12.6%), stool DNA test (5.8%), sigmoidoscopy (3.8%), and virtual colonoscopy (2.7%).

CONCLUSIONS

In this nationally representative survey of the US population from 2012 through 2020, the percentage reporting up to date with CRC screening has increased, but not equally among all subgroups.

Early onset colorectal cancer in Canterbury, New Zealand

BACKGROUND

The overall incidence of colorectal cancer is decreasing in much of the world, yet the incidence in those under 50 years of age is increasing (early onset colorectal cancer (EOCRC)). The reasons for this are unclear. This study was undertaken to describe the clinical, pathological and familial characteristics of patients with EOCRC and their oncological outcomes and compare this with previously published data on late onset colorectal cancer (LOCRC).

METHODS

A retrospective review of all patients diagnosed with EOCRC in Canterbury between 2010 and 2017 was conducted. Data was collected on demographics, family history, treatment, and oncologic outcomes. Kaplan-Meier survival curves were calculated to assess overall survival based on disease stage.

RESULTS

During the study period (2010-2017) there were 3340 colorectal cancers diagnosed in Canterbury, of which 201 (6%) were in patients under 50 years (range: 17-49). Of these, 87 (43.3%) were female and 125 (62.2%) were aged between 40 and 49 years. 28 (13.9%) were associated with hereditary conditions. Of the 201 patients, 139 (69.2%) had rectal or left-sided cancers. 142 (70.6%) patients presented with either stage 3 or 4 disease and the 5-year overall survival by stage was 79.1% and 14.4%, respectively.

CONCLUSION

EOCRC is increasing and usually presents as distal left sided cancers, and often at an advanced stage. They do not appear to have the common risk factors of family history or inherited pre-disposition for colorectal cancer. Planning by healthcare providers for this epidemiological change is imperative in investigating symptomatic patients under 50 and optimizing early detection and prevention.

Automated Detection of Anatomical Landmarks During Colonoscopy Using a Deep Learning Model

Background and aims

Identification and photo-documentation of the ileocecal valve (ICV) and appendiceal orifice (AO) confirm completeness of colonoscopy examinations. We aimed to develop and test a deep convolutional neural network (DCNN) model that can automatically identify ICV and AO, and differentiate these landmarks from normal mucosa and colorectal polyps.

Methods

We prospectively collected annotated full-length colonoscopy videos of 318 patients undergoing outpatient colonoscopies. We created three nonoverlapping training, validation, and test data sets with 25,444 unaltered frames extracted from the colonoscopy videos showing four landmarks/image classes (AO, ICV, normal mucosa, and polyps). A DCNN classification model was developed, validated, and tested in separate data sets of images containing the four different landmarks.

Results

After training and validation, the DCNN model could identify both AO and ICV in 18 out of 21 patients (85.7%). The accuracy of the model for differentiating AO from normal mucosa, and ICV from normal mucosa were 86.4% (95% CI 84.1% to 88.5%), and 86.4% (95% CI 84.1% to 88.6%), respectively. Furthermore, the accuracy of the model for differentiating polyps from normal mucosa was 88.6% (95% CI 86.6% to 90.3%).

Conclusion

This model offers a novel tool to assist endoscopists with automated identification of AO and ICV during colonoscopy. The model can reliably distinguish these anatomical landmarks from normal mucosa and colorectal polyps. It can be implemented into automated colonoscopy report generation, photo-documentation, and quality auditing solutions to improve colonoscopy reporting quality.

Field Synopsis of Environmental and Genetic Risk Factors of Sporadic Early-Onset Colorectal Cancer and Advanced Adenoma

BACKGROUND

To systematically appraise and synthesize available epidemiologic evidence on the associations of environmental and genetic factors with the risk of sporadic early-onset colorectal cancer (EOCRC) and early-onset advanced colorectal adenoma (EOCRA).

METHODS

Multiple databases were comprehensively searched to identify eligible observational studies. Genotype data from UK Biobank were incorporated to examine their associations with EOCRC in a nested case-control design. Meta-analyses of environmental risk factors were performed, and the strength of evidence was graded based on predefined criteria. Meta-analyses of genetic associations were conducted using the allelic, recessive, and dominant models, respectively.

RESULTS

A total of 61 studies were included, reporting 120 environmental factors and 62 genetic variants. We found 12 risk factors (current overweight, overweight in adolescence, high waist circumference, smoking, alcohol, sugary beverages intake, sedentary behavior, red meat intake, family history of colorectal cancer, hypertension, hyperlipidemia, and metabolic syndrome) and three protective factors (vitamin D, folate, and calcium intake) for EOCRC or EOCRA. No significant associations between the examined genetic variants and EOCRC risk were observed.

