Faecal haemoglobin concentrations are associated with all-cause mortality and cause of death in colorectal cancer screening.

BACKGROUND: Colorectal cancer (CRC) screening reduces all-cause and CRC-related mortality. New research demonstrates that the faecal haemoglobin concentration (f-Hb) may indicate the presence of other serious diseases not related to CRC. We investigated the association between f-Hb, measured by a faecal immunochemical test (FIT), and both all-cause mortality and cause of death in a population-wide cohort of screening participants. METHODS: Between 2014 and 2018, 1,262,165 participants submitted a FIT for the Danish CRC screening programme. We followed these participants, using the Danish CRC Screening Database and several other national registers on health and population, until December 31, 2018. We stratified participants by f-Hb and compared them using a Cox proportional hazards regression on all-cause mortality and cause of death reported as adjusted hazard ratios (aHRs). We adjusted for several covariates, including comorbidity, socioeconomic factors, demography and prescription medication. RESULTS: We observed 21,847 deaths in the study period. Our multivariate analyses indicated an association relationship between increasing f-Hb and the risk of dying in the study period. This risk increased steadily from aHR 1.38 (95% CI: 1.32, 1.44) in those with a f-Hb of 7.1-11.9 µg Hb/g faeces to 2.20 (95% CI: 2.10, 2.30) in those with a f-Hb ≥60.0 µg Hb/g faeces, when compared to those with a f-Hb ≤7.0 µg Hb/g faeces. The pattern remained when excluding CRC from the analysis. Similar patterns were observed between incrementally increasing f-Hb and the risk of dying from respiratory disease, cardiovascular disease and cancers other than CRC. Furthermore, we observed an increased risk of dying from CRC with increasing f-Hb. CONCLUSIONS: Our findings support the hypothesis that f-Hb may indicate an elevated risk of having chronic conditions if causes for the bleeding have not been identified. The mechanisms still need to be established, but f-Hb may be a potential biomarker for several non-CRC diseases.

Socioeconomic differences in expected discomfort from colonoscopy and colon capsule endoscopy.

Individual income and educational level are associated with participation rates in colorectal cancer screening. We aimed to investigate the expected discomfort from the endoscopic diagnostic modalities of colonoscopy and colon capsule endoscopy in different socioeconomic groups as a potential barrier for participation. In a randomized clinical trial within the Danish colorectal cancer screening program, we distributed questionnaires to 2031 individuals between August 2020 and December 2022 to investigate the expected procedural and overall discomfort from investigations using visual analogue scales. Socioeconomic status was determined by household income and educational level. Multivariate continuous ordinal regressions were performed to estimate the odds of higher expected discomfort. The expected procedural and overall discomfort from both modalities were significantly higher with increasing educational levels and income, except for procedural discomfort from colon capsule endoscopy between income quartiles. The odds ratios for higher expected discomfort increased significantly with increasing educational level, whereas the differences between income groups were less substantial. Bowel preparation contributed most to expected discomfort in colon capsule endoscopy, whereas in colonoscopy, the procedure itself was the largest contributor. Individuals with prior experiences of colonoscopy reported significantly lower expected overall but not procedural discomfort from colonoscopy. The threshold for acceptable discomfort between subgroups is unknown, but the expected discomfort in colon capsule endoscopy and colonoscopy was higher in higher socioeconomic subgroups, suggesting that expected discomfort is not a significant contributor to the inequalities in screening uptake.

Endoscopic full-thickness resection (eFTR) in colon and rectum: indications and outcomes in the first 37 cases in a single center.

