Rate of detection of advanced neoplasms in proximal colon by simulated sigmoidoscopy vs fecal immunochemical tests

Single-round performance of colorectal cancer screening programs: a network meta-analysis of randomized clinical trials

BACKGROUND

Demonstrating mortality reduction in new colorectal cancer (CRC) screening programs through randomized clinical trials (RCTs) is challenging. We systematically reviewed single-round program performance outcomes using a stepwise approach proposed by the World Endoscopy Organization CRC Screening Committee framework.

METHODS

The MEDLINE, EMBASE, Central, and Ichushi Web databases were searched until October 28, 2024, to find RCTs comparing guaiac-based and immunochemical fecal occult blood testing (gFOBT and FIT), flexible sigmoidoscopy (FS), computed tomographic colonography (CTC), and total colonoscopy (TCS). Paired reviewers screened studies, extracted data, and assessed bias risk. A Bayesian random-effects network meta-analysis was conducted, and the certainty of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation approach. The primary outcome was advanced neoplasia (AN) detection, and the secondary outcomes were participation and colorectal cancer (CRC) detection, all during the first screening round.

RESULTS

Eighteen RCTs (437,072 invitees) were included. The risk of bias was low or raised some concerns for screening participation, but it was high for detection outcomes. In the network meta-analysis of 15 RCTs not allowing crossover, the FIT-based program had a higher AN detection rate than the gFOBT-based program (relative risk [RR] 2.48; 95% credible interval [CrI] 1.52-4.21; moderate certainty). AN detection rates were not different in the CTC- (RR 1.01; CrI 0.43-2.23; very low certainty) and TCS-based (RR 1.03; CrI 0.54-1.78; low certainty) programs compared with the FS-based program. All the visualization modality programs had higher AN detection rates than the FIT-based program (FS: RR 2.13 [CrI 1.38-3.77]; CTC 2.16 [1.11-4.51]; and TCS 2.19 [1.43-3.48]; all with low certainty). Low event rates precluded definitive conclusions regarding CRC detection (very low to low certainty). The TCS-based program had the worst participation rate (very low to low certainty). Comparative data allowing crossover were limited.

CONCLUSIONS

This is the first network meta-analysis that evaluates program-level initial performance indicators. FIT-based programs likely detect more AN cases than gFOBT-based programs, while FS-, CTC-, and TCS-based programs may outperform FIT. Due to limitations in first-round results, long-term outcomes should be assessed after 10-15 years.

Cytology Smears: An Enhanced Alternative Method for Colorectal Cancer pN Stage-A Multicentre Study

Stage II colorectal cancer (CRC) recurrence remains a clinical problem. Some of these patients are true stage III CRC with a pN0 pathology stage. This large prospective multicentre cohort study aimed at evaluating the diagnostic ability of lymph node (LN) cytology smears to perform the pN stage and compare it with the conventional haematoxylin and eosin (H&E) pathology pN stage. Additionally, we used the One-Step Nucleic Acid Amplification (OSNA), a high-sensitive molecular method of LN staging. A total of 3936 fresh LNs from 217 CRC surgical specimens were examined by three methods, H&E, LN cytology smears, and OSNA. H&E detected 29% of patients with positive LNs, cytology smears 35%, and OSNA 33.2% (p < 0.0001). H&E and cytology concordantly classified 92.2% of tumours, and 88.5% between OSNA and H&E. Cytology had 96.8% sensitivity and 90.3% specificity to discriminate positive/negative patients compared to H&E (p = 0.004), and 87.3% sensitivity and 89% specificity when compared to OSNA (p = 0.56). Patients with positive LNs detected by any of the three methods had significantly worse disease-free and overall survival. We conclude that pN stage accuracy for detecting positive LNs is superior with LN cytological smears than with conventional H&E, which would enable a better pN stage and management of early-stage CRC patients.

