Natural history of colorectal adenomas: birth cohort analysis among 3.6 million participants of screening colonoscopy

Endoscopic Resection of Neoplasia in the Lower GI Tract: A Clinical Algorithm

Background

Colorectal cancer is a highly prevalent malignancy and a significant driver of cancer mortality and health-related expenditure worldwide. Polyp removal reduces the incidence and mortality of colorectal cancer. In 2024, endoscopists have an array of resection modalities at their disposal. Each technique requires a unique skillset and has individual advantages and limitations. Consequently, resection in the colorectum requires an evidence-based algorithm approach that considers these factors.

Summary

A literature review of endoscopic resection for colonic neoplasia was conducted. Best supporting scientific evidence was summarized for the endoscopic resection of diminutive polyps, large ≥20 mm lesions and polyps containing invasive cancer. Factors including resection modality, complications and lesion selection were explored to inform an algorithm approach to colorectal resection.

Key Messages

Endoscopic resection in the colorectum is not a one-size-fits-all approach. Detailed understanding of polyp size, location, morphology and predicted histology are critical factors that inform appropriate endoscopic resection practice.

Contributions of early detection and cancer prevention to colorectal cancer mortality reduction by screening colonoscopy: a validated modeling study

BACKGROUND AND AIMS

Screening colonoscopy, recommended every 10 years, reduces mortality from colorectal cancer (CRC) by early detection of prevalent but undiagnosed CRC, as well as by removal of precursor lesions. The aim of this study was to assess the relative contribution of both components to total CRC mortality reduction over time.

METHODS

Using a validated multistate Markov model, we simulated hypothetical cohorts of 100,000 individuals aged 55 to 64 years with and without screening at baseline. Main outcomes included proportions of prevented CRC deaths arising from (asymptomatic) CRC already present at baseline and from newly developed CRC during 15 years of follow-up, and mortality rate ratios of screened versus nonscreened groups over time.

RESULTS

Early detection of prevalent cases accounted for 52%, 30%, and 18% of deaths prevented by screening colonoscopy within 5, 10, and 15 years, respectively. Relative reduction of mortality was estimated to be much larger for mortality from incident cancers than for mortality from cancers that were already present and detected early at screening endoscopy and for total CRC mortality (ie, 88% versus 67% and 79%, respectively, within 10 years from screening).

CONCLUSIONS

Reduction of CRC mortality mainly arises from early detection of prevalent cancers during the early years after screening colonoscopy, but prevention of incident cases accounts for the majority of prevented deaths in the longer run. Prevention of incident cases leads to sustained strong reduction of CRC mortality, possibly warranting an extension of screening intervals.

Genome-wide polygenic risk scores for colorectal cancer have implications for risk-based screening

BACKGROUND

Hereditary factors, including single genetic variants and family history, can be used for targeting colorectal cancer (CRC) screening, but limited data exist on the impact of polygenic risk scores (PRS) on risk-based CRC screening.

METHODS

Using longitudinal health and genomics data on 453,733 Finnish individuals including 8801 CRC cases, we estimated the impact of a genome-wide CRC PRS on CRC screening initiation age through population-calibrated incidence estimation over the life course in men and women.

RESULTS

Compared to the cumulative incidence of CRC at age 60 in Finland (the current age for starting screening in Finland), a comparable cumulative incidence was reached 5 and 11 years earlier in persons with high PRS (80-99% and >99%, respectively), while those with a low PRS (< 20%) reached comparable incidence 7 years later. The PRS was associated with increased risk of post-colonoscopy CRC after negative colonoscopy (hazard ratio 1.76 per PRS SD, 95% CI 1.54-2.01). Moreover, the PRS predicted colorectal adenoma incidence and improved incident CRC risk prediction over non-genetic risk factors.

CONCLUSIONS

Our findings demonstrate that a CRC PRS can be used for risk stratification of CRC, with further research needed to optimally integrate the PRS into risk-based screening.

Reduction in colorectal cancer incidence by screening endoscopy

Colorectal cancer (CRC) incidence rates decreased by up to 50% in older age groups in the USA in the era of the widespread uptake of screening colonoscopy, despite adverse trends in CRC risk factors and increasing CRC incidence at younger ages. However, reported first results from a randomized trial, the NordICC study, suggested rather modest effects of screening colonoscopy. As outlined in this Perspective, the apparent discrepancy between real-world and trial evidence could be explained by strong attenuation of effect estimates from screening endoscopy trials by several factors, including limited screening adherence, widespread uptake of colonoscopy outside the screening offers and the inclusion of prevalent, non-preventable CRC cases in reported numbers of incident cases. Alternative interpretations of screening endoscopy trial results accounting for prevalence bias are in line with trends in CRC incidence reduction in countries offering CRC screening, and should encourage more widespread implementation and uptake of effective CRC screening.

Estimate of Increase in Colorectal Cancer Diagnoses with Expansion of Fecal Immunochemical Testing in an Urban Safety-Net Population

BACKGROUND

Fecal immunochemical test (FIT) is less effective in detecting advanced adenomas (AA) than colonoscopy. Increase in FIT for colorectal cancer (CRC) screening may lead to an increased number of undetected AAs which may develop into future CRCs.

AIM

We determined the potential impact of FIT expansion on missed AAs and future CRC diagnoses in an urban, tertiary-care, safety-net hospital.

METHODS

CRC and AA diagnoses were identified in patients undergoing colonoscopy for average-risk CRC screening or positive FIT between 2017 and 2019 at Boston Medical Center. Poisson regression modeling was used to estimate the frequency of AAs per year by age group using data from 2017 to 2019, assuming average outpatient volume and proportion of screening colonoscopies. Total number of patients who received FIT was extrapolated from those who underwent colonoscopy for positive FIT. We estimated AAs per year if 'one-time' FIT was used for screening in 75% and 100% of the population and subtracted this from the estimated AAs per year under the Poisson model to determine missed AAs. We used previously described, age and gender specific estimates of the annual progression of AA to CRC.

RESULTS

The estimated number of CRCs detected per year is 4.6/1785 males and 4.6/2086 females screened. With 75% FIT expansion, we estimate an additional 3.5 (95% CI 1.3, 9.5) and 2.2 (95% CI 0.64, 7.6) CRCs; with 100% FIT expansion, we estimate an additional 7.4 (95% CI 3.7, 14.9) and 4.2 (95% CI 1.7, 10.5) CRCs, in 5 years, in males and females, respectively.

CONCLUSION

Expansion of FIT may substantially increase CRC incidence.

Immunometabolic Profile Associated with Progressive Damage of the Intestinal Mucosa in Adults Screened for Colorectal Cancer: Association with Diet

Environmental factors such as diet and lifestyle have been shown to influence the development of some intestinal mucosal lesions that may be precursors of colorectal cancer (CRC). The presence of these alterations seems to be associated with misbalanced immunological parameter levels. However, it is still unclear as to which immunological parameters are altered in each phase of CRC development. In this work, we aimed to study the potential relationships of immunological and metabolic parameters with diet in a CRC-related lesion context. Dietary information was obtained using an annual semi-quantitative food-frequency questionnaire (FFQ) from 93 volunteers classified via colonoscopy examination according to the presence of intestinal polyps or adenocarcinoma. Cytokines, chemokines, and adipokines were determined from serum samples. We observed a reduction in adiponectin according to the damage to the mucosa, accompanied by an increase and decrease in C-X-C motif chemokine ligand 10 (CXCL10) and resistin, respectively, in CRC cases. The presence of aberrant crypt foci (ACF) in the polyp group was associated with higher tumor necrosis factor-alpha (TNF-α) concentrations. Vegetables were directly correlated with adiponectin and resistin levels, while the opposite occurred with red meat. A bioactive compound, soluble pectin, showed a negative association with TNF-α. Future dietary strategies could be developed to modulate specific immunological parameters in the context of CRC.

Metabolic-associated fatty liver disease is associated with colorectal adenomas in young and older Korean adults

BACKGROUND AND AIMS

Given that the majority of colorectal cancers (CRCs) develop from high-risk adenomas, identifying risk factors for high-risk adenomas is important. The relationship between metabolic dysfunction-associated fatty liver disease (MAFLD) and the risk of colorectal adenoma in young adults remains unclear. We aimed to evaluate this relationship in adults <50 (younger) and ≥50 (older) years of age.

METHODS

This cross-sectional study included 184 792 Korean adults (80% <50 years of age) who all underwent liver ultrasound and colonoscopy. Participants were grouped into those with and without MAFLD and classified by adenoma presence into no adenoma, low-risk adenoma, or high-risk adenoma (defined as ≥3 adenomas, any ≥10 mm, or adenoma with high-grade dysplasia/villous features).

