Colorectal Cancer Screening Options Research Articles

Decision-analytic modelling of costs & benefits of adding sigmoidoscopy to CRC screening in Germany

Abstract Background In Germany, a colorectal cancer (CRC) screening programme is in place that entitles individuals to a stool test or colonoscopy. However, less than half of those eligible participate. The inclusion of an additional screening option, such as the evidence-based sigmoidoscopy, could lead to a higher overall participation rate, but also to individuals preferring the additional option to the more effective colonoscopy. The objective of this modelling study is to estimate the impact of offering sigmoidoscopy as an additional option for CRC screening in Germany. Methods A life-time mathematical model (Markov model) is developed to analyse the long-term effects of the additional offer of sigmoidoscopy on benefits (prevalence, mortality, health-related quality of life (HRQoL)), costs, and cost-effectiveness. The model is based on systematic literature reviews and real-world healthcare data. It incorporates disease development, sensitivity and specificity of the options, compliance rates, survival probabilities and background mortality. A discrete choice experiment (DCE) was conducted to estimate the future uptake of the options (stool test, colonoscopy, sigmoidoscopy, no screening) based on stated preferences of n = 666 individuals. Results Adding sigmoidoscopy leads to greater effectiveness of the CRC screening programme in terms of increased screening participation, increased adenoma detection, decreased disease-specific mortality, and improved discounted HRQoL. However, it also incurs higher costs. The incremental cost-effectiveness ratios (ICER) for men and women are €507 per quality-adjusted life year gained (QALYg) and €74 per QALYg, respectively. Conclusions The results indicate that the inclusion of sigmoidoscopy in the German CRC screening programme would be cost-effective and that sigmoidoscopy should be piloted in practice. The expanded programme has the potential to enhance the program’s effectiveness, improve health outcomes, and reduce the burden of CRC. Key messages • Expanding the CRC screening programme may increase overall participation, resulting in higher costs, but also greater effectiveness in detecting more adenomas, reducing mortality, improving HRQoL. • Introducing sigmoidoscopy in Germany appears cost-effective and justifies practical piloting to enhance CRC screening efficacy and health outcomes.

Not just a Barbie in hijab: participant perspectives on culturally tailoring a virtual health assistant for Bangladeshi immigrants in the US promoting colorectal cancer screening.

Colorectal cancer (CRC) screening uptake among South Asian immigrants in the US is the lowest (61.1%) of all immigrant groups (e.g., 65.9% among East Asians and 71.3% among Hispanics). Culture-specific factors influence their reluctance to screen for CRC, despite the availability of easily accessible, non-invasive screening tools, like the fecal immunochemical test (FIT). The current study utilizes a virtual health assistant (VHA) tailored to inform and educate Bangladeshi immigrants about FIT. We conducted usability tests to understand Bangladeshi immigrants' informational needs, barriers, facilitators, and visual and linguistic preferences. After 20 minutes of interaction with the VHA, we conducted semi-structured interviews with 30 participants. Participants also filled out a questionnaire of demographic information and VHA gender and ethnic appearance preferences. A qualitative content analysis using the constant comparative method generated themes. A total of 30 participants (16 women, 14 men) with a mean age of 39.2 years participated. Informational needs included eight themes: (I) risk-reducing behaviors/habits, (II) post-intervention (information desired after interacting with the VHA), (III) CRC-related content (e.g., symptoms, causes, impact on the body, etc.), (IV) financial considerations of FIT, (V) personalized content/options, (VI) pre-test information (how to prepare for the FIT kit use, e.g., "do I need to fast?"), (VII) comparison to other CRC screening options, and (VIII) more specificity of information (i.e., using more measurable language, avoiding vague language like "some", "more", etc.). Major barriers were (I) lack of control, (II) lack of sophistication in VHA animation features, (III) lack of interactiveness, and (IV) lack of a trustworthy source. Facilitators were (I) convenience (of using VHA), (II) social cues (of interacting with a VHA), and (III) content (provided by the VHA). In terms of VHA's appearance, which was a combination of its apparent gender and ethnicity, participants demonstrated varied preferences but the majority (n=17) preferred gender concordant VHA. As for linguistic preference, participants generally mentioned either English or an option to choose a language for themselves while claiming that other Bangladeshi immigrants would prefer the Bangla language. Participants were open to using a VHA to learn about CRC, either instead of or along with talking to a clinician about it. However, recommendations to improve animated features of the VHA included more detailed and Bangladeshi population-specific information and provided choices to select preferred languages and appearance of the VHA. Future studies should empirically test the required levels of tailoring to effectively increase CRC screening among Bangladeshi immigrants.

