Single Colonoscopy Research Articles

Optimal timing of a colonoscopy screening schedule depends on adenoma detection, adenoma risk, adherence to screening and the screening objective: A microsimulation study.

Colonoscopy-based screening provides protection against colorectal cancer (CRC), but the optimal starting age and time intervals of screening colonoscopies are unknown. We aimed to determine an optimal screening schedule for the US population and its dependencies on the objective of screening (life years gained or incidence, mortality, or cost reduction) and the setting in which screening is performed. We used our established open-source microsimulation model CMOST to calculate optimized colonoscopy schedules with one, two, three or four screening colonoscopies between 20 and 90 years of age. A single screening colonoscopy was most effective in reducing life years lost from CRC when performed at 55 years of age. Two, three and four screening colonoscopy schedules saved a maximum number of life years when performed between 49-64 years; 44-69 years; and 40-72 years; respectively. However, for maximum incidence and mortality reduction, screening colonoscopies needed to be scheduled 4-8 years later in life. The optimum was also influenced by adenoma detection efficiency with lower values for these parameters favoring a later starting age of screening. Low adherence to screening consistently favored a later start and an earlier end of screening. In a personalized approach, optimal screening would start earlier for high-risk patients and later for low-risk individuals. In conclusion, our microsimulation-based approach supports colonoscopy screening schedule between 45 and 75 years of age but the precise timing depends on the objective of screening, as well as assumptions regarding individual CRC risk, efficiency of adenoma detection during colonoscopy and adherence to screening.

Cost-effectiveness analysis of single colonoscopy versus single fecal test for colorectal cancer diagnosis and treatment.

Regular endoscopy or fecal immunochemical test (FIT) is ideal for screening colorectal cancer. However, only a limited number of individuals undergo regular screening. This study aimed to compare the cost-effectiveness of a single colonoscopy with a single FIT performed for colorectal cancer screening. A microsimulation model was constructed based on real-world observational data collected from three institutions between 2019 and 2022 that compared colonoscopy-based screening with FIT-based screening. The total costs of diagnosis and treatment of the detected lesions using the two strategies were calculated. The incremental cost-effectiveness ratio (ICER) per life year gained (LYG) of the colonoscopy-based strategy was calculated. Data from 11 407 patients undergoing colonoscopies and 59 176 patients undergoing FITs were used to establish a model. In the base case analysis of screening strategies, colonoscopy was more cost-effective than FIT (ICER 415 193 yen/LYG). The ICER of the colonoscopy-based strategy among 60- to 69-year-old patients was lowest at 394 200 yen/LYG, whereas that in 20- to 29-year-old patients was highest. Monte Carlo simulations showed that the colonoscopy-based strategy was more cost-effective than the FIT-based strategy (net monetary benefit [NMB]: 5 695 957 yen vs 5 348 253 yen). When the adenoma detection rate in the colonoscopy was over 30% or the positive FIT rate was lower than 8.6% in the FIT-based strategy, the NMB of the colonoscopy-based strategy exceeded that of the FIT-based strategy. In the microsimulation model, colonoscopy is recommended as a one-time screening procedure in patients aged >60years with >30% ADR or <8.6% positive FIT rate.

Top 5 Research Studies of the month for Italian Primary Care Physicians: October 2023.

This monthly article provides a selection of summaries of the most relevant studies identified as POEMs (patient-oriented evidence that matters) for Italian primary care physicians. Amoxicillin is no more likely to cause a rash than any other antibiotic in children with infectious mononucleosis. According to a good quality systematic review and network meta-analysis, only a small number of randomized controlled trials, disappointing in overall quality, suggest that for managing neuropsychiatric symptoms in adults with dementia, risperidone has the best balance of effectiveness and adverse effects. In a rigorously conducted double-blind randomized controlled trial, adults with acute low back or neck pain treated with opioids had no benefit in pain relief as those treated with placebo. In a large study of more than 21,000 participants aged 60 to 84 years, taking 60,000 IU vitamin D each month slightly reduced their likelihood of experiencing a major cardiovascular event (number needed to treat = 172 over 5 years). A single screening colonoscopy had higher rates of participation than 5 years of fecal occult blood testing in a high-quality study in which patients were offered free screening with these two methods (84% vs 73%; p<0.001).