RESULTS

The prevalence of low- and high-risk adenomas among young and older adults was 9.6% and 0.8% and 22.3% and 4.8%, respectively. MAFLD was associated with an increased prevalence of low- and high-risk adenomas in young and older adults. Young adults with MAFLD had a 1.30 (95% CIs 1.26-1.35) and 1.40 (1.23-1.59) times higher prevalence of low- and high-risk adenomas, respectively, compared to those without MAFLD. These associations were consistent even in lean adults (BMI < 23 kg/m2 ) and those without a family history of CRC.

CONCLUSIONS

MAFLD is associated with an increased prevalence of low- and high-risk adenomas in Korean adults, regardless of age or obesity status. Whether reducing metabolic risk factors, such as MAFLD, reduces the risk of precancerous lesions and ultimately reduces the risk of early-onset CRC requires further investigation.

Is there a place for sigmoidoscopy in colorectal cancer screening? A systematic review and critical appraisal of cost-effectiveness models

INTRODUCTION

Screening for colorectal cancer (CRC) is effective in reducing both incidence and mortality. Colonoscopy and stool tests are most frequently used for this purpose. Sigmoidoscopy is an alternative screening measure with a strong evidence base. Due to its distinct characteristics, it might be preferred by subgroups. The aim of this systematic review is to analyze the cost-effectiveness of sigmoidoscopy for CRC screening compared to other screening methods and to identify influencing parameters.

METHODS

A systematic literature search for the time frame 01/2010-01/2023 was conducted using the databases MEDLINE, Embase, EconLit, Web of Science, NHS EED, as well as the Cost-Effectiveness Registry. Full economic analyses examining sigmoidoscopy as a screening measure for the general population at average risk for CRC were included. Incremental cost-effectiveness ratios were calculated. All included studies were critically assessed based on a questionnaire for modelling studies.

RESULTS

Twenty-five studies are included in the review. Compared to no screening, sigmoidoscopy is a cost-effective screening strategy for CRC. When modelled as a single measure strategy, sigmoidoscopy is mostly dominated by colonoscopy or modern stool tests. When combined with annual stool testing, sigmoidoscopy in 5-year intervals is more effective and less costly than the respective strategies alone. The results of the studies are influenced by varying assumptions on adherence, costs, and test characteristics.

CONCLUSION

The combination of sigmoidoscopy and stool testing represents a cost-effective screening strategy that has not received much attention in current guidelines. Further research is needed that goes beyond a narrow focus on screening technology and models different, preference-based participation behavior in subgroups.

Moxifloxacin as a contrast agent of two-photon microscopic imaging for detecting colorectal diseases

Since two-photon microscopy (TPM) can obtain high-resolution images at cellular and subcellular level and moxifloxacin has multiphoton fluorescence characteristic, our study aimed to explore the feasibility and diagnostic value of moxifloxacin-assisted TPM in different human colorectal diseases, including low-grade intraepithelial neoplasia (LGIN), high-grade intraepithelial neoplasia (HGIN) and cancer tissues. Excitation power for TPM imaging with and without moxifloxacin was (2.74 ± 0.16) mW and (0.28 ± 0.02) mW, respectively (p < 0.05). Whether labeled with moxifloxacin or not, images of normal, LGIN, HGIN and cancer tissues all reached the strongest signal at 30 μm from the mucosa. Normalized fluorescence intensity of TPM images with moxifloxacin was approximately 10 times stronger than that without moxifloxacin. Fluorescence signal was differed significantly in normal, LGIN, HGIN and cancer tissues with or without moxifloxacin (p < 0.05). Besides, moxifloxacin-assisted TPM could present variant tissue features with different colorectal diseases, such as the crypt opening, glandular structure, adjacent glandular space and fluorescence distribution.

Making colonoscopy-based screening more efficient: A "gateopener" approach

Screening colonoscopy for early detection and prevention of colorectal cancer (CRC) is mostly used inefficiently. Here, we assessed the potential of an innovative approach to colonoscopy-based screening, by use of a single, low threshold fecal immunochemical test (FIT) as a "gateopener" for screening colonoscopy. Using COSIMO, a validated simulation model, we modeled scenarios including either direct invitation to screening colonoscopy or an alternative approach involving mailing a single ("gateopener") FIT along with an invitation to colonoscopy contingent on a FIT value above a low threshold yielding a 50% positivity rate (ie, every other pretest will be positive). Under plausible assumptions on screening offer adherence, we found that such "gateopener screening" (use of screening colonoscopy contingent on a positive, low threshold gateopener FIT) approximately doubled cancer detection rates vs conventional screening. In those spared from screening colonoscopy due to a negative gateopener FIT pretest, numbers needed to screen were 10-times higher vs those for individuals with a positive FIT, peaking in >2000 and >3800 (hypothetically) needed colonoscopies to detect one case of cancer in men and women, respectively. Gateopener screening resulted in 42%-51% and 59%-65% more prevented CRC cases and deaths, respectively. In summary, by directing colonoscopy capacities to those most likely to benefit, offering screening colonoscopy contingent on a "gateopener" low-threshold FIT would substantially enhance efficiency of colonoscopy screening.

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

Background. Existing colorectal cancer (CRC) screening models mostly focus on the adenoma pathway of CRC development, overlooking the serrated neoplasia pathway, which might result in overly optimistic screening predictions. In addition, Bayesian inference methods have not been widely used for model calibration. We aimed to develop a CRC screening model accounting for both pathways, calibrate it with approximate Bayesian computation (ABC) methods, and validate it with large CRC screening trials. Methods. A discrete event simulation (DES) of the CRC natural history (DECAS) was constructed using the adenoma and serrated pathways in R software. The model simulates CRC-related events in a specific birth cohort through various natural history states. Calibration took advantage of 74 prevalence data points from the German screening colonoscopy program of 5.2 million average-risk participants using an ABC method. CRC incidence outputs from DECAS were validated with the German national cancer registry data; screening effects were validated using 17-y data from the UK Flexible Sigmoidoscopy Screening sigmoidoscopy trial and a German screening colonoscopy cohort study. Results. The Bayesian calibration rendered 1,000 sets of posterior parameter samples. With the calibrated parameters, the observed age- and sex-specific CRC prevalences from the German registries were within the 95% DECAS-predicted intervals. Regarding screening effects, DECAS predicted a 41% (95% intervals 30%-51%) and 62% (95% intervals 55%-68%) reduction in 17-y cumulative CRC mortality for a single screening sigmoidoscopy and colonoscopy, respectively, falling within 95% confidence intervals reported in the 2 clinical studies used for validation. Conclusions. We presented DECAS, the first Bayesian-calibrated DES model for CRC natural history and screening, accounting for 2 CRC tumorigenesis pathways. The validated model can serve as a valid tool to evaluate the (cost-)effectiveness of CRC screening strategies.

Highlights

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.

Colorectal surveillance outcomes from an institutional longitudinal cohort of lynch syndrome carriers

Objective

Lynch Syndrome (LS) carriers have a significantly increased risk of developing colorectal cancer (CRC) during their lifetimes. Further stratification of this patient population may help in identifying additional risk factors that predispose to colorectal carcinogenesis. In most LS patients CRC may arise from adenomas, although an alternative non-polypoid carcinogenesis pathway has been proposed for PMS2 carriers. Using data from our institutional LS cohort, our aim was to describe our current colorectal screening outcomes with a focus on the incidence of adenomas in the context of different MMR genotypes and patient demographics such as gender, race, and ethnicity.

Design

We collected demographics, genetic, colonoscopy, and pathology results from a total of 163 LS carriers who obtained regular screening care at MD Anderson Cancer Center. Data were extracted from the electronic health records into a REDCap database for analysis. Logistic regressions were performed to measure the association between MMR variants and the likelihood of adenomas, advanced adenomas, and CRC. Then, we analyzed the cumulative incidences of these outcomes for the first 36 months following enrollment using Kaplan-Meier incidence curves, and Cox proportional hazard regressions.

Results

On multivariate analysis, age (≥45 years old) was associated with an increased risk of developing adenomas (P=0.034). Patients with a prior or active cancer status were less likely to develop adenomas (P=0.015), despite of the lack of association between surgical history with this outcome (P=0.868). We found no statistically significant difference in likelihood of adenoma development between MLH1 and MSH2/EPCAM, MSH6, and PMS2 carriers. Moreover, we observed no statistically significant difference in the likelihood of advanced adenomas or CRC for any measured covariates. On Cox proportional hazard, compared to MLH1 carriers, the incidence of adenomas was highest among MSH2/EPCAM carriers during for the first 36-months of follow-up (P<0.001). We observed a non-statistically significant trend for Hispanics having a higher and earlier cumulative incidence of adenomas compared to non-Hispanics (P=0.073). No MMR carrier was more likely to develop advanced adenomas. No difference in the incidence of CRC by MMR gene (P=0.198).

Conclusion

Screening recommendations for CRC in LS patients should be based on specific MMR variants and should also be tailored to consider patient demographics.