S495 Mind the Gap: Identifying and Addressing the Knowledge Gap Among Internal Medicine Residents on Colorectal Cancer Screening Options

S495 Mind the Gap: Identifying and Addressing the Knowledge Gap Among Internal Medicine Residents on Colorectal Cancer Screening Options

Using the consolidated framework for implementation research to identify church leaders’ perspectives on contextual determinants of community-based colorectal cancer screening for Black Kentuckians

BackgroundBlack Kentuckians experience more deleterious colorectal cancer (CRC) outcomes than their White counterparts, a disparity that could be reduced by increased screening in Black communities. Previous research has shown that Black Kentuckians may not be equitably informed of different CRC screening options by health care providers, making community-based screening a potentially effective option among this disparate population. We used the Consolidated Framework for Implementation Research (CFIR) to identify church leaders’ perspectives of contextual factors that might influence community-based screening and explore the feasibility of using church-based screening outreach.MethodsSix participants were selected, based on leadership roles and interest in CRC screening, from five established Louisville-area church partners that had previously participated in community health initiatives. Data were collected, both virtually and in-person, in Summer 2021 using semi-structured interview guides developed with guidance from the CFIR Guide that focused on domains most relevant to community-based interventions. Data were transcribed verbatim, coded by two independent researchers, and member checked for accuracy.ResultsData were aligned primarily with six CFIR constructs: key stakeholders, champions, opinion leaders, tension for change, compatibility, and culture. Participants noted a strong tension for change in their community due to perceptions of inadequacy with clinical approaches to CRC screening. Additionally, they stressed the importance of identifying individuals both within the church who could champion CRC screening and help implement program activities, as well as those outside the church who could collaborate with other local organizations to increase participant reach. Finally, participants agreed that faith-based CRC screening aligned with church culture and would also likely be compatible with overall community values.ConclusionsOverall, our church partners strongly endorsed the need for, and importance of, community-based CRC screening. Given a history of successful implementation of health promotion programs within our partner churches, it is highly likely that a CRC screening intervention would also be effective. Findings from this study will be used to identify implementation strategies that might positively impact a future faith-based CRC screening intervention, as well as CFIR constructs that are most positively associated with CRC screening completion.

Unveiling Colorectal Cancer Biomarkers: Harnessing Biosensor Technology for Volatile Organic Compound Detection.

Conventional screening options for colorectal cancer (CRC) detection are mainly direct visualization and invasive methods including colonoscopy and flexible sigmoidoscopy, which must be performed in a clinical setting and may be linked to adverse effects for some patients. Non-invasive CRC diagnostic tests such as computed tomography colonography and stool tests are either too costly or less reliable than invasive ones. On the other hand, volatile organic compounds (VOCs) are potentially ideal non-invasive biomarkers for CRC detection and monitoring. The present review is a comprehensive presentation of the current state-of-the-art VOC-based CRC diagnostics, with a specific focus on recent advancements in biosensor design and application. Among them, breath-based chromatography pattern analysis and sampling techniques are overviewed, along with nanoparticle-based optical and electrochemical biosensor approaches. Limitations of the currently available technologies are also discussed with an outlook for improvement in combination with big data analytics and advanced instrumentation, as well as expanding the scope and specificity of CRC-related volatile biomarkers.

Patient-Provider Communication and Colorectal Cancer Screening Completion Using Multi-target Stool DNA Testing.

Colorectal cancer (CRC) screening continues to be underutilized in the USA despite the availability of multiple effective, guideline-recommended screening options. Provider recommendation has been consistently shown to improve screening completion. Understanding how patient-provider communication influences CRC screening can inform interventions to improve screening completion. We developed a behavioral theory-informed survey to identify patient-provider communication factors associated with multi-target stool DNA (mt-sDNA) screening completion. The survey was administered by RTI International between 03/2022 and 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 and 9/2021. Respondents completed an electronic or paper survey. Multivariable logistic regression was used to identify patient-provider communication factors associated with mt-sDNA test completion. A total of 2973 participants completed the survey (response rate, 21.7%) and 81.6% of them (n = 2427) reported having had a conversation with provider about mt-sDNA testing before the test was ordered. Having a conversation with the provider about the test, including discussions about costs, the need for follow-up testing and test instructions were associated with higher odds of test completion and being "very likely" to use the test in the future. Lack of discussion about advantages and disadvantages of available CRC screening options and lack of patient involvement in CRC screening decision-making were associated with reduced odds of test completion and likelihood of future use. Healthcare providers play a key role in patient adherence to CRC screening and must be appropriately prepared and resourced to educate and to engage patients in shared decision-making about CRC screening.