Ex vivo Fusion Confocal Microscopy of Colorectal Polyps: A Fast Turnaround Time of Pathological Diagnosis

BACKGROUND

Colorectal cancer screening programs have accomplished a mortality reduction from the disease but have created bottlenecks in endoscopy units and pathology departments. We aimed to explore the feasibility of ex vivo fusion confocal microscopy (FuCM) to improve the histopathology diagnostic efficiency and reduce laboratory workload.

METHODS

Consecutive fresh polyps removed at colonoscopy were scanned using ex vivo FuCM, then went through histopathologic workout and hematoxylin and eosin (H&amp;E) diagnosis. Two pathologists blinded to H&amp;E diagnosis made a diagnosis based on FuCM scanned images.

RESULTS

Thirty-six fresh polyps from 22 patients were diagnosed with FuCM and H&amp;E. Diagnostic agreement between H&amp;E and FuCM was 97.2% (kappa = 0.96) for pathologist #1 and 91.7% (kappa = 0.87) for pathologist #2. Diagnostic performance concordance between FuCM and H&amp;E to discern adenomatous from nonadenomatous polyps was 100% (kappa = 1) for pathologist #1 and 97.2% (kappa = 0.94) for pathologist #2. Global interobserver agreement was 94.44% (kappa = 0.91) and kappa = 0.94 to distinguish adenomatous from nonadenomatous polyps.

CONCLUSIONS

Ex vivo FuCM shows an excellent correlation with standard H&amp;E for the diagnosis of colorectal polyps. The clinical direct benefit for patients, pathologists, and endoscopists allows adapting personalized surveillance protocols after colonoscopy and a workload decrease in pathology departments.

Detection of serrated lesions in proximal colon by simulated sigmoidoscopy vs faecal immunochemical testing in a multicentre, pragmatic, randomised controlled trial

Background

The diagnostic yield of the faecal immunochemical test and sigmoidoscopy in detecting proximal serrated polyps in a colorectal cancer screening programme has not been fully assessed.

Aim

We determined the detection rate of proximal serrated polyps by simulated sigmoidoscopy and faecal immunochemical test compared with total colonoscopy in a population-based, multicentre, nationwide, randomised controlled trial (ColonPrev study).

Methods

Sigmoidoscopy yield was simulated based on the UK-Flexible Sigmoidoscopy Trial for total colonoscopy referral. Definitions were: proximal serrated polyp (proximal serrated polyp): sessile serrated polyp or hyperplastic polyp of any size and proximal at-risk serrated polyp (at-risk proximal serrated polyp): sessile serrated polyp of any size or hyperplastic polyp ≥ 10 mm, both located proximally to the splenic flexure.

Results

A total of 10,611 individuals underwent faecal immunochemical test and 5059 underwent total colonoscopy and were evaluated by simulated sigmoidoscopy. Sigmoidoscopy and faecal immunochemical test were less accurate in detecting proximal serrated polyps (odds ratio: 0.13; 95% confidence interval: 0.10-0.18 and 0.13; 0.09-0.18, p < 0.0001, respectively). Both tests were inferior to colonoscopy in detecting at-risk proximal serrated polyps, and sigmoidoscopy was inferior to faecal immunochemical test in detecting these lesions (odds ratio: 0.17; 95% confidence interval: 0.10-0.30 and 0.25; 0.17-0.37, p < 0.0001, respectively).

Conclusion

Sigmoidoscopy and faecal immunochemical test are less accurate in detecting proximal serrated polyps than colonoscopy, particularly in women.

Virtual reality simulation training for health professions trainees in gastrointestinal endoscopy

BACKGROUND

Endoscopy has traditionally been taught with novices practicing on real patients under the supervision of experienced endoscopists. Recently, the growing awareness of the need for patient safety has brought simulation training to the forefront. Simulation training can provide trainees with the chance to practice their skills in a learner-centred, risk-free environment. It is important to ensure that skills gained through simulation positively transfer to the clinical environment. This updated review was performed to evaluate the effectiveness of virtual reality (VR) simulation training in gastrointestinal endoscopy.