S1770 Random Drug Shortages Result in Single Center Observational Colonoscopy Preparation Study

S1770 Random Drug Shortages Result in Single Center Observational Colonoscopy Preparation Study

S400 Comparing Adenoma Detection Rate (ADR) in Single vs Dual Observer vs Artificial Intelligence-Assisted Colonoscopy: A Network Analysis of Randomized Controlled Trials

S400 Comparing Adenoma Detection Rate (ADR) in Single vs Dual Observer vs Artificial Intelligence-Assisted Colonoscopy: A Network Analysis of Randomized Controlled Trials

Computer-aided detection in real-world colonoscopy: enhancing detection or offering false hope?

Colorectal cancer stands as the second leading cause of cancer-related deaths worldwide, posing an important global health challenge. Screening colonoscopy with removal of neoplastic lesions has been recognised as one of the most effective methods of preventing colorectal cancer. 1 Zauber AG Winawer SJ O'Brien MJ et al. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. N Engl J Med. 2012; 366: 687-696 Crossref PubMed Scopus (2095) Google Scholar Adenoma detection rate (ADR) serves as a crucial quality indicator in colonoscopy, as it is inversely associated with post-colonoscopy (interval) colorectal cancer. 2 Kaminski MF Regula J Kraszewska E et al. Quality indicators for colonoscopy and the risk of interval cancer. N Engl J Med. 2010; 362: 1795-1803 Crossref PubMed Scopus (1431) Google Scholar However, it is estimated that around a quarter of colorectal neoplasms are missed during a single colonoscopy procedure. 3 van Rijn JC Reitsma JB Stoker J Bossuyt PM van Deventer SJ Dekker E Polyp miss rate determined by tandem colonoscopy: a systematic review. Am J Gastroenterol. 2006; 101: 343-350 Crossref PubMed Scopus (1056) Google Scholar To address this issue, computer-aided detection (CADe) systems using artificial intelligence (AI) have emerged as promising tools that allow increased detection of colorectal neoplastic lesions, thus enhancing the overall effectiveness of colonoscopy. 4 Misawa M Kudo SE Mori Y et al. Current status and future perspective on artificial intelligence for lower endoscopy. Dig Endosc. 2021; 33: 273-284 Crossref PubMed Scopus (16) Google Scholar Effect of real-time computer-aided detection of colorectal adenoma in routine colonoscopy (COLO-GENIUS): a single-centre randomised controlled trialOur findings support the benefits of CADe, even in a non-academic centre. Systematic use of CADe in routine colonoscopy should be considered. Full-Text PDF

Randomized Trial of Facilitated Adherence to Screening Colonoscopy vs Sequential Fecal-Based Blood Test