Acceptability of stool-based DNA colorectal cancer (CRC) screening among Black/African American patients served by a Federally Qualified Health Center (FQHC).

10530 Background: CRC has an increased burden among Black/African American populations in the United States. Following the COVID-19 pandemic, home-based CRC screening options are being used more frequently. We conducted focus groups to understand the acceptability of stool-based DNA testing for CRC screening in this population. Methods: 10 Focus group sessions were conducted at 2 FQHCs in Milwaukee, WI from 06/22/2023-10/30/2023. Participants were paid $40 for participation. Groups were categorized by gender and age (younger [40-50] vs. older [over 50]). Participants were recruited by fliers and direct text from the FQHC. Eligibility was verified by FQHC staff. Each session was 90 minutes, held at the FQHC, and led by the same facilitator. Participants were given an overview of CRC screening tests and shown a video about stool DNA tests before beginning the focus groups. Thematic analysis was carried out using NVivo. Results: Across 10 groups, there were 79 participants, 32 younger (40.5%) and 47 older (59.5%), with 42 males (53.2%) and 37 (46.8%) females. In the overall study population, there was minimal knowledge of one’s risk for CRC, including the concept of average versus high-risk. Also, there was limited awareness of CRC screening options among younger patients and widespread lack of knowledge about stool-based DNA testing. None of the participants had personal experience with stool-based DNA screening. Most participants were open to the idea of stool-based DNA testing for screening. Examination of DNA was not a pervasive concern in the groups. Most preferred colonoscopy as their first-choice screening test. Reasons for colonoscopy preference included: definitive removal of polyps, direct visualization of the colon, increased confidence level in effectiveness, potential longer periods between screenings, and no need for confirmatory evaluation. Conclusions: Study findings reveal that stool-based DNA testing was acceptable among our study population, however, colonoscopy was identified as the preferred screening modality among this population of Black/African American patients served by an FQHC. Given the low awareness/knowledge of screening modalities identified in our study, educational interventions and shared decision making by primary care providers are needed to promote patient awareness of CRC screening options within the population.

Fostering diversity and inclusion in the preempt CRC study through strategic site selection and innovative recruitment tools.

e23025 Background: Diversity in clinical studies is crucial in aligning the study population with the intended patient demographic. Freenome is developing a blood based test (MyTectCRC) intended to offer a convenient and accessible option for colorectal cancer (CRC) screening. Its clinical validation is supported by the PREEMPT CRC study, a prospective, multi-center observational study. PREEMPT CRC was able to achieve a diverse population representing various ethnic, racial, and geographical backgrounds that reflect the United States population. This analysis evaluates the significance of strategic site selection and use of forward-thinking study tools in achieving a diverse and inclusive study population. Methods: Starting in 2020, PREEMPT CRC enrolled participants aged 45-85 at average CRC risk. Eligible and consenting participants underwent a blood draw and a screening colonoscopy, with the blood sample analyzed by MyTectCRC. To ensure diversity, strategic site selection was employed beyond large academic institutions and hospitals to smaller sites and community hospitals. The study also incorporated a decentralized clinical trial (DCT) model to reach broader geographical areas and used electronic consenting and mobile phlebotomy (MP) services to facilitate enrollment. Results: PREEMPT CRC enrolled 48,995 participants and achieved ethnic/racial diversity comparable to 2020 U.S. Census for Blacks (11.2%, vs 13.6%), Asians (6.8%, vs 6.3%) and Hispanic or Hispanic/Latinx (11.2%, vs 19.1%), Native Hawaiian or Other Pacific Islander (0.3% vs 0.4%). The primary site types were community hospitals and regional clinics, accounting for 45.5% of all sites, followed by health systems (12.0%), research institutes (18.5%), and academic centers/teaching hospitals (16.0%). The community clinics and academic centers enrolled the highest proportion of Black participants within their sites (21.4% and 12.1%, respectively). Research institutions had the highest proportion of Asian (24.8%) and Hispanic/Latinx (18.3%) populations. There was no significant difference observed in male versus female distribution between site types. Within traditional sites, 32% used MP service. DCT enrolled 12,137 participants (24.7% of total) from every state in the U.S., including high representation from rural areas (24.5%). Conclusions: PREEMPT CRC integrated multiple methodologies and tools to enhance diversity and inclusivity. This multimodal approach ensured diversified representation through the participation of sites with harder-to-reach populations, which was reflected in ethnic and racial data, as well as the geographical diversity. PREEMPT CRC study underscores the importance of incorporating early diversity planning into study strategy and using multiple methods to broaden the representation of the patient population. Clinical trial information: NCT04369053 .

