Measures of longitudinal adherence to fecal-based colorectal cancer screening: Literature review and recommended approaches

Projected Impact and Cost-Effectiveness of Novel Molecular Blood-Based or Stool-Based Screening Tests for Colorectal Cancer

BACKGROUND

Cell-free DNA blood tests (cf-bDNA) and next-generation stool tests could change colorectal cancer (CRC) screening.

OBJECTIVE

To estimate the clinical and economic impacts of novel CRC screening tests.

DESIGN

Cost-effectiveness analysis using MOSAIC (Model of Screening and Surveillance for Colorectal Cancer).

DATA SOURCES

Published data.

TARGET POPULATION

Average-risk persons.

TIME HORIZON

Ages 45 to 100 years.

PERSPECTIVE

Health sector.

INTERVENTION

Novel versus established CRC screening tests.

OUTCOME MEASURES

Incidence and mortality of CRC, quality-adjusted life-years (QALYs), costs.

RESULTS OF BASE-CASE ANALYSIS

For colonoscopy every 10 years, annual fecal immunochemical test (FIT), and triennial next-generation multitarget stool DNA, FIT-RNA, cf-bDNA (Guardant Shield), or cf-bDNA (Freenome), the relative rates (RRs) and 95% uncertainty intervals (UIs) versus no screening for CRC incidence were 0.21 (0.19 to 0.22), 0.29 (0.27 to 0.31), 0.33 (0.32 to 0.36), 0.32 (0.30 to 0.34), 0.58 (0.55 to 0.61) and 0.58 (0.55 to 0.60), respectively; the RRs for CRC death were 0.19 (0.17 to 0.20), 0.25 (0.23 to 0.27), 0.28 (0.27 to 0.30), 0.28 (0.26 to 0.30), 0.44 (0.42 to 0.47), and 0.46 (0.44 to 0.49), respectively. The cf-bDNA test (Shield; list price $1495) cost $89 600 ($74 800 to $102 300) per QALY gained versus no screening; alternatives were less costly and more effective.

RESULTS OF SENSITIVITY ANALYSIS

Incremental costs exceeded incremental benefits when novel test intervals were shortened to 2 or 1 years. The cf-bDNA test matched FIT's impact on CRC mortality at 1.35 (1.30 to 1.40)-fold FIT's uptake rate, assuming equal colonoscopy follow-up. If persons who accept colonoscopy or stool tests shifted to cf-bDNA, CRC deaths increased. This adverse effect was overcome if every 3 such substitutions were counterbalanced by cf-bDNA uptake by 2 or more persons refusing alternatives, assuming equal colonoscopy follow-up.

LIMITATION

Longitudinal test-specific participation patterns are unknown.

CONCLUSION

First-generation cf-bDNA tests may deliver net benefit or harm, depending on the balance between achieving screening in persons who decline alternatives versus substituting cf-bDNA for more effective alternatives.

PRIMARY FUNDING SOURCE

The Gorrindo Family Fund.

Longitudinal screening adherence in the Australian National Bowel Cancer Screening Program from 2006 to 2022

OBJECTIVE

Australia's National Bowel Cancer Screening Program (NBCSP) offers two-yearly screening to 50-74-year-olds for the prevention and early detection of colorectal cancer (CRC). Internationally, detailed reporting of participation across multiple screening rounds - also known as longitudinal adherence - is becoming more common, but remains limited in Australia. We described the longitudinal screening adherence of individuals by age and sex invited to the NBCSP at least once, and quantified longitudinal adherence among individuals who received four NBCSP invitations.

METHODS

We obtained aggregate national data for individuals who received at least one NBCSP invitation between 1 August 2006 and 31 March 2022. We described screening adherence patterns including longitudinal adherence among individuals who received four invitations, and evaluated prior longitudinal adherence and adherence at most recent invitation as predictors of future participation.