BACKGROUND: Segmental resection of the colon or rectum for cancer is major surgery with substantial procedure-related morbidity and mortality. A steep increase in the frequency of early cancer and advanced adenoma detection has been evident these late years. Introducing more minimal invasive resection techniques may decrease procedure-related complications and mortality. We aimed to describe the results from introducing endoscopic full-thickness resection (eFTR) in a unit specialized in advanced endoscopic resection of colon neoplasias. Primary outcomes were R0 resection rate and complications. METHODS: endoscopic full-thickness resection was introduced in our unit in 2017. Patients were referred for eFTR based on indications: (i) completion of resection after unexpected cancer, (ii) suspicion of or clinically confirmed early cancer (T1) without signs of dissemination, or (iii) adenomas not suitable for other endoscopic resection techniques due to difficult position or recurrence. Data on eFTR procedures and follow-up were retrieved from patient journals. RESULTS: Thirty-seven eFTR procedures were commenced in the period of March 2017 until June 2020, and one of these was abandoned. The overall R0 resection rate was 83.3%. In subgroups of indications i-iii, it was 87.5, 80.0, and 80.0%, respectively. Three perforations and one case of late bleeding occurred. One patient died within 30 days due to late perforation. Six technical failures were evident including operator-induced failures. Five of the technical failures occurred in the first half of the procedures indicating the learning curve of the endoscopist. CONCLUSION: Implementation of the eFTR procedure has been largely successful, especially in patients referred for completion of resection after unexpected cancer. Complication rates were acceptable, and the technique and quality increased significantly during the study. Careful selection of patients for eFTR is crucial for achieving successful resection. Size and position of lesion seem more important than indication. eFTR is not effective for lesions > 30 mm.

Effects of Screening Compliance on Long-term Reductions in All-Cause and Colorectal Cancer Mortality.

BACKGROUND & AIMS: Randomized trials have shown that biennial fecal occult blood test (FOBT) screening reduces mortality from colorectal cancer (CRC), but not overall mortality. Differences in benefit for men vs women, and by age, are unknown. We sought to evaluate long-term reduction in all-cause and CRC-specific mortality in men and women who comply with offered screening, and in different age groups, using individual participant data from 2 large randomized trials of biennial FOBT screening, compared with an intention to treat analysis. METHODS: We updated the CRC and all-cause mortality from the Danish CRC screening trial (n = 61,933) through 30 years of follow up and pooled individual participant data with individual 30-year follow-up data from the Minnesota Colon Cancer Control trial (n = 46,551). We compared the biennial screening groups to usual care (controls) in individuals 50-80 years old using Kaplan Meier estimates of relative risks and risk differences, adjusted for study differences in age, sex, and compliance. RESULTS: Through 30 years of follow up, there were 33,478 (71.9%) and 33,479 (72.2%) total deaths and 1023 (2.2%) and 1146 (2.5%) CRC deaths in the biennial screening (n = 46,553) and control groups (n = 46,358), respectively. Among compliers, biennial FOBT screening significantly reduced CRC mortality by 16% (relative risk [RR], 0.84; 95% CI, 0.74-0.96) and all-cause mortality by 2% (RR, 0.98; 95% CI, 0.97-0.99). Among compliers, the reduction in CRC mortality was larger for men (RR, 0.75; 95% CI, 0.62-0.90) than women (RR, 0.91; 95% CI, 0.75-1.09). The largest reduction in CRC mortality was in compliant men 60-69 years old (RR, 0.59; 95% CI, 0.42-0.81) and women 70 years and older (RR, 0.53; 95% CI, 0.30-0.94). CONCLUSIONS: Long-term CRC mortality outcomes of screening among compliers using biennial FOBT are sustained, with a statistically significant reduction in all-cause mortality. The reduction in CRC mortality is greater in men than women-the benefit in women lags that of men by about 10 years.

Diagnostic accuracy of capsule endoscopy compared with colonoscopy for polyp detection: systematic review and meta-analyses.