Expanding diversity in colorectal cancer studies with a focus on Hispanic and Latino participant enrollment.

e13532 Background: Colorectal cancer (CRC) is a leading cause of cancer mortality among Hispanic and Latino groups (Hispanic/Latinx). Despite making up 18.9% of the U.S. population, Hispanic/Latinx representation is only 2.3%-3.9% of subjects in oncology trials, highlighting the need for diversity in CRC research. Freenome is developing a blood test (MyTectCRC) intended to provide a convenient and accessible option for CRC screening. Its clinical validation will be supported by PREEMPT CRC, a prospective multi-center observational study. To ensure a diverse enrollment, Freenome partnered with several sites, including IHS, in communities with a diverse population. This analysis explores strategies used at IHS Health to effectively enroll minority groups. Methods: Initiated in 2020, PREEMPT CRC study (NCT04369053) enrolled participants aged 45-85 at average CRC risk. Eligible and consenting participants underwent a blood draw and a screening colonoscopy (CS), with the blood sample analyzed by Freenome using the investigational blood test. IHS Health, a research institute in Kissimmee, Florida, utilized a variety of methods to maximize the enrollment of diverse populations reflective of its local communities, such as partnering with local organizations to establish community outreach and employing bilingual staff to translate, educate, answer study questions, with cultural sensitivity. Participants were also able to have blood drawn and undergo CS on the same day due to its proximity to a gastroenterology office. Results: The site of IHS Health enrolled 427 participants in the PREEMPT CRC study, including substantial representation of Hispanic/Latinx (78.7%) which exceeded their proportional representation in the U.S. population. The self-reported race of enrolled participants was predominantly White (71.2%), with a significant proportion of Black or African American (24.1%). The age distribution showed higher enrollment for the 65-74 age group, emphasizing inclusivity for older populations characteristic of the catchment area. Participants exhibited healthy lifestyle behavior with the majority of the population abstaining from tobacco (88.8%), alcohol (84.1%) or drug use (99.5%). Participants were very receptive to the blood test/CS with all undergoing blood draw and 96% CS adherence. Conclusions: The results underscore the success of IHS Health's recruitment methods in addressing health disparity by emphasizing the importance of inclusivity in clinical trials, leading to high enrollment of Hispanic/Latinx, reflective of local demographics. Success of PREEMPT CRC study highlights the need for careful site selection, robust recruitment strategies, and practical accessibility for patients to ensure a comprehensive understanding of medical interventions across diverse populations. Clinical trial information: NCT04369053 .

Enrollment strategies to promote inclusion in a colorectal cancer screening study.

e13530 Background: Colorectal cancer (CRC) is the second deadliest cancer in the U.S. and while rates vary among racial/ethnic groups, the Black community is disproportionately impacted with the highest incidence and mortality rates. Notably, CRC rates have also been rising among younger individuals aged 45 to 49. Recruitment of diverse and underrepresented groups, such as the populations described above, is increasingly important to enhance generalizability and real world performance in clinical studies. Freenome is developing a blood-based test (MyTectCRC) with the aim of providing a convenient and accessible option for CRC screening. Clinical validation of MyTectCRC test will be supported by PREEMPT CRC, a prospective, observational, multi-center study. The aim of this analysis is to assess the use of community-based recruitment approaches in a diverse inner-city population in Brooklyn, New York. Methods: PREEMPT CRC enrolled subjects aged 45-85 who were at average risk for CRC. To ensure representation of ethnic groups that have historically been difficult to recruit, the study deliberately engaged sites delivering care in diverse communities. Moskowitz Practice recruited from a patient base consisting largely of city workers in Brooklyn, New York, and deployed several patient-focused, ease-of-access methods such as convenient location for colonoscopy (CS) in an ambulatory surgery center, direct patient education from the physician, direct patient support from attentive and engaged site staff, customizable scheduling and screening reminders, and patient-to-patient referrals. Notably, the same approach was used for all study candidates, regardless of the participant’s ethnic/racial representation. Results: Community-based approaches contributed to strong participation from the site’s community in PREEMPT CRC. Importantly, the participants were representative of the local population with 87.4% of the enrollees identified as Black, a group historically underrepresented in oncology studies. The site also successfully enrolled young participants aged 45 to 50 (20.5%) and more females (58.2%) than males. Participants had relatively healthy lifestyles with 91.4% reporting as non-smokers, and 65% reporting no alcohol use. Study participants were highly compliant with study required procedures such as blood collection (100%) and CS (95%). Conclusions: The community-specific methods utilized by the site helped contribute to the diversity enrollment in PREEMPT CRC while recruiting participants that are representative of the local community. Ensuring diversity in clinical studies is the beginning to promoting equity in CRC screening, diagnosis and treatment. A blood-based test, supported by clinical evidence built on data from a diverse and representative population, may provide a convenient and accessible option for CRC screening and potentially increase the screening rate and reduce the CRC burden. Clinical trial information: NCT04369053 .

