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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. [ABSTRACT FROM AUTHOR]

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

Methylated circulating tumour DNA (ctDNA) blood tests for BCAT1/IKZF1 (COLVERA) and SEPT9 (Epi proColon) are used to detect colorectal cancer (CRC). However, there are no ctDNA assays approved for other gastrointestinal adenocarcinomas. We aimed to characterize BCAT1, IKZF1 and SEPT9 methylation in different gastrointestinal adenocarcinoma and non-gastrointestinal tumours to determine if these validated CRC biomarkers might be useful for pan-gastrointestinal adenocarcinoma detection. Tissue DNA methylation data from colorectal (COAD, READ), gastroesophageal (ESCA, STAD), pancreatic (PAAD) and cholangiocarcinoma (CHOL) adenocarcinoma cohorts within The Cancer Genome Atlas were used for differential methylation analyses. Clinicodemographic predictors of BCAT1, IKZF1 and SEPT9 methylation, and the selectivity of hypermethylated BCAT1, IKZF1 and SEPT9 for colorectal adenocarcinomas in comparison to other cancers were each explored with beta regression. Hypermethylated BCAT1, IKZF1 and SEPT9 were each differentially methylated in colorectal and gastroesophageal adenocarcinomas. IKZF1 was differentially methylated in pancreatic adenocarcinoma. Hypermethylated DNA biomarkers BCAT1, IKZF1 and SEPT9 were largely stable across different stages of disease and were highly selective for gastrointestinal adenocarcinomas relative to other cancer types. Existing CRC methylated ctDNA blood tests for BCAT1/IKZF1 and SEPT9 might be usefully repurposed for use in other gastrointestinal adenocarcinomas and warrant further prospective ctDNA studies. [ABSTRACT FROM AUTHOR]

Background and Aim: Surveillance colonoscopy for colorectal cancer (CRC) is generally not recommended beyond 75 years of age. The study determined incidence and predictors of advanced adenoma and CRC in older individuals undergoing surveillance colonoscopy. Methods: This was a retrospective cohort study of asymptomatic older participants (≥75 years), enrolled in a South Australian CRC surveillance program who underwent colonoscopy (2015–2020). Clinical records were extracted for demographics, personal or family history of CRC, comorbidities, polypharmacy, and colonoscopy findings. The associations between clinical variables and advanced adenoma or CRC at surveillance were assessed with multivariable Poisson regression analysis. Results: Totally 698 surveillance colonoscopies were analyzed from 574 participants aged 75–91 years (55.6% male). The incidence of CRC was 1.6% (11/698), while 37.9% (260/698) of procedures had advanced adenoma detected. Previous CRC (incidence rate ratio [IRR] 5.9, 95% CI 1.5–22.5), age ≥85 years (IRR 5.8, 95% CI 1.6–20.1) and active smoking (IRR 4.9, 95% CI 1.0–24.4) were independently associated with CRC diagnosis, while advanced adenoma at immediately preceding colonoscopy (IRR 1.6, 95% CI 1.3–2.0) and polypharmacy (IRR 1.2, 95% CI 1.0–1.5) were associated with advanced adenoma at surveillance colonoscopy in asymptomatic older participants (≥75 years). Conclusion: Advanced neoplasia was found in more than one third of the surveillance procedures completed in this cohort. Continuation of surveillance beyond age 75 yeasrs may be considered in participants who have previous CRC or are active smokers (provided they are fit to undergo colonoscopy). In other cases, such as past advanced adenoma only, the need for ongoing surveillance should be considered alongside participant preference and health status. [ABSTRACT FROM AUTHOR]