BACKGROUND: Colon capsule endoscopy (CCE) is a technology that might contribute to colorectal cancer (CRC) screening programs as a filter test between fecal immunochemical testing and standard colonoscopy. The aim was to systematically review the literature for studies investigating the diagnostic yield of second-generation CCE compared with standard colonoscopy. METHODS: A systematic literature search was performed in PubMed, Embase, and Web of Science. Study characteristics including quality of bowel preparation and completeness of CCE transits were extracted. Per-patient sensitivity and specificity were extracted for polyps (any size, ≥ 10 mm, ≥ 6 mm) and lesion characteristics. Meta-analyses of diagnostic yield were performed. RESULTS: The literature search revealed 1077 unique papers and 12 studies were included. Studies involved a total of 2199 patients, of whom 1898 were included in analyses. The rate of patients with adequate bowel preparation varied from 40 % to 100 %. The rates of complete CCE transit varied from 57 % to 100 %. Our meta-analyses demonstrated that mean (95 % confidence interval) sensitivity, specificity, and diagnostic odds ratio were: 0.85 (0.73-0.92), 0.85 (0.70-0.93), and 30.5 (16.2-57.2), respectively, for polyps of any size; 0.87 (0.82-0.90), 0.95 (0.92-0.97), and 136.0 (70.6-262.1), respectively, for polyps ≥ 10 mm; and 0.87 (0.83-0.90), 0.88 (0.75-0.95), and 51.1 (19.8-131.8), respectively, for polyps ≥ 6 mm. No serious adverse events were reported for CCE. CONCLUSION: CCE had high sensitivity and specificity for per-patient polyps compared with standard colonoscopy However, the relatively high rate of incomplete investigations limits the application of CCE in a CRC screening setting.

Local excision after (near) complete response of rectal cancer to neoadjuvant radiation: does it add value?

PURPOSE: Neoadjuvant radiotherapy is commonly used in rectal cancer. When used prior to radical surgery in locally advanced disease, up to one-quarter of patients have no residual cancer at surgery suggesting that radical surgery was unnecessary; those with complete clinical response may be managed on a rectal-preserving 'watch-and-wait' pathway. In those receiving radiotherapy for early stage cancer, local excision of small volume residual or recurrent tumour is possible, but its value is unclear. METHODS: Data were collected from two institutions (UK and Denmark) which maintain prospective databases on all patients undergoing local excision by transanal endoscopic microsurgery (TEM). The study group was all patients who had TEM after neoadjuvant radiation for rectal cancer over an 11-year period. RESULTS: Forty-five patients had TEM after neoadjuvant radiation, 18 after short course radiotherapy (SCRT) and 27 after chemoradiotherapy (CRT). Local recurrence occurred in 13 (29%) and distant metastases in 11 (24%). Complete pathological response was noted in 10 (22%), 28% after SCRT and 19% after CRT, p = 0.02. However, local recurrence still occurred in 60% of those with ypT0 after SCRT. The recurrence rate may be higher in those with residual disease at TEM compared with complete responders (40 vs 30%). CONCLUSION: If complete response can be determined clinically, local excision of the scar does not confer benefit, but follow-up should be maintained. If there is regrowth or residual tumour at TEM, further recurrence is common, and the benefits of TEM may not outweigh the risks, except in those unsuitable for radical surgery.

Risk of post colonoscopy colorectal cancer following screening colonoscopy with low-risk or no adenomas: A population-based study.

AIM: In the Danish faecal occult blood test based bowel cancer screening programme, the first round was rolled out over 4 years. After roll-out, the planned faecal test recall procedure for individuals with either no or low risk adenomas at colonoscopy is 8 and 2 years, respectively. Here, we aimed to investigate the post colonoscopy colorectal cancer incidence in these two groups. METHODS: All Danish screening individuals from 2014 to 2015 with a positive faecal test and either no or low risk adenomas at colonoscopy were included and followed for 3 years post screening for the event of colorectal cancer through national registries. RESULTS: Out of 533,023 submitted faecal tests and 36,673 positive tests, 17,627 had no or low risk adenomas. We identified 60 (0.34%) individuals diagnosed with colorectal cancer within 3 years, 18 (0.29%) in the low risk adenoma group, and 42 (0.37%) in the no adenomas group (p = 0.44). Advancing age (HR = 1.079, p < 0.001) and higher faecal test value (HR = 1.001, p = 0.002) increased hazard of colorectal cancer occurrence, whereas male sex (HR = 1.3, p = 0.308) and having low risk adenomas (HR = 0.729, p = 0.264) did not. CONCLUSION: We found no difference in post colonoscopy colorectal cancer occurrence between individuals with either no or low risk adenomas. Instead, advancing age and increased faecal test value was associated with a higher risk of post colonoscopy colorectal cancer.

Local excision after polypectomy for rectal polyp cancer: when is it worthwhile?