Colorectal cancer (CRC) screening guidelines include screening colonoscopy and sequential high-sensitivity fecal occult blood testing (HSgFOBT), with expectation of similar effectiveness based on the assumption of similar high adherence. However, adherence to screening colonoscopy compared with sequential HSgFOBT has not been reported. In this randomized clinical trial, we assessed adherence and pathology findings for a single screening colonoscopy vs sequential and nonsequential HSgFOBTs. Participants aged 40-69 years were enrolled at 3 centers representing different clinical settings. Participants were randomized into a single screening colonoscopy arm vs sequential HSgFOBT arm composed of 4-7 rounds. Initial adherence to screening colonoscopy and sequential adherence to HSgFOBT, follow-up colonoscopy for positive HSgFOBT tests, crossover to colonoscopy, and detection of advanced neoplasia or large serrated lesions (ADN-SERs) were measured. There were 3523 participants included in the trial; 1761 and 1762 participants were randomized to the screening colonoscopy and HSgFOBT arms, respectively. Adherence was 1473 (83.6%) for the screening colonoscopy arm vs 1288 (73.1%) for the HSgFOBT arm after 1 round (relative risk [RR], 1.14; 95% CI, 1.10-1.19; P ≤ .001), but only 674 (38.3%) over 4 sequential HSgFOBT rounds (RR, 2.19; 95% CI, 2.05-2.33). Overall adherence to any screening increased to 1558 (88.5%) in the screening colonoscopy arm during the entire study period and 1493 (84.7%) in the HSgFOBT arm (RR, 1.04; 95% CI, 1.02-1.07). Four hundred thirty-six participants (24.7%) crossed over to screening colonoscopy during the first 4 rounds. ADN-SERs were detected in 121 of the 1473 participants (8.2%) in the colonoscopy arm who were adherent to protocol in the first 12 months of the study, whereas detection of ADN-SERs among those who were not sequentially adherent (n= 709) to HSgFOBT was subpar (0.6%) (RR, 14.72; 95% CI, 5.46-39.67) compared with those who were sequentially adherent (3.3%) (n= 647) (RR, 2.52; 95% CI, 1.61-3.98) to HSgFOBT in the first 4 rounds. When including colonoscopies from HSgFOBT patients who were never positive yet crossed over (n= 1483), 5.5% of ADN-SERs were detected (RR, 1.50; 95% CI, 1.15-1.96) in the first 4 rounds. Observed adherence to sequential rounds of HSgFOBT was suboptimal compared with a single screening colonoscopy. Detection of ADN-SERs was inferior when nonsequential HSgFOBT adherence was compared with sequential adherence. However, the greatest number of ADN-SERs was detected among those who crossed over to colonoscopy and opted to receive a colonoscopy. The effectiveness of an HSgFOBT screening program may be enhanced if crossover to screening colonoscopy is permitted. gov, Number: NCT00102011.

In adults, a single colonoscopy screening invitation vs. no invitation reduced CRC incidence at 10 y.

Bretthauer M, Løberg M, Wieszczy P, et al. Effect of colonoscopy screening on risks of colorectal cancer and related death. N Engl J Med. 2022;387:1547-56. 36214590.

Modeling the Natural History and Screening Effects of Colorectal Cancer Using Both Adenoma and Serrated Neoplasia Pathways: The Development, Calibration, and Validation of a Discrete Event Simulation Model.

This article presents a new discrete event simulation model, DECAS, which models both adenoma-carcinoma and serrated neoplasia pathways for colorectal cancer (CRC) development and CRC screening effects.DECAS is calibrated based on a Bayesian inference method using the data from German screening colonoscopy program, which consists of more than 5 million first-time average-risk participants aged 55 years and older in 2003 to 2014.DECAS is flexible for evaluating various CRC screening strategies and can differentiate screening effects in different parts of the colon.DECAS is validated with large screening sigmoidoscopy and colonoscopy clinical study data and can be further used to evaluate the (cost-)effectiveness of German colorectal cancer screening strategies.

Editors' Selections from Relevant Scientific Publications

Editors' Selections from Relevant Scientific Publications

Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death

BackgroundAlthough colonoscopy is widely used as a screening test to detect colorectal cancer, its effect on the risks of colorectal cancer and related death is unclear.MethodsWe performed a pragmatic, randomized trial involving presumptively healthy men and women 55 to 64 years of age drawn from population registries in Poland, Norway, Sweden, and the Netherlands between 2009 and 2014. The participants were randomly assigned in a 1:2 ratio either to receive an invitation to undergo a single screening colonoscopy (the invited group) or to receive no invitation or screening (the usual-care group). The primary end points were the risks of colorectal cancer and related death, and the secondary end point was death from any cause.ResultsFollow-up data were available for 84,585 participants in Poland, Norway, and Sweden — 28,220 in the invited group, 11,843 of whom (42.0%) underwent screening, and 56,365 in the usual-care group. A total of 15 participants had major bleeding after polyp removal. No perforations or screening-related deaths occurred within 30 days after colonoscopy. During a median follow-up of 10 years, 259 cases of colorectal cancer were diagnosed in the invited group as compared with 622 cases in the usual-care group. In intention-to-screen analyses, the risk of colorectal cancer at 10 years was 0.98% in the invited group and 1.20% in the usual-care group, a risk reduction of 18% (risk ratio, 0.82; 95% confidence interval [CI], 0.70 to 0.93). The risk of death from colorectal cancer was 0.28% in the invited group and 0.31% in the usual-care group (risk ratio, 0.90; 95% CI, 0.64 to 1.16). The number needed to invite to undergo screening to prevent one case of colorectal cancer was 455 (95% CI, 270 to 1429). The risk of death from any cause was 11.03% in the invited group and 11.04% in the usual-care group (risk ratio, 0.99; 95% CI, 0.96 to 1.04).ConclusionsIn this randomized trial, the risk of colorectal cancer at 10 years was lower among participants who were invited to undergo screening colonoscopy than among those who were assigned to no screening. (Funded by the Research Council of Norway and others; NordICC ClinicalTrials.gov number, NCT00883792.)