Decentralized trial recruitment methods to facilitate broad coverage across urban and rural counties for a blood-based test in early colorectal cancer detection.

1607 Background: Based on the 2022 census, 20% of the U.S. population lives in rural areas. Recent literature suggests that individuals in these areas may encounter health disparities, potentially leading to higher mortality from colorectal cancer (CRC) when compared to their urban counterparts. The PREEMPT CRC is a prospective, multicenter clinical study designed to validate an investigational blood test (MyTectCRC) intended to provide a convenient and accessible option for CRC screening. PREEMPT CRC included a decentralized clinical trial (DCT) site to broaden enrollment from a wider range of geographical areas, including traditionally underrepresented rural regions. This analysis evaluates demographic characteristics of participants from rural and urban areas enrolled in two distinct strategies within the DCT sites. Methods: Eligibility criteria for PREEMPT CRC have been previously described (NCT04369053). All DCT activities occurred under one clinical study ‘Metasite’, enabled by a multichannel recruitment strategy that included 1) Direct-to-Participant (DTP) via digital enrollment and 2) Site-Based (SB) partners who supported the principal investigator by identifying participants scheduled to receive a screening colonoscopy. Participant zip codes were mapped to local counties and aligned with either 1) Metropolitan (Urban) or 2) non-Metropolitan (Rural) counties. Enrolled participants were analyzed for demographics and lifestyle behaviors such as tobacco, alcohol, and drug use. Results: The DCT site enrolled 12,137 participants, where 7,634 used DTP and 4,503 used SB. Of all DCT participants, 24.4% resided in rural areas. DTP's rural population recruitment (27.8%) was double that of the SB (13.5%). The female and male distribution was similar across the groups. A larger percentage of participants from underrepresented races overall were enrolled from urban areas; however, there were some noticeable trends in the rural population. For participants who resided in rural areas and reported their race, 12.5% of DTP participants were Black and 1.2% were Asian, compared to 9.6% and 1.2%, respectively, in SB. For participants in rural areas who reported ethnicity, within DTP, 5.1% identified as Hispanic/Latinx, compared to 14.3% Hispanic/Latinx in SB. Lifestyle behavior factors were similar between DTP and SB participants who resided in rural and urban areas. Conclusions: Through the use of a DCT, the PREEMPT CRC study reached rural areas especially through DTP methodology. Furthermore, the use of SB versus DTP showed certain shifts in demographics, these differences highlight the effectiveness of targeted outreach strategies and reflect the importance for integration of multiple methods and tools to enhance essential population characteristics across geographical locations. Clinical trial information: NCT04369053 .

Real-world multi-target stool DNA adherence in an underserved and vulnerable prison patient population.