Third Asia-Pacific consensus recommendations on colorectal cancer screening and postpolypectomy surveillance

The Asia-Pacific region has the largest number of cases of colorectal cancer (CRC) and one of the highest levels of mortality due to this condition in the world. Since the publishing of two consensus recommendations in 2008 and 2015, significant advancements have been made in our knowledge of epidemiology, pathology and the natural history of the adenoma-carcinoma progression. Based on the most updated epidemiological and clinical studies in this region, considering literature from international studies, and adopting the modified Delphi process, the Asia-Pacific Working Group on Colorectal Cancer Screening has updated and revised their recommendations on (1) screening methods and preferred strategies; (2) age for starting and terminating screening for CRC; (3) screening for individuals with a family history of CRC or advanced adenoma; (4) surveillance for those with adenomas; (5) screening and surveillance for sessile serrated lesions and (6) quality assurance of screening programmes. Thirteen countries/regions in the Asia-Pacific region were represented in this exercise. International advisors from North America and Europe were invited to participate.

Risk Scoring Systems for Predicting the Presence of Colorectal Neoplasia by Fecal Immunochemical Test Results in Chinese Population

INTRODUCTION

Adherence to colonoscopy screening for colorectal cancer (CRC) is low in general populations, including those tested positive in the fecal immunochemical test (FIT). Developing tailored risk scoring systems by FIT results may allow for more accurate identification of individuals for colonoscopy.

METHODS

Among 807,109 participants who completed the primary tests in the first-round Shanghai CRC screening program, 71,023 attended recommended colonoscopy. Predictors for colorectal neoplasia were used to develop respective scoring systems for FIT-positive or FIT-negative populations using logistic regression and artificial neural network methods.

RESULTS

Age, sex, area of residence, history of mucus or bloody stool, and CRC in first-degree relatives were identified as predictors for CRC in FIT-positive subjects, while a history of chronic diarrhea and prior cancer were additionally included for FIT-negative subjects. With an area under the receiver operating characteristic curve of more than 0.800 in predicting CRC, the logistic regression-based systems outperformed the artificial neural network-based ones and had a sensitivity of 68.9%, a specificity of 82.6%, and a detection rate of 0.24% by identifying 17.6% subjects at high risk. We also reported an area under the receiver operating characteristic curve of about 0.660 for the systems predicting CRC and adenoma, with a sensitivity of 57.8%, a specificity of 64.6%, and a detection rate of 6.87% through classifying 38.1% subjects as high-risk individuals. The performance of the scoring systems for CRC was superior to the currently used method in Mainland, China, and comparable with the scoring systems incorporating the FIT results.

DISCUSSION

The tailored risk scoring systems may better identify high-risk individuals of colorectal neoplasia and facilitate colonoscopy follow-up. External validation is warranted for widespread use of the scoring systems.

A two-phase approach to re-calibrating expensive computer simulation for sex-specific colorectal neoplasia development modeling

BACKGROUND

Medical evidence from more recent observational studies may significantly alter our understanding of disease incidence and progression, and would require recalibration of existing computational and predictive disease models. However, it is often challenging to perform recalibration when there are a large number of model parameters to be estimated. Moreover, comparing the fitting performances of candidate parameter designs can be difficult due to significant variation in simulated outcomes under limited computational budget and long runtime, even for one simulation replication.

METHODS

We developed a two-phase recalibration procedure. As a proof-of-the-concept study, we verified the procedure in the context of sex-specific colorectal neoplasia development. We considered two individual-based state-transition stochastic simulation models, estimating model parameters that govern colorectal adenoma occurrence and its growth through three preclinical states: non-advanced precancerous polyp, advanced precancerous polyp, and cancerous polyp. For the calibration, we used a weighted-sum-squared error between three prevalence values reported in the literature and the corresponding simulation outcomes. In phase 1 of the calibration procedure, we first extracted the baseline parameter design from relevant studies on the same model. We then performed sampling-based searches within a proper range around the baseline design to identify the initial set of good candidate designs. In phase 2, we performed local search (e.g., the Nelder-Mead algorithm), starting from the candidate designs identified at the end of phase 1. Further, we investigated the efficiency of exploring dimensions of the parameter space sequentially based on our prior knowledge of the system dynamics.

RESULTS

The efficiency of our two-phase re-calibration procedure was first investigated with CMOST, a relatively inexpensive computational model. It was then further verified with the V/NCS model, which is much more expensive. Overall, our two-phase procedure showed a better goodness-of-fit than the straightforward employment of the Nelder-Mead algorithm, when only a limited number of simulation replications were allowed. In addition, in phase 2, performing local search along parameter space dimensions sequentially was more efficient than performing the search over all dimensions concurrently.

CONCLUSION

The proposed two-phase re-calibration procedure is efficient at estimating parameters of computationally expensive stochastic dynamic disease models.

Asia-Pacific Colorectal Screening Score Combined With Stool DNA Test Improves the Detection Rate for Colorectal Advanced Neoplasms

BACKGROUND & AIMS

The Asia-Pacific Colorectal Screening (APCS) scoring system was developed to stratify the risk of colorectal advanced neoplasm (AN). We aimed to evaluate the performance of the APCS score combined with a stool DNA test used for colorectal cancer screening.

METHODS

A total of 2842 subjects who visited outpatient clinics or cancer screening centers were enrolled. Age, sex, smoking status, and family history were recorded and APCS scores were calculated in 2439 participants. A stool DNA test (SDC2 and SFRP2 tests) and fecal immunochemical test (FIT) were performed and colonoscopy was used as the gold standard among 2240 subjects who completed all study procedures. We used a threshold of 4.4 μg/g for the FIT, in addition to the manufacturer's recommended threshold of 20 μg/g to match the specificity of a stool DNA test.

RESULTS

Based on the APCS score, 38.8% (946 of 2439) of the subjects were categorized as high risk, and they had a 1.8-fold increase in risk for AN (95% CI, 1.4-2.3) compared with low and moderate risk. The APCS combined with the stool DNA test detected 95.2% of invasive cancers (40 of 42) and 73.5% of ANs (253 of 344), while the colonoscopy workload was only 47.1% (1056 of 2240). The sensitivity for AN of APCS combined with stool DNA test was significantly higher than that of APCS combined with FIT (73.5% vs 62.8% with FIT cut-off value of 20 μg/g, and 73.5% vs 68.0% with FIT cut-off value of 4.4 μg/g; both P < .01).

CONCLUSIONS

The APCS score combined with a stool DNA test significantly improved the detection of colorectal ANs, while limiting colonoscopy resource utilization (Chictr.org.cn, ChiCTR-DDD-17011169).

Mortality trend of cancer and main types according to macroregion in the state of Mato Grosso, Brazil, 2000 to 2015

OBJECTIVE

To describe the mortality trend from all cancers and the five main ones in the state of Mato Grosso, Brazil, from 2000 to 2015.

METHODS

This is a descriptive, ecological, time series study, with data referring to deaths of residents of Mato Grosso due to cancer (ICD-10 codes C00 to C97), from the Mortality Information System (SIM). Time trend analyses of the standardized mortality rate from all cancers and five specific cancers (lung, prostate, breast, colorectal and cervical) for the state and according to macroregion (South, West, North, East and Center-North) were performed using linear regression (p<0.05).

RESULTS

From 2000 to 2015, 28,525 deaths from all cancers in residents of the state of Mato Grosso were recorded. An increasing trend was observed for all cancers, in addition to lung, breast and colorectal cancers. The South and North macroregions showed an increasing trend for all cancers, breast and colorectal, and Center-North for breast and colorectal. East showed an increasing trend for all cancers, prostate and colorectal, and decreasing for cervical.

CONCLUSION

In the state of Mato Grosso, there was an increasing trend in mortality for all cancers and from specific ones, with emphasis on breast and colorectal cancer in most macroregions.

Colorectal Cancer: A Review of Carcinogenesis, Global Epidemiology, Current Challenges, Risk Factors, Preventive and Treatment Strategies

Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC.

Additional offer of sigmoidoscopy in colorectal cancer screening in Germany: rationale and protocol of the decision-analytic modelling approach in the SIGMO study

INTRODUCTION

In Germany, statutory insured persons are entitled to a stool test (faecal immunochemical test (FIT)) or colonoscopy for colorectal cancer (CRC) screening, depending on age and sex, yet participation rates are rather low. Sigmoidoscopy is a currently not available screening measure that has a strong evidence base for incidence and mortality reduction. Due to its distinct characteristics, it might be preferred by some, who now reject colonoscopy. The objective of this study is to estimate the economic consequences of the additional offer of sigmoidoscopy for CRC screening in Germany compared with the present screening practice while considering the preferences of the general population.

METHODS AND ANALYSIS

A decision-analytic modelling approach will be developed that compares the present CRC screening programme in Germany (FIT, colonoscopy) with a programme extended by sigmoidoscopy from a societal perspective. A decision tree and Markov model will be combined to assess both short-term and long-term effects, such as CRC and adenoma detection rates, the number of CRC cases, CRC mortality as well as complications. The incremental cost per quality-adjusted life year gained for each alternative will be calculated. The model will incorporate the general population's preferences based on a discrete choice experiment. Further, input parameters will be taken from the literature, the German cancer registry and health insurance claims data.