Updates in Screening Recommendations for Colorectal Cancer

In the past 2 years, several significant changes have been made to the NCCN Guidelines for Colorectal Cancer (CRC) Screening. The age for initiation of screening average-risk adults has been lowered from age 50 to 45 years—without differentiation by age and race—and from age50 to 45 years for those with second- and third-degree relatives with CRC. For several groups, surveillance intervals have been changed. Patients with 1 or 2 low-risk adenomas at index colonoscopy, on the other hand, can now wait 10 years rather than 5 to 7 years between surveillance examinations. The first surveillance examination following resection of large adenomas or sessile serrated polyps (SSPs) with unfavorable-risk characteristics or that were removed piecemeal should now occur at 6 months. For patients with ≥10 adenomas and SSPs on a single colonoscopy, time to first surveillance was lowered to 1 year.

The analysis of multilevel factors affecting adenoma detection rates for colonoscopies: a large-scale retrospective study

BackgroundAdenoma detection rate (ADR) is a validated primary quality indicator for colonoscopy procedures. However, there is growing concern over the variability associated with ADR indicators. Currently, the factors that influence ADRs are not well understood.AimsIn this large-scale retrospective study, the impact of multilevel factors on the quality of ADR-based colonoscopy was assessed.MethodsA total of 10,788 patients, who underwent colonoscopies performed by 21 endoscopists between January 2019 and December 2019, were retrospectively enrolled in this study. Multilevel factors, including patient-, procedure-, and endoscopist-level characteristics were analyzed to determine their relationship with ADR.ResultsThe overall ADR was 20.21% and ranged from 11.4 to 32.8%. Multivariate regression analysis revealed that higher ADRs were strongly correlated with the following multilevel factors: patient age per stage (OR 1.645; 95% CI 1.577–1.717), male gender (OR 1.959; 95% CI 1.772–2.166), sedation (OR 1.402; 95% CI 1.246–1.578), single examiner colonoscopy (OR 1.330; 95% CI 1.194–1.482) and senior level endoscopists (OR 1.609; 95% CI 1.449–1.787).ConclusionThe ADR is positively correlated with senior level endoscopists and single examiner colonoscopies in patients under sedation. As such, these procedure- and endoscopist-level characteristics are important considerations to improve the colonoscopy quality.

Diagnostic Accuracy of Artificial Intelligence and Computer-Aided Diagnosis for the Detection and Characterization of Colorectal Polyps: Systematic Review and Meta-analysis.