Background: Colorectal cancer (CRC) has a high rate of recurrence, in particular for advanced disease, but prognosis based on staging and pathology at surgery can have limited efficacy. The presence of circulating tumor DNA (ctDNA) at diagnosis could be used to improve the prediction for disease recurrence. Objectives: To assess the impact of detecting methylated BCAT1/IKZF1 ctDNA at diagnosis in combination with demographic, lifestyle, clinical factors and tumor pathology, to assess predictive value for recurrence. Design: A retrospective cohort study. Methods: The cohort included 180 patients (36 with recurrent CRC), who had undergone complete treatment and surveillance for a minimum of 3 years. Participant clinical details and ctDNA methylated BCAT1 / IKZF1 results were compared between those with and without recurrence, and cox regression analysis assessed each factor on disease-free survival. Results: Clinical factors independently associated with reduced disease-free survival included nodal involvement (HR = 3.83, 95% CI 1.56-9.43, P =.003), M1 stage (HR = 4.41, 95% CI 1.18-16.45, P =.027), a resection margin less than 2 mm (HR = 4.60, 95% CI 1.19-17.76, P =.027), perineural involvement (HR = 2.50, 95% CI 1.01-6.17, P =.047) and distal tumors (HR = 3.13, 95% CI 1.07-9.18, P =.037). Methylated BCAT1 / IKZF1 was detected in 51.7% (93/180) of pre-treatment plasma samples. When a positive ctDNA finding was considered in combination with these clinical prognostic factors, there was improved predictive power of recurrence for patients with perineural involvement (HR = 4.44, 95% CI 1.92-10.26, P <.001), and it marginally improved the predictive factor for M1 stage (HR = 7.59, 95% CI 2.30-25.07, P =.001) and distal tumors (HR = 5.04, 95% CI 1.88-13.49, P =.001). Conclusions: Nodal invasion, metastatic disease, distal tumor site, low resection margins and perineural invasion were associated with disease recurrence. Pre-treatment methylated ctDNA measurement can improve the predictive value for recurrence in a subset of patients, particularly those with perineural involvement. Registration: Australian and New Zealand Clinical Trials Registry #12611000318987. [ABSTRACT FROM AUTHOR]

Background. Iron deficiency (ID) is a common micronutrient deficiency and the leading cause of anemia worldwide. ID can be caused by chronic occult blood loss from colorectal neoplasia including colorectal cancer (CRC) and advanced precancerous colorectal lesions. Current guidelines recommend colonoscopy in both men and postmenopausal women presenting with ID anemia (IDA). However, there is controversy on the investigation of patients presenting with a lower risk of CRC including younger women with ID and those with nonanemic ID (NAID). There is a need for a triaging tool to identify which ID patients may benefit from colonoscopy. The fecal immunochemical test (FIT) is sensitive for CRC screening in an asymptomatic population, but its role in ID patients is unclear. The aim of this study is to conduct a systematic review to determine the diagnostic accuracy of FIT for detecting CRC and advanced precancerous neoplasia in individuals presenting with ID with or without anemia. Methods and Analysis. This protocol conforms with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols and Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy. A comprehensive search of the MEDLINE, Embase, and Web of Science databases will be undertaken for studies published after 2010 which involve patients with ID, who completed a FIT in the 6 months prior to colonoscopy, with FIT sensitivity and specificity calculated against the reference standard colonoscopy. The search will be limited to studies conducted after 2010 to reduce variability in colonoscopy quality. Risk of bias assessment will be conducted using the Quality Assessment of Diagnostic Accuracy Studies version 2. FIT sensitivity and specificity will be the primary measure of diagnostic accuracy, and data will be analysed using a random effects meta-analysis. Discussion. This review and meta-analysis will be the first to systematically explore the value of the FIT as a triaging tool for patients with ID. This trial is registered with CRD42022367162. [ABSTRACT FROM AUTHOR]

