British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland/Public Health England post-polypectomy and post-colorectal cancer resection surveillance guidelines

Development and Multi-center validation of a machine learning Model for advanced colorectal neoplasms screening

BACKGROUND

In colorectal cancer (CRC) screening programs, accurately identifying individuals at high risk for advanced colorectal neoplasia (ACN) is essential as they require further colonoscopy, early intervention, and monitoring follow-up. This study aimed to develop a machine learning (ML)-based risk prediction model, serving as an effective tool for the early identification of high-risk individuals for ACN.

METHODS

This study analyzed data from the Tianjin CRC screening program. The dataset from 2012 to 2022 was divided into a training set and 11 validation sets across 12 medical centers. The 2023 data was used as an independent temporal external validation set. First, the least absolute shrinkage and selection operator and logistic regression (LR) analysis were used to select significant features. Next, six ML models were constructed to predict ACN and validate its predictive capability on the validation sets. Among the classifiers, the best-performing model, Tianjin ML (TML), was selected, and its performance was compared with the Asia Pacific Colorectal Screening (APCS) and LR. Moreover, we developed a stacked ensemble learning model to improve the prediction performance for ACN. Finally, we conducted an interpretability analysis using SHapley Additive exPlanations (SHAP) values and deployed a web application tool based on the Streamlit framework.

FINDINGS

Among the trained models, the TML achieved the best performance, with an area under the curve (AUC) of 0.690, a sensitivity of 0.649, a specificity of 0.626, an F1 score of 0.320, and an accuracy of 0.629. Furthermore, the TML performed well in 11 validation sets and the independent temporal external validation set. A predictive probability threshold of 0.140 was identified for stratifying individuals into low- and high-risk groups. The TML exhibited superior performance compared to APCS and LR. The stacked ensemble learning model, S-TML, further improved the AUC to 0.709. Additionally, SHAP analysis identified age, gender, and fecal immunochemical tests as the top three predictive factors for ACN.

INTERPRETATION

The TML outperformed traditional models, including APCS and LR, in predicting ACN and could serve as a screening decision support tool to identify high-risk individuals for ACN.

Colorectal cancer screening in the UK: A public health intervention of unrealised potential

The United Kingdom was one of the first countries in the world to have a fully rolled out colorectal cancer screening programme and, although the four constituent countries have taken somewhat different approaches, they all commenced with guaiac faecal occult blood testing and have all now transitioned to faecal immunochemical testing. In this Commentary, we trace the development of the Scottish Bowel Screening Programme, with reference to the other UK programmes, reflect on its successes and shortcomings, and make suggestions for the future.

Margin thermal ablation eliminates size as a risk factor for recurrence after piecemeal endoscopic mucosal resection of large non-pedunculated colorectal polyps

BACKGROUND

Lesion size is an independent risk factor for recurrence following endoscopic mucosal resection of large (≥20 mm) non-pedunculated colorectal polyps. Post-resection margin thermal ablation (MTA) reduces the risk of recurrence. Its impact on the uncommon larger (≥40 mm) lesions is unknown.

OBJECTIVE

We sought to analyse the impact of MTA on ≥40 mm lesions in a large, prospective cohort.

DESIGN

A prospective cohort of patients with colorectal polyps ≥20 mm treated with piecemeal endoscopic mucosal resection in an expert tissue resection centre was divided into three phases: 'pre-MTA', July 2009-June 2012; 'MTA-adoption', July 2012-June 2017 and 'standardised-MTA', July 2017-July 2023. Recurrence was defined as adenomatous tissue endoscopically and/or histologically detected at the first surveillance colonoscopy. The primary outcome was the recurrence rate over the three time periods in three size groups: 20-39 mm, 40-59 mm and ≥60 mm.

RESULTS

Over 14 years until July 2023, 1872 sporadic colorectal polyps ≥20 mm in 1872 patients underwent endoscopic mucosal resection (median lesion size 35 mm (IQR 25-45mm)). Of these, 1349 patients underwent surveillance colonoscopy at a median of 6 months (IQR 4-8 months). The overall rates of recurrence in the pre-MTA, MTA-adoption and standardised-MTA phases were 13.5% (n=42/310), 12.6% (n=72/560) and 2.1% (n=10/479), respectively, (p≤0.001). When MTA was applied in the standardised-MTA phase, the rate of recurrence was the same among 20-39 mm (1.5% (3/205)), 40-59 mm (1.6% (3/190)) and ≥60 mm polyps (1.4% (1/73)) (p=1.00).

CONCLUSION

MTA negates the effect of size on the incidence of recurrence after piecemeal endoscopic mucosal resection of colorectal polyps ≥40 mm.

TRIAL REGISTRATION NUMBER

Australian Colonic Endoscopic Resection cohort (NCT01368289; NCT02000141).

Colorectal cancer incidence after the first surveillance colonoscopy and the need for ongoing surveillance: a retrospective, cohort analysis

BACKGROUND

Recommendations for the first postpolypectomy surveillance colonoscopy (SC1), based on stratifying postpolypectomy colorectal cancer (CRC) risk, are well established. Limited data inform recommendations for surveillance beyond SC1.

OBJECTIVE

We investigated which patient groups need surveillance beyond SC1.

DESIGN

Retrospective analysis of patients who underwent colonoscopy with polypectomy at 17 UK hospitals, mostly from 2000 to 2010, and had ≥1 surveillance colonoscopies. Cancer and death data were collected through 2017. We examined patients in groups defined by risk at baseline and SC1, applying risk definitions from the 2020 UK postpolypectomy surveillance guidelines: 'low risk, low risk' (LR-LR), 'high risk, low risk' (HR-LR), 'low risk, high risk' (LR-HR) and 'high risk, high risk' (HR-HR). We examined CRC incidence after SC1, censoring at any second surveillance colonoscopy (SC2), and after SC2 through end of follow-up. We compared incidence with general population incidence using standardised incidence ratios (SIRs).

RESULTS

Analyses included 10 508 patients: LR-LR=6587 (63%), HR-LR=3272 (31%), LR-HR=248 (2%) and HR-HR=401 (4%). Median follow-up from SC1 was 8.0 years and 151 CRCs were diagnosed. Compared with the general population, CRC incidence after SC1 was lower in the LR-LR group (SIR 0.48, 95% CI 0.34 to 0.67), non-significantly different in the HR-LR (SIR 1.17, 0.85 to 1.58) or LR-HR (SIR 2.51, 0.81 to 5.85) groups, but higher in the HR-HR group (SIR 2.84, 1.30 to 5.39). After SC2, CRC incidence in the HR-HR group was no longer higher than in the general population (SIR 1.86, 0.89 to 3.42).

CONCLUSION

Patients with high-risk findings at both baseline and SC1 needed an SC2, while those with low-risk findings at SC1 did not, regardless of their baseline findings.

New predictors of recurrence in post-polypectomy surveillance - A retrospective analysis of risk stratification for advanced adenomas and polyps

BACKGROUND AND AIMS

recent guidelines emphasized that not all patients with recurrent polyps benefit from post-polypectomy surveillance, except for advanced adenomas recurrence. This study aimed to analyze the recurrence risk factors for advanced adenomas and investigated the difference from any polyp recurrence.

METHODS

this retrospective observational study included patients who underwent colonoscopy and at least one post-polypectomy surveillance. Multivariate regression models identified risk factors for the recurrence of polyps and advanced adenomas. The Youden index determined the optimal cut-off value for risk factors. Kaplan-Meier curve estimated the cumulative recurrence rates, and the log-rank tests compared the differences between these curves.

RESULTS

a total of 1,818 patients had polyps at baseline examination. During post-polypectomy surveillance, 1,063 patients had recurrent polyps, and 64 patients experienced recurrent advanced adenomas. Multivariate logistic analysis identified age as an independent risk factor for both advanced adenoma (OR [95 % CI]: 1.028 [1.003-1.056]) and polyps (OR [95 % CI]: 1.019 [1.009-1.028]), with cut-off values of 57 years and 53 years, respectively. A cut-off value of 40 years can increase the predictive sensitivity to 95 %. Polyps size (OR [95 % CI]: 1.070 [1.014-1.147]) and high-risk pathology (OR [95 % CI]: 6.339 [2.057-23.919]) were significantly associated with recurrence of advanced adenomas, but not with any polyps, with a size cut-off value of 7.5 mm. Except for high-risk pathology, neither hyperplastic polyps nor tubular adenomas with low-grade dysplasia increased the recurrence risk of advanced adenomas.

CONCLUSIONS

a cut-off value of 40 years can increase the predictive sensitivity to 95 % for both advanced adenomas and any polyps. Polyps size and high-risk pathology were associated with the recurrence of advanced adenoma, but not with any polyps.

Efficacy of Jianpi formulas in reducing the recurrence of colorectal adenoma after polypectomy: a systematic review and Meta-analysis

OBJECTIVES

To systematically review the efficacy and safety of Jianpi formulas in reducing the recurrence of colorectal adenoma (CRA) after poly-pectomy.

METHODS

Randomized controlled trials (RCTs) investigating Jianpi formulas for CRA post-polypectomy were systematically retrieved from eight electronic databases. The quality of the methodology was assessed using the Cochrane collaboration tool. The Grades of Recommendations Assessment Development and Evaluation (GRADE) approach was employed for evidence assessment. Statistical analyses were conducted using Statistics and Data Analysis (STATA) 17 (StataCorp (College Station, TX, USA) and Review Manager (RevMan) 5.4 (The Cochrane Collaboration (London, UK).