BackgroundColonoscopy reduces the incidence of colorectal cancer (CRC) by allowing detection and resection of neoplastic polyps. Evidence shows that many small polyps are missed on a single colonoscopy. There has been a successful adoption of artificial intelligence (AI) technologies to tackle the issues around missed polyps and as tools to increase the adenoma detection rate (ADR).ObjectiveThe aim of this review was to examine the diagnostic accuracy of AI-based technologies in assessing colorectal polyps.MethodsA comprehensive literature search was undertaken using the databases of Embase, MEDLINE, and the Cochrane Library. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Studies reporting the use of computer-aided diagnosis for polyp detection or characterization during colonoscopy were included. Independent proportions and their differences were calculated and pooled through DerSimonian and Laird random-effects modeling.ResultsA total of 48 studies were included. The meta-analysis showed a significant increase in pooled polyp detection rate in patients with the use of AI for polyp detection during colonoscopy compared with patients who had standard colonoscopy (odds ratio [OR] 1.75, 95% CI 1.56-1.96; P<.001). When comparing patients undergoing colonoscopy with the use of AI to those without, there was also a significant increase in ADR (OR 1.53, 95% CI 1.32-1.77; P<.001).ConclusionsWith the aid of machine learning, there is potential to improve ADR and, consequently, reduce the incidence of CRC. The current generation of AI-based systems demonstrate impressive accuracy for the detection and characterization of colorectal polyps. However, this is an evolving field and before its adoption into a clinical setting, AI systems must prove worthy to patients and clinicians.Trial RegistrationPROSPERO International Prospective Register of Systematic Reviews CRD42020169786; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020169786

Medico-legal implications for the colon perforation during colonoscopy

Colon perforation is the most serious complication of colonoscopy, and tends to be considered as malpractice. The aim of this study was to identify the characteristics and causes of medical accidents by analyzing lawsuit cases on colon perforation during colonoscopy. We collected judgment results that were ruled from 2005 to 2015 using the keyword ‘colonoscopy’ in the ‘Korea's Written Judgment Public Reading System’ of the Supreme Court, and extracted the cases of colon perforation. Characteristics of medical accidents and the decisions of courts were analyzed from written judgments. Twenty-two lawsuits were analyzed. Most cases were ruled in favor of the plaintiff (n = 20). The allegations against defendants, as filed by the plaintiffs, were performance error (n = 22), improper monitoring after colonoscopy (n = 7), and a lack of informed consent (n = 8). The median compensation was 9335.47 US dollars; this is about 130 times the cost of a single colonoscopy in Korea. The greater the intestinal damage, the greater the amount of compensation (p = 0.016). The time interval from procedure to diagnosis of perforation was most frequently 24 h later (n = 9). It is important to educate patients completely about the symptoms of colon perforation and to guide them to contact medical institutions immediately when symptoms occur. In addition, doctors should explain sufficiently the possibility of perforation before colonoscopy to the patient, and not the caregiver, and get informed consent.

A146 EVALUATION OF A COLONOSCOPY REFERRAL FORM IN QUEBEC: WHICH INDICATIONS CARRIES A HIGHER RISK OF ADVANCED NEOPLASIA?

BackgroundPatients referral for colonoscopy in the province of Quebec are organized through a standardized triage sheet that includes all indications categorized in 5 hierarchal scheduling priorities. In the context of a restricted access to colonoscopy, exacerbated by the COVID-19 pandemic, postponed elective endoscopies lead to potential diagnostic and therapeutic delays in patients with colorectal neoplasia. There is currently an important need to evaluate available tools to improve patients prioritization.AimsThis study aims to determine CRC and advanced adenomas (AA) rates associated with indications of priority 3 (P3 fig.1). The secondary objective is to regroup and compare indications with higher and lower rate of CRC and AA.MethodsThis retrospective study included all adult patients who underwent a single diagnostic colonoscopy from March 2013 to March 2016 following a single FIT test in a tertiary teaching hospital. A literature review informed the adopted definition of higher-risk of CRC and AA according to P3 colonoscopy indications. These include: Positive FIT test (IN5), hematochezia in ≥ 40 years old patients (IN4), unexplained iron deficiency anemia (IN6) and symptoms suspicious of occult colorectal cancer (IN18). Lower risk P3 indications were defined as: suspicion of IBD (IN3), recent change in bowel habits (IN7), polyp viewed on imaging (IN17), inadequate bowel preparation (IN19), and diverticulitis follow-up (IN20). Higher and lower risk indications findings were analyzed.ResultsIn our cohort of 2226 patients, indications for colonoscopy referral according to the standardized form were available for 1806 patients (10 P1, 69 P2, 1056 P3, 56 P4 and 615 P5). In our studied group of P3 indications, the mean age was 62.6±11.3 years, 54.1% were female and 173 (16.4%) patients had a significant finding of CRC or AA (table 1). Patients referred for higher risk indications had a significantly increased rate of CRC and AA (19.3% vs 5.1% p≤ 0.01) compared to patients referred for lower risk indications.ConclusionsA standardized colonoscopy referral tool may be adapted to improve prioritization of patients at risk of advanced neoplasia. These findings are especially relevant in the context of limited access to colonoscopy like during a pandemic.Table 1. Detection rate of neoplastic findings for P3 indications(%) Higher-risk indications Lower-risk indications IN4 (N=230)IN5 (N=453)IN6 (N=156)IN18 (N=3)IN3 (N=41)IN7 (N=135)IN17 (N=5)IN20 (N=33) Non-advanced adenomas (NAA)47(20.4)192(42.6)41(26.5)1(33)5(12.2)25(18.5)4(80)6(18.2) Advanced adenomas (AA)21(9.2)116(25.7)8(5.2)01(2.4)8(5.9)01(3) Serrated polyps 11(4.8)42(9.4)5(3.2)006(4.5)01(3) Carcinoma (CRC)5(2.2)7(1.6)6(3.9)001(0.7)00 AA and CRC 26(11.3)123(27.2)14(9.0)01(2.4)9(6.6)01(3)Figure 1: Provincial colonoscopy referral form in Quebec (AH-702)Funding AgenciesNone