e15632 Background: In 2024, colorectal cancer (CRC) is estimated to be the fourth most diagnosed cancer, as well as the second leading cause of cancer death in the United States. While adherence to regular CRC screening has been suboptimal in the general population, this holds to be especially true in populations that are medically underserved. Non-invasive tests, such as the guideline recommended multi-target stool DNA (mt-sDNA) test, offer a more accessible option to increase screening participation in difficult to reach populations. Herein, we evaluated adherence to CRC screening in a cohort of prisoners who received the mt-sDNA test at a Nebraska Department of Corrections facility in Nebraska. Methods: This was a retrospective cohort study in a small prison population. Participants included both males and females between the ages of 45 and 75 years who underwent CRC screening evaluation at the prison’s medical center between June 1st – December 31st, 2023 and were offered multiple CRC screening options, including the mt-sDNA test. No inducements were provided for completion of the mt-sDNA test. Baseline demographics were collected for cohort description. The primary variable of interest was mt-sDNA test return rate (adherence), defined as completion of the mt-sDNA test within 60 days of kit receipt. We also evaluated mt-sDNA test results in secondary analyses. Results: Once inclusion criteria were applied, the resulting analysis cohort included 129 patients who were first time mt-sDNA screeners. The cohort was largely male (96.9%) and between the ages of 50-64 years (78.3%). Overall mt-sDNA test adherence was 95.3%, with the average time to test completion being 20 days. No significant difference was seen in test completion among males and females (95.2% vs 100%, respectively). Completion rates increased with patient age, at 90.9% (45-49 years), 95% (50-64 years), and 100% (65-75 years). The shortest time to completion in the population was observed amongst patients who were females (18.8 days), and those between the ages of 45-49 years (17.1 days). Negative and positive mt-sDNA test results were observed in 82.9% and 17.1% of the cohort, respectively. Conclusions: CRC screening with the mt-sDNA test in this single-center study of incarcerated participants yielded exceptionally high adherence rates within 60 days of kit receipt. Assessment of follow up colonoscopy rates for test-positive participants is ongoing. While based on a relatively small sample size in this initial study, the mt-sDNA test exhibited favorable completion rates in a difficult to reach population, supporting further efforts to characterize patient, provider, and system-level benefits that may be obtained through broader adoption of this highly accessible screening approach in this challenging healthcare setting.

The underestimated preventive effects of flexible sigmoidoscopy screening: re-analysis and meta-analysis of randomized trials

Flexible sigmoidoscopy (FS), which is less invasive, resource intensive and costly than colonoscopy, is among the recommended screening options for colorectal cancer (CRC). Four large randomized trials consistently reported statistically significant, albeit modest effects of screening by FS on CRC incidence. However, their effect estimates included cancers that were already prevalent at recruitment and could not have been prevented by screening. We performed a re-analysis and meta-analysis of two of the trials (including the largest one) to estimate reduction of truly incident cases by a single FS offered between 55 and 64 years of age among the “at risk study population” without prevalent CRC at recruitment. In meta-analyses of data reported after more than 15 years of follow-up, relative risk (95% CI) in intention-to-screen and per-protocol analyses were 0.71 (0.66–0.76) and 0.59 (0.55–0.65) for any CRC, and 0.52 (0.47–0.57) and 0.34 (0.30–0.39) for distal CRC, respectively. These results indicate much stronger effects than those suggested by the original reports and imply that a single screening FS can prevent approximately two out of three distal incident CRC cases within 15 + years of follow-up.

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

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.

Screening Implications for Distribution of Colorectal Cancer Subsite by Age and Role of Flexible Sigmoidoscopy.

Objectives: The effectiveness of colonoscopy to reduce colorectal cancer (CRC) mortality is extrapolated from cohort studies in the absence of randomized controlled trial (RCT) data, whereas flexible sigmoidoscopy is supported by RCT data and may be easier to implement in practice. We characterized the anatomic distribution of CRC to determine the proportion that is visible with sigmoidoscopy. Methods: Patients with a primary diagnosis of colorectal adenocarcinoma were identified in the Surveillance, Epidemiology, and End Results program (2000-2020). Tumors from the rectum to the descending colon were categorized as visible by sigmoidoscopy, whereas more proximal tumors required colonoscopy. Differential prognosis between tumor locations, stratified by age groups and stage, was assessed using the overall restricted mean survival time (RMST) at 2, 5, and 10 years. Results: Among 309,466 patients, 58% had tumors visible by sigmoidoscopy, including 73% of those under age 50 (OR 2.10, 95% CI 2.03-2.16 age < 45, OR 2.20, 95% CI 2.13-2.27 age 45-49 versus age ≥ 50). Male sex (OR 1.54, 95% CI 1.51-1.56) and Asian or Pacific Islander race (OR 1.60, 95% CI 1.56-1.64) were also positively associated with tumors visualizable by sigmoidoscopy. Across age groups, for local disease, RMST was comparable for tumors visible versus not visible on sigmoidoscopy. For regional and metastatic cancer, patients with tumors visible by sigmoidoscopy had improved RMST versus those with more proximal tumors. Conclusions: 58% of CRC arises in locations visible by flexible sigmoidoscopy. Flexible sigmoidoscopy should be considered as a viable option for CRC screening, particularly in younger patients unwilling or unable to undergo colonoscopy.

Comparing a fecal immunochemical test and circulating tumor DNA blood test for colorectal cancer screening adherence.