CONCLUSIONS

Recent data indicate that the changing patterns of traditional colorectal cancer risk factors may explain the rising incidence of EOCRC. However, research on novel risk factors for EOCRC is limited; therefore, we cannot rule out the possibility of EOCRC having different risk factors than late-onset colorectal cancer (LOCRC).

IMPACT

The potential for the identified risk factors to enhance the identification of at-risk groups for personalized EOCRC screening and prevention and for the prediction of EOCRC risk should be comprehensively addressed by future studies.

The impact of neighborhood disadvantage on colorectal cancer screening among African Americans in Chicago

Historically, colorectal cancer (CRC) screening rates have been lower among African Americans. Previous studies that have examined the relationship between community characteristics and adherence to CRC screening have generally focused on a single community parameter, making it challenging to evaluate the overall impact of the social and built environment. In this study, we will estimate the overall effect of social and built environment and identify the most important community factors relevant to CRC screening. Data are from the Multiethnic Prevention and Surveillance Study (COMPASS), a longitudinal study among adults in Chicago, collected between May 2013 to March 2020. A total 2,836 African Americans completed the survey. Participants' addresses were geocoded and linked to seven community characteristics (i.e., community safety, community crime, household poverty, community unemployment, housing cost burden, housing vacancies, low food access). A structured questionnaire measured adherence to CRC screening. Weighted quantile sum (WQS) regression was used to evaluate the impact of community disadvantages on CRC screening. When analyzing all community characteristics as a mixture, overall community disadvantage was associated with less adherence to CRC screening even after controlling for individual-level factors. In the adjusted WQS model, unemployment was the most important community characteristic (37.6%), followed by community insecurity (26.1%) and severe housing cost burden (16.3%). Results from this study indicate that successful efforts to improve adherence to CRC screening rates should prioritize individuals living in communities with high rates of insecurity and low socioeconomic status.

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

Importance

The Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) randomized clinical trial sought to recruit 50 000 adults into a study comparing colorectal cancer (CRC) mortality outcomes after randomization to either an annual fecal immunochemical test (FIT) or colonoscopy.

Objective

To (1) describe study participant characteristics and (2) examine who declined participation because of a preference for colonoscopy or stool testing (ie, fecal occult blood test [FOBT]/FIT) and assess that preference's association with geographic and temporal factors.

Design, Setting, and Participants

This cross-sectional study within CONFIRM, which completed enrollment through 46 Department of Veterans Affairs medical centers between May 22, 2012, and December 1, 2017, with follow-up planned through 2028, comprised veterans aged 50 to 75 years with an average CRC risk and due for screening. Data were analyzed between March 7 and December 5, 2022.

Exposure

Case report forms were used to capture enrolled participant data and reasons for declining participation among otherwise eligible individuals.

Main Outcomes and Measures

Descriptive statistics were used to characterize the cohort overall and by intervention. Among individuals declining participation, logistic regression was used to compare preference for FOBT/FIT or colonoscopy by recruitment region and year.

Results

A total of 50 126 participants were recruited (mean [SD] age, 59.1 [6.9] years; 46 618 [93.0%] male and 3508 [7.0%] female). The cohort was racially and ethnically diverse, with 748 (1.5%) identifying as Asian, 12 021 (24.0%) as Black, 415 (0.8%) as Native American or Alaska Native, 34 629 (69.1%) as White, and 1877 (3.7%) as other race, including multiracial; and 5734 (11.4%) as having Hispanic ethnicity. Of the 11 109 eligible individuals who declined participation (18.0%), 4824 (43.4%) declined due to a stated preference for a specific screening test, with FOBT/FIT being the most preferred method (2820 [58.5%]) vs colonoscopy (1958 [40.6%]; P < .001) or other screening tests (46 [1.0%] P < .001). Preference for FOBT/FIT was strongest in the West (963 of 1472 [65.4%]) and modest elsewhere, ranging from 199 of 371 (53.6%) in the Northeast to 884 of 1543 (57.3%) in the Midwest (P = .001). Adjusting for region, the preference for FOBT/FIT increased by 19% per recruitment year (odds ratio, 1.19; 95% CI, 1.14-1.25).