ETHICS AND DISSEMINATION

Ethical approval for the study was obtained from the Ethics Committee of Hannover Medical School (ID: 8671_BO_K_2019). The findings of the study will be published in peer-reviewed journals and presented at national and/or international conferences.

TRIAL REGISTRATION NUMBER

DRKS00019010.

Tendência da mortalidade por câncer e principais tipos segundo macrorregiões do Estado de Mato Grosso, 2000 a 2015

RESUMO: Objetivo: Descrever a tendência da mortalidade por todas as causas de câncer e as cinco principais causas no Estado de Mato Grosso, Brasil, no período de 2000 a 2015. Métodos: Trata-se de um estudo descritivo, ecológico, do tipo série temporal, com dados referentes aos óbitos de residentes de Mato Grosso por neoplasias (códigos C00 a C97 da Classificação Internacional de Doenças — CID-10), provenientes do Sistema de Informações sobre Mortalidade. A tendência temporal da taxa de mortalidade padronizada de todas as causas de câncer e de cinco causas específicas (pulmão, próstata, mama feminina, colorretal e colo do útero) para o Estado e segundo macrorregiões (Sul, Oeste, Norte, Leste e Centro-Norte) foi analisada por meio de regressão linear (p<0,05). Resultados: De 2000 a 2015, ocorreram 28.525 óbitos por todas as causas de câncer em residentes do Estado de Mato Grosso. Tendência crescente foi observada para todas as causas de câncer, além dos cânceres de pulmão, mama e colorretal. As macrorregiões Sul e Norte apresentaram tendência crescente para todas as causas, mama e colorretal; Centro-Norte para mama e colorretal; Leste foi crescente para todas as causas, próstata e colorretal e decrescente para colo do útero. Conclusão: No Estado de Mato Grosso, verificou-se tendência crescente de mortalidade por todas as causas de câncer e por causas específicas, com destaque para mama e colorretal na maioria das macrorregiões.

Model based evaluation of long-term efficacy of existing and alternative colorectal cancer screening offers: A case study for Germany

For individuals willing to minimize their lifetime risk of colorectal cancer (CRC), the most effective screening approach remains unclear. Here, we sought to compare the long-term performance of existing and alternative CRC screening offers in a case study for Germany. Applying the perspective of a perfectly adhering man or woman at average risk, we used COSIMO, a validated Markov-based multistate model, to simulate the effects of current CRC screening offers in Germany. These include age- and sex-dependent offers for fecal immunochemical testing (FIT) or screening colonoscopy, which may be used twice starting at age 50 in men and age 55 in women. For comparison, we modeled screening colonoscopies at ages 50, 60 and 70, screening colonoscopies at ages 50 and 60, followed by biennial FITs and conventional FIT-based strategies at varying intervals. We found that the highest reductions in lifetime risks of developing (76%-84%) and dying from CRC (82%-90%) were achieved by three colonoscopies, followed by annual FIT screening and strategies combining both modalities. In men, additional screening from age 70 onwards reduced the risk of dying from CRC by another 9% units and resulted in 32 to 39 additional life-years-gained per 1000 individuals. Among women, three colonoscopies outperformed current screening offers in all outcomes, at little risk of screening-related complications. In summary, several FIT- and colonoscopy-based offers yield comparably high CRC risk reductions, including approaches combining both modalities. German screening offers may be optimized by lowering the eligibility age for screening colonoscopy for women, along with additional offers for the elderly.

Multivariable models for advanced colorectal neoplasms in screen-eligible individuals at low-to-moderate risk of colorectal cancer: towards improving colonoscopy prioritization

Background

Advanced colorectal neoplasms (ACNs), including colorectal cancers (CRC) and high-risk adenomas (HRA), are detected in less than 20% of persons aged 50 years or older who undergo colonoscopy. We sought to derive personalized predictive models of risk of harbouring ACNs to improve colonoscopy wait times for high-risk patients and allocation of colonoscopy resources.

Methods

We characterized colonoscopy indications, neoplasia risk factors and colonoscopy findings through chart review for consecutive individuals aged 50 years or older who underwent outpatient colonoscopy at The Ottawa Hospital (Ottawa, Canada) between April 1, 2008 and March 31, 2012 for non-life threatening indications. We linked patients to population-level health administrative datasets to ascertain additional historical predictor variables and derive multivariable logistic regression models for risk of harboring ACNs at colonoscopy. We assessed model discriminatory capacity and calibration and the ability of the models to improve colonoscopy specificity while maintaining excellent sensitivity for ACN capture.

Results

We modelled 17 candidate predictors in 11,724 individuals who met eligibility criteria. The final CRC model comprised 8 variables and had a c-statistic value of 0.957 and a goodness-of-fit p-value of 0.527. Application of the models to our cohort permitted 100% sensitivity for identifying persons with CRC and > 90% sensitivity for identifying persons with HRA, while improving colonoscopy specificity for ACNs by 23.8%.

Conclusions

Our multivariable models show excellent discriminatory capacity for persons with ACNs and could significantly increase colonoscopy specificity without overly sacrificing sensitivity. If validated, these models could allow more efficient allocation of colonoscopy resources, potentially reducing wait times for those at higher risk while deferring unnecessary colonoscopies in low-risk individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01965-5.

Impact of restrictions due to COVID-19 on a quality-assured screening colonoscopy program

Background and study aims  On February 25, 2020, the first patient was diagnosed with COVID-19 in Austria. On March 16, 2020, the Austrian government imposed restrictions and subsequently the Austrian Medical Association recommended minimizing screening examinations in compliance with government restrictions. The aims of this study were to evaluate the impact of this recommendation on the number of colonoscopies performed weekly and detection of non-advanced adenomas, advanced adenomas (AA) and colorectal cancer (CRC) and to calculate how many undetected adenomas could have developed into CRC. Methods  We analyzed the number of colonoscopies and pathological findings within a quality assured national colorectal cancer screening program before the COVID-19 pandemic (March 1, ^t 2019 to September 1, 2019, Period 1) and compared those rates to months during which access to colonoscopy was limited (March 1, 2020 and September 1, 2020, Period 2) with a Wilcoxon-rank-test and a chi-square test. Results  A total of 29,199 screening colonoscopies were performed during Period 1 and 24,010 during Period 2. The mean rate of colonoscopies per week during Period 1 was significantly higher than during Period 2 (808,35 [SD = 163,75] versus 594,50 [SD = 282,24], P  = 0.005). A total of 4,498 non-advanced adenomas were detected during Period 1 versus 3,562 during Period 2 ( P  < 0.001). In total 1,317 AAs and 140 CRCs were detected during Period 1 versus 919 AAs and 106 CRCs during Period 2. These rates did not differ significantly ( P  = 0.2 and P  = 0.9). Conclusions  During the COVID-19 crisis, the number of colonoscopies performed per week was significantly lower compared to the year before, but there was no difference in the detection of CRCs and AAs.

The Costs and Benefits of Risk Stratification for Colorectal Cancer Screening Based On Phenotypic and Genetic Risk: A Health Economic Analysis

Population-based screening for colorectal cancer is an effective and cost-effective way of reducing colorectal cancer incidence and mortality. Many genetic and phenotypic risk factors for colorectal cancer have been identified, leading to development of colorectal cancer risk scores with varying discrimination. However, these are not currently used by population screening programs. We performed an economic analysis to assess the cost-effectiveness, clinical outcomes, and resource impact of using risk-stratification based on phenotypic and genetic risk, taking a UK National Health Service perspective. Biennial fecal immunochemical test (FIT), starting at an age determined through risk-assessment at age 40, was compared with FIT screening starting at a fixed age for all individuals. Compared with inviting everyone from age 60, using a risk score with area under the receiver operating characteristic curve of 0.721 to determine FIT screening start age, produces 418 QALYs, costs £247,000, and results in 218 fewer colorectal cancer cases and 156 fewer colorectal cancer deaths per 100,000 people, with similar FIT screening invites. There is 96% probability that risk-stratification is cost-effective, with net monetary benefit (based on £20,000 per QALY threshold) estimated at £8.1 million per 100,000 people. The maximum that could be spent on risk-assessment and still be cost-effective is £114 per person. Lower benefits are produced with lower discrimination risk scores, lower mean screening start age, or higher FIT thresholds. Risk-stratified screening benefits men more than women. Using risk to determine FIT screening start age could improve the clinical outcomes and cost effectiveness of colorectal cancer screening without using significant additional screening resources. PREVENTION RELEVANCE: Colorectal cancer screening is essential for early detection and prevention of colorectal cancer, but implementation is often limited by resource constraints. This work shows that risk-stratification using genetic and phenotypic risk could improve the effectiveness and cost-effectiveness of screening programs, without using substantially more screening resources than are currently available.