RESULTS

The Meta-analysis, encompassing 18 RCTs with 1838 patients, revealed that Jianpi formulas significantly outperformed postoperative routine treatment. It demonstrated a reduction in the half-year recurrence rate [relative risk (RR) = 0.41, 95% confidence interval (CI) = 0.33-0.49, Z = 9.08, P < 0.000 01], the one-year recurrence rate [RR = 0.58, 95% CI= 0.49-0.69, Z= 6.12, P < 0.000 01], and an enhancement in the clinical effective rate [RR = 1.27, 95% CI = 1.19-1.36, Z= 7.06, P < 0.000 01]. The half-year recurrence rate and the clinical effective rate were medium-quality evidence. The one-year recurrence rate was low-quality evidence. Additionally, Jianpi formulas appear to be safe and do not increase adverse reactions compared to postoperative routine treatment alone.

CONCLUSION

Jianpi formulas exhibit efficacy in reducing postoperative half-year and one-year recurrence rates while improving the clinical effective rate after polypectomy for CRA.

Colorectal cancer incidence following a negative colonoscopy in fecal immunochemical test-based screening: a nationwide cohort study after 8 years of screening in Denmark

Screening participants with a positive fecal immunochemical test (FIT) result and a subsequent negative colonoscopy are quarantined from the Danish bowel cancer screening program for 8 years. This recommendation is based on evidence from settings other than FIT-based screening, but referral of this evidence is not necessarily sufficient. We estimated the colorectal cancer (CRC) risk among these FIT-positive/colonoscopy-negative individuals and compared it with the risk in a historical unscreened population.Using national health registers in Denmark, we compared 29 936 participants with a positive FIT but negative colonoscopy with 720 850 randomly selected unscreened controls born 9 years earlier (ratio 1:24). Controls were assigned a pseudo-colonoscopy date 9 years prior to the negative colonoscopy group. We examined cases per 10 000 person-years and estimated relative risks (RR) and 95%CIs for CRC.After 8 years' follow-up, CRC risk was lower among FIT-positive/colonoscopy-negative participants compared with controls (RR 0.72, 95%CI 0.61-0.84). By age group and sex, the lower risk was only evident for women and men in their 60s (RR 0.67 [95%CI 0.47-0.96] and RR 0.65 [95%CI 0.48-0.88], respectively) and men in their 70s (RR 0.60 [95%CI 0.44-0.84]).The overall risk for CRC was lower for individuals with a positive FIT but negative colonoscopy compared with unscreened controls. However, the lower risk might not justify 8 years of quarantine, especially for women and younger age groups. Individualized screening is warranted and transfer of evidence from non-FIT screening should be done carefully.

Construction and validation of machine learning-based predictive model for colorectal polyp recurrence one year after endoscopic mucosal resection

BACKGROUND

Colorectal polyps are precancerous diseases of colorectal cancer. Early detection and resection of colorectal polyps can effectively reduce the mortality of colorectal cancer. Endoscopic mucosal resection (EMR) is a common polypectomy procedure in clinical practice, but it has a high postoperative recurrence rate. Currently, there is no predictive model for the recurrence of colorectal polyps after EMR.

AIM

To construct and validate a machine learning (ML) model for predicting the risk of colorectal polyp recurrence one year after EMR.

METHODS

This study retrospectively collected data from 1694 patients at three medical centers in Xuzhou. Additionally, a total of 166 patients were collected to form a prospective validation set. Feature variable screening was conducted using univariate and multivariate logistic regression analyses, and five ML algorithms were used to construct the predictive models. The optimal models were evaluated based on different performance metrics. Decision curve analysis (DCA) and SHapley Additive exPlanation (SHAP) analysis were performed to assess clinical applicability and predictor importance.

RESULTS

Multivariate logistic regression analysis identified 8 independent risk factors for colorectal polyp recurrence one year after EMR (P < 0.05). Among the models, eXtreme Gradient Boosting (XGBoost) demonstrated the highest area under the curve (AUC) in the training set, internal validation set, and prospective validation set, with AUCs of 0.909 (95%CI: 0.89-0.92), 0.921 (95%CI: 0.90-0.94), and 0.963 (95%CI: 0.94-0.99), respectively. DCA indicated favorable clinical utility for the XGBoost model. SHAP analysis identified smoking history, family history, and age as the top three most important predictors in the model.

CONCLUSION

The XGBoost model has the best predictive performance and can assist clinicians in providing individualized colonoscopy follow-up recommendations.

The impact of patient-reported factors of endoscopic screening experience on attendance at future examinations and distal colorectal cancer incidence

BACKGROUND

Endoscopic examinations can reduce colorectal cancer (CRC) burden through early detection and removal of precancerous lesions; however, after initial endoscopy, some patients do not attend subsequent examinations.

AIMS

To investigate the impact of patient experience of endoscopic screening on attendance at future examinations and distal CRC incidence.

METHODS

In a cohort study including 40,141 participants who received flexible sigmoidoscopy (FS) screening in the UK FS Screening Trial, median follow-up was 16.8 years. We examined family history of CRC, bowel preparation quality, segment of bowel reached, and responses to patient-reported post-examination questionnaires. We estimated multivariable odds ratios (OR) for attendance at future examinations by logistic regression and hazard ratios (HR) for associations between patient experience at FS and distal CRC incidence.

RESULTS

Of those recommended a future endoscopy, 7.1% did not attend repeat FS, 3.4% did not attend colonoscopy, 18.3% did not attend surveillance, and 0.5% developed distal CRC. Symptoms of faintness/dizziness (OR = 5.10 95%CI 1.49-17.42) were associated with non-attendance at repeat FS. Non-attendance at surveillance was associated with whether participants felt they had made the right decision to take the tests; that taking the tests was tempting fate; that they needed the tests; or that they would rather have let nature take its course. A FS more painful than expected (HR = 0.57 95%CI 0.37-0.88) was inversely associated with distal CRC incidence.

CONCLUSIONS

We identified aspects of patient experience at endoscopy that could be used to improve attendance at future endoscopic examinations, which in turn could reduce CRC incidence.

TRIAL REGISTRATION NUMBER

ISRCTN28352761. Trial registration date: April 2000.

The Impact of Age on Preferences for Colorectal Cancer Surveillance Strategies: Are Fecal Immunochemical Tests FIT for Surveillance?

INTRODUCTION

Individuals with a known risk of colorectal cancer (CRC) are recommended regular surveillance colonoscopies. Alternative surveillance strategies incorporating fecal immunochemical tests (FIT) may improve colonoscopy resource utilization and be more appropriate for those with a lower risk of CRC, particularly younger adults. This study compared younger (< 50 years) and older (≥ 50 years) adults' preferences for different CRC surveillance strategies.

METHODS

Eight hundred individuals enrolled in a colonoscopy-based surveillance program were invited to complete a survey assessing CRC surveillance preferences. Preferences for colonoscopy frequency and the acceptability of two alternative protocols were assessed: (1) providing FIT between colonoscopies, and (2) a FIT-only strategy where colonoscopy would only be required after a positive FIT result.

RESULTS

A total of 102 younger (median age 41.4 years, 67.6% female) and 187 older (median age 68.5 years, 49.2% female) adults completed the survey. Surveillance preferences did not significantly vary by age group; most respondents preferred colonoscopies more often than their current frequency (< 50 years: 54.1%; ≥ 50 years: 58.1%). Although most participants (< 50 years: 91.2%; ≥ 50 years: 93.0%) agreed that FIT is important to complete between surveillance colonoscopies, only a small proportion were comfortable with FIT-only surveillance replacing colonoscopies (< 50 years: 27.5%; ≥ 50 years: 37.4%). Fear of CRC was a significant predictor of preferences for more frequent surveillance incorporating FIT in younger, but not older, adults.

CONCLUSION

Many individuals with an elevated risk of CRC wanted more frequent surveillance, regardless of their age. Extending surveillance colonoscopy intervals using FIT may be a more acceptable method of reducing colonoscopy frequency rather than utilizing a FIT-only approach.

TRIAL REGISTRATION

This study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN #12619001743156).

Impact of Surveillance Colonoscopy Timing on Colorectal Cancer Incidence After Advanced Adenoma Resection

INTRODUCTION

Index colonoscopy findings can affect surveillance decisions that have an impact on the future risk of colorectal cancer (CRC). However, the effectiveness of surveillance colonoscopy in reducing CRC risk remains unclear. The aim of this study was to evaluate whether the timing of the first surveillance colonoscopy affected CRC incidence rates.

METHODS

We conducted a retrospective cohort study at 2 community endoscopy clinics between 2005 and 2021, including 20,397 individuals. Based on the findings at index colonoscopy, we categorized into 4 groups: advanced adenoma (AA), ≥3 non-AAs, 1-2 non-AAs, and no adenoma. We compared the cumulative incidence of CRC among these groups, focusing on whether the first surveillance interval was less than or greater than 3 years after index colonoscopy.

RESULTS

Index colonoscopy findings identified 11,601 subjects with no adenoma, 5,288 with 1-2 non-AA, 1,484 with ≥3 non-AA, and 2,024 with AA. There were 50 cases of CRC: 23 in the no adenoma, 10 in the 1-2 non-AA, 6 in the ≥3 non-AA, and 11 in the AA group. First surveillance after 3 years was associated with a higher incidence of subsequent CRC in the AA group (hazard ratio 3.49, 95% confidence interval 1.06-11.46, P = 0.04).