Colorectal cancer (CRC) screening programs are most effective at reducing disease incidence and mortality through sustained screening participation. A novel blood test modality is being explored for CRC screening, but it is unclear whether it will provide sustained screening participation. This study aimed to investigate whether a circulating tumor DNA (ctDNA) blood test improved CRC screening re-participation when compared with a fecal immunochemical test (FIT) and to define the predictors of sustained CRC screening in an Australian population. South Australians who initially participated in CRC screening using a ctDNA blood test (n=36) or FIT (n=547) were offered the same CRC screening test approximately 2years later through an extended phase of a randomized controlled trial. Surveys collected demographic, psychosocial, and clinical information. Predictors of CRC screening re-participation were explored using chi-square, Wilcoxon tests, and logistic regression. Participants offered a second ctDNA blood test were equally likely to re-participate in CRC screening as those who completed a FIT in the first round and who were offered the same test (61% vs 66% re-participation respectively, P=0.6). CRC fatalism, health activation, and self-efficacy were associated with repeated screening participation. Test awareness was predictive of repeated FIT-based CRC screening. Targeted interventions to improve CRC screening awareness and increase patient health activation may improve CRC screening adherence. A ctDNA blood test may be a suitable CRC screening option to maintain CRC screening adherence in people who do not participate in screening with FIT.

Prospective study of a multi-modal blood-based test for colorectal cancer screening.

70 Background: Colorectal cancer (CRC) screening has proven to be a useful tool for the detection and prevention of CRC. However, adherence is low despite the multiple screening options available. A blood-based CRC screening test with optimized sensitivity and specificity may improve screening adherence. We aimed to prospectively evaluate the performance of a multimodal blood-based colorectal neoplasia screening test in individuals presenting for colonoscopy. Methods: This prospective, observational study was developed in four hospitals in Spain and enrolled individuals (45 – 84 years of age) undergoing colonoscopy, including diagnostic and screening colonoscopies, between March 2020 and September 2021. Eligible individuals consented to use of medical records for research and to provide a blood sample prior to colonoscopy procedure. Individuals were followed for one year. Whole blood was collected and shipped ambient to a central laboratory for analysis (Shield, Guardant Health, Redwood City, CA, USA). The blood-based colorectal neoplasia test is a 500kb next-generation sequencing based panel and bioinformatic platform that incorporates cell-free DNA (cfDNA) methylation-based partitioning to identify cancer related genomic alterations and epigenomic modifications (methylation and modifications in chromatin state). Results are integrated to yield a binary “positive” or “negative” result. Here we present findings correlating the blood-based test results with colonoscopy findings and findings from available 1-year follow-up data. Results: 556 out of 598 eligible individuals had an evaluable colonoscopy and a blood-based test result that passed quality control standards. Of the 556 individuals, 52% were female; median age was 55 years (21% age 45 – 49, 74% age 50 – 74, 4% age 75+). Reasons for colonoscopy were symptoms (49%), average risk screening (33%), positive stool-based test (6%), positive family history (11%) or other reasons (1%). Colorectal adenocarcinoma prevalence rate was 1.4%. Sensitivity for CRC detection was 100% (8/8; Stage I, 1; Stage II, 3; Stage III, 2; Stage IV, 2). Sensitivity for advanced adenoma (AA) detection was 22%. Specificity for advanced neoplasia (CRC + AA) was 91%. Negative predictive value (NPV) for CRC detection was 100% and positive predictive value (PPV) was 13%. 1-year follow-up data was available for 504 individuals, of whom 9 patients developed cancer (none CRC), of whom 1 had an initial positive Shield result. Conclusions: In this prospective study of individuals eligible for colonoscopy, sensitivity and specificity of the blood-based test showed a performance consistent with the available stool-based non-invasive screening options. This, combined with a more acceptable mode of testing suggests that this blood-based test may be a viable CRC screening option.

Colorectal cancer screening uptake and adherence by modality at a large tertiary care center in the United States: a retrospective analysis

