Stage at diagnosis of colorectal cancer through diagnostic route:Who should be screened?

BACKGROUND Colorectal cancer(CRC)is a global health concern,with advanced-stage diagnoses contributing to poor prognoses.The efficacy of CRC screening has been well-established;nevertheless,a significant proportion of patients remain unscreened,with>70%of cases diagnosed outside screening.Although identifying specific subgroups for whom CRC screening should be particularly recommended is crucial owing to limited resources,the association between the diagnostic routes and identification of these subgroups has been less appreciated.In the Japanese cancer registry,the diagnostic routes for groups discovered outside of screening are primarily categorized into those with comorbidities found during hospital visits and those with CRC-related symptoms.AIM To clarify the stage at CRC diagnosis based on diagnostic routes.METHODS We conducted a retrospective observational study using a cancer registry of patients with CRC between January 2016 and December 2019 at two hospitals.The diagnostic routes were primarily classified into three groups:Cancer screening,follow-up,and symptomatic.The early-stage was defined as Stages 0 or I.Multivariate and univariate logistic regressions were exploited to determine the odds of early-stage diagnosis in the symptomatic and cancer screening groups,referencing the follow-up group.The adjusted covariates were age,sex,and tumor location.RESULTS Of the 2083 patients,715(34.4%),1064(51.1%),and 304(14.6%)belonged to the follow-up,symptomatic,and cancer screening groups,respectively.Among the 2083 patients,CRCs diagnosed at an early stage were 57.3%(410 of 715),23.9%(254 of 1064),and 59.5%(181 of 304)in the follow-up,symptomatic,and cancer screening groups,respectively.The symptomatic group exhibited a lower likelihood of early-stage diagnosis than the follow-up group[P<0.001,adjusted odds ratio(aOR),0.23;95%confidence interval(95%CI):0.19-0.29].The likelihood of diagnosis at an early stage was similar between the follow-up and cancer screening groups(P=0.493,aOR for early-stage diagnosis in the cancer screening group vs follow-up group=1.11;95%CI=0.82-1.49).CONCLUSION CRCs detected during hospital visits for comorbidities were diagnosed earlier,similar to cancer screening.CRC screening should be recommended,particularly for patients without periodical hospital visits for comorbidities.

Non-participation of asymptomatic candidates in screening protocols reduces early diagnosis and worsens prognosis of colorectal cancer

The Agatsuma et al’s study shows that despite the evidence of the benefits of an early colorectal cancer(CRC)diagnosis,through screening in asymptomatic subjects,up to 50%of candidates reject this option and many of those affected are diagnosed later,in advanced stages.The efficacy of screening programs has been well-established for several years,which reduces the risk of CRC morbidity and mortality,without taking into account the test used for screening,or other tools.Nevertheless,a significant proportion of patients remain unscreened,so understanding the factors involved,as well as the barriers of the population to adherence is the first step to possibly modify the participation rate.These barriers could include a full range of social and political aspects,especially the type of financial provision of each health service.In Japan,health services are universal,and this advantageous situation makes it easier for citizens to access to these services,contributing to the detection of various diseases,including CRC.Interestingly,the symptomatic CRC group had a lower early-stage diagnosis rate than the patients detected during follow-up for other comorbidities,and symptomatic and cancer screening groups showed similar early-stage diagnosis.

Colonoscopy plays an important role in detecting colorectal neoplasms in patients with gastric neoplasms

BACKGROUND Gastric cancer(GC)and colorectal cancer(CRC)are the fifth and third most common cancer worldwide,respectively.Nowadays,GC is reported to have a potential predictive value for CRC,especially for advanced CRC.AIM To evaluate the necessity of colonoscopy for gastric neoplasm(GN)patients.METHODS Four databases,including PubMed,EMBASE,the Cochrane Library,and Ovid,were used to perform the search strategy on May 2,2023.The prevalence of colorectal neoplasms(CRN)and baseline characteristics were compared between the neoplasm group and the control group.Continuous variables are expressed as the mean difference and standard deviation.Relationships of categorical variables in the two groups are expressed as odds ratios(OR)and 95%confidence intervals(95%CIs).Subgroup analysis according to different kinds of GNs was conducted for more in-depth analysis.The results of this study are represented by forest plots.Publication bias was evaluated by a funnel plot.All data analyses were performed by STATA SE 16.0 software.RESULTS A total of 3018 patients with GNs and 3905 healthy controls(age and sex matched)were enrolled for analysis.After comparing the prevalence of CRNs between the two groups,CRNs were detected significantly more frequently in GN patients than in controls(OR=1.69,95%CI=1.28 to 2.23,I^(2)=85.12%,P=0.00),especially in patients with GC(OR=1.80,95%CI=1.49 to 2.18,I^(2)=25.55%,P<0.1).Moreover,other risk factors including age(OR=1.08,95%CI=1.00 to 1.17,I^(2)=90.13%,P=0.00)and male sex(OR=2.31,95%CI=1.26 to 4.22,I^(2)=87.35%,P=0.00),were related to the prevalence of CRNs.For patients in the GN group,body mass index(BMI,OR=0.88,95%CI=0.80 to 0.98,I^(2)=0.00%,P=0.92)and smoking(OR=1.03,95%CI=1.01 to 1.05,I^(2)=0.00%,P=0.57)were protective and risk factors for CRNs,respectively.CONCLUSION Patients are recommended to undergo colonoscopy when diagnosed with GNs,especially GC patients with a low BMI and a history of smoking.