DISCUSSION

In the AA group, surveillance colonoscopy within 3 years was associated with a lower risk of CRC. These findings suggest that a first surveillance within 3 years is particularly effective in subjects with AA.

Leaving colorectal polyps in situ with endocytoscopy assisted by computer-aided diagnosis: a cost-effectiveness study

BACKGROUND

 Computer-aided diagnosis (CADx) enables the distinction between neoplastic and non-neoplastic polyps during colonoscopy. We aimed to estimate the patient-level benefit and harm of CADx.

METHODS

 We conducted a comparative analysis on data from the EndoBRAIN international clinical trial, evaluating the effect of optical diagnosis during colonoscopy with and without CADx. Three hypothetical scenarios were compared: "endoscopist-alone" and "CADx-assisted" leave-in-situ strategies (leaving non-neoplastic rectosigmoid polyps ≤ 5 mm), and "total removal" (removing all detected polyps). Primary outcomes included patient-level colonoscopy-related cost and surveillance interval agreement (colorectal cancer risk category). Estimates were calculated based on national reimbursement rates and guidelines in four countries.

RESULTS

 We analyzed 1134 patients (59 % men, median age 67 years) with 1716 polyps. Compared with total removal, the endoscopist-alone and CADx-assisted leave-in-situ strategies reduced the removed polyps per patient from 1.51 (95 %CI 1.48-1.54) to 1.18 (95 %CI 1.16-1.20) and 1.12 (95 %CI 1.00-1.14), respectively; however, 0.023 (95 %CI 0.015-0.033) and 0.021 (95 %CI 0.014-0.031) neoplasms per patient were left in situ, respectively. The mean colonoscopy cost decreased by $44 (endoscopist alone) and $46 (CADx assistance) in the USA, $22 and $19 in the UK, $21 and $19 in Japan, and $32 and $30 in Norway, respectively. Surveillance interval agreement decreased to 99.2 % (endoscopist alone) and 99.0 % (CADx assistance) in the USA, 99.8 % and 99.8 % in the UK, 97.9 % and 97.1 % in Japan, and 99.9 % and 99.9 % in Norway, respectively.

CONCLUSIONS

 Both endoscopist-alone and CADx-assisted optical diagnosis reduce colonoscopy costs. The risk of missed adenomas and surveillance interval deviations appear marginal.

Long-Term Outcomes of Patients with Poor Prognostic Factors Following Transanal Endoscopic Microsurgery (TEMS) for Early Rectal Cancer

Background: Transanal endoscopic microsurgery (TEMS) is an organ-preserving approach for treatment of early rectal cancer (ERC). However, adverse histopathological features identified post-TEMS often necessitate adjuvant therapy. This study aims to compare the long-term oncological outcomes of patients who underwent TEMS and were offered adjuvant treatments with total mesorectal excision (TME), chemoradiotherapy (CRT), radiotherapy (RT), active surveillance, or dose escalation with contact X-ray brachytherapy (CXB). Methods: This study included patients treated with TEMS for ERC between September 2012 and December 2022, with follow-up until December 2023. Patients with adverse histopathological features (extra-mural venous invasion, lympho-vascular invasion, R1 margins, tumour budding) were assigned to adjuvant treatments. Inverse probability of treatment weighting (IPTW) was applied to mitigate selection bias. Results: Of the 117 patients, 24 underwent TME, 17 received CRT, 25 received RT, 14 underwent active surveillance, and 37 patients received CXB boost along with CRT. The median follow-up was 60 months (IQR 52-73). During this time, 29 patients developed recurrence, and 15 died. The 5-year overall survival (OS) was 78.6%, and disease-free survival (DFS) was 70.9%. Compared to CXB, the mortality risk for CRT (HR = 0.81; 95% CI: 0.20-3.28; p = 0.77) and TME (HR = 3.68; 95% CI: 0.46-29.79; p = 0.22) was not significantly different. However, TME was associated with a significantly higher recurrence risk compared to CXB (HR = 7.57; 95% CI: 1.23-46.84; p = 0.029). Conclusions: An organ-preserving strategy with CRT or CRT combined with a CXB boost may offer comparable long-term outcomes and reduced recurrence risks for patients undergoing TEMS for ERC with poor prognostic features. Further research with larger cohorts is needed to validate these results.

Changes in faecal haemoglobin values over sequential rounds of faecal immunochemical tests (FIT) in a surveillance population

OBJECTIVE

Colorectal cancer (CRC) screening enables resection of polyp precursor lesions, preventing cancer or detecting it earlier. Post-polypectomy, people can remain at increased CRC risk, prompting surveillance colonoscopy. Less invasive faecal immunochemical tests (FIT) could reduce the burden of surveillance colonoscopy. We investigated whether changes in FIT values over multiple rounds were associated with advanced colorectal neoplasia (ACN) detection.

METHODS

A cohort of men and women aged 60-72 years deemed intermediate risk by the 2002 UK adenoma surveillance guidelines and scheduled for three yearly colonoscopies were recruited (January 2012-December 2013) within the English Bowel Cancer Screening Programme and offered a quantitative FIT at 1, 2 and 3 years post-baseline colonoscopy for a prospective analysis within a diagnostic accuracy study. Participants positive (≥40 µg haemoglobin/g faeces) at 1 year or 2 years were offered early colonoscopy and excluded, otherwise, colonoscopy was offered at 3 years. Only those who completed three FIT rounds and attended the 3-year colonoscopy were included. Participants were grouped based on changes between FIT rounds, with changes defined as absolute differences ≥4 µg/g, and positivity at round 3.

RESULTS

Among 4412 participants, the largest group (n=2773) was the no change category, which had the lowest ACN detection rate (4.7%, 95% CI: 3.9 to 5.5). The serial increase group with a positive round 3 value (n=46) had the highest ACN detection rate (32.6%, 95% CI: 19.5 to 48.0).

CONCLUSION

No change in FIT result across multiple rounds was associated with a low ACN detection rate, while a serial increase was associated with higher ACN detection rates. Further research should consider if sequential rounds of FIT could be used for stratifying individual risk.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evaluating the pathological and clinical implications of errors made by an artificial intelligence colon biopsy screening tool

OBJECTIVE

Artificial intelligence (AI) tools for histological diagnosis offer great potential to healthcare, yet failure to understand their clinical context is delaying adoption. IGUANA (Interpretable Gland-Graphs using a Neural Aggregator) is an AI algorithm that can effectively classify colonic biopsies into normal versus abnormal categories, designed to automatically report normal cases. We performed a retrospective pathological and clinical review of the errors made by IGUANA.

METHODS

False negative (FN) errors were the primary focus due to the greatest propensity for harm. Pathological evaluation involved assessment of whole slide image (WSI) quality, precise diagnoses for each missed entity and identification of factors impeding diagnosis. Clinical evaluation scored the impact of each error on the patient and detailed the type of impact in terms of missed diagnosis, investigations or treatment.

RESULTS

Across 5054 WSIs from 2080 UK National Health Service patients there were 220 FN errors across 164 cases (4.4% of WSI, 7.9% of cases). Diagnostic errors varied from cases of adenocarcinoma to mild inflammation. 88.4% of FN errors would have no impact on patient care, with only one error causing major patient harm. Factors that protected against harm included biopsies being low-risk polyps or diagnostic features were detected in other biopsies.

CONCLUSION

Most FN errors would not result in patient harm, suggesting that even with a 7.9% case-level error rate, this AI tool might be more suitable for adoption than statistics portray. Consideration of the clinical context of AI tool errors is essential to facilitate safe implementation.

Adenoma detection rate by colonoscopy in real-world population-based studies: a systematic review and meta-analysis

BACKGROUND

Adenoma detection rate (ADR) is a quality indicator set at a minimum of 25% in unselected populations by the European Society of Gastrointestinal Endoscopy (ESGE). Nevertheless, a lack of pooled observational data resembling real-world practice limits support for this threshold. We aimed to perform a systematic review with meta-analysis to evaluate the pooled rates for conventional adenoma detection, polyp detection (PDR), cecal intubation, bowel preparation, and complications in population-based studies.

METHODS

The PubMed, Scopus, and Web of Science databases were searched until May 2023 for populational-based studies reporting overall ADR in unselected individuals. A random-effects model was used for meta-analysis.

RESULTS

31 studies were included, comprising 3 644 561 subjects. A high quality of procedures was noticeable, with a high cecal intubation rate and low complication rate. The overall pooled ADR, PDR, and rate of cancer detection were 26.5% (95%CI 23.3% to 29.7%), 38.3% (95%CI 32.5% to 44.1%), and 2.7% (95%CI 1.5% to 3.9%), respectively. ADR varied according to indication: screening 33.3% (95%CI 24.5% to 42.2%), surveillance 42.9% (95%CI 36.9% to 49.0%), and diagnostic 24.7% (95%CI 19.5% to 29.9%), with subgroup analysis revealing rates of 34.4% (95%CI 22.0% to 40.5%) for post-fecal occult blood test and 26.6% (95%CI 22.6% to 30.5%) for primary colonoscopy screening. Diminutive conventional adenomas yielded a pooled rate of 59.9% (95%CI 43.4% to 76.3%). The pooled rate for overall serrated lesion detection was 12.4% (95%CI 8.8% to 16.0%). Male sex and higher age were significantly associated with an ADR above the benchmark.

CONCLUSION

This first meta-analysis relying on real-world observational studies supports the ESGE benchmark for ADR, while suggesting that different benchmarks might be used according to indication, sex, and age.