[Post-colonoscopy Colorectal Cancer: Causes and Prevention of Interval Colorectal Cancer]

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the fourth leading cause of cancer death in the worldwide. Colonoscopy is the gold standard for screening and surveillance of CRC. Removing adenomas by colonoscopy has lowered the incidence and mortality of CRC. However, colonoscopy is imperfect for detection of colorectal neoplasia. After a colonoscopy that is negative for malignancy, CRC can be diagnosed. These are termed as post-colonoscopy CRC (PCCRC). The proportion of PCCRC, among all CRC was reported to be 1.8% to 9.0%. It occurred 2.4 times more in the right colon than in the left colon. The causes of PCCRC are missed lesions, incomplete resection, and new lesions. Among these causes, missed lesion and incomplete resection are procedural factors and preventable. Therefore, it is necessary to improve the quality of colonoscopy to minimize the occurrence of PCCRC.

Population-based organized screening by faecal immunochemical testing and colorectal cancer mortality: a natural experiment

BACKGROUND

Population-based organized screening programmes for colorectal cancer (CRC) are underway worldwide, with many based on the faecal immunochemical test (FIT). No clinical trials assessing FIT compared with no screening are planned, and few studies have assessed the population impact of such programmes.

METHODS

Before 2010, 11 out of 50 Spanish provinces initiated population-based organized screening programmes with FIT for an average-risk population aged 50-69 years. We used a quasi-experimental design across Spanish provinces between 1999 and 2016 to evaluate their impact on population age-standardized mortality and incidence rates due to CRC. Difference-in-differences and synthetic control analyses were performed to test for validation of statistical assumptions and to assess the dynamics of screening-associated changes in outcomes over time.

RESULTS

No differences in outcome trends between exposed (n = 11) and control (n = 36) provinces were observed for up to 7 years preceding the implementation of screening. Relative to controls, exposed provinces experienced a mean increase in age-standardized incidence of 10.08% [95% confidence interval (CI) (5.09, 15.07)] 2 years after implementation, followed by a reduction in age-standardized mortality rates due to CRC of 8.82% [95% CI (3.77, 13.86)] after 7 years. Results were similar for both women and men. No associated changes were observed in adjacent age bands not targeted by screening, nor for 10 other major causes of death in the exposed provinces.

CONCLUSIONS

FIT-based organized screening in Spain was associated with reductions in population colorectal cancer mortality. Further research is warranted in order to assess the replicability and external validity of our findings, and on gender-specific use of FIT in organized screening.

A delay in colonoscopy after positive fecal tests leads to higher incidence of colorectal cancer: A systematic review and meta-analysis

BACKGROUND AND AIM

A delay in performing colonoscopies after positive fecal tests in a screening program may risk neoplastic progression. Our objective is to conduct a systematic review and meta-analysis to evaluate the effects of timing of a colonoscopy after a positive fecal test on the detection of colorectal cancer.

METHODS

Cochrane guidelines and PRISMA statement were followed for this review. Digital dissertation databases were searched from inception to June 1, 2020, and all studies reporting the detection rates of colorectal cancer on the basis of different time intervals between a positive fecal test and the post-test colonoscopy were included. We compared the detection rates of colorectal cancer (overall and advanced-stage) and advanced adenoma based on different time intervals.

RESULTS

A total of 361 637 patients from six observational studies were included for the analysis. The odds of detecting any colorectal cancer (odds ratio [OR] 1.58, 95% confidence interval [CI] 1.23-2.03, P < 0.001), advanced-stage colorectal cancer (OR 2.16, 95% CI 1.47-3.16, P < 0.001), or advanced adenomas (OR 1.17, 95% CI 1.06-1.28, P = 0.001) are significantly higher if the colonoscopies are performed after 6 months from a positive fecal test, compared with within 6 months. There was no significant difference in the detection rates based on a 1-month, a 2-month, or a 3-month cut-off.

CONCLUSIONS

A delay of colonoscopies beyond 6 months after positive fecal tests is associated with a higher odds of detecting colorectal cancer. A timely follow up of patients with positive fecal tests is warranted.

Estimation of overdiagnosis in colorectal cancer screening with sigmoidoscopy and faecal occult blood testing: comparison of simulation models

OBJECTIVE

To estimate overdiagnosis of colorectal cancer (CRC) for screening with sigmoidoscopy and faecal occult blood testing (FOBT).

DESIGN

Simulation study using data from randomised trials.

SETTING

Primary screening, UK, Norway PARTICIPANTS: 152 850 individuals from the Nottingham trial and 98 678 individuals from the Norwegian Colorectal Cancer Prevention (NORCCAP) trial.

INTERVENTION

CRC screening.

OUTCOME MEASURE

We estimated overdiagnosis using long-term data from two randomised trials: the Nottingham trial comparing FOBT screening every other year to no-screening, and the NORCCAP trial comparing once-only sigmoidoscopy screening to no-screening. To estimate the natural growth of adenomas to CRC, we used the following microsimulation models: (i) the Microsimulation Screening Analysis; (ii) the CRC Simulated Population model for Incidence and Natural history; (iii) the Simulation Model of Colorectal Cancer; (iv) a model derived by the German Cancer Research Center. We defined overdiagnosed cancers as the difference between the observed number of CRCs in the no-screening arm and the expected number of cancers in screening arm (sum of observed and prevented by adenoma removal). The amount of overdiagnosis is defined as the number of overdiagnosed cancers over the number of cancers observed in the no-screening arm.

RESULTS

Overdiagnosis estimates were highly dependent on model assumptions. For FOBT screening with 2354 cancers observed in control arm, four out of five models predicted overdiagnosis, range 2.0% (2400 cancers expected in screening) to 7.6% (2533 cancers expected in screening). For sigmoidoscopy screening with 452 cancers observed in control arm, all models predicted overdiagnosis, range 25.2% (566 cancers expected in screening) to 128.1% (1031 cancers expected in screening).

CONCLUSIONS

The amount of overdiagnosis estimated based on the microsimulation models varied substantially. Microsimulation models may not give reliable estimates of the preventive effect of adenoma removal, and should be used with caution to inform guidelines.

Second-generation colon capsule endoscopy for detection of colorectal polyps: Systematic review and meta-analysis of clinical trials

Background and study aims  Adherence to colorectal cancer (CRC) screening is still unsatisfactory in many countries, thereby limiting prevention of CRC. Colon capsule endoscopy (CCE), a minimally invasive procedure, could be an alternative to fecal immunochemical tests or optical colonoscopy for CRC screening, and might increase adherence in CRC screening. This systematic review and meta-analysis evaluates the diagnostic accuracy of CCE compared to optical colonoscopy (OC) as the gold standard, adequacy of bowel preparation regimes and the patient perspective on diagnostic measures. Methods  We conducted a systematic literature search in PubMed, EMBASE and the Cochrane Register for Clinical Trials. Pooled estimates for sensitivity, specificity and the diagnostic odds ratio with their respective 95 % confidence intervals (CI) were calculated for studies providing sufficient data. Results  Of 840 initially identified studies, 13 were included in the systematic review and up to 9 in the meta-analysis. The pooled sensitivities and specificities for polyps ≥ 6 mm were 87 % (95 % CI: 83 %-90 %) and 87 % (95 % CI: 76 %-93 %) in 8 studies, respectively. For polyps ≥ 10 mm, the pooled estimates for sensitivities and specificities were 87 % (95 % CI: 83 %-90 %) and 95 % (95 % CI: 92 %-97 %) in 9 studies, respectively. A patients' perspective was assessed in 31 % (n = 4) of studies, and no preference of CCE over OC was reported. Bowel preparation was adequate in 61 % to 92 % of CCE exams. Conclusions  CCE provides high diagnostic accuracy in an adequately cleaned large bowel. Conclusive findings on patient perspectives require further studies to increase acceptance/adherence of CCE for CRC screening.

Very-low-dose aspirin and surveillance colonoscopy is cost-effective in secondary prevention of colorectal cancer in individuals with advanced adenomas: network meta-analysis and cost-effectiveness analysis

BACKGROUND

Individuals with advanced colorectal adenomas (ACAs) are at high risk for colorectal cancer (CRC), and it is unclear which chemopreventive agent (CPA) is safe and cost-effective for secondary prevention. We aimed to determine, firstly, the most suitable CPA using network meta-analysis (NMA) and secondly, cost-effectiveness of CPA with or without surveillance colonoscopy (SC).

METHODS

Systematic review and NMA of randomised controlled trials were performed, and the most suitable CPA was chosen based on efficacy and the most favourable risk-benefit profile. The economic benefits of CPA alone, 3 yearly SC alone, and a combination of CPA and SC were determined using the cost-effectiveness analysis (CEA) in the Malaysian health-care perspective. Outcomes were reported as incremental cost-effectiveness ratios (ICERs) in 2018 US Dollars ($) per quality-adjusted life-year (QALY), and life-years (LYs) gained.