OBJECTIVES

To determine whether virtual reality simulation training can supplement and/or replace early conventional endoscopy training (apprenticeship model) in diagnostic oesophagogastroduodenoscopy, colonoscopy, and/or sigmoidoscopy for health professions trainees with limited or no prior endoscopic experience.

SEARCH METHODS

We searched the following health professions, educational, and computer databases until 12 July 2017: the Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Ovid Embase, Scopus, Web of Science, BIOSIS Previews, CINAHL, AMED, ERIC, Education Full Text, CBCA Education, ACM Digital Library, IEEE Xplore, Abstracts in New Technology and Engineering, Computer and Information Systems Abstracts, and ProQuest Dissertations and Theses Global. We also searched the grey literature until November 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised clinical trials comparing VR endoscopy simulation training versus any other method of endoscopy training with outcomes measured on humans in the clinical setting, including conventional patient-based training, training using another form of endoscopy simulation, or no training. We also included trials comparing two different methods of VR training.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of trials, and extracted data on the trial characteristics and outcomes. We pooled data for meta-analysis where participant groups were similar, studies assessed the same intervention and comparator, and had similar definitions of outcome measures. We calculated risk ratio for dichotomous outcomes with 95% confidence intervals (CI). We calculated mean difference (MD) and standardised mean difference (SMD) with 95% CI for continuous outcomes when studies reported the same or different outcome measures, respectively. We used GRADE to rate the quality of the evidence.

MAIN RESULTS

We included 18 trials (421 participants; 3817 endoscopic procedures). We judged three trials as at low risk of bias. Ten trials compared VR training with no training, five trials with conventional endoscopy training, one trial with another form of endoscopy simulation training, and two trials compared two different methods of VR training. Due to substantial clinical and methodological heterogeneity across our four comparisons, we did not perform a meta-analysis for several outcomes. We rated the quality of evidence as moderate, low, or very low due to risk of bias, imprecision, and heterogeneity.Virtual reality endoscopy simulation training versus no training: There was insufficient evidence to determine the effect on composite score of competency (MD 3.10, 95% CI -0.16 to 6.36; 1 trial, 24 procedures; low-quality evidence). Composite score of competency was based on 5-point Likert scales assessing seven domains: atraumatic technique, colonoscope advancement, use of instrument controls, flow of procedure, use of assistants, knowledge of specific procedure, and overall performance. Scoring range was from 7 to 35, a higher score representing a higher level of competence. Virtual reality training compared to no training likely provides participants with some benefit, as measured by independent procedure completion (RR 1.62, 95% CI 1.15 to 2.26; 6 trials, 815 procedures; moderate-quality evidence). We evaluated overall rating of performance (MD 0.45, 95% CI 0.15 to 0.75; 1 trial, 18 procedures), visualisation of mucosa (MD 0.60, 95% CI 0.20 to 1.00; 1 trial, 55 procedures), performance time (MD -0.20 minutes, 95% CI -0.71 to 0.30; 2 trials, 29 procedures), and patient discomfort (SMD -0.16, 95% CI -0.68 to 0.35; 2 trials, 145 procedures), all with very low-quality evidence. No trials reported procedure-related complications or critical flaws (e.g. bleeding, luminal perforation) (3 trials, 550 procedures; moderate-quality evidence).Virtual reality endoscopy simulation training versus conventional patient-based training: One trial reported composite score of competency but did not provide sufficient data for quantitative analysis. Virtual reality training compared to conventional patient-based training resulted in fewer independent procedure completions (RR 0.45, 95% CI 0.27 to 0.74; 2 trials, 174 procedures; low-quality evidence). We evaluated performance time (SMD 0.12, 95% CI -0.55 to 0.80; 2 trials, 34 procedures), overall rating of performance (MD -0.90, 95% CI -4.40 to 2.60; 1 trial, 16 procedures), and visualisation of mucosa (MD 0.0, 95% CI -6.02 to 6.02; 1 trial, 18 procedures), all with very low-quality evidence. Virtual reality training in combination with conventional training appears to be advantageous over VR training alone. No trials reported any procedure-related complications or critical flaws (3 trials, 72 procedures; very low-quality evidence).Virtual reality endoscopy simulation training versus another form of endoscopy simulation: Based on one study, there were no differences between groups with respect to composite score of competency, performance time, and visualisation of mucosa. Virtual reality training in combination with another form of endoscopy simulation training did not appear to confer any benefit compared to VR training alone.Two methods of virtual reality training: Based on one study, a structured VR simulation-based training curriculum compared to self regulated learning on a VR simulator appears to provide benefit with respect to a composite score evaluating competency. Based on another study, a progressive-learning curriculum that sequentially increases task difficulty provides benefit with respect to a composite score of competency over the structured VR training curriculum.