How many polyps need to be histologically assessed when multiple polyps are submitted for the Bowel Cancer Screening Program?

AIMS

Since 2020 there has been an increase in the number of polyps removed from patients scoped for the Bowel Cancer Screening Programme (BCSP) of England. General cellular pathology workload also continues to increase disproportionately ahead of consultant pathologist numbers in the United Kingdom. The Optical Diagnosis initiative for BCSP patients has not yet, and may not be, implemented at every hospital in England. The following study therefore aimed to determine whether only a certain number of removed polyps need to be histologically assessed to consistently guide a BCSP patient's post-polypectomy management, and whether all remaining smaller polyps beyond that number could then be discarded.

METHODS

This retrospective study considered all BCSP specimens/cases submitted to the Cellular Pathology department of a large English teaching hospital from 2016 to 2024. Only cases with six or more resected polyps, for which the endoscopic report stated individual sizes, were included in the final study cohort.

RESULTS

Of the 8066 BCSP cases submitted to the aforementioned department, there were six or more polyps for 345 cases. Analysis of the final study cohort of 135 cases showed that assessment of the seven largest polyps measured endoscopically was sufficient to correctly guide follow-up management of the BCSP patient as per the 2020 British Society of Gastroenterology post-polypectomy guidelines.

CONCLUSIONS

When colonoscopy of a BCSP patient leads to removal of multiple polyps, only the seven largest polyps need to be assessed histologically and the remaining smaller polyps could be discarded with no impact to the patient's BCSP-related management.

Diagnostic accuracy of the faecal immunochemical test and volatile organic compound analysis in detecting colorectal polyps: meta-analysis

BACKGROUND

For the early detection of colorectal cancer, it is important to identify the premalignant lesions to prevent cancer development. Non-invasive testing methods such as the faecal immunochemical test are well established for the screening and triage of patients with suspected colorectal cancer but are not routinely used for polyps. Additionally, the role of volatile organic compounds has been tested for cancer detection. The aim of this review was to determine the diagnostic accuracy of the faecal immunochemical test and volatile organic compounds in detecting colorectal polyps.

METHODS

Original articles with diagnostic test accuracy measures for both the faecal immunochemical test and volatile organic compounds for advanced adenomas were included. Four databases including Medical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, and Web of Science were searched. The quality assessment tool for diagnostic accuracy study was used to assess the risk of bias and applicability. Meta-analysis was performed using RStudio® and the combined faecal immunochemical test-volatile organic compounds sensitivity and specificity were computed.

RESULTS

Twenty-two faecal immunochemical tests and 12 volatile organic compound-related articles were included in the systematic review whilst 18 faecal immunochemical tests and eight volatile organic compound-related studies qualified for the meta-analysis. The estimated pooled sensitivity and specificity of the faecal immunochemical test to diagnose advanced adenoma(s) were 36% (95% c.i. 30 to 41) and 89% (95% c.i. 86 to 91) respectively, with an area under the curve of 0.65, whilst volatile organic compounds pooled sensitivity and specificity was 83% (95% c.i. 70 to 91) and 76% (95% c.i. 60 to 87) respectively, with an area under the curve of 0.84. The combined faecal immunochemical test-volatile organic compounds increased the sensitivity to 89% with a specificity of 67%.

CONCLUSION

Faecal immunochemical testing has a higher specificity but poor sensitivity for detecting advanced adenomas, while volatile organic compound analysis is more sensitive. The combination of both tests enhances the detection rate of advanced adenomas.

Development of a National Colorectal Cancer Screening Research Agenda: An Initiative of the Canadian Screening for Colorectal Cancer Research Network (CanSCCRN)

The Canadian Screening for Colorectal Cancer Research Network (CanSCCRN) recently set out to develop a national CRC screening research agenda and identify priority research areas. The specific objectives were to (1) identify evidence gaps relevant to CRC screening and the barriers and facilitators to evidence generation and uptake by CRC screening programs, (2) establish high-priority collaborative research ideas to inform best CRC screening practices, and (3) identify one to two research topics for grant development and submission within 12 to 18 months. Three focus groups were conducted with network members and relevant parties (n = 15) to identify evidence gaps, barriers, and facilitators to evidence generation and uptake. Three workshops were subsequently held to discuss focus group findings and develop an action plan for research. An electronic survey was used to prioritize the evidence gaps to be addressed. Overall, five categories of barriers and six categories of facilitators to evidence uptake and generation were identified, as well as 23 evidence gaps to be addressed. Screening participation, post-polypectomy surveillance, and screening age range were identified as research priority research areas. Adequate resourcing and infrastructure, as well as partnerships with knowledge end users, are integral to addressing these research areas and advancing CRC screening programs in Canada and beyond.

Colon capsule endoscopy polyp detection rate vs colonoscopy polyp detection rate: Systematic review and meta-analysis

BACKGROUND

Colon capsule endoscopy (CCE) is a modern, non-invasive method for large bowel visualization, offering a less invasive alternative to traditional colonoscopy (TC). While TC remains the gold standard for comprehensive large bowel assessment, including the detection and treatment of various conditions, the effectiveness of CCE in detecting polyps is less established.

AIM

To systematically review and compare the polyp detection rates (PDR) of CCE and TC.

METHODS

A systematic literature search was conducted using four scientific databases: CINAHL, MEDLINE via EBSCO, Cochrane Library, and MEDLINE/PubMed. A standardized search command was utilized to ensure consistency. Full papers were retrieved if they compared PDR between CCE and TC and involved patients over 18 years old. A meta-analysis was then conducted using the meta package in R software.

RESULTS

Initially, 339 articles were identified, with 128 duplicates and 15 non-English articles excluded, leaving 196 for screening. After further exclusions, 9 articles were included in the review. The meta-analysis revealed minimal differences in PDR between CCE and TC. The pooled PDR for TC was 0.61 (95%CI: 0.48–0.72), and for CCE, it was 0.61 (95%CI: 0.48–0.73). The overall comparison of the pooled PDR of both methods was 0.96 (95%CI: 0.90–1.02), indicating that CCE is non-inferior to TC.

CONCLUSION

CCE has emerged as a modern and safe diagnostic alternative to TC for polyp detection, demonstrating non-inferiority when compared to the conventional method.

Systematic review: risk prediction models for metachronous advanced colorectal neoplasia after polypectomy

BACKGROUND AND AIM

Colorectal cancer (CRC) is the fourth leading cause of cancer death globally. CRC surveillance is a common indication for colonoscopy, representing a considerable burden for endoscopy services. Accurate identification of high-risk patients who would benefit from more intensive surveillance, as well as low-risk patients suitable for less frequent follow-up, could improve the effectiveness of surveillance protocols and resource use. Our aim was to identify and critically appraise published risk models for the occurrence of metachronous advanced colorectal neoplasia (ACN), defined here as CRC or advanced adenomas detected during surveillance colonoscopy.

METHODS

We searched PubMed and EMBASE for primary research studies reporting the development and/or validation of multivariable models that predict metachronous ACN risk. Screening of studies for inclusion, data extraction, and risk of bias assessment were conducted by two researchers independently.

RESULTS

We identified nine studies describing nine risk models. Six models were internally validated and two were externally validated. No model underwent both internal and external validation. Good model discrimination (concordance index > 0.7) was reported for two models during internal validation and for one model during external validation. Calibration was acceptable when assessed (n = 4). Methodological limitations and a high risk of bias were observed for all studies.

CONCLUSIONS

Several published models predicting metachronous ACN risk showed some promise. However, adherence to methodological standards was limited, and only two models were externally validated. Head-to-head comparisons of existing models using populations independent from model development cohorts should be prioritized to identify models suitable for use in clinical practice.

Optimizing Urgent Suspected Colon Cancer Referrals and Reducing Colonoscopy Wait Times in Wales

AIM

To assess recent colonoscopies and CT scans in conjunction with the feacal immunochemical test (FIT) for possibly downgrading urgent suspected cancer (USC) referrals.

METHODS

 A retrospective single-centre study was conducted, including all USC referrals for colonoscopy in 2022, excluding anal cancers. The CT and colonoscopy findings for a two-year period prior to the referral, along with the FIT result (if done), were noted. Combinations of tests were used to ascertain if any such combination would predict a negative colonoscopy (no cancer detected).

RESULTS

 Out of 500 USC referrals made, 160 were positive for colorectal cancer (CRC). Twelve cases had prior negative CT scans and colonoscopies, and none showed cancer (three were FIT and nine FIT not performed). A total of 54 cases had a prior CT with no FIT, four of which showed cancer. Fifteen cases had a prior CT with a negative FIT, and none showed cancer. Sixteen cases had prior negative colonoscopies, and all were negative for cancer (five negative FIT, one positive FIT, and 10 FIT not done ). Combining the categories where no cancer was missed, potentially 40 referrals could have been downgraded safely (8%).

CONCLUSIONS

 The above data indicate that, among the patients being considered for a colorectal USC referral, a combined prior negative colonoscopy and CT scan warrants a downgrading of the referral (irrespective of the FIT result). Referrals with a prior negative CT (abdomen) with a negative FIT or normal colonoscopy within the last two years can be safely downgraded. This will have a positive impact on waiting times and monetary expenditure on the USC pathway, but larger studies would be required to prove the external validity of these findings.