Early detection of pre-cancerous adenomas through screening can reduce colorectal cancer (CRC) incidence. Fecal immunochemical tests are commonly used, but have limited sensitivity for pre-cancerous lesions. Blood-based screening may improve test sensitivity. This systematic review and meta-analysis was conducted to evaluate the accuracy of blood-based biomarkers for detection of advanced pre-cancerous lesions. We present the accuracy of blood-based biomarkers for the detection of advanced pre-cancerous lesions. EMBASE, Web of Science and PubMed databases were searched, with study populations limited to adults diagnosed with advanced pre-cancerous lesions at colonoscopy, who had a blood-based biomarker test analyzed with reports of sensitivity and specificity. 69 studies were identified, which assessed 133 unique biomarkers sets. The best performing test was a panel of 6 miRNAs, with a sensitivity of 95% and specificity of 90% for advanced pre-cancerous lesions. Only 6 biomarkers demonstrated sensitivity ≥ 50% and specificity ≥ 90% for the detection of advanced pre-cancerous lesions. Many different blood-based biomarkers have been assessed for detection of advanced pre-cancerous lesions, but few have progressed beyond the discovery stage. While some biomarkers have reported high sensitivity and specificity, larger prospective studies in unbiased intended-use screening populations are required for validation. [ABSTRACT FROM AUTHOR]

Background: The risk of recurrence after completion of curative‐intent treatment of colorectal cancer (CRC) is hard to predict. Post‐treatment assaying for circulating tumor DNA (ctDNA) is an encouraging approach for stratifying patients for therapy, but the prognostic value of this approach is less explored. This study aimed to determine if detection of methylated BCAT1 and IKZF1 following completion of initial treatment identified patients with a poorer recurrence‐free survival (RFS). Methods: 142 CRC stage I‐III cases with at least 2 years of follow up (unless recurrence was evident sooner) and a methylated BCAT1/IKZF1 test result between 2 weeks and 12 months after completion of initial treatment were eligible for study inclusion. The association between BCAT1/IKZF1 and RFS was assessed by the log‐rank (Mantel‐Cox) method. Cox proportional hazard regression analysis was used for multivariable survival analysis. Results: Thirty‐three (23.2%) had recurrence at a median 1.6y (interquartile range: 0.8–2.4). Methylated BCAT1/IKZF1 was detected in 19 of the 142 patients (13.4%) and was associated with a significant risk of recurrence (hazard ratio [HR] 5.7, 95%CI: 1.9–17.3, p = 0.002). Three‐year RFS for patients with or without detectable methylated BCAT1/IKZF1 was 56.5% and 83.3%, respectively. Multivariable analysis showed that detection of methylated BCAT1/IKZF1 (HR = 2.6, p = 0.049) and site of the primary tumor (HR = 4.2, p = 0.002) were the only significant prognostic indicators of poor RFS. Conclusions: BCAT1/IKZF1 methylation testing after curative‐intent treatment is an independent prognostic indicator for RFS and identifies a subgroup at high risk. Personalized surveillance is warranted for patients with these ctDNA biomarkers detectable after curative‐intent treatment. [ABSTRACT FROM AUTHOR]

Objective: This is to determine whether health beliefs regarding colorectal cancer (CRC) screening could predict discomfort with a change to CRC surveillance proposing regular faecal immunochemical tests (FIT) instead of colonoscopy. Methods: Eight hundred individuals enrolled in a South Australian colonoscopy surveillance programme were invited to complete a survey on surveillance preferences. Responses were analysed using binary logistic regression predicting discomfort with a hypothetical FIT‐based surveillance change. Predictor variables included constructs based on the Health Belief Model: perceived threat of CRC, perceived confidence to complete FIT and colonoscopy (self‐efficacy), perceived benefits from current surveillance and perceived barriers to FIT and colonoscopy. Results: A total of 408 participants (51%) returned the survey (complete data n = 303; mean age 62 years, 52% male). Most participants (72%) were uncomfortable with FIT‐based surveillance reducing colonoscopy frequency. This attitude was predicted by a higher perceived threat of CRC (OR = 1.03 [95% CI 1.01–1.04]), higher colonoscopy self‐efficacy (OR = 1.34 [95% CI 1.13–1.59]) and lower perceived barriers to colonoscopy (OR = 0.92 [95% CI 0.86–0.99]). Conclusions: Health beliefs regarding colonoscopy and perceived threat of CRC may be important to consider when changing CRC surveillance protocols. If guideline changes were introduced, these factors should be addressed to provide patients reassurance concerning the efficacy of the alternative protocol. [ABSTRACT FROM AUTHOR]