AUTHORS' CONCLUSIONS

VR simulation-based training can be used to supplement early conventional endoscopy training for health professions trainees with limited or no prior endoscopic experience. However, we found insufficient evidence to advise for or against the use of VR simulation-based training as a replacement for early conventional endoscopy training. The quality of the current evidence was low due to inadequate randomisation, allocation concealment, and/or blinding of outcome assessment in several trials. Further trials are needed that are at low risk of bias, utilise outcome measures with strong evidence of validity and reliability, and examine the optimal nature and duration of training.

Distribution of colorectal polyps: Implications for screening

BACKGROUND

During the last decades data from different studies reported modifications of the topographic distribution of colorectal cancers (CRCs), with an increased frequency of tumours in proximal colonic segments. Given the documented link between adenomas and CRC, a proximal migration of adenomas over time could be expected as well.

AIM

To evaluate available evidence about the prevalence of adenomas and of sessile serrated polyps across colonic segments, the changing trends in their distribution across the colon and the diagnostic performance of screening tests currently adopted in population based screening programs for lesions located in different colonic segments.

METHODS

Literature search on PubMed, Embase, and Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects with reference to preferred reporting items for systematic reviews and meta-analysis (PRISMA), considering all adult human studies in English, published between January 2000 and February 2017.

RESULTS

Cross-sectional analysis of endoscopy and pathology data-bases are consistently showing a trend toward an increase with age of the proportion of adenomas located in the proximal colon. Several observational studies analysed the site distribution of adenomas, testing the hypothesis of a proximal shift of these lesions, and most of them reported an increase in the proportion of right-sided adenomas over time, although a similar trend was not confirmed by others. Also the quality of the retrieved evidence was low. Both endoscopy and FIT are showing a different level of sensitivity for lesions arising in different colonic segments, depending also on screenees characteristics.

CONCLUSION

Available evidence is supporting the hypothesis of an increase in the proportion of right-sided adenomas with age, while a similar increase has not been reported for SSP/A, at least among subjects aged 50 or older. The trend toward a proximalization of colorectal adenomas over time, reported by some authors, likely results from improved diagnostic performances and/or the process of population ageing.

Recommendations on Fecal Immunochemical Testing to Screen for Colorectal Neoplasia: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer

The use of the fecal occult blood test (FOBT) for colorectal cancer (CRC) screening is supported by randomized trials demonstrating effectiveness in cancer prevention and widely recommended by guidelines for this purpose. The fecal immunochemical test (FIT), as a direct measure of human hemoglobin in stool has a number of advantages relative to conventional FOBT and is increasingly used relative to that test. This review summarizes current evidence for FIT in colorectal neoplasia detection and the comparative effectiveness of FIT relative to other commonly used CRC screening modalities. Based on evidence, guidance statements on FIT application were developed and quality metrics for program implementation proposed.

A systematic review of the clinical validity of the Cologuard™ genetic test for screening colorectal cancer

OBJECTIVES

The aim of this study was to assess the available evidence on the validity, diagnostic accuracy and clinical utility of the multitarget DNA test in faeces (Cologuard™) for screening for colorectal cancer (CRC).