Prevalence of Abnormalities at Tandem Endoscopy in Patients Referred for Colorectal Cancer Screening/Surveillance Colonoscopy

Introduction: Performing a tandem endoscopy and colonoscopy in selected individuals has advantages, such as the early detection of benign and/or precancerous foregut diseases; it is efficient, and it may allow added therapies. It may also have disadvantages, such as generating anxiety from false-positive screening, possible harm from further testing, and unproven cost-effectiveness. Aims: We aimed to examine the prevalence of foregut endoscopic and histologic abnormalities in subjects referred for screening/surveillance colonoscopy who also underwent a tandem endoscopy. We wanted to (1) assess implications for cancer detection, intervention, and surveillance of precancerous foregut abnormalities, (2) identify benign foregut lesions, and (3) generate data on the utilities of this tandem approach. Patients and Methods: A retrospective cohort study of consecutive subjects referred for screening or surveillance colonoscopy who also underwent an endoscopy. Based on national screening guidelines, responses to prompting questions, personal or family history, or other risk factors, subjects were assigned to tandem endoscopy with biopsies (modified Seattle and Sydney protocols), under one anesthesia. Results: Of the 1004 patients referred for colonoscopy, 317 (32%) underwent tandem endoscopy. There were 214 women and 103 men. There were 237 Whites, 16 Asians, 40 Blacks, and 24 Hispanics. Median age was 59 (range 19-85). At endoscopy, we identified actionable benign (45%) peptic, inflammatory, and H. pylori-related abnormalities, and premalignant findings (i.e., intestinal metaplasia, 27%, dysplasia, 2%, and cancer 0.9%), comparable to the premalignant (40.3%) and malignant (0.6%) colonoscopy yield. Conclusions: When implemented based on national screening guidelines, tandem EGD and colonoscopy combines Barrett's esophagus and gastric cancer screening in one examination, and it has a high yield in a diverse US population.

Detection of colorectal cancer and advanced neoplasia during first surveillance interval after detection of adenomas in fecal immunochemical test cancer screening: a nationwide study

BACKGROUND

Adenoma surveillance guidelines are based on non-fecal immunochemical test (FIT)-based screening settings. However, colorectal cancer (CRC) risk may be different in FIT-positive screening populations. We evaluated the CRC and advanced adenoma risk within the recommended surveillance periods in the Danish FIT-based CRC screening program for participants with intermediate or high risk adenomas according to 2010 European guidelines. Furthermore, we estimated CRC risk for those who were not recommended surveillance according to European Society of Gastrointestinal Endoscopy (ESGE) 2020 guidelines.

METHODS

Using nationwide health registries, we identified 17 936 FIT-screening participants from 2014-2017 with adenomas undergoing surveillance (high risk 1 year, intermediate risk 3 years). Participants with a follow-up examination were included (N = 10 068). Relative risk (RR) of CRC and advance adenoma was compared between intermediate and high risk groups and between intermediates who were recommended surveillance (S) or no surveillance (NS) according to 2020 ESGE guidelines.

RESULTS

During surveillance, CRC occurred in 0.59% of the high risk group and 1.11% of the intermediate risk group (RR 0.53 [95%CI 0.34-0.84]). The high risk group had a 24% increased risk of advanced adenoma. CRC occurred in 1.69% of the intermediateNS group and 0.87% of the intermediateS group (RR 1.94 [95%CI 1.18-3.21]), and RR for advanced adenoma was 1.19 (95%CI 1.03-1.37).

CONCLUSION

CRC detection was lower among participants rated at higher risk at initial CRC screening. Findings at first screen-derived colonoscopy might not be as good a predictor of CRC risk in a FIT-positive screening population.

Dye-based chromoendoscopy detects more neoplasia than white light endoscopy in patients with primary sclerosing cholangitis and IBD

Background and study aims Patients with primary sclerosing cholangitis and inflammatory bowel disease (IBD) have a high risk of colorectal cancer. There is no agreement on the best technique for surveillance for colorectal neoplasia. We aimed to assess whether chromoendoscopy and/or high-definition endoscopy is associated with increased detection of neoplasia in patients with primary sclerosing cholangitis undergoing surveillance compared with when they were not used. Patients and methods This was a single-center, retrospective, observational study designed to analyze differences in the detection of neoplasia (adenomatous and serrated) among patients with primary sclerosing cholangitis and IBD who underwent annual surveillance between 2010 and 2020. Multilevel logistic regression was used to adjust for confounders. Results Ninety-one patients were identified, resulting in 359 colonoscopies with 360 person-years of follow up. Over the study period, 22 of 91 patients (24%) had at least one neoplastic lesion identified; however, the mean neoplastic lesion rate was 0.87 (54/63) for the primary sclerosing cholangitis-ulcerative colitis subgroup compared with 0.24 (4/17) for the primary sclerosing cholangitis-Crohn's disease subgroup. Chromoendoscopy was associated with a significantly higher detection rate for neoplasia (odds ratio [OR] 5.58, 95% confidence interval [CI] 2.08-14.9, P =0.001), and this association remained after adjusting for confounders, including high-definition endoscopy. High-definition endoscopes had a higher rate of neoplasia detection, but the significance was lost after adjustment for confounders, including chromoendoscopy (OR 1.93, 95% CI 0.69-5.40, P =0.21). Conclusions Chromoendoscopy is associated with a higher detection rate for neoplasia in patients with primary sclerosing cholangitis and IBD even with high-definition colonoscopes.

Polyp size is associated with colorectal cancer death across histologic polyp subtypes: a retrospective study of a screening colonoscopy registry

BACKGROUND

Surveillance colonoscopy after polyps have been detected at screening aims to reduce the risk for subsequent colorectal cancer, so-called post-colonoscopy colorectal cancer (PCCRC). Inconsistencies exist as to whether the risk should be stratified by histologic subtype. We aimed to compare the risk for PCCRC mortality in screening participants with sessile serrated lesions (SSLs)/traditional serrated adenomas (TSAs), hyperplastic polyps (HPPs), or conventional adenomas.

METHODS

Screening colonoscopy registry data were linked to death registry data between 2010 and 2022. We assessed the association of PCCRC death after a diagnosis of SSL/TSA, conventional adenoma, or HPP by Cox regression, and stratified by polyp size ≥10 and <10 mm.

RESULTS

383,801 participants were included in the analysis. There were 1490 HPPs ≥10 mm (2.6%), compared with 1853 SSL/TSAs (19.6%) and 10,960 conventional adenomas (12.9%). When adjusted for polyp location, the association of polyp size ≥10 mm with PCCRC death was of similar magnitude in participants with conventional adenomas (hazard ratio [HR] 3.68, 95%CI 2.49-5.44), SSL/TSAs (HR 2.55, 95%CI 1.13-5.72), and HPPs (HR 5.01, 95%CI 2.45-10.22). Participants with HPPs mostly died of tumors in the distal colon (54.1%; n = 20), while participants with SSL/TSAs more frequently died of proximal tumors (33.3%; n = 3).

CONCLUSIONS

Across all histologic types, participants with polyps ≥10 mm had at least a two-fold increase in the likelihood of PCCRC death compared with those with polyps <10 mm. These data suggest that size, rather than histologic subtype, should be a determinant for risk stratification after screening colonoscopy.

Exploring the feasibility of home-delivered capsule endoscopy with 5G support: innovations and carbon footprint insights

INTRODUCTION

Colorectal cancer (CRC) poses a significant global health threat, necessitating early detection. Traditional diagnostic tools like optical colonoscopy have limitations prompting our '5G-SUCCEEDS' initiative to explore a novel approach involving remote colon capsule endoscopy (CCE).

METHODS

This prospective feasibility study was conducted at a single hospital in England. Between December 2022 and September 2023, we introduced a remote CCE service within the 5G-SUCCEEDS framework. We undertook a feasibility study of CCE in patients with low-risk/moderate-risk CRC stratified by faecal haemoglobin. Outcomes included carbon footprint analysis (outlined through three potential clinical pathways) and patient-reported outcomes through structured questionnaires and interviews.

RESULTS

Among 25 participants, 88% expressed satisfaction with remote CCE. 82% were willing to have remote CCE if clinically indicated in future. CCE findings included adenomatous polyps (58%), normal results (17%) and diverticulosis (21%), with no cancers identified in this pilot. Notably, we found that the carbon footprint associated with delivery of CCE at home (pathway 3) was lower compared with CCE delivered in a clinical setting (pathway 2). A fully optimised, automated scaled-up pathway would combine the delivery and collection of CCE equipment within a local area to reduce the carbon footprint of the travel element by 75%. Moreover, the conversion rate into a colonoscopy pathway is not static and clinicians acknowledge that this could be as low as 28%. Carbon footprint is more favourable for home-delivered CCE in the optimised scenario, while less so when considering the need for additional procedures (colonoscopy conversion).

CONCLUSION

The 5G-SUCCEEDS initiative highlights the feasibility and advantages of home-based diagnostics using CCE.

Considerations on Multimorbidity and Frailty in Inflammatory Bowel Diseases

There are growing numbers of older people with inflammatory bowel diseases [IBD]. These older patients are more likely to have other comorbidities and polypharmacy, which can make recognizing and treating IBD complex. Frailty is a newer concept in the IBD field, and we are beginning to recognize the importance of this as a marker of biological age and its association with risk of adverse IBD-related outcomes. In this review article we aim to provide practical insight into the specific challenges facing older patients and their clinicians at each stage of the patient journey. We also discuss the latest understanding of the impact of frailty for these patients with IBD and highlight areas for future research.