Background and Aim: Surveillance colonoscopies may be delayed because of pressure on resources, such as the COVID‐19 pandemic. This study aimed to determine whether delayed surveillance colonoscopy increases the risk for advanced neoplasia and whether interval screening with faecal immunochemical tests (FITs) and other known risk factors can mitigate this risk. Methods: A retrospective cohort study of individuals undergoing surveillance colonoscopy for personal or family history of colorectal neoplasia was being provided with FIT between colonoscopies. Colonoscopy ≥ 6 months after the guideline‐recommended interval was considered "delayed." Individuals were stratified based on prime colonoscopy findings to nonneoplastic findings, non‐advanced adenoma, and advanced adenoma. The relative risk (RR) for developing advanced neoplasia was determined using a robust multivariable modified Poisson regression. Results: Of 2548 surveillance colonoscopies, 1457 (57.18%) were delayed. Prior advanced adenoma, older age (> 60 years) and nonparticipation in interval FIT were associated with increased risk for advanced neoplasia (P < 0.05). There was a trend to increased risk in those with prior advanced adenoma with an increasing colonoscopy delay (P trend = 0.01). In participants who did not complete interval FIT and having advanced adenoma in the prime colonoscopy, risk of advanced neoplasia was 2.48 times higher (RR = 2.48, 95% confidence interval: 1.20–5.13) in participants who had beyond 2 years of delayed colonoscopy compared with those with on‐time colonoscopy. Colonoscopy delay did not increase the risk of advanced neoplasia in participants with negative interval FIT results. Conclusion: Surveillance colonoscopy can be safely extended beyond 6 months in elevated colorectal cancer risk patients who do not have prior advanced adenoma diagnosis, particularly if interval FIT is negative. [ABSTRACT FROM AUTHOR]

Failure of colorectal cancer (CRC) treatment is due to residual disease, and its timely identification is critical for patient survival. Detecting CRC-associated mutations in patient circulating cell-free DNA is confounded by tumor mutation heterogeneity, requiring primary tumor sequencing to identify relevant mutations. In this study, we assessed BCAT1 and IKZF1 methylation levels to quantify circulating tumor DNA (ctDNA) and investigated whether this method can be used to assess tumor burden and efficacy of therapy. In 175 patients with CRC who were ctDNA-positive pretreatment, ctDNA levels were higher with advancing stage (P < 0.05) and correlated with tumor diameter (r = 0.35, P < 0.001) and volume (r = 0.58, P < 0.01). After completion of treatment (median of 70 days [IQR 49-109] after surgery, +/- radiotherapy, +/- chemotherapy), ctDNA levels were reduced in 98% (47/48) and were undetectable in 88% (42/48) of patients tested. For those with incomplete adjuvant chemotherapy after surgery, roughly half remained ctDNA-positive (11/21, 52.4%). The presence of ctDNA after treatment was associated with disease progression (HR 9.7, 95%CI 2.5-37.6) compared to no ctDNA. Assaying blood for ctDNA methylated in BCAT1/IKZF1 has the potential for identifying residual disease due to treatment failure, informing a potential need for therapy adjustment in advanced disease. [ABSTRACT FROM AUTHOR]