AIM: The optimal management of a polyp cancer that has been removed endoscopically is unclear. Further local excision is often advocated to remove the polyp stalk or scar or to ensure clear margins, but the benefit of this is unclear. The aim of this paper is to determine whether the indications for further local excision can be better defined. METHOD: Data were collected from two institutions (in UK and Denmark) which maintain prospective databases to collect information on all patients undergoing transanal endoscopic microsurgery (TEM). The study group was all patients who had a TEM after macroscopically complete polypectomy for rectal cancer. Data covering an 11-year period were analysed. RESULTS: Sixty three patients had TEM with no residual cancer after macroscopically complete polypectomy. Residual adenoma was found in 23 (37%). A postpolypectomy endoscopy had not detected the residual adenoma in three. Malignant local recurrence occurred in five patients (8%) and distant metastases in another two (3%). Recurrence occurred in 4/23 (17%) when there was residual adenoma in the TEM specimen and in 3/40 (7.5%) where there was scar only, although this did not reach significance. In two instances recurrence was around 10 years after TEM. Those with residual adenoma at TEM tended to have poorer survival. CONCLUSION: Further local excision often reveals no residual cancer despite microscopically involved polypectomy margins. Careful endoscopy is required to assess the polypectomy site as residual tumour can be missed. In the absence of residual adenoma, TEM does not appear to be of benefit, although a small risk of recurrence exists.

Magnetic resonance imaging of the anal sphincter and spine in patients with anorectal malformations after posterior sagittal anorectoplasty: a late follow-up cross-sectional study.

PURPOSE: We aimed to assess the association of fecal incontinence to the anatomy of the anal sphincter complex and lower bony spinal anomalies as investigated with magnetic resonance imaging (MRI) in adolescents and adults with anorectal malformations (ARM) after posterior sagittal anorectoplasty (PSARP). METHODS: We conducted a cross-sectional study in 20 patients with ARM after PSARP. Anatomy of the anorectum and spine were examined with MRI and functional outcome assessed with the Wexner incontinence score. RESULTS: We included 20 patient (12 males) had a median age of 19.5 years (14-27). One patient was excluded leaving 19 patients for outcome analysis. Fecal incontinence was found in 12 out of 19 patients (63%). Interposed fat was present in 9 patients (47%). The presence (r = 0.597, p = 0.012) and thickness of interposed fat (r = 0.832, p = 0.005) between the anal sphincter complex and bowel were positively correlated to the Wexner fecal incontinence score. No correlation was found between lower bony spinal anomalies and fecal incontinence. CONCLUSIONS: A positive correlation between interposed fat and higher Wexner fecal incontinence score was found indicating a more severe fecal incontinence but no other correlation between anatomy of the anal sphincter complex and neorectum to functional bowel outcome was observed.

Addressing priority challenges in the detection and assessment of colorectal polyps from capsule endoscopy and colonoscopy in colorectal cancer screening using machine learning.

BACKGROUND: Colorectal capsule endoscopy (CCE) is a potentially valuable patient-friendly technique for colorectal cancer screening in large populations. Before it can be widely applied, significant research priorities need to be addressed. We present two innovative data science algorithms which can considerably improve acquisition and analysis of relevant data on colorectal polyps obtained from capsule endoscopy. MATERIAL AND METHODS: A fully paired study was performed (2015-2016), where 255 participants from the Danish national screening program had CCE, colonoscopy, and histopathology of all detected polyps. We developed: (1) a new algorithm to match CCE and colonoscopy polyps, based on objective measures of similarity between polyps, and (2) a deep convolutional neural network (CNN) for autonomous detection and localization of colorectal polyps in colon capsule endoscopy. RESULTS AND CONCLUSION: Unlike previous matching methods, our matching algorithm is able to objectively quantify the similarity between CCE and colonoscopy polyps based on their size, morphology and location, and provides a one-to-one unequivocal match between CCE and colonoscopy polyps. Compared to previous methods, the autonomous detection algorithm showed unprecedented high accuracy (96.4%), sensitivity (97.1%) and specificity (93.3%), calculated in respect to the number of polyps detected by trained nurses and gastroenterologists after visualizing frame-by-frame the CCE videos.