Risk factors for advanced colorectal neoplasia and colorectal cancer detected at surveillance: a nationwide study in the modern era

AIM

Recommendations for surveillance after colonoscopy are based on risk factors for metachronous advanced colorectal neoplasia (AN) and colorectal cancer (CRC). The value of these risk factors remains unclear in populations enriched by individuals with a positive faecal immunochemical test and were investigated in a modern setting.

METHODS AND RESULTS

This population-based cohort study included all individuals in the Netherlands of ≥55 years old with a first adenoma diagnosis in 2015. A total of 22,471 patients were included. Data were retrieved from the Dutch Nationwide Pathology Databank (Palga). Primary outcomes were metachronous AN and CRC. Patient and polyp characteristics were evaluated by multivariable Cox regression analyses. During follow-up, 2416 (10.8%) patients were diagnosed with AN, of which 557 (2.5% from the total population) were CRC. Adenomas with high-grade dysplasia (hazard ratio [HR] 1.60, 95% confidence interval [CI] 1.40-1.83), villous histology (HR 1.91, 95% CI 1.59-2.28), size ≥10 mm (HR 1.12, 95% CI 1.02-1.23), proximal location (HR 1.12, 95% CI 1.02-1.23), two or more adenomas (HR 1.28, 95% CI 1.16-1.41), and serrated polyps ≥10 mm (HR 1.67, 95% CI 1.42-1.97) were independent risk factors for metachronous AN. In contrast, only adenomas with high-grade dysplasia (HR 2.49, 95% CI 1.92-3.24) were an independent risk factor for metachronous CRC.

CONCLUSIONS

Risk factors for metachronous AN and CRC were identified for populations with access to a faecal immunochemical test (FIT)-based screening programme. If only risk factors for metachronous CRC are considered, a reduction in criteria for surveillance seems reasonable.

Risk factors for metachronous colorectal cancer or advanced lesions after endoscopic resection of serrated polyps: a systematic review and meta-analysis

BACKGROUND AND AIMS

Serrated polyps (SPs) are precursors to 15% to 20% of colorectal cancers (CRCs). However, there are uncertainties regarding which SPs require surveillance and at what intervals, with recommendations adapted from those for adenomas in the absence of solid evidence. Our aim was to assess which SP risk characteristics relate to a higher risk of metachronous CRC or advanced polyps.

METHODS

We systematically searched PubMed, Embase, and Cochrane for cohort studies, case-control studies, and clinical trials from inception to December 31, 2023, of CRC or advanced polyps (advanced adenoma [AA] or advanced SP) incidence at surveillance stratified by baseline SP size, dysplasia, location, and multiplicity. We defined advanced SPs as those ≥10 mm or with dysplasia. CRC and advanced polyp incidence per 1000 person-years were estimated. We performed a meta-analysis by calculating pooled relative risks (RRs) using a random-effects model.

RESULTS

A total of 5903 studies were reviewed, and 14 were included with 493,949 patients (mean age, 59.5 years; 55% men). The mean follow-up was 4.9 years. CRC incidence per 1000 person-years was 2.09 (95% confidence interval [CI], 1.29-2.90) for advanced SPs, 1.52 (95% CI, 0.78-2.25) for SPs of ≥10 mm, 5.86 (95% CI, 2.16-9.56) for SPs with dysplasia, 1.18 (95% CI, 0.77-1.60) for proximal SPs, 0.52 (95% CI, 0.08-1.12) for ≥3 SPs, 0.50 (95% CI, 0.35-0.66) for nonadvanced SPs, and 0.44 (95% CI, 0.41-0.46) for normal colonoscopy findings. Metachronous CRC risk was higher in advanced SPs versus nonadvanced SPs (RR, 1.84; 95% CI, 1.11-3.04) and versus normal colonoscopy findings (RR, 2.92; 95% CI, 2.26-3.77), in SPs of ≥10 mm versus <10 mm (RR, 2.61; 95% CI, 1.43-4.77) and versus normal colonoscopy findings (RR: 3.52; 95% CI, 2.17-5.69); and in SPs with dysplasia versus normal colonoscopy findings (RR: 2.71; 95% CI, 2.00-3.67). No increase in CRC or advanced polyp risk was found in patients with proximal versus distal SPs, nor in ≥3 SPs versus 1 or 2 SPs.

CONCLUSIONS

CRC risk is significantly higher in patients with baseline advanced SPs after 4.9 years of follow-up, with risk magnitudes similar to those described for AA, supporting the current recommendation for 3-year surveillance in patients with advanced SPs.

Significant Missed Polyps in the UK Bowel Cancer Screening Programme (BCSP): A Retrospective Analysis of Prevalence and Contributing Factors

Background Colorectal cancer (CRC) remains a significant public health challenge. Patients having abnormal faecal immunochemical test (FIT) results are offered a colonoscopy. The effectiveness of colonoscopies can, however, often be challenged by the occurrence of missed polyps. This study aims to assess the rate of significant missed polyps in the Bowel Cancer Screening Programme (BCSP) in the UK. Methods A retrospective analysis of BSCP screening data in the Cheshire region in the UK from 2020 to March 2023 was conducted. A significant polyp was defined as a polyp ≥ 10mm. The inclusion criteria included patients (age range: 54-74 years) who had had an index colonoscopy followed by site checks, repeats, or planned polypectomies. Results Out of 2,759 index colonoscopies, 261 (9.5%) met our criteria, and 23 (8.8%) of these had significant polyps. Of the 261, the missed polyp rate was 30% (453/1531 polyps). The overall significant missed polyp rate was 1.6% (24/1531). Of the missed polyps, 5% (24/453) were significant polyps. The majority (71%) of the significant polyps were found on the left of the colon. Men had a higher missed polyp rate (22%) compared to women (7%) (relative risk (RR) = 2.56, 95% CI: 2.1-3.13, p<0.0001). They also had a higher significant missed polyp rate (1.1%) compared to women (0.4%) (RR = 2.41, 95% CI: 1-5.8, p<0.05). A total of 50% of the bowel prep at index colonoscopy was rated as 'adequate/fair' and 79% of the bowel prep at the discovery of the significant polyp was rated as either 'excellent' or 'good' (odds ratio (OR) = 3.8, 95% CI: 1.07-13.5, p<0.05); 92% (22/24) of the significant polyps found were either tubular adenoma (TA) low-grade dysplasia (LGD) or tubular villous adenoma (TVA) LGD, and none were found to be cancerous. Conclusions Almost a third of all polyps detected were missed, and one in 20 of these were significant polyps, putting these patients in the high-risk group for CRC. Improving bowel preparation and monitoring patients with multiple polyps could reduce the rate of missed polyps.

Polyp detection with colonoscopy assisted by the GI Genius artificial intelligence endoscopy module compared with standard colonoscopy in routine colonoscopy practice (COLO-DETECT): a multicentre, open-label, parallel-arm, pragmatic randomised controlled trial

BACKGROUND

Increased polyp detection during colonoscopy is associated with decreased post-colonoscopy colorectal cancer incidence and mortality. The COLO-DETECT trial aimed to assess the clinical effectiveness of the GI Genius intelligent endoscopy module for polyp detection, comparing colonoscopy assisted by GI Genius (computer-aided detection [CADe]-assisted colonoscopy) with standard colonoscopy in routine practice.

METHODS

We did a multicentre, open-label, parallel-arm, pragmatic randomised controlled trial in 12 National Health Service (NHS) hospitals (ten NHS Trusts) in England, among adults (aged ≥18 years) undergoing planned colonoscopy for gastrointestinal symptoms or for surveillance due to personal or family history (ie, symptomatic indications), or colorectal cancer screening. Randomisation (1:1) to CADe-assisted colonoscopy or standard colonoscopy was done with a web-based dynamic adaptive algorithm, immediately before colonoscopy, with stratification by age group, sex, colonoscopy indication (screening or symptomatic), and NHS Trust. Recruiting staff, participants, and colonoscopists were unmasked to trial allocation; histopathologists, co-chief investigators, and trial statisticians were masked. CADe-assisted colonoscopy consisted of standard colonoscopy plus the GI Genius module active for at least the entire inspection phase of colonoscope withdrawal. The primary outcome was mean adenomas per procedure (total number of adenomas detected divided by total number of procedures); the key secondary outcome was adenoma detection rate (proportion of colonoscopies with at least one adenoma). Analysis was by intention to treat (ITT), with outcomes compared between groups by mixed-effects regression modelling, in which effect estimates were adjusted for randomisation stratification variables. Data were imputed for outcome measures with more than 5% missing values. All participants who underwent colonoscopy were assessed for safety. The trial is registered on ISRCTN (ISRCTN10451355) and ClinicalTrials.gov (NCT04723758), and is complete.

FINDINGS

Between March 29, 2021, and April 6, 2023, 2032 participants (1132 [55·7%] male, 900 [44·3%] female; mean age 62·4 years [SD 10·8]) were recruited and randomly assigned: 1015 to CADe-assisted colonoscopy and 1017 to standard colonoscopy. 1231 (60·6%) participants were undergoing screening and 801 (39·4%) had symptomatic indications. Mean adenomas per procedure was 1·56 (SD 2·82; n=1001 participants with available data) in the CADe-assisted colonoscopy group versus 1·21 (1·91; n=1009) in the standard colonoscopy group, representing an adjusted mean difference of 0·36 (95% CI 0·14-0·57; adjusted incidence rate ratio 1·30 [95% CI 1·15-1·47], p<0·0001). Adenomas were detected in 555 (56·6%) of 980 participants in the CADe-assisted colonoscopy group versus 477 (48·4%) of 986 in the standard colonoscopy group, representing a proportion difference of 8·3% (95% CI 3·9-12·7; adjusted odds ratio 1·47 [95% CI 1·21-1·78], p<0·0001). Numbers of adverse events were similar between the CADe-assisted colonoscopy and standard colonoscopy groups (adverse events: 25 vs 19; serious adverse events: four vs six), and no adverse events in the CADe-assisted colonoscopy group were deemed to be related to GI Genius use on independent review.