Background: A blood assay measuring methylated BCAT1 and IKZF1 can detect recurrent colorectal cancer (CRC) with high sensitivity but suboptimal specificity. This study aimed to establish an upper reference limit (URL) of these biomarkers in a reference population without CRC, apply that threshold to detecting clinical recurrence in patients who had undergone definitive therapy for CRC, and compare the performance of the biomarkers with carcinoembryonic antigen (CEA). Methods: The level of methylation was reported as the aggregate methylated BCAT1 and IKZF1 expressed as a percentage of total plasma DNA. A reference population of patients confirmed to have no colorectal neoplasia (n = 857) was used to determine the URL. Test accuracy for clinical recurrence was determined in a post‐treatment surveillance population (n = 549; 77 recurrence cases). Results: A methylation level of 0.07%, corresponding to the 98th percentile in the reference population, was set as the URL. In the surveillance population, 60 patients had methylation levels above 0.07%, and 81.7% of these had recurrence. In comparison with no minimum threshold being applied, assay sensitivity with a URL of 0.07% yielded similar sensitivity (63.6% [CI, 51.9%‐74.3%] vs 64.9% [CI, 53.8%‐74.7%]; P =.87) and higher specificity (97.7% [CI, 95.9%‐98.8%] vs 91.3% [CI, 88.4%‐93.5%]; P <.001). The BCAT1/IKZF1 test was 2.5‐fold more sensitive than CEA for detecting recurrences considered amenable to surgery with curative intent (50.0% vs 20.8%; P =.016). Conclusions: Applying a threshold for positivity to the methylated BCAT1/IKZF1 blood assay improved the specificity for CRC recurrence without compromising sensitivity. Both the sensitivity and the specificity were superior to those of CEA. Applying a threshold for positivity to the methylated BCAT1/IKZF1 blood assay improves the specificity for colorectal cancer recurrence without compromising sensitivity. Higher specificity may reduce unnecessary follow‐up procedures and minimize patient anxiety. [ABSTRACT FROM AUTHOR]

Ingestion of starch from corn (naturally enriched with [sup.13]C should produce [sup.13]C[O.sub.2] after small intestinal digestion and [sup.13]C[O.sub.2] and [H.sub.2] from colonic fermentation. This study used a combined [sup.13]C[O.sub.2]/[H.sub.2] breath test to assess the digestion and fermentation of resistant starch and to show that the test could detect changes in digestibility due to cooking. Volunteers consumed 40 g digestible cornstarch with water (n = 8), or 40 g resistant cornstarch in liquid (n = 12) or cooked into a pancake (n = 4). Interval breath sampling was performed and analyzed for [sup.13]C[O.sub.2] and [H.sub.2]. Ingestion of resistant starch produced a double-peaked [sup.13]C[O.sub.2] excretion curve. The first increase in [sup.13]C[O.sub.2] occurred at the same time as excretion from digestible starch (55 [+ or -] 9 and 68 [+ or -] 9 min, respectively), which was due to small intestinal digestion. The second increase in [sup.13]C[O.sub.2] was accompanied by an increase in [H.sub.2] excretion (432 [+ or -] 15 and 428 [+ or -] 48 min, respectively), which was indicative of colonic bacterial fermentation. Cooking resistant starch increased its degree of digestion from 36 to 72%. The [sup.13]C[O.sub.2]/[H.sub.2] breath test can be used to estimate digestion and fermentation of starches in different physiologic and pathologic conditions. KEY WORDS: * resistant starch, breath testing * fermentation * [sup.13]C[O.sub.2]