Clinical significance of peripheral blood UL16 and DR-70 for the early diagnosis and prognostic evaluation of colorectal cancer

BACKGROUND Early diagnosis of colorectal cancer(CRC)is of great significance to improve the survival rate and quality of life of patients,but early diagnosis of CRC requires more sensitive techniques.Peripheral blood UL16-binding protein 2(ULBP2)and human fibrinogen degradation products(DR-70)are the main indicators for the diagnosis of malignant tumors.AIM To assess ULBP2 and DR-70 potential for the early diagnosis and prognostic evaluation of CRC to provide a reference.METHODS This study involved 60 patients with early-stage CRC(CRC group),50 patients with benign colorectal tumors(benign group),and 50 healthy patients(control group)enrolled at the Affiliated Hospital of Jiangnan University and Jiangsu Province Official Hospital between January,2020 and January,2022.ULBP2 and DR-70 levels in the blood were determined and differences among the three groups and early diagnostic values for CRC were determined.Patients with CRC were divided into the good prognosis and poor prognosis groups,and ULBP2 and DR-70 levels in the blood and diagnostic values were compared.RESULTS ULBP2 and DR-70 serum levels were significantly higher in the CRC group than in the control and benign groups(P<0.05);however,no significant differences were observed between the benign and control groups(P>0.05).Among the 60 patients with CRC followed up for two years,two died(3.33%)and 15 exhibited tumor metastasis,progression,or recurrence(25.00%).ULBP2 and DR-70 serum levels were significantly higher in the poor prognosis group than in the good prognosis group(P<0.05).A receiver operating characteristic curve was plotted.Area under the curve,sensitivity,and specificity of serum ULBP2 with DR-70 for the early diagnosis of CRC were higher than those of the single serum indices(P<0.05)in both the good and poor prognosis groups.CONCLUSION ULBP2 and DR-70 serum levels were significantly high in patients with early-stage CRC.They improved the diagnostic rate of early-stage CRC and predicted patient prognosis,thereby showing clinical application potential.

Advances in endoscopic diagnosis and management of colorectal cancer

Colorectal cancer(CRC)is a leading global health concern,and early identification and precise prognosis play a vital role in enhancing patient results.Endoscopy is a minimally invasive imaging technique that is crucial for the screening,diagnosis,and treatment of CRC.This editorial discusses the importance of advances in endoscopic techniques,the integration of artificial intelligence,and the potential of novel technologies in enhancing the diagnosis and management of CRC.

Different lymph node staging systems for predicting the prognosis of colorectal neuroendocrine neoplasms