INTERPRETATION

Results of the COLO-DETECT trial support the use of GI Genius to increase detection of premalignant colorectal polyps in routine colonoscopy practice.

FUNDING

Medtronic.

Diagnostic application of the ColonFlag AI tool in combination with faecal immunochemical test in patients on an urgent lower gastrointestinal cancer pathway

OBJECTIVE

Colorectal cancer (CRC) is the fourth most common cancer in the UK. Patients with symptoms suggestive of CRC should be referred for urgent investigation. However, gastrointestinal symptoms are often non-specific and there is a need for suitable triage tools to enable prioritisation of investigations. In this study, the performance of the faecal immunochemical test (FIT), anaemia and the artificial intelligence algorithm ColonFlag were retrospectively examined and evaluated for their potential clinical benefits in patients who had been referred on an urgent lower gastrointestinal cancer pathway.

DESIGN

All patients aged over 40 years referred in a 12-month period were included. After 6 months, clinical outcomes were determined and the performance of the triage tests was evaluated.

RESULTS

A total of 3822 patients completed investigations and received a diagnosis. 143 had CRC, 126 high-risk adenomas (HRA). ColonFlag would have missed 27 CRC and 29 HRA. Faecal haemoglobin (f-Hb) at a cut-off of 10 µg/g would have missed 10 CRC and 26 HRA; f-Hb in combination with anaemia would have missed 2 CRC and 14 HRA. Using f-Hb in combination with ColonFlag would have missed only 1 CRC and 5 HRA and would have reduced the need for urgent referral by over 400 patients.

CONCLUSION

ColonFlag has potential to assist detection of CRC and HRA, alone where no faecal sample is present and in combination with FIT and to reduce the need for urgent referral.

Risk of colorectal neoplasia after removal of conventional adenomas and serrated polyps: a comprehensive evaluation of risk factors and surveillance use

BACKGROUND

Surveillance colonoscopy after polyp removal is recommended to prevent subsequent colorectal cancer (CRC). It is known that advanced adenomas have a substantially higher risk than non-advanced ones, but optimal intervals for surveillance remain unclear.

DESIGN

We prospectively followed 156 699 participants who had undergone a colonoscopy from 2007 to 2017 in a large integrated healthcare system. Using multivariable Cox proportional hazards regression we estimated the subsequent risk of CRC and high-risk polyps, respectively, according to index colonoscopy polyps, colonoscopy quality measures, patient characteristics and the use of surveillance colonoscopy.

RESULTS

After a median follow-up of 5.3 years, we documented 309 CRC and 3053 high-risk polyp cases. Compared with participants with no polyps at index colonoscopy, those with high-risk adenomas and high-risk serrated polyps had a consistently higher risk of CRC during follow-up, with the highest risk observed at 3 years after polypectomy (multivariable HR 5.44 (95% CI 3.56 to 8.29) and 8.35 (95% CI 4.20 to 16.59), respectively). Recurrence of high-risk polyps showed a similar risk distribution. The use of surveillance colonoscopy was associated with lower risk of CRC, with an HR of 0.61 (95% CI 0.39 to 0.98) among patients with high-risk polyps and 0.57 (95% CI 0.35 to 0.92) among low-risk polyps. Among 1548 patients who had high-risk polyps at both index and surveillance colonoscopies, 65% had their index polyps in the proximal colon and 30% had index and interval polyps in the same segments.

CONCLUSION

Patients with high-risk polyp findings were at higher risk of subsequent CRC and high-risk polyps and may benefit from early surveillance within 3 years. The subsite distribution of the index and recurrent high-risk polyps suggests the contribution of incomplete resection and missed lesions to the development of interval neoplasia.

Early follow-up colonoscopy after colorectal cancer resection detects significant pathology

BACKGROUND

Colonoscopy is a key component of surveillance after colorectal cancer (CRC) resection. Surveillance intervals for colonoscopy vary across the world, with a limited evidence-base to support guidelines.

OBJECTIVE

To evaluate the timing and outcome of colonoscopies after CRC resection.

METHODS

Retrospective cohort study on prospectively collected data. Included adult patients under surveillance following CRC resection. Patients with organ transplant, inflammatory bowel disease or colon cancer syndromes were excluded. The outcomes of the first (up to) three follow-up colonoscopies were audited and classified for presence of advanced neoplasia (advanced adenoma or adenocarcinoma).

RESULTS

980 patients underwent at least one follow-up colonoscopy with a median time to first colonoscopy of 12.4 months. The findings included 2.7% CRC and 13.2% advanced adenoma. Older age, stage IV disease, and synchronous cancers at surgery were significantly associated with a finding of advanced neoplasia at first colonoscopy. 562 patients underwent a second colonoscopy (median of 35 months after the first surveillance colonoscopy) with findings of 1.8% CRC and 11.4% advanced adenoma. Advanced adenoma on prior colonoscopy was associated with finding advanced neoplasia at the second colonoscopy. 288 patients underwent a third colonoscopy (median of 37 months from the preceding colonoscopy), with similar outcomes of advanced neoplasia being associated with advanced adenoma at the previous colonoscopy. 43 (4.4%) patients developed CRC whilst on surveillance.

CONCLUSIONS

Timely surveillance after CRC resection is important for detecting advanced neoplasia, and prolonged intervals between colonoscopies in the early years after surgery should be avoided.

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.

Low Colorectal Cancer Risk After Resection of High-Risk Pedunculated Polyps

BACKGROUND

Post-fecal immunochemical test (FIT) colonoscopy represents a setting with an enriched prevalence of advanced adenomas. Due to an expected higher risk of colorectal cancer (CRC), postpolypectomy surveillance is recommended, generating a substantially increased load on endoscopy services. The aim of our study was to investigate postpolypectomy CRC risk in a screening population of FIT+ subjects after resection of low-risk adenomas (LRAs) or high-risk adenomas (HRAs).

METHODS

We retrieved data from a cohort of patients undergoing postpolypectomy surveillance within a FIT-based CRC screening program in Italy between 2002 and 2017 and followed-up to December 2021. Main outcomes were postpolypectomy CRC incidence and mortality risks according to type of adenoma (LRA/HRA) removed at colonoscopy as well as morphology, size, dysplasia, and location of the index lesion. We adopted as comparators FIT+/colonoscopy-negative and FIT- patients. The absolute risk was calculated as the number of incident CRCs per 100,000 person-years of follow-up. We used Cox multivariable regression models to identify associations between CRC risks and patient- and polyp-related variables.

RESULTS

Overall, we included 87,248 post-FIT+ colonoscopies (133 endoscopists). Of these, 42,899 (49.2%) were negative, 21,650 (24.8%) had an LRA, and 22,709 (26.0%) an HRA. After a median follow-up of 7.25 years, a total of 635 CRCs were observed. For patients with LRAs, CRC incidence (hazard ratio [HR], 1.18; 95% confidence interval [CI], 0.92-1.53) was not increased compared with the FIT+/colonoscopy-negative group, while for HRAs a significant increase in CRC incidence (HR, 1.53; 95% CI, 1.14-2.04) was found. The presence of 1 or more risk factors among proximal location, nonpedunculated morphology, and high-grade dysplasia explained most of this excess CRC risk in the HRA group (HR, 1.85; 95% CI, 1.36-2.52). Patients with only distal pedunculated polyps without high-grade dysplasia, representing 39.2% of HRA, did not have increased risk compared with the FIT- group (HR, 0.87; 95% CI, 0.59-1.28).

CONCLUSIONS

CRC incidence is significantly higher in patients with HRAs diagnosed at colonoscopy. However, such excess risk does not appear to apply to patients with only distal pedunculated polyps without high-grade dysplasia, an observation that could potentially reduce the burden of surveillance in FIT programs.

Accuracy, Acceptability, and Application: Fecal Immunochemical Tests for Early Detection of Advanced Neoplasia in Colonoscopy-Based Surveillance

BACKGROUND

The fecal immunochemical test (FIT) is widely used in colorectal cancer (CRC) screening, but limited data exist for its application in individuals at above-average risk for CRC who complete surveillance colonoscopies.

AIM

To assess the accuracy, acceptability, and effectiveness of FIT in the interval between surveillance colonoscopies, for predicting advanced neoplasia (advanced adenoma or CRC) at the next colonoscopy.

METHODS

Individuals enrolled in an Australian surveillance program were included. Diagnostic accuracy was determined for 614 individuals completing a two-sample FIT (OC-Sensor) ≤ 3 months preceding surveillance colonoscopy. 386 Individuals were surveyed to assess acceptability of interval FIT. Additionally, a retrospective analysis was performed on 7331 individuals offered interval FIT between colonoscopies, where a positive FIT (≥ 20 µg hemoglobin/g feces) triggered an early colonoscopy. Associations between interval FIT results and advanced neoplasia were determined using regression analysis.