BACKGROUND: Detection of circulating cell-free DNA (ccfDNA) methylated in BCAT1 and IKZF1 is sensitive for detection of colorectal cancer (CRC), but it is not known if these biomarkers are present in other common adenocarcinomas. OBJECTIVE: Compare methylation levels of BCAT1 and IKZF1 in tissue and plasma from breast, prostate, and colorectal cancer patients. METHODS: Blood was collected from 290 CRC, 32 breast and 101 prostate cancer patients, and 606 cancer-free controls. Tumor and matched normal tissues were collected at surgery: 26 breast, 9 prostate and 15 CRC. DNA methylation in BCAT1 and IKZF1 was measured in blood and tissues. RESULTS: Either biomarker was detected in blood from 175/290 (60.3%) of CRC patients. The detection rate was higher than that measured in controls (48/606 (8.1%), OR = 18.2, 95%CI: 11.1–29.0). The test positivity rates in breast and prostate cancer patients were 9.4% (3/32) and 6.9% (7/101), respectively, and not significantly different to that measured in gender-matched controls (8.0% (33/382) females (OR = 0.84, 95%CI: 0.23–3.1) and 7.6% (26/318) males (OR = 0.86, 95%CI: 0.65–2.1). In tumor and non-neoplastic tissues, 93.5% (14/15) of CRC tumors were methylated in BCAT1 and/or IKZF1 (p < 0.004). Only 11.5% (3/26) and 44.4% (4/9) (p = 0.083) of breast and prostate tumors were hypermethylated in these two genes. CONCLUSIONS: Detection of circulating DNA methylated in BCAT1 and IKZF1 is sensitive and specific for CRC but not breast or prostate cancer. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the incidence of advanced neoplasia (colorectal cancer or advanced adenoma) at surveillance colonoscopy following removal of non‐advanced adenoma; to determine whether the time interval before surveillance colonoscopy influences the likelihood of advanced neoplasia. Design: Retrospective cohort study. Setting, participants: Patients enrolled in a South Australian surveillance colonoscopy program with findings of non‐advanced adenoma during 1999–2016 who subsequently underwent surveillance colonoscopy. Main outcome measures: Incidence of advanced neoplasia at follow‐up surveillance colonoscopy. Results: Advanced neoplasia was detected in 169 of 965 eligible surveillance colonoscopies (18%) for 904 unique patients (median age, 62.0 years; interquartile range [IQR], 54.0–69.0 years), of whom 570 were men (59.1%). The median interval between the initial and surveillance procedures was 5.2 years (IQR, 4.4–6.0 years; range, 2.0–14 years). Factors associated with increased risk of advanced neoplasia at follow‐up included age (per year: odds ratio [OR], 1.03; 95% CI, 1.01–1.05), prior history of adenoma (OR, 1.48; 95% CI, 1.01–2.15), two non‐advanced adenomas identified at baseline procedure (v one: OR, 1.74; 95% CI, 1.18–2.57), and time to surveillance colonoscopy (OR, 1.21; 95% CI, 1.08–1.37). The estimated incidence of advanced neoplasia was 19% five years after non‐advanced adenoma removal, and 30% at ten years. Conclusions: Increasing the surveillance colonoscopy interval beyond five years after removal of non‐advanced adenoma increases the risk of detection of advanced neoplasia at follow‐up colonoscopy. [ABSTRACT FROM AUTHOR]

Background and Aim: Clinically significant serrated polyps are precursors of colorectal cancers, with features considered high risk including size ≥10 mm, dysplasia, and presence of synchronous conventional adenoma. While these features have been described in cohorts undergoing screening colonoscopy, there is little information regarding the prevalence and patient characteristics associated with high‐risk sessile serrated polyps (SSPs) in those undergoing surveillance colonoscopy. Methods: Polyp pathology at the index and first follow‐up colonoscopy performed between 2004 and 2019 were examined in patients enrolled in a surveillance program because of an index finding of adenoma and/or SSP. Demographics and pathology features for SSP were compared between the colonoscopies. Results: Of 6297 patients undergoing index colonoscopy, 2035 underwent follow‐up colonoscopy after 3.3 years (interquartile range 2.1–4.8 years). The proportion with SSP decreased from 7.6% at index to 5.0% at follow‐up (P < 0.001); however, the proportion of SSPs that were considered high risk was not different between the colonoscopies (62.8% vs 62.4%). Female gender was associated with the presence of high‐risk SSP at index colonoscopy (odds ratio [OR] 1.62, 95% confidence interval [CI] 1.28–2.06), while age ≥75 years (OR 3.38, 95% CI 1.67–6.81) and previous high‐risk SSP (OR 9.40, 95% CI 4.23–20.88) were independently associated with high‐risk SSP at follow‐up. Conclusions: The prevalence of SSP falls by one‐third at first follow‐up colonoscopy although the proportion of SSP with high‐risk features remains the same. While females were more likely to have a high‐risk SSP at the index colonoscopy, those at greatest risk for high‐risk SSP at follow‐up colonoscopy were age >75 years and an index high‐risk SSP. [ABSTRACT FROM AUTHOR]