RESULTS

According to NMA, the risk-benefit profile favours the use of aspirin at very-low-dose (ASAVLD, ≤ 100 mg/day) for secondary prevention in individuals with previous ACAs. Celecoxib is the most effective CPA but the cardiovascular adverse events are of concern. According to CEA, the combination strategy (ASAVLD with 3-yearly SC) was cost-saving and dominates its competitors as the best buy option. The probability of being cost-effective for ASAVLD alone, 3-yearly SC alone, and combination strategy were 22%, 26%, and 53%, respectively. Extending the SC interval to five years in combination strategy was more cost-effective when compared to 3-yearly SC alone (ICER of $484/LY gain and $1875/QALY). However, extending to ten years in combination strategy was not cost-effective.

CONCLUSION

ASAVLD combined with 3-yearly SC in individuals with ACAs may be a cost-effective strategy for CRC prevention. An extension of SC intervals to five years can be considered in resource-limited countries.

Histomorphological analysis of gastric polyps

Introduction

Incidence of gastric carcinoma and gastric polyps is on rise all over the world. Chronic atrophic gastritis to intestinal metaplasia progressing to adenocarcinoma has been documented pathway for gastric carcinogenesis. Another pathway for gastric carcinoma is adenoma carcinoma sequence similar to colon cancer.

Aim

To study prevalence, endoscopic, and histomorphological features of gastric polyps.

Methods and Material

This was retrospective analysis of gastric polyps from 2012 to 2019 in consecutive 10,800 upper gastrointestinal endoscopies. Demographic, endoscopic, and histopathological data were obtained from hospital records. All gastric polyps were classified as per standard histologic criteria. Additional histological features noted were presence of dysplasia, focus of adenoma, or malignancy.

Results

The prevalence of gastric polyps was 434 (4%) of 10,800 upper gastrointestinal endoscopies. Majority of polyps were found in the last 4 years (277: 63.8%). Mean age was 55.4 years with male to female ratio 1:1.2. Most of the polyps (94.9%) were less than 1 cm, located in gastric antrum. Multiple polyps were seen in 20.9% cases. On histopathology, fundic gland polyps were most common (147: 33.8%), followed by hyperplastic (128: 29.4%) polyps. Adenomatous polyps were nine (2%); of these, two cases of hyperplastic polyps and one each of fundic gland polyp and benign epithelial polyp showed adenomatous foci.

Conclusion

Fundic gland polyps were the most common polyps. With rising incidence of gastric carcinoma, identification of gastric polyps on endoscopy with biopsy can prevent progression to carcinogenesis.

Patient Preferences in Surveillance: Findings From a Discrete Choice Experiment in the "My Follow-Up" Study

OBJECTIVES

Approximately 800 000 people die globally from colorectal cancer (CRC) every year. Prevention programs promote early detection, but for people with precancerous lesions, tailoring surveillance to include lifestyle-change programs could enhance prevention potential and improve outcomes.

METHODS

Those with intermediate or high-risk polyps removed during CRC screening colonoscopy within the Northern Ireland CRC Screening Programme were invited to complete 8 discrete choice questions about tailored surveillance, analyzed using random-parameters logit and a latent class modeling approach.

RESULTS

A total of 231 participants (77% male) self-reported comorbid hypertension (53%), high cholesterol (48%), and mean body mass index of 28.7 (overweight). Although 39% of participants were unaware of their CRC risk status, 30.9% indicated they were already making changes to reduce their risk. Although all respondents were significantly risk- and cost-averse, the latent class analysis identified 3 segments (classes): 1. Class 1 (26.8%) significantly favored phone or email support for a lifestyle change, a 17-month testing interval, and noninvasive testing. 2. Class 2 (48.4%) preferred the status quo. 3. Class 3 (24.7%) significantly favored further risk reduction and invasive testing.

CONCLUSIONS

This is the first documented preference study focusing on postpolypectomy surveillance offering lifestyle interventions. Although current care is strongly preferred, risk and cost aversion are important for participants. Latent class analysis shows that some respondents are willing to change diet and lifestyle behaviors, reflecting a teachable moment, with opportunities to personalize and optimize surveillance. Significant discordance between perceived and known risk of recurrence and limited recall of risk information provided within current practice suggest necessary improvements to surveillance programs.

Colonoscopy later than 270 days in a fecal immunochemical test-based population screening program is associated with higher prevalence of colorectal cancer

BACKGROUND : Colorectal cancer (CRC) screening programs based on fecal immunochemical testing (FIT) generate substantial pressure on colonoscopy capacity in Europe. Thus, a relevant proportion of FIT-positive patients undergo colonoscopy after the recommended 30-day interval, which may be associated with an excess CRC risk. METHODS : In a cohort of 50-69-year-old patients undergoing biennial rounds of FIT (OC-Hemodia latex agglutination test; cutoff 20 µg hemoglobin/g feces) between 2004 and 2017, we assessed the outcome at colonoscopy (low/high risk adenoma/CRC/advanced stage CRC) among FIT-positive patients, according to different time intervals. The association of each outcome with waiting time, and demographic and clinical factors, was analyzed through multivariable analysis. RESULTS : 123 138/154 213 FIT-positive patients (79.8 %) underwent post-FIT colonoscopy. Time to colonoscopy was ≤ 30 days, 31-180 days, and ≥ 181 days in 50 406 (40.9 %), 71 724 (58.3 %), and 1008 (0.8 %) patients, respectively. At colonoscopy, CRC, high risk adenoma, and low risk adenoma were diagnosed in 4813 (3.9 %), 30 500 (24.8 %), and 22 986 (18.7 %) patients, respectively. An increased CRC prevalence at colonoscopy was observed for a time to colonoscopy of ≥ 270 days (odds ratio [OR] 1.75, 95 % confidence interval [CI] 1.15-2.67), whereas it was stable for waiting times of < 180 days. The proportion of advanced CRC also increased after 270 days (OR 2.79, 95 %CI 1.03-7.57). No increase for low or high risk adenomas according to time to colonoscopy was observed. CONCLUSION : In a European FIT-based screening program, post-FIT colonoscopy after 9 months was associated with an increased risk of CRC and CRC progression.

Comparative Evaluation of Participation and Diagnostic Yield of Colonoscopy vs Fecal Immunochemical Test vs Risk-Adapted Screening in Colorectal Cancer Screening: Interim Analysis of a Multicenter Randomized Controlled Trial (TARGET-C)

INTRODUCTION

In colorectal cancer screening, implementing risk-adapted screening might be more effective than traditional screening strategies. We aimed to compare the effectiveness of a risk-adapted screening strategy with colonoscopy and fecal immunochemical test (FIT) in colorectal cancer screening.

METHODS

A randomized controlled trial was conducted in 6 centers in China since May 2018. Nineteen thousand five hundred forty-six eligible participants aged 50-74 years were recruited and randomly allocated into 1 of the 3 screening groups in a 1:2:2 ratio: (i) one-time colonoscopy (n = 3,916), (ii) annual FIT (n = 7,854), and (iii) annual risk-adapted screening (n = 7,776). Based on the risk-stratification score, high-risk subjects were referred for colonoscopy and low-risk ones were referred for FIT. All subjects with positive FIT were referred for diagnostic colonoscopy. The detection rate of advanced neoplasm was the primary outcome. The study is registered with the China Clinical Trial Registry (www.chictr.org.cn Identifier: ChiCTR1800015506).

RESULTS

For baseline screening, the participation rates of the colonoscopy, FIT, and risk-adapted screening groups were 42.5% (1,665/3,916), 94.0% (7,386/7,854), and 85.2% (6,628/7,776), respectively. For the intention-to-screen analysis, the detection rates of advanced neoplasm were 2.40% (94/3,916), 1.13% (89/7,854), and 1.66% (129/7,776), with odds ratios (95% confidence intervals) of 2.16 (1.61-2.90; P < 0.001) for colonoscopy vs FIT, 1.45 (1.10-1.90; P < 0.001) for colonoscopy vs risk-adapted screening, and 1.49 (1.13-1.97; P < 0.001) for risk-adapted screening vs FIT, respectively. The numbers of subjects who required a colonoscopic examination to detect 1 advanced neoplasm were 18 in the colonoscopy group, 10 in the FIT group, and 11 in the risk-adapted screening group.

DISCUSSION

For baseline screening, the risk-adapted screening approach showed a high participation rate, and its diagnostic yield was superior to that of FIT at a similarly low load of colonoscopy.