Artificial intelligence for identification and characterization of colonic polyps.

Colonoscopy remains the gold standard exam for colorectal cancer screening due to its ability to detect and resect pre-cancerous lesions in the colon. However, its performance is greatly operator dependent. Studies have shown that up to one-quarter of colorectal polyps can be missed on a single colonoscopy, leading to high rates of interval colorectal cancer. In addition, the American Society for Gastrointestinal Endoscopy has proposed the “resect-and-discard” and “diagnose-and-leave” strategies for diminutive colorectal polyps to reduce the costs of unnecessary polyp resection and pathology evaluation. However, the performance of optical biopsy has been suboptimal in community practice. With recent improvements in machine-learning techniques, artificial intelligence–assisted computer-aided detection and diagnosis have been increasingly utilized by endoscopists. The application of computer-aided design on real-time colonoscopy has been shown to increase the adenoma detection rate while decreasing the withdrawal time and improve endoscopists’ optical biopsy accuracy, while reducing the time to make the diagnosis. These are promising steps toward standardization and improvement of colonoscopy quality, and implementation of “resect-and-discard” and “diagnose-and-leave” strategies. Yet, issues such as real-world applications and regulatory approval need to be addressed before artificial intelligence models can be successfully implemented in clinical practice. In this review, we summarize the recent literature on the application of artificial intelligence for detection and characterization of colorectal polyps and review the limitation of existing artificial intelligence technologies and future directions for this field.

Should Colorectal Cancer Screening in Portugal Start at the Age of 45 Years? A Cost-Utility Analysis

Background and Objective: Colorectal cancer (CRC) is one of the most common cancers in Europe. Recently, new data from the USA and Europe revealed an increase in the incidence of CRC in individuals aged <55 years and a reduction in those aged >65 years. Mortality rate was stable in patients aged <55 years and decreased after the age of 55 years. Based on the USA data, the American Cancer Society (ACS) published a qualified recommendation advocating the start of CRC screening at the age of 45 years. We aimed to evaluate if the changes in the CRC incidence/mortality observed in the USA and the rest of Europe also occur in Portugal, and then perform a cost-utility analysis of CRC screening that starts at 45 years of age. Methods: We evaluated the incidence of CRC by age group using data from the National Cancer Registry, and the mortality rate according to the National Statistics Institute in the periods 1993–2010 and 2003–2016. A cost-utility analysis was performed with a decision tree from a societal perspective comparing biennial fecal immunochemical test (FIT) or a single colonoscopy screening versus nonscreening at the age of 45 years in Portugal. Results: In Portugal, in 1993–2010, there was an increase in CRC incidence of 17% (from 25 to 30/100,000), 35% (from 39 to 54/100,000), and 71% (from 52 to 97/100,000) in patients aged 45–49 years, 50–54 years, and 55–59 years, respectively. The mortality rate of patients aged 45–54 years remained stable between 2003 and 2016 (12/100,000) as a counterpoint to a moderate decrease in those aged 55–64 years (from 38 to 35/100,000) and a sharp reduction in those aged 65–75 years (from 93 to 75/100,000). Screening for CRC at the age of 45 years has no cost utility with the current incidence. FIT screening provided an ICUR of EUR 84,304/quality-adjusted life years (QALY) while colonoscopy provided an ICUR of EUR 3,112,244/QALY. On one-way sensitivity analysis, FIT screening would only have cost utility at the present cost of colonoscopy under sedation (EUR 150) and acceptance rates if the incidence rate rises above 47.5/100,000; colonoscopy at this age would have no cost utility despite changes in costs and/or incidence rates. Conclusion: In Portugal, the incidence of CRC in patients aged 45–55 years has been increasing with a stable mortality rate, in contrast to the decrease in mortality in the age groups covered by the current CRC screening program. However, at present, CRC screening in Portugal at the age of 45 years has no cost utility and will only have this if the incidence rate rises above 47.5/100,000 (vs. the actual incidence of 30/100,000).