Patient-reported minor adverse events after colonoscopy: a systematic review.

OBJECTIVE: The purpose of this systematic review was to investigate the incidence and nature of minor adverse events (MAEs) after colonoscopy, and response rates to questionnaires concerning MAEs in patients undergoing colonoscopy. MATERIALS AND METHODS: A systematic literature search was conducted in the databases PubMed and Embase. Predictor variables were patient-reported MAEs after colonoscopy. The outcome was frequency and types of MAEs and the patients' response rate to questionnaires after colonoscopy. Quality assessment for potential risk of bias and level of evidence was evaluated using the National Health and Medical Research Council guidelines. RESULTS: Seven prospective cohorts were included with a pooled total of 6172 participants. Patients undergoing colonoscopy had a response rate to questionnaires ranging from 64% to 100%, with a mean of 81%. One-third of the patients experienced MAEs, most prominently in the first 1-2 weeks after colonoscopy, and less common at 30 days post colonoscopy. The most frequently reported MAEs were abdominal pain, bloating and abdominal discomfort. CONCLUSIONS: In general, patients undergoing colonoscopy have a high response rate to questionnaires about MAEs. MAEs after colonoscopy are commonly seen. High age and score of American Society of Anesthesiologists (ASA) classification, female gender and duration of procedure seem to be associated with a higher risk of MAEs, whereas adequate sedation seems to decreases the risk. MAEs after colonoscopy seems to be underreported in the current literature and the existing evidence is based on inhomogeneous reports. In the current study, it was not possible to conduct a meta-analysis. There is a need for larger scale studies addressing the MAEs patients experience in conjunction with a colonoscopy. Furthermore, the assessment of the MAEs should rely on questionnaires tested for validity, comprehensibility and reliability, to reflect the patient-reported experience of a colonoscopy as precise as possible.

Differentiation between malignant and benign rectal tumors by dual-energy computed tomography - a feasibility study.

INTRODUCTION: To assess the performance of Dual Energy Computed Tomography (DECT) in the differentiation between benign and malignant tumors in the rectum. MATERIAL AND METHODS: We enrolled 8 subjects with rectal tumors suspected to be an early rectal cancer during colonoscopy. All subjects underwent Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Endorectal Ultrasound (ERUS) for staging. Furthermore, all subjects underwent fast switching of tube voltage between 80 and 140 kVp DECT of the pelvis. The 8 subjects had histopathological verified benign adenomas after transanal endoscopic microsurgery resection (TEM). The 8 subjects were matched with 8 consecutively selected subjects with histopathologically verified malignant rectal tumors. The DECT images were analyzed to assess the difference between malignant and benign rectal tumors. All DECT images were reviewed by experienced radiologists. In each DECT scanning, we applied three regions of interest (ROIs) for the acquisition of the DECT unique quantitative parameters. The mean atomic mass (effective Z value), iodine concentration, dual energy ratio (DER) and dual-energy index (DEI) was determined in both groups. RESULTS: The comparison of the 2 groups showed a significant difference in effective Z and a nonsignificant difference regarding iodine concentration, DER, and DEI in the two groups. CONCLUSION: Dual-energy CT demonstrated a difference in the mean atomic mass in benign colorectal tumors in comparison to malignant colorectal tumors.

Patient-reported complications related to colonoscopy: a prospective feasibility study of an email-based survey.

OBJECTIVE: This prospective pilot study assessed the feasibility of electronic email-based questionnaires about patient-reported complications after colonoscopy. MATERIAL AND METHODS: A newly internally validated questionnaire on patient-reported complications related to colonoscopy was conducted as an online survey. RESULTS: Out of 200 patients (mean age 65 years), 83% completed the first questionnaire immediately after the procedure, 77% completed the second follow-up questionnaire after 24 h at home, and 70% the third one after 30 d. Forty-four percent of the patients reported minor adverse events after 24 h, and 23% at the follow-up after 30 d. The rate of sick leave in the 30-d period after the colonoscopy was 6%. CONCLUSIONS: This study shows that email-based questionnaires give a high response rate independent of age or gender, but that the response rate declines with time after colonoscopy. Minor adverse events are underestimated, and colonoscopy could lead to sick leave in a minor subgroup of patients.

