The Diagnostic Performance of Fecal Immunochemical Tests for Detecting Advanced Neoplasia at Surveillance Colonoscopy.

BACKGROUND & AIMS: An increasing burden on health care resources has resulted in a backlog of individuals requiring colonoscopy, with delays in surveillance possibly detrimental for individuals at increased risk of colorectal cancer (CRC). This study investigated the use of a 2-sample fecal immunochemical test (FIT) to establish those most likely to have advanced neoplasia (AN) and in need of prioritized surveillance colonoscopy. METHODS: This was a prospective study conducted in the tertiary care setting. Participants completed a 2-sample FIT (OC-Sensor, Eiken Chemical Company) within 90 days of surveillance colonoscopy. The sensitivity of FIT for detection of AN (CRC or advanced adenoma) in moderate- and high-risk individuals was determined at fecal hemoglobin thresholds between 2 and 80 µg/g feces. RESULTS: A total of 766 patients were included (median age, 66.1 years [interquartile range, 58.1-72.9]; 49.9% male), with AN detected in 8.6% (66/766, including 5 CRC). For moderate-risk individuals (with prior history of adenoma or a significant family history of CRC), sensitivity of FIT for AN ranged from 73.5% at 2 µg/g feces, to 10.2% at 80 µg/g feces. For high-risk conditions (confirmed/suspected genetic syndromes or prior CRC), sensitivity of FIT was similar, ranging from 70.6% at the lowest positivity threshold of 2 µg/g feces, to 11.8% at 80 µg/g feces. Independent variables in the whole cohort for association with detection of AN at surveillance colonoscopy were age (odds ratio, 1.03; 95% confidence interval, 1.00-1.06) and FIT hemoglobin result ≥10 µg/g feces (odds ratio, 1.81; 95% confidence interval, 1.04-3.16). CONCLUSIONS: The use of FIT before surveillance colonoscopy provides clinicians with insights into the risk of AN. This raises the possibility of a method to triage individuals, facilitating the more efficient management of endoscopic resources.

Health utility assessments in individuals undergoing diagnostic and surveillance colonoscopy: improved discrimination with a cancer-specific scale.

PURPOSE: To compare the sensitivity and discriminant validity of generic and cancer-specific measures for assessing health-related quality of life (HRQoL) for individuals undergoing diagnostic or surveillance colonoscopy for colorectal cancer. METHODS: HRQoL was assessed using EQ-5D-5L (generic), and EORTC QLQ-C30 (cancer-specific) scales, 14 days after (baseline) and one-year following colonoscopy (follow-up). Utility scores were calculated by mapping EORTC-QLQ-C30 onto QLU-C10D. Differences between participants with different indications for colonoscopy (positive faecal occult blood test (FOBT), surveillance, or symptoms) and colonoscopy findings (no polyps, polyps, or cancer) were tested using Wilcoxon-Mann-Whitney and Kruskal-Wallis H tests. Sensitivity was assessed by calculating the ceiling effects (proportion reporting the best possible level). RESULTS: 246 adults completed the survey, including those undergoing colonoscopy for symptoms (n = 87), positive FOBT (n = 92) or surveillance (n = 67). Those with symptoms had the lowest HRQoL at both baseline and follow-up, with differences observed within the HRQoL domains/areas of role function, appetite loss and bowel function on the QLU-C10D. No differences were found in HRQoL when stratified by findings at colonoscopy with both measures or when comparing baseline and follow-up responses. Participants reporting full health with EQ-5D-5L (21% at baseline and 16% at follow-up) still had problems on the QLU-C10D, with fatigue and sleep at baseline and with role function and fatigue at follow-up. CONCLUSION: Patients undergoing colonoscopy for symptoms had lower HRQoL compared to surveillance or positive FOBT. The cancer-specific QLU-C10D was more sensitive and had greater discriminant ability between patients undergoing colonoscopy for different indications.

BCAT1, IKZF1 and SEPT9: methylated DNA biomarkers for detection of pan-gastrointestinal adenocarcinomas.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. DISCUSSION: 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.

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

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.

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.

An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles.

OBJECTIVE: New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers. DESIGN: A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles. RESULTS: Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence. CONCLUSION: New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact.

Multiple Negative Fecal Immunochemical Tests Reduce Risk of Advanced Neoplasia in a Colonoscopy Surveillance Program.