RESULTS

FIT detected CRC and advanced adenoma with sensitivities of 60.0% (3/5) and 27.1% (35/129), respectively. Most (89.1%, 344/386) survey respondents preferred completing interval FIT every 1-2 years. The detection rate of interval FIT for advanced neoplasia decreased with increasing FIT completion. Individuals returning a positive FIT had a higher risk of advanced neoplasia than those who did not complete FIT. Positive interval FIT reduced time-to-diagnosis for CRC and advanced adenoma by a median of 30 and 20 months, respectively.

CONCLUSION

Interval FIT was well accepted and enabled earlier detection of advanced neoplasia in individuals at above-average risk of CRC. Given that interval FIT predicts advanced neoplasia, it may be used to personalize surveillance colonoscopy intervals.

Risk of advanced neoplasia after removal of colorectal adenomas with high-grade dysplasia

BACKGROUND

Many studies reported the presence of adenomas with high-grade dysplasia (HGD) at index colonoscopy increased the incidence of advanced neoplasia (AN) and colorectal cancer (CRC) following. However, the conclusion remains obscure due to lack of studies on the specific population of adenomas with HGD. This study aimed to assess the long-term risk of AN and CRC after removal of adenomas with HGD.

METHODS

A total of 814 patients who underwent adenomas with HGD removal between 2010 and 2019 were retrospectively analyzed. The outcomes were the incidences of AN and CRC during surveillance colonoscopy. Cox proportional hazards models were utilized to identify risk factors associated with AN and CRC.

RESULTS

During more than 2000 person-years of follow-up, we found that AN and CRC incidence densities were 44.3 and 4.4 per 1000 person-years, respectively. The 10-year cumulative incidence of AN and CRC were 39.1% and 5.5%, respectively. In the multivariate model, synchronous low-risk polyps (HR 1.80, 95% CI 1.10-2.93) and synchronous high-risk polyps (HR 3.99, 95% CI 2.37-6.72) were risk factors for AN, whereas participation in surveillance colonoscopy visits (HR 0.56, 95% CI 0.36-0.88 for 1 visit; HR 0.10, 95% CI 0.06-0.19 for ≥ 2 visits) were associated with decreased AN incidence. Additionally, elevated baseline carcinoembryonic antigen (CEA) level (HR 10.19, 95% CI 1.77-58.59) was a risk factor for CRC, while participation in ≥ 2 surveillance colonoscopy visits (HR 0.11, 95% CI 0.02-0.56) were associated with decreased CRC incidence. Interestingly, for 11 patients who developed CRC after removal of adenomas with HGD, immunohistochemistry revealed that 8 cases (73%) were deficient mismatch repair CRCs.

CONCLUSIONS

Patients who have undergone adenoma with HGD removal are at higher risk of developing AN and CRC, while surveillance colonoscopy can reduce the risk. Patients with synchronous polyps, or with elevated baseline CEA level are considered high-risk populations and require more frequent surveillance.

Quantifying the cost savings and health impacts of improving colonoscopy quality: an economic evaluation

OBJECTIVE

To estimate and quantify the cost implications and health impacts of improving the performance of English endoscopy services to the optimum quality as defined by postcolonoscopy colorectal cancer (PCCRC) rates.

DESIGN

A semi-Markov state-transition model was constructed, following the logical treatment pathway of individuals who could potentially undergo a diagnostic colonoscopy. The model consisted of three identical arms, each representing a high, middle or low-performing trust's endoscopy service, defined by PCCRC rates. A cohort of 40-year-old individuals was simulated in each arm of the model. The model's time horizon was when the cohort reached 90 years of age and the total costs and quality-adjusted life-years (QALYs) were calculated for all trusts. Scenario and sensitivity analyses were also conducted.

RESULTS

A 40-year-old individual gains 0.0006 QALYs and savings of £6.75 over the model lifetime by attending a high-performing trust compared with attending a middle-performing trust and gains 0.0012 QALYs and savings of £14.64 compared with attending a low-performing trust. For the population of England aged between 40 and 86, if all low and middle-performing trusts were improved to the level of a high-performing trust, QALY gains of 14 044 and cost savings of £249 311 295 are possible. Higher quality trusts dominated lower quality trusts; any improvement in the PCCRC rate was cost-effective.

CONCLUSION

Improving the quality of endoscopy services would lead to QALY gains among the population, in addition to cost savings to the healthcare provider. If all middle and low-performing trusts were improved to the level of a high-performing trust, our results estimate that the English National Health Service would save approximately £5 million per year.

Risk factors for synchronous high-risk polyps in patients with colorectal cancer

Purpose

Colorectal cancer (CRC) patients may experience inadequate preoperative colonoscopy due to bowel obstruction or inadequate bowel preparation, leading to potential oversight of other polyps. We aimed to identify risk factors for CRC complicated with synchronous high-risk polyps.

Methods

A retrospective analysis of 6,674 CRC patients from December 2014 to September 2018 was conducted. High-risk polyps were defined as adenomas or serrated polyps that were ≥10 mm, or with tubulovillous/villous components or high-grade dysplasia. All other polyps were defined as low-risk polyps. Patients with complete pathological and clinical information were categorized into three groups: the no polyp group, the low-risk polyp group, and the high-risk polyp group. Univariate and multivariate logistic regression analyses were performed to calculate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for all potential risk factors.

Results

Among the 4,659 eligible patients, 848 (18.2%) were found to have low-risk polyps, while 675 (14.5%) were diagnosed with high-risk polyps. In a multivariate logistic regression model, compared to patients without polyps, those with synchronous high-risk polyps were more likely to be male (OR = 2.07), aged 50 or older (OR = 2.77), have early-stage tumors (OR = 1.46), colon tumors (OR = 1.53), NRAS mutant tumors (OR = 1.66), and BRAF wild-type tumors (OR = 2.43).

Conclusion

Our study has identified several risk factors associated with the presence of synchronous high-risk polyps in CRC patients. Based on these findings, we recommend that patients who exhibit these high-risk factors undergo early follow-up of colonoscopy to detect synchronous polyps early.

Unmasking early colorectal cancer clues: in silico and in vitro investigation of downregulated IGF2, SOCS1, MLH1, and CACNA1G in SSA polyps

BACKGROUND AND AIM

Colorectal cancer (CRC) originates from pre-existing polyps in the colon. The development of different subtypes of CRC is influenced by various genetic and epigenetic characteristics. CpG island methylator phenotype (CIMP) is found in about 15-20% of sporadic CRCs and is associated with hypermethylation of certain gene promoters. This study aims to find prognostic genes and compare their expression and methylation status as potential biomarkers in patients with serrated sessile adenomas/polyps (SSAP) and CRC, in order to evaluate which, one is a better predictor of disease.

METHOD

This study employed a multi-phase approach to investigate genes associated with CRC and SSAP. Initially, two gene expression datasets were analyzed using R and Limma package to identify differentially expressed genes (DEGs). Venn diagram analysis further refined the selection, revealing four genes from the Weissenberg panel with significant changes. These genes, underwent thorough in silico evaluations. Once confirmed, they proceeded to wet lab experimentation, focusing on expression and methylation status. This comprehensive methodology ensured a robust examination of the genes involved in CRC and SSAP.

RESULT

This study identified cancer-specific genes, with 8,351 and 1,769 genes specifically down-regulated in SSAP and CRC tissues, respectively. The down-regulated genes were associated with cell adhesion, negative regulation of cell proliferation, and drug response. Four highly downregulated genes in the Weissenberg panel, including CACNA1G, IGF2, MLH1, and SOCS1. In vitro analysis showed that they are hypermethylated in both SSAP and CRC samples while their expressions decreased only in CRC samples.

CONCLUSION

This suggests that the decrease in gene expression could help determine whether a polyp will become cancerous. Using both methylation status and gene expression status of genes in the Weissenberg panel in prognostic tests may lead to better prognoses for patients.

The impact on clinical outcomes and healthcare resources from discontinuing colonoscopy surveillance subsequent to low-risk adenoma removal: A simulation study using the OncoSim-Colorectal model

OBJECTIVE

To estimate the impact on clinical outcomes and healthcare resource use from recommending that patients with 1-2 low-risk adenomas (LRAs) return to routine fecal immunochemical test (FIT) screening instead of surveillance colonoscopy, from a Canadian provincial healthcare system perspective.

METHODS

The OncoSim-Colorectal microsimulation model simulated average-risk individuals eligible for FIT-based colorectal cancer (CRC) screening in Alberta, Canada. We simulated two surveillance strategies that applied to individuals with 1-2 LRAs (<10 mm) removed as part of the average risk CRC screening program: (a) Surveillance colonoscopy (status quo) and (b) return to FIT screening (new strategy); both at 5 years after polypectomy. A 75 ng/mL FIT positivity threshold was used in the base case. The simulations projected average annual CRC outcomes and healthcare resource use from 2023 to 2042. We conducted alternative scenarios and sensitivity analyses on key variables.

RESULTS

Returning to FIT screening (versus surveillance colonoscopy) after polypectomy was projected to have minimal impact on long-term CRC incidence and deaths (not statistically significant). There was a projected decrease of one (4%) major bleeding event and seven (5%) perforation events per year. There was a projected increase of 4800 (1.5%) FIT screens, decrease of 3900 (5.1%) colonoscopies, and a decrease of $3.4 million (1.2%) in total healthcare costs per year, on average. The annual colonoscopies averted and healthcare cost savings increased over time. Results were similar in the alternative scenarios and sensitivity analyses.

CONCLUSIONS

Returning to FIT screening would have similar clinical outcomes as surveillance colonoscopy but could reduce colonoscopy demand and healthcare costs.