BACKGROUND Colorectal neuroendocrine neoplasms(NENs)are a rare malignancy that primarily arises from the diffuse distribution of neuroendocrine cells in the colon and rectum.Previous studies have pointed out that the status of lymph node may be used to predict the prognosis.AIM To investigate the predictive values of lymph node ratio(LNR),positive lymph node(PLN),and log odds of PLNs(LODDS)staging systems on the prognosis of colorectal NENs treated surgically,and compare their predictive values.METHODS This cohort study included 895 patients with colorectal NENs treated surgically from the Surveillance,Epidemiology,and End Results database.The endpoint was mortality of patients with colorectal NENs treated surgically.X-tile software was utilized to identify most suitable thresholds for categorizing the LNR,PLN,and LODDS.Participants were selected in a random manner to form training and testing sets.The prognosis of surgically treating colorectal NENs was examined using multivariate cox analysis to assess the associations of LNR,PLN,and LODDS with the prognosis of colorectal NENs.C-index was used for assessing the predictive effectiveness.We conducted a subgroup analysis to explore the different lymph node staging systems’predictive values.RESULTS After adjusting all confounding factors,PLN,LNR and LODDS staging systems were linked with mortality in patients with colorectal NENs treated surgically(P<0.05).We found that LODDS staging had a higher prognostic value for patients with colorectal NENs treated surgically than PLN and LNR staging systems.Similar results were obtained in the different G staging subgroup analyses.Furthermore,the area under the receiver operating characteristic curve values for LODDS staging system remained consistently higher than those of PLN or LNR,even at the 1-,2-,3-,4-,5-and 6-year follow-up periods.CONCLUSION LNR,PLN,and LODDS were found to significantly predict the prognosis of patients with colorectal NENs treated surgically.

Artificial intelligence for characterization of diminutive colorectal polyps:A feasibility study comparing two computer-aided diagnosis systems

BACKGROUND Artificial intelligence(AI)has potential in the optical diagnosis of colorectal polyps.AIM To evaluate the feasibility of the real-time use of the computer-aided diagnosis system(CADx)AI for ColoRectal Polyps(AI4CRP)for the optical diagnosis of diminutive colorectal polyps and to compare the performance with CAD EYE^(TM)(Fujifilm,Tokyo,Japan).CADx influence on the optical diagnosis of an expert endoscopist was also investigated.METHODS AI4CRP was developed in-house and CAD EYE was proprietary software provided by Fujifilm.Both CADxsystems exploit convolutional neural networks.Colorectal polyps were characterized as benign or premalignant and histopathology was used as gold standard.AI4CRP provided an objective assessment of its characterization by presenting a calibrated confidence characterization value(range 0.0-1.0).A predefined cut-off value of 0.6 was set with values<0.6 indicating benign and values≥0.6 indicating premalignant colorectal polyps.Low confidence characterizations were defined as values 40%around the cut-off value of 0.6(<0.36 and>0.76).Self-critical AI4CRP’s diagnostic performances excluded low confidence characterizations.RESULTS AI4CRP use was feasible and performed on 30 patients with 51 colorectal polyps.Self-critical AI4CRP,excluding 14 low confidence characterizations[27.5%(14/51)],had a diagnostic accuracy of 89.2%,sensitivity of 89.7%,and specificity of 87.5%,which was higher compared to AI4CRP.CAD EYE had a 83.7%diagnostic accuracy,74.2%sensitivity,and 100.0%specificity.Diagnostic performances of the endoscopist alone(before AI)increased nonsignificantly after reviewing the CADx characterizations of both AI4CRP and CAD EYE(AI-assisted endoscopist).Diagnostic performances of the AI-assisted endoscopist were higher compared to both CADx-systems,except for specificity for which CAD EYE performed best.CONCLUSION Real-time use of AI4CRP was feasible.Objective confidence values provided by a CADx is novel and self-critical AI4CRP showed higher diagnostic performances compared to AI4CRP.

Expenditure and financial burden for the diagnosis and treatment of colorectal cancer in China:a hospital.based,multicenter,cross-sectional survey

Background: The increasing prevalence of colorectal cancer(CRC) in China and the paucity of information about relevant expenditure highlight the necessity of better understanding the financial burden and effect of CRC diagnosis and treatment. We performed a survey to quantify the direct medical and non-medical expenditure as well as the resulting financial burden of CRC patients in China.Methods: We conducted a multicenter, cross-sectional survey in 37 tertiary hospitals in 13 provinces across China between 2012 and 2014. Each enrolled patient was interviewed using a structured questionnaire. All expenditure data were inflated to the 2014 Chinese Yuan(CNY; 1 CNY = 0.163 USD). We quantified the overall expenditure and financial burden and by subgroup(hospital type, age at diagnosis, sex, education, occupation, insurance type, household income, clinical stage, pathologic type, and therapeutic regimen). We then performed generalized linear modeling to determine the factors associated with overall expenditure.Results: A total of 2356 patients with a mean age of 57.4 years were included, 57.1 % of whom were men; 13.9% of patients had stage I cancer; and the average previous-year household income was 54,525 CNY.The overall average direct expenditure per patient was estimated to be 67,408 CNY, and the expenditures for stage Ⅰ, Ⅱ, Ⅲ, and Ⅳ disease were 56,099 CNY, 59,952 CNY, 67,292 CNY, and 82,729 CNY, respectively. Non-medical expenditure accounted for 8.3%of the overall expenditure. The 1-year out-of-pocket expenditure of a newly diagnosed patient was 32,649 CNY, which accounted for 59.9% of their previous-year household income and caused 75.0% of families to suffer an unmanageable financial burden. Univariate analysis showed that financial burden and overall expenditure differed in almost all subgroups(P < 0.05), except for sex. Multivariate analysis showed that patients who were treated in specialized hospitals and those who were diagnosed with adenocarcinoma or diagnosed at a later stage were likely to spend more,whereas those with a lower household income and those who underwent surgery spent less(all P < 0.05).Conclusions: For patients in China, direct expenditure for the diagnosis and treatment of CRC seemed catastrophic,and non-medical expenditure was non-ignorable. The financial burden varied among subgroups, especially among patients with different clinical stages of disease, which suggests that, in China, CRC screening might be cost-effective.