RESULTS

Over the study period, 8.5 million individuals were invited to screen in the NBCSP; 51.9% of these individuals screened at least once. Of the >2.5 million individuals who received four invitations, 23.3% consistently screened, 38.3% never screened, and 38.3% inconsistently screened. The longitudinal adherence at the fourth invitation round for individuals who previously returned none, one, two, or three of their previous three invitations was 9.5%, 37.4%, 70.1% and 88.8%, respectively. Both longitudinal adherence and adherence at the most recent invitation were significant predictors of future participation.

CONCLUSION

Our study is the first detailed report of longitudinal adherence to the NBCSP in >2 screening rounds. These insights into long-term behaviours can inform planning for interventions to improve screening participation.

Colorectal cancer screening program implementation: biennial adherence and participation patterns

INTRODUCTION AND AIM

Adherence to colorectal cancer (CRC) screening is essential for the effectiveness of screening programs. Even though organized screening programs can improve the quality of the process and adherence, there are still challenges to overcome. The aim of the present study, in which we implemented a biennial organized screening program for CRC, was to describe adherence and participation patterns.

MATERIALS AND METHODS

A longitudinal, descriptive study was conducted, in which a team of trained patient navigators carried out interventions, with reminders via cellphone communication, to follow a cohort of 301 subjects eligible for CRC screening, utilizing a fecal immunochemical test (FIT). All the follow-up subjects received a FIT kit.

RESULTS

A total of 747 cellphone calls were made and divided into three interventions. From the initial cohort, 126 subjects completed their biennial screening process through the FIT, indicating a consistent adherence rate of 41.8% to our program. The participation patterns were: 126 consistent participants (41.8%), 160 inconsistent participants (53.2%), and 15 participants that were never contacted (5%).

CONCLUSIONS

In conclusion, our study underlines the importance of organized screening programs in the early detection of CRC. The implementation of follow-up interventions, through reminders and the training of patient navigators, can improve adherence, but there is a need for examining new strategies, to overcome barriers to communication via cellphone.

Longitudinal adherence to annual colorectal cancer screening among Black persons living in the United States enrolled in a community-based randomized trial

BACKGROUND

This study examined repeat colorectal cancer screening rates at 12 and 24 months as part of a randomized intervention trial among Black persons living in the United States and factors associated with screening adherence.

METHODS

Participants completed a survey assessing demographics and Preventive Health Model (PHM) factors (e.g., self efficacy, susceptibility) and received either a culturally targeted photonovella plus free fecal immunochemical test (FIT) kits (intervention group) or a standard educational brochure plus free FIT kits (comparison group). FIT return was assessed at 6, 12, and 24 months. Descriptive statistics summarized patterns of repeat screening. Logistic regression models assessed FIT uptake overtime, and demographic and PHM factors associated with screening adherence.

RESULTS

Participants (N = 330) were U.S.-born (93%), non-Hispanic (97%), and male (52%). Initial FIT uptake within 6 months of enrollment was 86.6%, and subsequently dropped to 54.5% at 12 months and 36.6% at 24 months. Higher FIT return rates were observed for the brochure group at 24 months (51.5% vs 33.3% photonovella, p = .023). Multiple patterns of FIT kit return were observed: 37% completed FIT at all three time points (full adherence), 22% completed two of three (partial adherence), 29% completed one of three (partial adherence), and 12% did not return any FIT kits (complete nonadherence). Predictors of full adherence were higher levels of education and self-efficacy.

CONCLUSIONS

Full adherence to repeat screening was suboptimal. Most participants had partial adherence (one or two of three) to annual FIT screening. Future studies should focus on strategies to support repeat FIT screening.