BACKGROUND & AIMS: In above-average-risk individuals undergoing colonoscopy-based surveillance for colorectal cancer (CRC), screening with fecal immunochemical tests (FIT) between colonoscopies might facilitate personalization of surveillance intervals. Because a negative FIT is associated with a reduced risk for CRC, we examined the relationship between number of rounds of negative FIT and risk for advanced neoplasia in individuals undergoing surveillance colonoscopy. METHODS: We conducted a retrospective cohort study on 4021 surveillance intervals in 3369 individuals (50-74 years), who had completed a 2-sample FIT between colonoscopies, from 1 to 4 rounds at 1-2 yearly intervals, each with a negative result (<20 µg hemoglobin/g feces). Incidence of advanced neoplasia (CRC or advanced adenoma) was determined at the follow-up colonoscopy. Competing-risk regression was used to assess the association between multiple negative FIT results and the risk of advanced neoplasia within 2 years. RESULTS: The incidence of advanced neoplasia in the cohort was 9.9% and decreased with increasing numbers of rounds of negative FIT results: 11.1% after 1 negative FIT to 5.7% after 4 negative FIT. The risk of advanced neoplasia was significantly lower in participants with 3 (subdistribution hazard ratio, 0.50; 95% confidence interval, 0.24-0.97) and 4 (subdistribution hazard ratio, 0.33; 95% confidence interval, 0.15-0.73) rounds of negative FIT compared with only 1 negative FIT. CONCLUSIONS: There was a low risk of advanced neoplasia after multiple rounds of negative FIT in above-average-risk people undergoing surveillance with no neoplasia or nonadvanced adenoma at prior colonoscopy. This supports the use of interval FIT to personalize surveillance by lengthening colonoscopy intervals following multiple negative FIT results.

Hot Mail: Temperature Exposure during Mail Return of an Immunochemical Fecal Occult Blood Test.

BACKGROUND: Fecal immunochemical tests (FITs) are widely used for colorectal cancer (CRC) screening; however, high ambient temperatures were found to reduce test accuracy. More recently, proprietary globin stabilizers were added to FIT sample buffers to prevent temperature-associated hemoglobin (Hb) degradation, but their effectiveness remains uncertain. We aimed to determine the impact of high temperature (>30°C) on OC-Sensor FIT Hb concentration with current FITs, characterize FIT temperatures during mail transit, and determine impact of ambient temperature on FIT Hb concentration using data from a CRC screening program. METHODS: FITs were analyzed for Hb concentration after in vitro incubation at different temperatures. Data loggers packaged alongside FITs measured temperatures during mail transit. Separately, screening program participants completed and mailed FITs to the laboratory for Hb analysis. Regression analyses compared the impact of environmental variables on FIT temperatures and separately on FIT sample Hb concentration. RESULTS: In vitro incubation at 30 to 35°C reduced FIT Hb concentration after >4 days. During mail transit, maximum FIT temperature averaged 6.4°C above maximum ambient temperature, but exposure to temperature above 30°C was for less than 24 hours. Screening program data showed no association between FIT Hb concentration and maximum ambient temperatures. CONCLUSIONS: Although FIT samples are exposed to elevated temperatures during mail transit, this is brief and does not significantly reduce FIT Hb concentration. These data support continuation of CRC screening during warm weather with modern FITs with a stabilizing agent when mail delivery is ≤4 days.

Risk of Gastroenteritis from Swimming at a Wastewater-Impacted Tropical Beach Varies across Localized Scales.

Population growth and changing climate are expected to increase human exposure to pathogens in tropical coastal waters. We examined microbiological water quality in three rivers within 2.3 km of each other that impact a Costa Rican beach and in the ocean outside their plumes during the rainy and dry seasons. We performed quantitative microbial risk assessment (QMRA) to predict the risk of gastroenteritis associated with swimming and the amount of pathogen reduction needed to achieve safe conditions. Recreational water quality criteria based on enterococci were exceeded in >90% of river samples but in only 13% of ocean samples. Multivariate analysis grouped microbial observations by subwatershed and season in river samples but only by subwatershed in the ocean. The modeled median risk from all pathogens in river samples was between 0.345 and 0.577, 10-fold above the U.S. Environmental Protection Agency (U.S. EPA) benchmark of 0.036 (36 illnesses/1,000 swimmers). Norovirus genogroup I (NoVGI) contributed most to risk, but adenoviruses raised risk above the threshold in the two most urban subwatersheds. The risk was greater in the dry compared to the rainy season, due largely to the greater frequency of NoVGI detection (100% versus 41%). Viral log10 reduction needed to ensure safe swimming conditions varied by subwatershed and season and was greatest in the dry season (3.8 to 4.1 dry; 2.7 to 3.2 rainy). QMRA that accounts for seasonal and local variability of water quality contributes to understanding the complex influences of hydrology, land use, and environment on human health risk in tropical coastal areas and can contribute to improved beach management. IMPORTANCE This holistic investigation of sanitary water quality at a Costa Rican beach assessed microbial source tracking (MST) marker genes, pathogens, and indicators of sewage. Such studies are still rare in tropical climates. Quantitative microbial risk assessment (QMRA) found that rivers impacting the beach consistently exceeded the U.S. EPA risk threshold for gastroenteritis of 36/1,000 swimmers. The study improves upon many QMRA studies by measuring specific pathogens, rather than relying on surrogates (indicator organisms or MST markers) or estimating pathogen concentrations from the literature. By analyzing microbial levels and estimating the risk of gastrointestinal illness in each river, we were able to discern differences in pathogen levels and human health risks even though all rivers were highly polluted by wastewater and were located less than 2.5 km from one another. This variability on a localized scale has not, to our knowledge, previously been demonstrated.