Screening individuals' experiences of colonoscopy and colon capsule endoscopy; a mixed methods study.

BACKGROUND: The standard investigation in colorectal cancer screening (optical colonoscopy [OC]) has a less invasive alternative with the colon capsule endoscopy (CCE). The experiences of screening individuals are needed to support a decision aid (DA) and to provide a patient view in future health technology assessments (HTA). We aimed to explore the experiences of CCE at home and OC in an outpatient clinic by screening participants who experienced both investigations on the same bowel preparation. METHODS: In a mixed methods study, Danish screening individuals with a positive immunological fecal occult blood test (FIT) were consecutively included and underwent both CCE and OC in the same bowel preparation. They answered questionnaires about discomfort during CCE, delivered at home, and during a following OC in the outpatient clinic. Data were calculated in percentages and Wilcoxon signed rank test was used for comparisons. Among the 253 included patients, 10 participants were selected for a semi-structured interview about their experiences of the two examinations. The analysis and interpretation of the transcribed data were inspired by Ricoeur. RESULTS: Questionnaire data were received from 239 participants and revealed significant less discomfort during the CCE than the OC. Interview data included explained discomfort elements in two categories: 'The examination' and 'The setting'. Compared to OC, the CCE was experienced with less pain, embarrassment and invasiveness, but presented challenges and disadvantages as well, i.e., a large camera capsule to swallow, a longer waiting time for test results after CCE and an additional OC, if pathologies were found. The home setting for CCE delivery made the participants feel less like they were ill or patients less restricted and that they received more personal care, but could induce technical challenges. CONCLUSION: In screening individuals, CCE at home was associated with significantly less discomfort compared to OC at a hospital, and multiple reasons for this was identified.

Reproducibility and accuracy of visual estimation of polyp size in large colorectal polyps.

BACKGROUND: Previous studies indicate that visual size estimation (in situ) of polyp size tends to differ from postfixation measurements, which effects allocation to surveillance intervals. Little is known about interobserver variation of in-situ measurements of large polyps. The primary objective was to assess interobserver variation of in situ measurements of large colorectal polyps. Secondary objectives were the agreement of in situ measurements with postfixation measurements, and the agreement on detection of ≥20 mm polyps between these measurements. MATERIAL AND METHODS: Interobserver variability of in situ polyp size measurements was assessed between a diagnostic colonoscopy and the secondary therapeutic colonoscopy by dedicated endoscopists, in patients that were referred for an advanced polypectomy. After excision pre- and postfixation polyp sizes were measured with a ruler in three dimensions. RESULTS: A total of 40 patients, with 45 polyps, were included in the study. The average difference between the two in situ measurements was 2.4 mm (95% confidence interval (CI): -0.4-5.2). The differences between the first in situ, second in situ and pre-fixation measurement in comparison to postfixation measurements were 1.8 mm (95% CI: -1.2-4.9), 0.1 mm (95% CI: -1.5-1.8) and 1.0 mm (95% CI: -0.2-2.2). Cohen's Kappa on detection of ≥20 mm polyps in agreement with postfixation measurements was 0.65 in the primary and 0.88 in the secondary in situ measurements. CONCLUSION: This study shows a variation between in situ size measurements of large polyps. Improvements in daily clinical routines can be made by using an instrument to compare polyp size with and refraining from rounding sizes up or down. A randomized controlled trial assessing which instruments should be used for in-situ measurements of large polyps is warranted, in order to optimize size measurements of large colorectal polyps.

Can coffee or chewing gum decrease transit times in Colon capsule endoscopy? A randomized controlled trial.