COVID-related disruptions to colorectal cancer screening, diagnosis, and treatment could increase cancer Burden in Australia and Canada: A modelling study

COVID-19 disrupted cancer control worldwide, impacting preventative screening, diagnoses, and treatment services. This modelling study estimates the impact of disruptions on colorectal cancer cases and deaths in Canada and Australia, informed by data on screening, diagnosis, and treatment procedures. Modelling was used to estimate short- and long-term effects on colorectal cancer incidence and mortality, including ongoing impact of patient backlogs. A hypothetical mitigation strategy was simulated, with diagnostic and treatment capacities increased by 5% from 2022 to address backlogs. Colorectal cancer screening dropped by 40% in Canada and 6.3% in Australia in 2020. Significant decreases to diagnostic and treatment procedures were also observed in Australia and Canada, which were estimated to lead to additional patient wait times. These changes would lead to an estimated increase of 255 colorectal cancer cases and 1,820 colorectal cancer deaths in Canada and 234 cases and 1,186 deaths in Australia over 2020-2030; a 1.9% and 2.4% increase in mortality, respectively, vs a scenario with no screening disruption or diagnostic/treatment delays. Diagnostic and treatment capacity mitigation would avert 789 and 350 deaths in Canada and Australia, respectively. COVID-related disruptions had a significant impact on colorectal cancer screening, diagnostic, and treatment procedures in Canada and Australia. Modelling demonstrates that downstream effects on disease burden could be substantial. However, backlogs can be managed and deaths averted with even small increases to diagnostic and treatment capacity. Careful management of resources can improve patient outcomes after any temporary disruption, and these results can inform targeted approaches early detection of cancers.

Delays in Colorectal Cancer Screening for Latino Patients: The Role of Immigrant Healthcare in Stemming the Rising Global Incidence of Colorectal Cancer

The significant global burden of colorectal cancer accentuates disparities in access to preventive healthcare in most low- and middle-income countries (LMICs) as well as large sections of underserved populations within high-income countries. The barriers to colorectal cancer screening in economically transitioning Latin America are multiple. At the same time, immigration from these countries to the USA continues to increase. This case highlights the delays in diagnosis experienced by a recent immigrant from a country with no established colorectal cancer screening program, to an immigrant population in the USA with similar poor screening coverage. We discuss common challenges faced by Latinos in their home countries and the USA, as well as strategies that could be implemented to improve screening coverage in US immigrant populations.

Risk prediction for advanced neoplasia using longitudinal adherence measures to fecal immunochemical test-based colorectal cancer screening programs

BACKGROUND

Patterns of longitudinal adherence may predict advanced neoplasia (AN) detection in subsequent rounds of colorectal cancer (CRC) screening. However, after more than five rounds, it is important to obtain a simplified measure. The aim was to determine the best simplified measure of longitudinal adherence to predict AN detection in CRC screening.

METHODS

Individuals with four invitations from a Dutch Fecal immunochemical testing (FIT-)based pilot study and two Italian FIT-based CRC screening programs were included. We calculated AN detection in the fourth round, stratified by prior adherence. Five simplified measures were compared to full information (permutations) using chi-squared goodness-of-fit: adherence previous invitation, consistency, frequency, frequency + adherence previous invitation, and proportion of invitations covered.

RESULTS

AN detection in the fourth round was highly dependent on prior adherence behavior. For inconsistent adherence, detection in the fourth round was strongly dependent on frequency and time since last participation. The performance of the simplified measures to capture this variation differed considerably. 'Adherence previous invitation' scored worst in predicting AN detection. 'Frequency+adherence previous invitation' had lowest chi-squared goodness-of-fit.

DISCUSSION

The simplified measure 'frequency+adherence previous invitation' is the best measure to reflect patterns of longitudinal adherence and could be used to emphasize to individuals the importance of CRC screening.