FIT for purpose: study protocol for a randomized controlled trial to personalize surveillance colonoscopy for individuals at elevated risk of colorectal cancer.

PURPOSE: There is increasing demand for colorectal cancer (CRC) surveillance, but healthcare capacity is limited. The burden on colonoscopy resources could be reduced by personalizing surveillance frequency using the fecal immunochemical test (FIT). This study will determine the safety, cost-effectiveness, and patient acceptance of using FIT to extend surveillance colonoscopy intervals for individuals at elevated risk of CRC. METHODS: This multicenter, prospective, randomized controlled trial will invite participants who are scheduled for surveillance colonoscopy (due to a personal history of adenomas or a family history of CRC) and who have returned a low fecal hemoglobin (< 2 µg Hb/g feces; F-Hb) using a two-sample FIT (OC Sensor, Eiken Chemical Company) in the prior 3 years. A total of 1344 individuals will be randomized to either surveillance colonoscopy as scheduled or delayed by 1 or 2 years for individuals originally recommended a 3- or 5-year surveillance interval, respectively. The primary endpoint is incidence of advanced neoplasia (advanced adenoma and/or CRC). Secondary endpoints include cost-effectiveness and consumer acceptability of extending surveillance intervals, determined using surveys and discrete choice experiments. CONCLUSION: This study will establish the safety, cost-effectiveness, and acceptability of utilizing a low FIT Hb result to extend colonoscopy surveillance intervals in a cohort at elevated risk for CRC. This personalized approach to CRC surveillance will lead to a reduction in unnecessary colonoscopies, increases in healthcare savings, and a better patient experience.  TRIAL REGISTRATION: Registration was approved on December 9, 2019 with the Australian New Zealand Clinical Trials Registry ANZCTR 12619001743156.

Low Incidence of Colorectal Advanced Neoplasia During Surveillance in Individuals with a Family History of Colorectal Cancer.

BACKGROUND: Family history of colorectal cancer (CRC) is used to stratify individuals into risk categories which determine timing of initial screening and ongoing CRC surveillance. Evidence for long-term CRC risk following a normal index colonoscopy in family history populations is limited. AIMS: To assess the incidence of advanced neoplasia and associated risk factors in a population undergoing surveillance colonoscopies due to family history of CRC. METHODS: Surveillance colonoscopy findings were examined in 425 individuals with a family history of CRC, a normal index colonoscopy and a minimum of 10 years of follow-up colonoscopies. Advanced neoplasia risk was determined for three CRC family history categories (near-average, medium and high-risk), accounting for demographics and time after the first colonoscopy. RESULTS: The median follow-up was 13.5 years (IQR 11.5-16.0), with an incidence of advanced neoplasia of 14.35% (61/425). The number of affected relatives and age of CRC diagnosis in the youngest relative did not predict the risk of advanced neoplasia (p > 0.05), with no significant differences in advanced neoplasia incidence between the family history categories (p = 0.16). Patients ≥ 60 years showed a fourfold (HR 4.14, 95% CI 1.33-12.89) higher advanced neoplasia risk during surveillance than those < 40 years at index colonoscopy. With each subsequent negative colonoscopy, the risk of advanced neoplasia at ongoing surveillance was reduced. CONCLUSIONS: The incidence of advanced neoplasia was low (14.35%), regardless of the family history risk category, with older age being the main risk for advanced neoplasia. Delaying onset of colonoscopy or lengthening surveillance intervals could be a more efficient use of resources in this population.