Medical expenditures for colorectal cancer diagnosis and treatment: A 10-year high-level-hospital-based multicenter retrospective survey in China, 2002-2011

Objective: Colorectal cancer(CRC) causes a substantial burden of disease in China and the evidence of economic burden triggered is fundamental for priority setting. The aim of this survey was to quantify medical expenditures and the time trends for CRC diagnosis and treatment in China.Methods: From 2012 to 2014, a hospital-based multicenter retrospective survey was conducted in 13 provinces across China. For each eligible CRC patient diagnosed from 2002 to 2011, clinical information and expenditure data were extracted using a uniform questionnaire. All expenditure data were reported in Chinese Yuan(CNY)using 2011 values.Results: Of the 14,536 CRC patients included, the average age at diagnosis was 58.2 years and 15.8% were stageI cases. The average medical expenditure per patient was estimated at 37,902 CNY [95 % confidence interval(95%CI): 37,282-38,522], and the annual average increase rate was 9.2% from 2002 to 2011(P for trend <0.001), with a cumulative increase of 2.4 times(from 23,275 CNY to 56,010 CNY). The expenditure per patient in stages Ⅰ, Ⅱ, Ⅲ and Ⅳ were 31,698 CNY, 37,067 CNY, 38,918 CNY and 42,614 CNY, respectively(P<0.001). Expenditure significantly differed within various subgroups. Expenses for drugs contributed the largest proportion(52.6%).Conclusions: These conservative estimates illustrated that medical expenditures for CRC diagnosis and treatment in tertiary hospitals in China were substantial and increased rapidly over the 10 years, with drugs continually being the main expense by 2011. Relatively, medical expenditures are lower for CRC in the earlier stages. These findings will facilitate the economic evaluation of CRC prevention and control in China.

Risk factors for bleeding after endoscopic submucosal dissection of colorectal neoplasms

AIM: To investigate the risk factors for delayed bleeding following endoscopic submucosal dissection (ESD) treatment for colorectal neoplasms.

Current perspectives on pancreatic serous cystic neoplasms:Diagnosis, management and beyond

Pancreatic cystic neoplasms have been increasingly recognized recently. Comprising about 16% of all resected pancreatic cystic neoplasms, serous cystic neoplasms are uncommon benign lesions that are usually asymptomatic and found incidentally. Despite overall low risk of malignancy, these pancreatic cysts still generate anxiety, leading to intensive medical investigations with considerable financial cost to health care systems. This review discusses the general background of serous cystic neoplasms, including epidemiology and clinical characteristics, and provides an updated overview of diagnostic approaches based on clinical features, relevant imaging studies and new findings that are being discovered pertaining to diagnostic evaluation. We also concisely discuss and propose management strategies for better quality of life.

Chinese Society of Clinical Oncology (CSCO) diagnosis and treatment guidelines for colorectal cancer 2018(English version)

Contents1. General guidelines for diagnosis and treatment of colorectal cancer2. Diagnostic principles for colorectal cancer2.1 Colorectal cancer screening of asymptomatic healthy population2.2 Basic diagnostic principles2.2.1 Colorectal cancer diagnosis2.2.2 Appendix on colorectal cancer imaging staging and diagnosis2.3 Principles of pathological diagnosis2.4 Staging.

National Health Commission guidelines for diagnosis and treatment of colorectal cancer 2023 in China(English version)

1. Overview The incidence and mortality of colorectal cancer (CRC) in China have been on the rise. The Cancer Statistics Report of China in 2020 showed that the incidence and mortality of CRC ranked second and fifth among all malignant tumors, of which 555,000 new cases and 286,000 deaths.