MATERIAL AND METHODS

A systematic review was performed by consulting MedLine, EMBASE and Web of Science to July 2014. Studies on diagnostic tests were selected that evaluated the test in asymptomatic adults who underwent CRC screening. The quality and risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. The level of evidence was defined according to the National Institute for Health and Clinical Excellence. A qualitative synthesis was conducted.

RESULTS

A total of 299 literature references were identified, including 1 synthesis report and 5 diagnostic test studies. Three of the 5 studies had a case-control design in Sackett phase II and were of moderate quality, and 2 had a prospective design in Sacket phase III and were of high quality. The sensitivity for detecting CRC was greater than 90%, but only 40% for detecting advanced adenomas. The test provided conclusive diagnostic evidence to rule out CRC (negative likelihood ratio, LR-: 0.02-0.09), although it was not useful for ruling out advanced adenoma (LR-: 0.5-0.7).

CONCLUSIONS

The Cologuard™ test is a valid screening test for ruling out cancerous lesions but is suboptimal for ruling out precancerous lesions. There is no evidence in terms of mortality, survival or cost-effectiveness.

Diagnostic performance of fecal immunochemical test and sigmoidoscopy for advanced right-sided colorectal neoplasms

BACKGROUND

Colorectal cancer screening effect on right-sided colorectal neoplasia is limited. We compared fecal immunochemical test and simulated sigmoidoscopy diagnostic accuracy for advanced right-sided neoplasia detection.

METHODS

We analyzed 1,292 individuals with complete screening colonoscopy with a fecal immunochemical test determination before colonoscopy. Sigmoidoscopy and "hybrid strategy" (sigmoidoscopy or fecal hemoglobin concentration ≥ 20 µg hemoglobin/g) diagnostic yield were simulated according to UK Flexible Sigmoidoscopy, Screening for COlon REctum (SCORE), and Norwegian Colorectal Cancer Prevention (NORCCAP) trials criteria to complete colonic examination. We compared sensitivity and specificity of both strategies and of "hybrid strategy" for advanced right-sided neoplasia with McNemar test.

RESULTS

An advanced right-sided neoplasia was detected in 47 (3.6 %) subjects. A fecal hemoglobin concentration ≥ 20 µg hemoglobin/g was determined in 6.6 % of the subjects and 10.1, 12.7, and 23.5 % met UK, SCORE, and NORCCAP criteria, respectively. Fecal immunochemical test was statistically more specific than sigmoidoscopy strategies (93.8 %, UK 90.3 %, SCORE 87.7 %, NORCCAP 77.8 %; p < 0.001). In contrast, fecal immunochemical test sensitivity for advanced right-sided neoplasia (17 %) was not statistically different than UK (21.3 %; p = 0.7) or SCORE (23.4 %; p = 0.5), although it was inferior than NORCCAP strategy (42.5 %; p < 0.001). Adding fecal immunochemical test to sigmoidoscopy increased number of positives (8.5-25.7 %), sensitivity (10-30 %), and significantly reduced advanced right-sided neoplasia specificity (p < 0.001).

CONCLUSIONS

Fecal immunochemical test and sigmoidoscopy diagnostic yield for advanced right-sided neoplasia are low. Fecal immunochemical test is more specific than sigmoidoscopy but less sensitive than sigmoidoscopy according to NORCCAP criteria.

Programmatic screening for colorectal cancer: the COLONPREV study

The COLONPREV study is an ongoing multicenter, nationwide, randomized controlled trial aimed at evaluating the efficacy of once-only colonoscopy and biennial fecal immunochemical testing with respect to the reduction of CRC-related mortality at 10 years in average-risk colorectal cancer screening population. Following a pragmatic approach, this study may contribute to establishing the most cost-effective strategy in a programmatic, population-based setting. In this review, we report the results obtained at the first screening round, as well as others achieved in nested evaluations using the COLONPREV dataset with the aim of clarifying some controversial issues on the different strategies of colorectal cancer screening.