Detection of recurrent colorectal cancer with high specificity using a reporting threshold for circulating tumor DNA methylated in BCAT1 and IKZF1.

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.

A longitudinal cohort study of watch and wait in complete clinical responders after chemo-radiotherapy for localised rectal cancer: study protocol.

BACKGROUND: Rectal Cancer is a common malignancy. The current treatment approach for patients with locally advanced rectal cancer involves neoadjuvant chemoradiotherapy followed by surgical resection of the rectum. The resection can lead to complications and long-term consequences. A clinical complete response is observed in some patients after chemoradiotherapy. A number of recent studies have shown that patients can be observed safely after completing chemoradiotherapy (without surgery), provided clinical complete response has been achieved. In this approach, resection is reserved for cases of regrowth. This is called the watch and wait approach. This approach potentially avoids unnecessary surgical resection of the rectum and the resulting complications. In this study, we will prospectively investigate this approach. METHODS: Adult patients with a diagnosis of rectal cancer planned to receive neoadjuvant long course chemoradiotherapy (± subsequent combination chemotherapy) will be consented into the study prior to commencing treatment. After completing the chemoradiotherapy (± subsequent combination chemotherapy), based on the clinical response, subjects will be allocated to one of the following arms: subjects who achieved a clinical complete response will be allocated to the watch and wait arm and others to the standard management arm (which includes resection). The aim of the study is to determine the rate of local failure and other safety and efficacy outcomes in the watch and wait arm. Patient reported outcome measures and the use of biomarkers as part of the clinical monitoring will be studied in both arms of the study. DISCUSSION: This study will prospectively investigate the safety of the watch and wait approach. We will investigate predictive biomarkers (molecular biomarkers and imaging biomarkers) and patient reported outcome measures in the study population and the cost effectiveness of the watch and wait approach. This study will also help evaluate a defined monitoring schedule for patients managed with the watch and wait approach. This protocol covers the first two years of follow up, we are planning a subsequent study which covers year 3-5 follow up for the study population. TRIAL REGISTRATION: Name of the registry: Australia and New Zealand Clinical Trials Registry (ANZCTR). TRIAL REGISTRATION NUMBER: Trial ID: ACTRN12619000207112 Registered 13 February 2019, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=376810.

Faecal immunochemical test mitigates risk of delayed colonoscopy in people with elevated risk of colorectal neoplasia.

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.

Patient attitudes towards changes in colorectal cancer surveillance: An application of the Health Belief Model.

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.

The influence of the surveillance time interval on the risk of advanced neoplasia after non-advanced adenoma removal.

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.

Features associated with high-risk sessile serrated polyps at index and follow-up colonoscopy.

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.

Circulating epigenetic biomarkers for detection of recurrent colorectal cancer.

BACKGROUND: The sensitive detection of recurrent colorectal cancer (CRC) by the measurement of circulating tumor DNA (ctDNA) might improve the chance of a cure. This study compared a quantitative methylated ctDNA test with carcinoembryonic antigen (CEA) in the setting of surveillance for recurrence. METHODS: Blood samples collected either during surveillance or within 12 months of the confirmation of recurrence were assayed for ctDNA (methylated branched-chain amino acid transaminase 1 [BCAT1]/Ikaros family zinc-finger 1 protein [IKZF1]) and CEA. The optimal ctDNA threshold was determined by receiver operating characteristic analysis, and the test performance for the detection of recurrence was compared with CEA (5 ng/mL threshold). RESULTS: The study cohort comprised 144 eligible patients and included 50 recurrence events. The sensitivity of the methylated ctDNA test for recurrence was 66.0% (95% confidence interval [CI], 57.1%-69.3%), which was significantly higher than the sensitivity of CEA (31.9%; 95% CI, 22.8%-36.6%; P < .001). The sensitivity for resectable recurrence (n = 20) was also higher (ctDNA, 60.0%; CEA, 20.0%; P = .01). The specificity did not differ between the tests (ctDNA, 97.9%; 95% CI, 93.2%-99.6%; CEA, 96.4%; 95% CI, 91.4%-99.0%). When adjustments were made for other predictors of the presence of recurrence, a positive ctDNA test was an independent predictor (odds ratio, 155.7; 95% CI, 17.9-1360.6; P < .001), whereas CEA was not (odds ratio, 2.5; 95% CI, 0.3-20.6; P = .407). CONCLUSIONS: The quantitative ctDNA test showed superior sensitivity in comparison with CEA without a difference in the specificity for detecting recurrent CRC. Longitudinal studies are warranted to further assess the utility (specifically the survival benefit) of methylated BCAT1/IKZF1 ctDNA in the surveillance of patients with CRC.