Colonoscopy Colorectal Cancer Screening Programme in Southern Iraq: Challenges, Knowledge Gaps and Future Potential

Data on current colorectal cancer screening practices in Iraq are limited. This study aimed to better understand the current colorectal cancer screening practice and perceived barriers. The project also aimed to use UK expertise to introduce Bowel Cancer Screening Programme (BCSP) in Basra, Iraq. The study consisted of two parts: A pre-visit online survey of clinicians to test the project's feasibility. A public survey was conducted to understand and gauge the general knowledge and perceived barriers to having colorectal cancer screening. The second phase included a short visit to Basra and the delivery of a multidisciplinary meeting for bowel screening colonoscopists. Fifty healthcare providers completed the survey. Basra has no established bowel cancer screening programme, let alone the country. Opportunistic colonoscopy surveillance is done on an ad hoc base. A total of 350 individuals completed the public survey. The survey showed that more than 50% of participants were not familiar with the concept of a BCSP and less than 25% were aware of "red flag" symptoms of bowel cancer. The short visit to Basra included a roundtable discussion and delivered a training workshop for screening colonoscopists using UK training materials in conjunction with the Iraqi Medical Association. Feedback from the course was extremely positive. Several potential barriers were identified to participate in BCSP. The study highlighted potential barriers, including a lack of public awareness and insufficient training resources to be addressed in future screening programmes. The study has identified several potential areas for future collaboration to support the development of a BCSP centre in Basra.

Guidance for setting international standards on reporting longitudinal adherence to stool-based colorectal cancer screening

Longitudinal adherence to colorectal cancer (CRC) screening is reported using different summarizing measures, which hampers international comparison. We provide evidence to guide recommendations on which longitudinal adherence measure to report. Using adherence data over four stool-based CRC screening rounds in three countries, we calculated six summarizing adherence measures; adherence over all rounds, adherence per round, rescreening, full programme adherence (yes/no), regularity (never/inconsistent/consistent screenees) and number of times participated. For each measure, we calculated the accuracy in capturing the observed adherence patterns. Using the ASCCA model, we predicted screening effectiveness when using summarizing measures as model input versus the observed adherence patterns. Adherence over all rounds in the Italian, Spanish and Dutch cohorts was 64.9%, 42.8% and 61.5%, respectively, and the proportion of consistent screenees was 50.9%, 26.3% and 45.7%. Number of times participated and regularity were most accurate and resulted in similar model-predicted screening effectiveness as simulating the observed adherence patterns of Italy, Spain and the Netherlands (mortality reductions: 24.4%, 16.9% and 23.5%). Adherence over all rounds and adherence per round were least accurate. Screening effectiveness was overestimated when using adherence over all rounds (mortality reductions: 26.8%, 19.4% and 25.7%) and adherence per round (mortality reductions: 26.8%, 19.5% and 25.9%). To conclude, number of times participated and regularity were most accurate and resulted in similar model-predicted screening effectiveness as using the observed adherence patterns. However they require longitudinal data. To facilitate international comparison of CRC screening programme performance, consensus on an accurate adherence measure to report should be reached.

A Metabolomics-Based Screening Proposal for Colorectal Cancer

Colorectal cancer (CRC) is a high incidence disease, characterized by high morbidity and mortality rates. Early diagnosis remains challenging because fecal occult blood screening tests have performed sub-optimally, especially due to hemorrhoidal, inflammatory, and vascular diseases, while colonoscopy is invasive and requires a medical setting to be performed. The objective of the present study was to determine if serum metabolomic profiles could be used to develop a novel screening approach for colorectal cancer. Furthermore, the study evaluated the metabolic alterations associated with the disease. Untargeted serum metabolomic profiles were collected from 100 CRC subjects, 50 healthy controls, and 50 individuals with benign colorectal disease. Different machine learning models, as well as an ensemble model based on a voting scheme, were built to discern CRC patients from CTRLs. The ensemble model correctly classified all CRC and CTRL subjects (accuracy = 100%) using a random subset of the cohort as a test set. Relevant metabolites were examined in a metabolite-set enrichment analysis, revealing differences in patients and controls primarily associated with cell glucose metabolism. These results support a potential use of the metabolomic signature as a non-invasive screening tool for CRC. Moreover, metabolic pathway analysis can provide valuable information to enhance understanding of the pathophysiological mechanisms underlying cancer. Further studies with larger cohorts, including blind trials, could potentially validate the reported results.