Conclusions and Relevance

In this cross-sectional analysis of veterans choosing nonenrollment in the CONFIRM study, those who declined participation more often preferred FOBT or FIT over colonoscopy. This preference increased over time and was strongest in the western US and may provide insight into trends in CRC screening preferences.

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

BACKGROUND & AIMS

Colorectal cancer (CRC) screening guidelines include screening colonoscopy and sequential high-sensitivity fecal occult blood testing (HSgFOBT), with expectation of similar effectiveness based on the assumption of similar high adherence. However, adherence to screening colonoscopy compared with sequential HSgFOBT has not been reported. In this randomized clinical trial, we assessed adherence and pathology findings for a single screening colonoscopy vs sequential and nonsequential HSgFOBTs.

METHODS

Participants aged 40-69 years were enrolled at 3 centers representing different clinical settings. Participants were randomized into a single screening colonoscopy arm vs sequential HSgFOBT arm composed of 4-7 rounds. Initial adherence to screening colonoscopy and sequential adherence to HSgFOBT, follow-up colonoscopy for positive HSgFOBT tests, crossover to colonoscopy, and detection of advanced neoplasia or large serrated lesions (ADN-SERs) were measured.

RESULTS

There were 3523 participants included in the trial; 1761 and 1762 participants were randomized to the screening colonoscopy and HSgFOBT arms, respectively. Adherence was 1473 (83.6%) for the screening colonoscopy arm vs 1288 (73.1%) for the HSgFOBT arm after 1 round (relative risk [RR], 1.14; 95% CI, 1.10-1.19; P ≤ .001), but only 674 (38.3%) over 4 sequential HSgFOBT rounds (RR, 2.19; 95% CI, 2.05-2.33). Overall adherence to any screening increased to 1558 (88.5%) in the screening colonoscopy arm during the entire study period and 1493 (84.7%) in the HSgFOBT arm (RR, 1.04; 95% CI, 1.02-1.07). Four hundred thirty-six participants (24.7%) crossed over to screening colonoscopy during the first 4 rounds. ADN-SERs were detected in 121 of the 1473 participants (8.2%) in the colonoscopy arm who were adherent to protocol in the first 12 months of the study, whereas detection of ADN-SERs among those who were not sequentially adherent (n = 709) to HSgFOBT was subpar (0.6%) (RR, 14.72; 95% CI, 5.46-39.67) compared with those who were sequentially adherent (3.3%) (n = 647) (RR, 2.52; 95% CI, 1.61-3.98) to HSgFOBT in the first 4 rounds. When including colonoscopies from HSgFOBT patients who were never positive yet crossed over (n = 1483), 5.5% of ADN-SERs were detected (RR, 1.50; 95% CI, 1.15-1.96) in the first 4 rounds.

CONCLUSIONS

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

CLINICALTRIALS

gov, Number: NCT00102011.

Adenoma detection rate in colonoscopy: how can it be improved?

INTRODUCTION

The introduction of widespread colonoscopy screening programs has helped in decreasing the incidence of Colorectal Cancer (CRC). However, 'back-to-back' colonoscopies revealed relevant percentage of missed adenomas. Quality indicators were created to further homogenize detection performances and decrease the incidence of post-colonoscopy CRC. Among them, the Adenoma Detection Rate (ADR), defined as the percentage obtained by dividing the number of endoscopic procedures in which at least one adenoma was resected, by the total number of procedures, was found to be inversely associated with the risks of interval colorectal cancer, advanced-stage interval cancer, and fatal interval cancer.

AREAS COVERED

In this paper, we performed a comprehensive review of the literature focusing on promising new devices and technologies, which are meant to positively affect the endoscopist performance in detecting adenomas, therefore increasing ADR.

EXPERT OPINION

Considering the current knowledge, although several devices and technologies have been proposed with this intent, the recent implementation of AI ranked over all of the other strategies and it is likely to become the new standard within few years. However, the combination of different device/technologies need to be investigated in the future aiming at even further increasing of endoscopist detection performances.

Stool DNA testing for early detection of colorectal cancer: systematic review using the HTA Core Model® for Rapid Relative Effectiveness Assessment

Background

Stool DNA testing for early detection of colorectal cancer (CRC) is a non-invasive technology with the potential to supplement established CRC screening tests. The aim of this health technology assessment was to evaluate effectiveness and safety of currently CE-marked stool DNA tests, compared to other CRC tests in CRC screening strategies in an asymptomatic screening population.