A Somatic Coliphage Threshold Approach To Improve the Management of Activated Sludge Wastewater Treatment Plant Effluents in Resource-Limited Regions.

Effective wastewater management is crucial to ensure the safety of water reuse projects and effluent discharge into surface waters. Multiple studies have demonstrated that municipal wastewater treatment with conventional activated sludge processes is inefficient for the removal of a wide spectrum of viruses in sewage. In this study, a well-accepted statistical approach was used to investigate the relationship between viral indicators and human enteric viruses during wastewater treatment in a resource-limited region. Influent and effluent samples from five urban wastewater treatment plants (WWTPs) in Costa Rica were analyzed for somatic coliphage and human enterovirus, hepatitis A virus, norovirus genotypes I and II, and rotavirus. All WWTPs provide primary treatment followed by conventional activated sludge treatment prior to discharge into surface waters that are indirectly used for agricultural irrigation. The results revealed a statistically significant relationship between the detection of at least one of the five human enteric viruses and somatic coliphage. Multiple logistic regression and receiver operating characteristic curve analysis identified a threshold of 3.0 × 103 (3.5 log10) somatic coliphage PFU per 100 ml, which corresponded to an increased likelihood of encountering enteric viruses above the limit of detection (>1.83 × 102 virus targets/100 ml). Additionally, quantitative microbial risk assessment was executed for farmers indirectly reusing WWTP effluent that met the proposed threshold. The resulting estimated median cumulative annual disease burden complied with World Health Organization recommendations. Future studies are needed to validate the proposed threshold for use in Costa Rica and other regions.IMPORTANCE Effective wastewater management is crucial to ensure safe direct and indirect water reuse; nevertheless, few countries have adopted the virus log reduction value management approach established by the World Health Organization. In this study, we investigated an alternative and/or complementary approach to the virus log reduction value framework for the indirect reuse of activated sludge-treated wastewater effluent. Specifically, we employed a well-accepted statistical approach to identify a statistically sound somatic coliphage threshold value which corresponded to an increased likelihood of human enteric virus detection. This study demonstrates an alternative approach to the virus log reduction value framework which can be applied to improve wastewater reuse practices and effluent management.

Older age, symptoms, or anemia: Which factors increase colorectal cancer risk with a positive fecal immunochemical test?

BACKGROUND AND AIM: Fecal immunochemical tests (FIT) are used to screen asymptomatic individuals aged 50-74 years for colorectal cancer (CRC) within the Australian screening program. Gastrointestinal symptoms or iron deficiency anemia (IDA) may also drive primary care physicians to request a FIT. This study aimed to examine factors that may increase neoplasia risk associated with a positive FIT, specifically age, gastrointestinal symptoms, or IDA. METHODS: A retrospective audit was performed on colonoscopies performed in a single hospital in South Australia for a positive FIT (from all referral sources) between 2014 and 2017. Patients aged < 50 years, or who had a colonoscopy in the preceding 5 years, were excluded. A subgroup (n = 198) was evaluated to assess whether age ≥ 75 years, symptoms, or IDA, as well as other demographics, comorbidities, and medications, were associated with risk of neoplasia. Features found to be associated with risk for CRC or high-risk adenoma were examined in the entire cohort using multivariate analysis. RESULTS: Colonoscopies (750/4221, 17.8%) were completed in patients ≥ 50 years for a positive FIT. Of these, 7.6% (n = 57) also had gastrointestinal symptoms, 5.5% (n = 41) IDA, and 13.1% (n = 98) were ≥ 75 years. At colonoscopy, 2.8% (n = 21) were diagnosed with CRC and 23.2% (n = 174) with high-risk adenoma. CRC was more prevalent in ≥ 75 years compared with 50-74 years (7.1% vs 2.1%, P = 0.005), and associated with symptoms (15.8% vs 1.7%, P < 0.001), and IDA (14.6% vs 2.1%, P < 0.001). Multivariate analysis showed that IDA (odds ratio 7.68, P < 0.001) and symptoms (odds ratio 10.37, P < 0.001), but not age, were independent risk factors for CRC. CONCLUSION: The presence of gastrointestinal symptoms or IDA, independent of age, is associated with an increased risk for CRC following a positive FIT.