Abstract The APCmin/+ mouse is commonly used in cancer research and is just one of many genetically altered models that is currently being developed. With high numbers of breeding programs, it is important to have a simple method that can be used to genotype the mice non-invasively. Here we report a reproducible method for genotyping mice with DNA extracted from fecal samples. Comparison of fecal results with those obtained from intestinal tissue DNA and clinical outcome (presence/absence of tumors) showed this technique to have 100% accuracy. This non-invasive method of genotyping may be applied to other transgenic mouse models.

Background: DNA methylated in BCAT1 and IKZF1 are promising circulating tumor DNA (ctDNA) biomarkers for colorectal cancer detection. This study tested for variables that might be associated with their detection in patients without colonoscopically evident colorectal cancer so-called false positives. Methods: A retrospective review of demographic and clinical variables was conducted on patients who were assayed for these biomarkers prior to a colonoscopy for any indication. Potential relationships between detection of these biomarkers and patient variables in patients without colorectal cancer were identified by logistic regression. An age- and sex-matched case-control study was undertaken to identify additional associations. Results: A total of 196 of 1,593 patients undergoing colonoscopy were positive for BCAT1 and/or IKZF1 methylation; 70 (35.7%) had confirmed diagnosis of colorectal cancer. Of the 126 false positives, biomarker levels were significantly lower than in those with colorectal cancer (P < 0.05), with the total cell-free circulating DNA concentration associated with biomarker detection (OR, 1.16; 95% CI, 1.10-1.22), and 83 (65.9%) of the non-colorectal cancer cases positive for methylated BCAT1 only. Age =70 years was the only demographic variable associated with biomarker detection (OR, 4.31; 95% CI, 1.50-12.41). No significant associations were seen with medications or comorbidities (P > 0.05). Four cases without colonoscopically evident colorectal cancer but with biomarker levels above the median for patients with colorectal cancer were diagnosed with metastatic adenocarcinoma within 1 year. Conclusions: False-positive results were most commonly associated with detection of methylated BCAT1 only, as well as age =70 years. [ABSTRACT FROM AUTHOR]

Background and Aim: The coronavirus disease 2019 (COVID‐19) global pandemic has affected elective procedures, including colonoscopy, worldwide. Delayed colorectal cancer surveillance may increase cancer risk. This study aimed to determine the impact of COVID‐19 on the proportion of surveillance colonoscopies booked and completed and the extent to which that surveillance was delayed. Methods: This was a retrospective analysis of colonoscopy data during the 3 months (April–June 2020) when clinical services were most affected by COVID‐19 in South Australia compared to the same period in 2019. Data on colonoscopies and responses to surveillance recall letters were reviewed to determine the numbers and proportions of colonoscopies that were delayed. Results: During 2020, the total number of colonoscopies decreased by 51.1% (n = 569) compared to 2019 (n = 1164). In 2019, 45.5% (n = 530) of colonoscopies were completed for surveillance, but this proportion decreased to 32.0% (n = 182) during 2020, an overall decrease in the number of surveillance colonoscopies of 65.6%. Of surveillance colonoscopies that were due in 2020, 46.1% (134/291) were delayed >6 months, a significant increase compared to 2019 (19.3%; 59/306, P < 0.001). A decrease in response to surveillance recall letters was only observed in patients ≥75 years, with more nonresponders (51.6%) in 2020 compared to that observed in 2019 (25.6%, P = 0.03). Conclusions: Significant delays in surveillance colonoscopies occurred during the COVID‐19 pandemic in South Australia. These effects are likely to be in areas more severely affected by the pandemic. Planning for post‐COVID‐19 colonoscopy capacity is required to avoid cancer progression due to delays in surveillance colonoscopies. [ABSTRACT FROM AUTHOR]