Clinical significance of type V_I pit pattern subclassification in determining the depth of invasion of colorectal neoplasms

AIM: To clarify whether subclassification of the type VI pit pattern on the basis of magnifying colonoscopy findings is useful in determining the type and depth of invasion of colorectal neoplasms.METHODS: We retrospectively analyzed 272 colorectal neoplasms (117 dysplasias and 155 submucosal invasive carcinomas; 228 patients) with a type V pit pattern [type VI, n = 202; type VN, n = 70 (Kudo and Tsuruta classification system)]. We divided lesions with a type VI pit pattern into two subclasses, mildly irregular lesions and severely irregular lesions, according to the prominent and detailed magnifying colonoscopy findings. We examined the relation between these two subclasses and histology/invasion depth.RESULTS: One hundred and four lesions (51.5%) were judged to be mildly irregular, and 98 lesions (48.5%) were judged to be severely irregular. Ninety-seven (93.3%) mildly irregular lesions showed dysplasias or submucosal invasion of less than 1000 μm (SM < 1000 μm). Fifty-five (56.1%) severely irregular lesions showed submucosal invasion equal to or deeper than 1000 μm (SM ≥ 1000 μm). Mild irregularity was found significantly more often in dysplasias or lesions with SM < 1000 μm than in lesions with SM ≥ 1000 μm (P < 0.01).CONCLUSION: Subclassification of the type VI pit pattern is useful for identifying dysplasias or lesions with SM < 1000 μm.

Imaging diagnosis of colorectal liver metastases

Rapid advances in imaging technology have improved the detection, characterization and staging of colorectal liver metastases. Multi-modality imaging approach is usually the more useful in diagnosis colorectal liver metastases. It is well established that hepatic resection improves the long-term prognosis of many patients with liver metastases. However, incomplete resection does not prolong survival, so knowledge of the exact extent of intra-hepatic disease is crucially important in determining patient management and outcome. The diagnosis of liver metastases relies first and totally on imaging to decide which patients may be surgical candidates. This review will discuss the imaging options and their appropriate indications. Imaging and evaluating of colorectal liver metastases （CRLM） have been performed with contrast-enhanced ultrasound, multidetector computed tomography, magnetic resonance imaging （MRI） with extra-cellular contrast media and liver-specific contrast media MRI, and positron emission tomography/computed tomography. This review

Use of blood-based biomarkers for early diagnosis and surveillance of colorectal cancer

Early screening for colorectal cancer(CRC) holds the key to combat and control the increasing global burden of CRC morbidity and mortality. However, the current available screening modalities are severely inadequate because of their high cost and cumbersome preparatory procedures that ultimately lead to a low participation rate. People simply do not like to have colonoscopies. It would be ideal, therefore, to develop an alternative modality based on blood biomarkers as the first line screening test. This will allow for the differentiation of the general population from high risk individuals. Colonoscopy would then become the secondary test, to further screen the high risk segment of the population. This will encourage participation and therefore help to reach the goal of early detection and thereby reduce the anticipated increasing global CRC incidence rate. A blood-based screening test is anappealing alternative as it is non-invasive and poses minimal risk to patients. It is easy to perform, can be repeated at shorter intervals, and therefore would likely lead to a much higher participation rate. This review surveys various blood-based test strategies currently under investigation, discusses the potency of what is available, and assesses how new technology may contribute to future test design.

Development of artificial intelligence technology in diagnosis,treatment,and prognosis of colorectal cancer

Artificial intelligence(AI)technology has made leaps and bounds since its invention.AI technology can be subdivided into many technologies such as machine learning and deep learning.The application scope and prospect of different technologies are also totally different.Currently,AI technologies play a pivotal role in the highly complex and wide-ranging medical field,such as medical image recognition,biotechnology,auxiliary diagnosis,drug research and development,and nutrition.Colorectal cancer(CRC)is a common gastrointestinal cancer that has a high mortality,posing a serious threat to human health.Many CRCs are caused by the malignant transformation of colorectal polyps.Therefore,early diagnosis and treatment are crucial to CRC prognosis.The methods of diagnosing CRC are divided into imaging diagnosis,endoscopy,and pathology diagnosis.Treatment methods are divided into endoscopic treatment,surgical treatment,and drug treatment.AI technology is in the weak era and does not have communication capabilities.Therefore,the current AI technology is mainly used for image recognition and auxiliary analysis without in-depth communication with patients.This article reviews the application of AI in the diagnosis,treatment,and prognosis of CRC and provides the prospects for the broader application of AI in CRC.