Methods

The assessment was carried out following the guidelines of the European Network for Health Technology Assessment (EUnetHTA). This included a systematic literature search in MED-LINE, Cochrane and EMBASE in 2018. Manufacturers were asked to provide additional data. Five patient interviews helped assessing potential ethical or social aspects and patients' experiences and preferences. We assessed the risk of bias using QUADAS-2, and the quality of the body of evidence using GRADE.

Results

We identified three test accuracy studies, two of which investigated a multitarget stool DNA test (Cologuard^®, compared fecal immunochemical test (FIT)) and one a combined DNA stool assay (ColoAlert^®, compared to guaiac-based fecal occult blood test (gFOBT), Pyruvate Kinase Isoenzyme Type M2 (M2-PK) and combined gFOBT/M2-PK). We found five published surveys on patient satisfaction. No primary study investigating screening effects on CRC incidence or on overall mortality was found. Both stool DNA tests showed in direct comparison higher sensitivity for the detection of CRC and (advanced) adenoma compared to FIT, or gFOBT, respectively, but had lower specificity. However, these comparative results may depend on the exact type of FIT used. The reported test failure rates were higher for stool DNA testing than for FIT. The certainty of evidence was moderate to high for Cologuard^® studies, and low to very low for the ColoAlert^® study which refers to a former version of the product and yielded no direct evidence on the test accuracy for ad-vanced versus non-advanced adenoma.

Conclusions

ColoAlert^® is the only stool DNA test currently sold in Europe and is available at a lower price than Cologuard^®, but reliable evidence is lacking. A screening study including the current product version of ColoAlert^® and suitable comparators would, therefore, help evaluate the effectiveness of this screening option in a European context.

Frequency of Use and Outcomes of Colonoscopy in Individuals Older Than 75 Years

Importance

The benefits from colorectal cancer (CRC) screening may take 10 to 15 years to accrue. Therefore, screening is recommended for older adults who are in good health.

Objective

To determine the number of screening colonoscopies done in patients older than 75 years with a life expectancy of fewer than 10 years, diagnostic yield, and associated adverse events within 10 days and 30 days of the procedure.

Design

This cross-sectional study with a nested cohort between January 2009 and January 2022 in an integrated health system assessed asymptomatic patients older than 75 years who underwent screening colonoscopy in the outpatient setting. Reports with incomplete data, any indication other than screening, patients who had a colonoscopy within the previous 5 years, and patients with a personal history of inflammatory bowel disease or CRC were excluded.

Exposures

Life expectancy based on a prediction model from previous literature.

Main Outcomes and Measures

The primary outcome was the percentage of screened patients who had limited (<10 years) life expectancy. Other outcomes included colonoscopy findings and adverse events that developed within 10 days and 30 days of the procedure.

Results

A total of 7067 patients older than 75 years were included. The median (IQR) age was 78 (77-79) years, 3967 (56%) were women, and 5431 (77%) were White with an average of 2 comorbidities (taken from a select group of comorbidities). The proportion of colonoscopies performed on patients with a life expectancy of fewer than 10 years aged 76 to 80 years was 30% in both sexes and increased with age-82% of men and 61% of women aged 81 to 85 years (71% total), and 100% of patients beyond the age of 85 years. Adverse events requiring hospitalizations were common at 10 days (13.58 per 1000) and increased with age, particularly among patients older than 85 years. The detection of advanced neoplasia varied from 5.4% among patients aged 76 to 80 years to 6.2% in those aged 81 to 85 years and 9.5% among patients older than 85 years (P = .02). Of the total population, 15 patients (0.2%) had invasive adenocarcinoma; among patients with a life expectancy of fewer than 10 years, 1 of 9 was treated, whereas 4 of 6 patients with a life expectancy of greater than or equal to 10 years were treated.

Conclusions and Relevance

In this cross-sectional study with a nested cohort, most screening colonoscopies performed in patients older than 75 years were in patients with limited life expectancy and associated with increased risk of complications. Colorectal cancer was exceedingly rare.

Optimizing adenoma detection in screening-related colonoscopy

INTRODUCTION

Screening-related colonoscopy is a vital component of screening initiatives to both diagnose and prevent colorectal cancer (CRC), with prevention being reliant upon early and accurate detection of pre-malignant lesions. Several strategies, techniques, and interventions exist to optimize endoscopists' adenoma detection rates (ADR).