Utilisation of Colorectal Cancer Screening Tests in European Countries by Type of Screening Offer: Results from the European Health Interview Survey

In the past two decades, an extensive rollout of colorectal cancer (CRC) screening programmes has been initiated in European countries with a large heterogeneity of screening offers. Using data from a population-based cross-sectional survey conducted between 2013 and 2016 in all European Union countries, we analysed the utilisation of faecal tests and colonoscopy among people aged 50–74 years and the factors associated with uptake by type of screening offer. We observed the highest utilisation of either test for countries with fully rolled out organised programmes with faecal tests (ranging from 29.7% in Croatia to 66.7% in the UK) and countries offering both faecal tests and colonoscopy (from 22.7% in Greece to 70.9% in Germany). Utilisation was very low for countries with no programme (from 6.3% in Romania to 30.5% in Norway). Younger age (50–54 years), longer time since last consultation with a doctor and a lifestyle score associated with increased CRC risk were significantly associated with lower test use, a pattern observed across all types of screening offers. Our results suggest that more countries should implement organised programmes with faecal immunochemical tests, in combination with alternative endoscopy offers where resources allow. Furthermore, there is a large potential for increasing screening use in Europe by better reaching the younger eligible individuals, those who have not been to the doctor recently and those at increased risk for CRC.

A twelve-year study of the prevalence, risk factors and characteristics of interval colorectal cancers after negative colonoscopy

INTRODUCTION

The objective of our study was to describe and analyse the Post-Colonoscopy Colorectal Cancers (PCCRCs) and endoscopist performance-related risk factors in the Isère regional screening programme.

METHOD

This was a population-based retrospective cohort study between 2002-2013, where Post-Colonoscopy Colorectal Cancers (PCCRCs) were defined as colorectal adenocarcinoma diagnosed between six and sixty months post-colonoscopy following a positive gFOBT. We analysed the endoscopist performance-related risk factors of the 62 gastroenterologists who had carried out at least 30 colonoscopies during this period.

RESULTS

During the period reviewed, there were 10,557 negative colonoscopies performed. Fifteen post-colonoscopy colorectal cancers were diagnosed from 2002-2013 with an average patient age of 67.1 years. Men comprised 73% of the cases and 53% of all the cases were found in the distal colon. These 15 cases comprised 1.1% of all Colorectal Cancers (CRCs) diagnosed in the screening programme, with an incidence rate of 0.42 (0.21-0.77) per 1,000 person-years. The aetiological breakdown was as follows: 47% related to missed cancers, 27% were new cancers, 20% were failed biopsy detection, and 6% related to incomplete removal. The Adenoma Detection Rate (ADR) among gastroenterologists was an average of 30%, but large heterogeneity was present within this number, ranging from 11% to 49%.

CONCLUSION

The post-colonoscopy colorectal cancer prevalence and incident rate were low relative to the literature. However, significant heterogeneity was present in the adenoma detection rate. Decreasing this heterogeneity by establishing a national benchmark, regular performance feedback and training modules should homogenise adenoma detection rates and decrease the number of interval cancers in the region.

An international polypectomy practice survey

Background and study aims: In recent years, cold snare polypectomy (CSP) has been recommended as the preferred approach for removal of small and diminutive colorectal polyps. We conducted an international survey among endoscopists to understand the uptake of CSP and changes in polypectomy practice during recent years.Patients and methods: Endoscopists were invited through gastroenterology, colorectal surgery and endoscopy societies to participate in an online survey. The primary outcome was to identify the predominant polypectomy approach used to remove 4‒10 mm colorectal polyps. Secondary outcomes included the uptake of CSP in the past 5 years, current polypectomy practice patterns for 1‒20 mm polyps, practice changes in recent years, and perceived benefits/concerns related to different polypectomy techniques.Results: The survey was distributed internationally by nine societies and completed by 808 endoscopists (response rate 3.7%). CSP was the predominant polypectomy technique for 4‒5 mm polyps (67.0%, 95% CI, 63.7-70.2%) and 6‒10 mm polyps (55.2%, 95% CI, 51.8-58.6%). For 1‒3 mm polyps, cold forceps remained the predominant technique (78.4%, 95% CI, 75.6-81.3%), whereas hot snare polypectomy (HSP) remained the predominant technique for 10‒20 mm polyps (92.5%, 95% CI, 90.7-94.3%). 87.5% (95% CI, 85.2-89.8%) of endoscopists reported an increase in CSP use during the past 5 years.Conclusions: This survey found a substantial increase in CSP use during recent years. CSP has become the predominant polypectomy approach for 4‒10 mm colorectal polyps, while HSP remained the predominant approach for larger (10‒20 mm) polyps. Clinical practice patterns are well aligned with recently issued guideline recommendations.

A longitudinal study of prediagnostic metabolic biomarkers and the risk of molecular subtypes of colorectal cancer

Body fatness increases the risk of colorectal cancer (CRC). Insulin resistance and altered adipokines are potential mechanisms, but previous biomarker studies have been inconsistent. Intertumoral heterogeneity might provide an explanation. We investigated insulin, C-peptide, adiponectin, and leptin in relation to CRC molecular subtypes using a nested case-control design (1010 cases, 1010 matched controls, median 12.3 years from baseline to CRC diagnosis) from the population-based Northern Sweden Health and Disease Study. Repeated samples were available from 518 participants. Risks of CRC and subtypes, defined by tumor BRAF and KRAS mutations and microsatellite instability (MSI) status, were estimated using conditional logistic regression and linear mixed models. Higher C-peptide and lower adiponectin were associated with increased CRC risk (odds ratios per standard deviation increase (95% CI): 1.11 (1.01, 1.23) and 0.91 (0.83, 1.00), respectively), though weakened when adjusted for body mass index. Insulin and leptin were not associated with CRC risk. Within-individual time trajectories were similar in cases and controls, and no subtype-specific relationships were identified (all P_{heterogeneity} > 0.1). Adiponectin was weakly inversely associated with the risk of KRAS-mutated (P = 0.08) but not BRAF-mutated or KRAS/BRAF-wildtype CRC, consistent with the one previous study. These findings contribute to an increased understanding of the complex role of body size in CRC.

Baseline Colonoscopy Findings Associated With 10-Year Outcomes in a Screening Cohort Undergoing Colonoscopy Surveillance

BACKGROUND & AIMS

Few studies have evaluated long-term outcomes of ongoing colonoscopic screening and surveillance in a screening population. We aimed to determine the 10-year risk for advanced neoplasia (defined as adenomas ≥10mm, adenomas with villous histology or high-grade dysplasia, or colorectal cancer [CRC]) and assessed whether baseline colonoscopy findings were associated with long-term outcomes.

METHODS

We collected data from the Department of Veterans Affairs Cooperative Studies Program Study on 3121 asymptomatic veterans (50-75 years old) who underwent a screening colonoscopy from 1994 through 1997 at 13 medical centers and were then followed for 10 years or until death. We included 1915 subjects with at least 1 surveillance colonoscopy and estimated cumulative incidence of advanced neoplasia by Kaplan-Meier curves. We then fit a longitudinal joint model to estimate risk of advanced neoplasia at each subsequent examination after baseline, adjusting for multiple colonoscopies within individuals.

RESULTS

Through 10 years of follow-up, there were 146 individuals among all baseline colonoscopy groups found to have at least 1 incident advanced neoplasia. The cumulative 10-year incidence of advanced neoplasia was highest among those with baseline CRC (43.7%; 95% CI 13.0%-74.4%), followed by those with baseline advanced adenoma (AA) (21.9%; 95% CI 15.7-28.1). The cumulative 10-year incidence of advanced neoplasia was 6.3% (95% CI 4.1%-8.5%) and 4.1% (95% CI 2.7%-5.4%) for baseline 1 to 2 small adenomas (<1cm, and without villous histology or high-grade dysplasia) and no neoplasia, respectively (log-rank P = .10). After adjusting for prior surveillance, the risk of advanced neoplasia at each subsequent examination was not significantly increased in veterans with 1 or 2 small adenomas at baseline (odds ratio 0.96; 95% CI 0.67-1.41) compared with veterans with no baseline neoplasia.

CONCLUSIONS

Baseline screening colonoscopy findings associate with advanced neoplasia within 10 years. Individuals with only 1 or 2 small adenomas at baseline have a low risk of advanced neoplasia over 10 years. Alternative surveillance strategies, could be considered for these individuals.

Impact of adenoma detection rate on detection of advanced adenomas and endoscopic adverse events in a study of over 200,000 screening colonoscopies

BACKGROUND AND AIMS

Adenoma detection rate (ADR) is the best established quality parameter for screening colonoscopy. Guidelines recommend a target ADR >25% because previous studies have shown that patients of endoscopists with higher ADRs have a lower risk of postcolonoscopy interval cancers. However, studies have shown that improvement in ADR mainly results in increased detection of clinically irrelevant nonadvanced adenomas (NAAs). The impact of ADR on the detection of advanced adenomas (AAs) as well as adverse event rates has yet to be determined.

METHODS

A total of 218,193 screening colonoscopies performed between 2007 and 2010 by 262 endoscopists within the Austrian quality assurance program were analyzed. We divided endoscopists into quintiles based on ADRs and calculated mean advanced ADRs (AADRs), NAA detection rates (NAADRs), and adverse event rates for each quintile. Spearman rank-order was used to calculate overall correlations between ADRs and AADRs as well as adverse event rates. Endoscopists with an ADR <25% were compared with those with an ADR >25%.