Usefulness of fecal lactoferrin and hemoglobin in diagnosis of colorectal diseases

AIM:To evaluate prospectively usefulness of fecal lactoferrin(Lf)and fecal hemoglobin(Hb)in the diagnosis of colorectal diseases.METHODS:Fecal Lf and Hb were measured using ELISA in 872 patients before they underwent colorectal endoscopy.RESULTS:Lf was positive in 18(50%)of 36 patients with colorectal cancer,25(15.9%)of 157 with colorectal polyps,29(46.8%)of 62 with ulcerative colitis,and 25(62.5%)of 40(62.5%)with Crohn's disease.The Hb-positive rates were 50%,12.1%,41.9% and 32.5%,respectively.Of the 318 patients free of abnormalities by colorectal endoscopy,Lf was positive in 29(9.1%)and Hb was positive in 15(4.7%).Among patients with Crohn's disease,the Lf-positive rate was significantly higher than the Hb-positive rate.If either high Lf or Hb levels were considered positive,the positive rates rose to 61.1%,51.6%,and 67.5% in the colorectal cancer group,ulcerative colitis group,and Crohn's disease group,respectively.If both high Lf and Hb levels were rated positive,the positive predictive values(PPV)were 21% for colorectal cancer,33% for ulcerative colitis,and 17% for Crohn's disease,and PPV of high Hb level alone was 18%,25% and 13%,respectively.CONCLUSION:Fecal Lf and Hb were found useful in the detection of colorectal diseases,and the combination of the two measurements appears to increase the sensitivity and efficacy of diagnosis.

Biliary carcinoembryonic antigen levels in diagnosis of occult hepatic metastases from colorectal carcinoma

AIM:To prospectively explore the role of carcinoembryonic antigen (CEA) in gallbladder bile in patients with colorectal carcinoma and the morphological and clinical features of neoplasia and the occurrence of hepatic metastases. METHODS:CEA levels in the gallbladder and peripheral blood were studied in 44 patients with colorectal carcinoma and 10 patients with uncomplicated cholelithiasis.CEA samples were collected from the gallbladder bile and peripheral blood during the operation,immediately before extirpating the colorectal neoplasia or cholecystectomy. Values of up to 5 ng/ml were considered normal for bile and serum CEA. RESULTS:In the 44 patients with colorectal carcinoma who underwent operation with curative intent,the average level of serum CEA was 8.5 ng/ml (range:0.1 to 111.0 ng/ ml) and for bile CEA it was 74.5 ng/ml (range:0.2 to 571.0 ng/ml).In the patients with uncomplicated cholelithiasis who underwent cholecystectomy,the average level of serum CEA was 2.9 ng/ml (range:1.0 to 3.5 ng/ml) and for bile CEA it was 1.2 ng/ml (range:0.3 to 2.9 ng/ml). The average duration of follow-up time was 16.5 months (range:6 to 48 months).Four patients who underwent extirpation of the colorectal carcinoma without evidence of hepatic metastasis and with an average bile CEA value of 213.2 ng/ml presented hepatic metastases between three and seventeen months after removal of the primary colorectal neoplasia.Three of them successfully underwent extirpation of the hepatic lesions. CONCLUSION:High CEA levels in gallbladders of patients undergoing curative operation for colorectal carcinoma may indicate the presence of hepatic metastases.Such patients must be followed up with special attention to the diagnosis of such lesions.

Optical diagnosis of colorectal polyps using convolutional neural networks

Colonoscopy remains the gold standard investigation for colorectal cancer screening as it offers the opportunity to both detect and resect pre-malignant and neoplastic polyps.Although technologies for image-enhanced endoscopy are widely available,optical diagnosis has not been incorporated into routine clinical practice,mainly due to significant inter-operator variability.In recent years,there has been a growing number of studies demonstrating the potential of convolutional neural networks(CNN)to enhance optical diagnosis of polyps.Data suggest that the use of CNNs might mitigate the inter-operator variability amongst endoscopists,potentially enabling a“resect and discard”or“leave in”strategy to be adopted in real-time.This would have significant financial benefits for healthcare systems,avoid unnecessary polypectomies of non-neoplastic polyps and improve the efficiency of colonoscopy.Here,we review advances in CNN for the optical diagnosis of colorectal polyps,current limitations and future directions.