BACKGROUND: A high rate of complete colon capsule endoscopy (CCE) investigations is required for a more widespread use of CCE. The objective of this study was to assess if coffee or chewing gum can increase excretion of the colon capsule within battery life time (excretion rate). METHODS: One hundred eighty six screening participants with a positive immunochemical fecal occult blood test were included in this single-centre randomized controlled trial with blinding of the investigators to the randomization. Participants received instant coffee, chewing gum or nothing in addition to the standard bowel preparation. RESULTS: The intention was to include 57 participants in the coffee group, 61 in the chewing gum group and 60 in the control group, on 8 participants data were missing. A total of 165 participants were included in a per protocol analysis. Exclusion was due to not receiving the allocated intervention (8 coffee, 4 chewing gum) and technical failure of the capsule (1 coffee). The excretion rate was 58% in the coffee group (n = 48), 63% in the chewing gum group (n = 57) and 55% in the control group (n = 60, p > 0.2). Transit times were similar in all groups. The excretion rate was low in participants who had transit times over 10 h (14%). A strong correlation was found between adequate cleansing and excretion of the capsule. There were no serious adverse events related to the interventions or CCE investigations. CONCLUSIONS: Chewing gum and coffee did not improve excretion rate in this study. An effect of chewing gum could not be proven, possibly due to sample size. Since chewing gum might improve excretion rates, is cheap and has no known side effects, it needs to be considered in future bowel preparation trials for CCE. TRIAL REGISTRATION: NCT02303756 , registered on December 1st 2014.

Capsule endoscopy vs. colonoscopy vs. histopathology in colorectal cancer screening: matched analyses of polyp size, morphology, and location estimates.

PURPOSE: Colon capsule endoscopy (CCE) is considered a potential alternative to optical colonoscopy (OC) for colorectal cancer screening. However, the accuracy of CCE in polyp size and morphology estimation is unknown. METHODS: A fully paired study was performed (2015-2016), where 255 participants from the Danish national screening program had CCE, OC, and histopathology (HP) of all detected polyps. We developed a new algorithm to match CCE and OC polyps, based on objective measures of similarity between polyps. We performed paired comparisons of size, morphology and location of CCE, and OC- and HP-matched polyps. We used cross-validation to develop a model able to predict HP polyp size, based on CCE. RESULTS: CCE overestimated size assessed by HP (by 4.3 mm; 95%CI 3.3-5.2 mm) and OC (by 2.7 mm; 95%CI 1.4-3.9 mm). Polyps were more likely to being assessed as "pedunculated" and less likely to being assessed as "flat" in CCE, compared to OC (p < 0.0001). Our model could predict HP polyp size ≥ 6 mm, solely using CCE-assessed size, location, and morphology as model inputs, with a sensitivity = 0.93 (95%CI 0.66-1.00) and specificity = 0.50 (95%CI 0.32-0.68). CONCLUSIONS: If CCE is to be used as a screening test, it is essential: (1) to translate CCE polyp estimations into histopathologic polyp sizes and (2) to consider that, compared to OC, CCE has a higher tendency to assess polyps as pedunculated and a lower tendency to assess them as flat. TRIAL REGISTRATION: Clinicaltrials.gov No. NCT02303756.

Dual energy CT - a possible new method to assess regression of rectal cancers after neoadjuvant treatment.

BACKGROUND AND OBJECTIVES: The measurement of tumor regression after neoadjuvant oncological treatment has gained increasing interest because it has a prognostic value and because it may influence the method of treatment in rectal cancer. The assessment of tumor regression remains difficult and inaccurate with existing methods. Dual Energy Computed Tomography (DECT) enables qualitative tissue differentiation by simultaneous scanning with different levels of energy. We aimed to assess the feasibility of DECT in quantifying tumor response to neoadjuvant therapy in loco-advanced rectal cancer. METHODS: We enrolled 11 patients with histological and MRI verified loco-advanced rectal adenocarcinoma and followed up on them prospectively. All patients had one DECT scanning before neoadjuvant treatment and one 12 weeks after using the spectral imaging scan mode. DECT analyzing tools were used to determine the average quantitative parameters; effective-Z, water- and iodine-concentration, Dual Energy Index (DEI), and Dual Energy Ratio (DER). These parameters were compared to the regression in the resection specimen as measured by the pathologist. RESULTS: Changes in the quantitative parameters differed significantly after treatment in comparison with pre-treatment, and the results were different in patients with different CRT response rates. CONCLUSION: DECT might be helpful in the assessment of rectal cancer regression grade after neoadjuvant treatment.