Current status and future perspective on artificial intelligence for lower endoscopy.

The global incidence and mortality rate of colorectal cancer remains high. Colonoscopy is regarded as the gold standard examination for detecting and eradicating neoplastic lesions. However, there are some uncertainties in colonoscopy practice that are related to limitations in human performance. First, approximately one-fourth of colorectal neoplasms are missed on a single colonoscopy. Second, it is still difficult for non-experts to perform adequately regarding optical biopsy. Third, recording of some quality indicators (e.g. cecal intubation, bowel preparation, and withdrawal speed) which are related to adenoma detection rate, is sometimes incomplete. With recent improvements in machine learning techniques and advances in computer performance, artificial intelligence-assisted computer-aided diagnosis is being increasingly utilized by endoscopists. In particular, the emergence of deep-learning, data-driven machine learning techniques have made the development of computer-aided systems easier than that of conventional machine learning techniques, the former currently being considered the standard artificial intelligence engine of computer-aided diagnosis by colonoscopy. To date, computer-aided detection systems seem to have improved the rate of detection of neoplasms. Additionally, computer-aided characterization systems may have the potential to improve diagnostic accuracy in real-time clinical practice. Furthermore, some artificial intelligence-assisted systems that aim to improve the quality of colonoscopy have been reported. The implementation of computer-aided system clinical practice may provide additional benefits such as helping in educational poorly performing endoscopists and supporting real-time clinical decision-making. In this review, we have focused on computer-aided diagnosis during colonoscopy reported by gastroenterologists and discussed its status, limitations, and future prospects.

One negative colonoscopy associated with a significant reduction in colorectal cancer risk.

An observational study published in the Annals of Internal Medicine1 found significant reductions in both colorectal cancer (CRC) incidence and mortality associated with a single negative high-quality screening colonoscopy. The findings indicate an 84% reduction in incidence and a 90% reduction in mortality for up to 17.4 years. As a result, the study authors suggest that the currently recommended 10-year screening interval is safe and could safely be extended. Under current guidelines, average-risk individuals aged 50 years or older who have previously had negative colonoscopy results are recommended to undergo screening every 10 years. That recommendation is based on estimates for how long it takes for adenomas and carcinomas to develop. However, longterm data are lacking on optimum follow-up intervals. The study was conducted by researchers from the Maria Sklodowska-Curie National Research Institute for Oncology in Warsaw, Poland. They analyzed a screening registry of 165,887 people and assessed both long-term CRC risk and CRC death after a single negative low- or high-quality screening colonoscopy. Their findings show that although a single negative screening colonoscopy was associated with significantly reduced CRC incidence and mortality during the 17-year screening period, only a high-quality colonoscopy led to a profound and stable reduction. Among women, high quality was key for long-term efficacy in screening colonoscopy in the proximal colon. These findings are particularly important because previous studies have questioned the efficacy of colonoscopy in the proximal colon as well as screening sigmoidoscopy in women.