Objective Real-world data regarding colorectal cancer (CRC) screening adherence and use of various screening modalities is critical to improving efficacy of CRC prevention programs. We assessed overall CRC screening adherence rates and utilization by modality over a three-year period (2017-2019) within a large Primary Care network. Methods A retrospective review of individuals aged 50-75 years at average risk for CRC with at least one clinic visit in the previous 24 months. The primary outcome was CRC screening adherence each calendar year, overall and by modality, among the entire eligible population and among individuals newly completing screening (i.e., newly adherent). The final sample included 107,366 patients and 218,878 records. Results Overall CRC screening adherence increased from 2017 to 2019 (71% to 78%). Colonoscopy was the most utilized modality (up to approximately 74% were “up-to-date” with colonoscopy versus 4% for non-invasive options). However, utilization of various modalities accounting for individuals being “up-to-date” with screening changed over time, with the highest increase for mt-sDNA (10.2-fold increase), followed by FIT (1.6-fold increase) and colonoscopy (1.1-fold increase). Among newly adherent individuals, the proportion screened by colonoscopy and FOBT decreased (89% to 80% and 2.4% to 1.2%, respectively), while uptake of FIT and mt-sDNA increased (7.7% to 11.5% and 0.9% to 6.8%, respectively). Notably, FIT and mt-sDNA increased disproportionately among the age and race-ethnicity groups with the lowest overall screening rates. Conclusions In an opportunistic CRC screening program, adherence increased over time but remained below the national goal of 80%. Although colonoscopy remained the most utilized screening modality, colonoscopy uptake rates decreased, while utilization rates of mt-sDNA and FIT increased. Among minority populations, new uptake increased most with mt-sDNA and FIT. Multiple CRC screening options should be leveraged by patients and Providers to potentially improve the effectiveness and help address disparities in CRC prevention programs.

RNA-Based Stool Molecular Testing—A Novel Potential Option for Colorectal Cancer Screening

RNA-Based Stool Molecular Testing—A Novel Potential Option for Colorectal Cancer Screening

Abstract C117: Implementing on overdue colorectal cancer (CRC) screening in the Federally Qualified Health Center (FQHC) primary care setting: 12-month post intervention results

Abstract PURPOSE: We partnered with the largest FQHC in New Haven, CT to address overdue colorectal cancer screening with evidence-based interventions (EBI). We report on the 12-month follow up of a cohort of 3,127 patients overdue for CRC screening who received 1 or more evidence based interventions (EBIs) in October, 2021. BACKGROUND: Sociocultural and medical concerns are barriers to colonoscopy uptake contributing to disparities in CRC screening. An additional barrier is system level capacity. COVID-19 associated delays exacerbated the existing backlog of individuals overdue for CRC screening, underscoring the need to expand Fecal Immunochemical Testing (FIT) screening capacity. At the time of the study, colonoscopy was the front-line cancer screening strategy in this and other primary care settings in this region. METHODS: We tested the unique and additive value of multiple EBIs for increasing CRC screening in this low-income urban population. The EBIs included: medical reminder to all recipients (Arms 1-4), supplemented with information to address social determinants of health [SDOH]) barriers (Arm 2), offer of assistance from trained community health workers (CHW) to address SDOH barriers (Arm 3), and offer of educational intervention (video and pre- and post- survey) (Arm 4). Twelve-month outcomes include: 1) CRC screening test ordered; 2) CRC screening completed. RESULTS: Of the 3,127 randomized patients, ages 50-75, 77% were Hispanic (33%) or Black (44%). At 12 months post-intervention, 1,692 (54.1%) of the cohort received an order for CRC screening, and 541 (17.3%) of the cohort completed screening. With no path to CRC screening other than a provider order, among patients for whom CRC screening was ordered, nearly one-third (32%) completed screening within 12 months of the intervention. There were no differences in either outcome based on intervention Arm. DISCUSSION: Among the 3,127 individuals who were due or overdue for screening at the time of intervention, only 9 had documented CRC cancer screening in the 5 years before randomization. The promotion of stool-based testing may have brought individuals into CRC screening. There were no differences in CRC screening (colonoscopy or FIT) orders or completed tests across the 4 arms of the study, suggesting that the provider endorsed mailed screening reminder with information on in-home, stool-based testing option (FIT), and notice that CRC screening is now recommended beginning at age 45 was key to behavior change. Provider engagement and post-pandemic care-seeking on part of patients, as well as increased awareness of CRC screening following the death of high-profile actor at age 43 likely contributed to increased uptake of CRC screening. SUMMARY: A mailed reminder is a cost effective, scalable intervention that may be effective in safety net primary care settings that serve high-risk individuals. Closing the screening gap in CRC screening should include educating patients about their CRC screening options as well as the change in recommended age to begin CRC screening. Citation Format: Beth A. Jones, Sakinah C. Suttiratana, Sarah A. DeGiovanni, Levita Robinson, Michael Couturie, Steven J. Parra, Louie M. Gangcuangco, Laney Zhang, Denise Stevens, Margarita Vargas-Torres. Implementing on overdue colorectal cancer (CRC) screening in the Federally Qualified Health Center (FQHC) primary care setting: 12-month post intervention results [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C117.