AREAS COVERED

This narrative review provides an overview of the importance of ADR and other colonoscopy quality indicators. It then summarizes the available evidence regarding the effectiveness of the following domains in terms of improving ADR: endoscopist factors, pre-procedural parameters, peri-procedural parameters, intra-procedural strategies and techniques, antispasmodics, distal attachment devices, enhanced colonoscopy technologies, enhanced optics, and artificial intelligence. These summaries are based on an electronic search of the databases Embase, Pubmed, and Cochrane performed on December 12, 2022.

EXPERT OPINION

Given the prevalence and associated morbidity and mortality of CRC, the quality of screening-related colonoscopy quality is appropriately prioritized by patients, endoscopists, units, and payers alike. Endoscopists performing colonoscopy should be up to date regarding available strategies, techniques, and interventions to optimize their performance.

DLGNet: A dual-branch lesion-aware network with the supervised Gaussian Mixture model for colon lesions classification in colonoscopy images

Colorectal cancer is one of the malignant tumors with the highest mortality due to the lack of obvious early symptoms. It is usually in the advanced stage when it is discovered. Thus the automatic and accurate classification of early colon lesions is of great significance for clinically estimating the status of colon lesions and formulating appropriate diagnostic programs. However, it is challenging to classify full-stage colon lesions due to the large inter-class similarities and intra-class differences of the images. In this work, we propose a novel dual-branch lesion-aware neural network (DLGNet) to classify intestinal lesions by exploring the intrinsic relationship between diseases, composed of four modules: lesion location module, dual-branch classification module, attention guidance module, and inter-class Gaussian loss function. Specifically, the elaborate dual-branch module integrates the original image and the lesion patch obtained by the lesion localization module to explore and interact with lesion-specific features from a global and local perspective. Also, the feature-guided module guides the model to pay attention to the disease-specific features by learning remote dependencies through spatial and channel attention after network feature learning. Finally, the inter-class Gaussian loss function is proposed, which assumes that each feature extracted by the network is an independent Gaussian distribution, and the inter-class clustering is more compact, thereby improving the discriminative ability of the network. The extensive experiments on the collected 2568 colonoscopy images have an average accuracy of 91.50%, and the proposed method surpasses the state-of-the-art methods. This study is the first time that colon lesions are classified at each stage and achieves promising colon disease classification performance. To motivate the community, we have made our code publicly available via https://github.com/soleilssss/DLGNet.

Prevalence and Clinical Implications of Mismatch Repair-Proficient Colorectal Cancer in Patients With Lynch Syndrome

PURPOSE

Lynch syndrome (LS)-associated colorectal cancer (CRC) is characterized by mismatch repair-deficiency (MMR-D) and/or microsatellite instability (MSI). However, with increasing utilization of germline testing, MMR-proficient (MMR-P) and/or microsatellite stable (MSS) CRC has also been observed. We sought to characterize MMR-P/MSS CRC among patients with LS.

METHODS

Patients with solid tumors with germline MMR pathogenic/likely pathogenic (P/LP) variants were identified on a prospective matched tumor-normal next-generation sequencing (NGS) protocol. CRCs were evaluated for MMR-D via immunohistochemical (IHC) staining and/or MSI via NGS. Clinical variables were correlated with MMR status using nonparametric tests.

RESULTS

Among 17,617 patients with solid tumors, 1.4% (n = 242) had LS. A total of 36% (86 of 242) of patients with LS had at least one CRC that underwent NGS profiling, amounting to 99 pooled CRCs assessed. A total of 10% (10 of 99) of CRCs were MMR-P, with 100% concordance between MSS status and retained MMR protein staining. A total of 89% (8 of 9) of patients in the MMR-P group had MSH6 or PMS2 variants, compared with 30% (23 of 77) in the MMR-D group (P = .001). A total of 46% (6 of 13) of PMS2+ patients had MMR-P CRC. The median age of onset was 58 and 43 years for MMR-P and MMR-D CRC, respectively (P = .07). Despite the later median age of onset, 40% (4 of 10) of MMR-P CRCs were diagnosed <50. A total of 60% (6 of 10) of MMR-P CRCs were metastatic compared with 13% (12 of 89) of MMR-D CRCs (P = .002). A total of 33% (3 of 9) of patients with MMR-P CRC did not meet LS testing criteria.

CONCLUSION

Patients with LS remained at risk for MMR-P CRC, which was more prevalent among patients with MSH6 and PMS2 variants. MMR-P CRC was later onset and more commonly metastatic compared with MMR-D CRC. Confirmation of tumor MMR/MSI status is critical for patient management and familial risk estimation.