RESULTS

Fifty-one percent of patients were women. Mean ADR was 23.03% (95% confidence interval [CI], 21.93-24.13), AADRs 7.72% (95% CI, 7.19-8.25), and NAADRs 15.31% (95% CI, 14.36-16.27). Overall, there was a significant correlation between ADR and AADR (rho = .51; P < .001). When ADR was divided into quintiles, mean AADR increased with increasing ADR. Even in the highest ADR group (ADR, 31.36%-52.27%) there was a further increase in AADR with a mean of 10.75% (95% CI, 9.31-12.19). Importantly, NAADRs increased continuously with improvement in ADRs but never dissociated from a simultaneous improvement in AADRs. However, there was also a significant correlation of ADRs and endoscopic adverse events (rho = .26, P < .001), even if the perforation rate of .028% (95% CI, .004-.052) in the highest ADR group still remained within the accepted limits based on guidelines.

CONCLUSIONS

Increasing ADR is associated with improved detection of AAs and therefore is likely to prevent more cases of colorectal cancer. However, higher ADR was also associated with a higher rate of adverse events, although the adverse event rate was low.

Overestimated Sensitivity of Fecal Immunochemical Tests in Screening Cohorts With Registry-Based Follow-up

OBJECTIVES

Several recent studies have reported very high estimates of sensitivity and specificity of fecal immunochemical tests (FITs) at seemingly high levels of precision using registry-based follow-up of participants in very large FIT-based screening programs. We aimed to assess the validity of estimates of diagnostic performance parameters derived by this indirect approach.

METHODS

We modeled expected values of sensitivity and specificity of colorectal cancer detection in studies using the indirect approach and their deviation from true values under a broad range of plausible assumptions, and we compared these expected values with recently reported estimates of FIT sensitivity and specificity from such studies.

RESULTS

Using a sensitivity of 75% and specificity of 93.6% (from studies using a direct approach, i.e., colonoscopy follow-up of all participants), the indirect approach would be expected to yield sensitivities between 84.5% and 91.1% and specificities between 93.4% and 93.6% under a range of realistic assumptions regarding colonoscopic follow-up rates of positive FITs and clinical manifestation rates of preclinical colorectal cancer.

DISCUSSION

Very high sensitivities of FITs recently reported with seemingly very high levels of precision by several large-scale registry-based studies, which are in line with expected results based on our model calculations, are likely to be strongly overestimated and need to be interpreted with due caution.

Colorectal carcinoma screening: Established methods and emerging technology

Colorectal carcinoma screening programs have shown success in lowering both the incidence and mortality rate of colorectal carcinoma at a population level, in part because this carcinoma is relatively slow growing and has an identifiable premalignant lesion. Still, many patients do not undergo the recommended screening for colorectal carcinoma, and of those who do, a subset may be over- or under-diagnosed by the currently available testing methods. The primary purpose of this article is to review the data regarding currently available colorectal cancer screening modalities, which include fecal occult blood testing, direct colonic visualization, and noninvasive imaging techniques. In addition, readers will be introduced to a variety of biomarkers that may serve as stand-alone or adjunct tests in the future. Finally, there is a brief discussion of the current epidemiologic considerations that public health officials must address as they create population screening guidelines. The data we provide as laboratory physicians and scientists are critical to the construction of appropriate recommendations that ultimately decrease the burden of disease from colorectal carcinoma.

Head-to-Head Comparison of the Performance of 17 Risk Models for Predicting Presence of Advanced Neoplasms in Colorectal Cancer Screening

OBJECTIVES

Many risk scores have been proposed to predict presence of advanced colorectal neoplasms, but a comprehensive comparison conducted in the same population is sparse. The aim of this study was to evaluate and directly compare the diagnostic performance of published risk prediction models for advanced colorectal neoplasms.

METHODS

Data were drawn from 2 cohorts of subjects undergoing screening colonoscopy in Germany, i.e., KolosSal (n = 16,195) and BliTz (n = 7,444). Absolute risks and relative risks were generated for the presence of at least 1 advanced neoplasm, taking the lowest risk group as the reference group. Performance of risk models was assessed by the area under the receiver operating characteristic curve (AUC) and compared by the net reclassification improvement.

RESULTS

The 2 cohorts included 1,917 (11.8%) and 848 (11.4%) participants with advanced neoplasm, respectively. Absolute risks were mostly between 5% and 10% among participants in the lowest risk group and between 15% and 20% among participants in the highest risk group, and relative risks mostly ranged from 2.0 to 4.0 across the risk models in both cohorts. The AUCs ranged from 0.58 to 0.65 in KolosSal and from 0.57 to 0.61 in BliTz for all risk scores. Compared to models with lower AUC, classification was significantly improved in most models with higher AUC.

DISCUSSION

Risk models for advanced colorectal neoplasms generally yielded modest discriminatory power, despite some variation in performance between models. Future studies should evaluate the performance of these risk models in racially diverse populations and investigate possible extensions, such as combination with polygenic risk scores.

Multiobjective Calibration of Disease Simulation Models Using Gaussian Processes

Background. Developing efficient procedures of model calibration, which entails matching model predictions to observed outcomes, has gained increasing attention. With faithful but complex simulation models established for cancer diseases, key parameters of cancer natural history can be investigated for possible fits, which can subsequently inform optimal prevention and treatment strategies. When multiple calibration targets exist, one approach to identifying optimal parameters relies on the Pareto frontier. However, computational burdens associated with higher-dimensional parameter spaces require a metamodeling approach. The goal of this work is to explore multiobjective calibration using Gaussian process regression (GPR) with an eye toward how multiple goodness-of-fit (GOF) criteria identify Pareto-optimal parameters. Methods. We applied GPR, a metamodeling technique, to estimate colorectal cancer (CRC)-related prevalence rates simulated from a microsimulation model of CRC natural history, known as the Colon Modeling Open Source Tool (CMOST). We embedded GPR metamodels within a Pareto optimization framework to identify best-fitting parameters for age-, adenoma-, and adenoma staging-dependent transition probabilities and risk factors. The Pareto frontier approach is demonstrated using genetic algorithms with both sum-of-squared errors (SSEs) and Poisson deviance GOF criteria. Results. The GPR metamodel is able to approximate CMOST outputs accurately on 2 separate parameter sets. Both GOF criteria are able to identify different best-fitting parameter sets on the Pareto frontier. The SSE criterion emphasizes the importance of age-specific adenoma progression parameters, while the Poisson criterion prioritizes adenoma-specific progression parameters. Conclusion. Different GOF criteria assert different components of the CRC natural history. The combination of multiobjective optimization and nonparametric regression, along with diverse GOF criteria, can advance the calibration process by identifying optimal regions of the underlying parameter landscape.

Colorectal Adenomas and Cancers After Childhood Cancer Treatment: A DCOG-LATER Record Linkage Study

Background

Although colorectal adenomas serve as prime target for colorectal cancer (CRC) surveillance in other high-risk groups, data on adenoma risk after childhood cancer are lacking. We evaluated the risk of histologically confirmed colorectal adenomas among childhood cancer survivors. A secondary aim was to assess CRC risk.

Methods

The DCOG-LATER cohort study includes five-year Dutch childhood cancer survivors and a sibling comparison group (n = 883). Colorectal tumors were identified from the population-based Dutch Pathology Registry (PALGA). We calculated cumulative incidences of adenomas/CRCs for survivors and siblings. For adenomas, multivariable Cox regression models were used to evaluate potential risk factors. All statistical tests were two-sided.

Results

Among 5843 five-year survivors (median follow-up = 24.9 years), 78 individuals developed an adenoma. Cumulative incidence by age 45 years was 3.6% (95% confidence interval [CI] = 2.2% to 5.6%) after abdominopelvic radiotherapy (AP-RT; 49 cases) vs 2.0% (95% CI = 1.3% to 2.8%) among survivors without AP-RT (28 cases; Pdifference = .07) and vs 1.0% (95% CI = 0.3% to 2.6%) among siblings (6 cases) (Pdifference = .03). Factors associated with adenoma risk were AP-RT (hazard ratio [HR] = 2.12, 95% CI = 1.24 to 3.60), total body irradiation (TBI; HR = 10.55, 95% CI = 5.20 to 21.42), cisplatin (HR = 2.13; 95% CI = 0.74 to 6.07 for <480 mg/m²; HR = 3.85, 95% CI = 1.45 to 10.26 for ≥480 mg/m²; Ptrend = .62), a hepatoblastoma diagnosis (HR = 27.12, 95% CI = 8.80 to 83.58), and family history of early-onset CRC (HR = 20.46, 95% CI = 8.10 to 51.70). Procarbazine was statistically significantly associated among survivors without AP-RT/TBI (HR = 2.71, 95% CI = 1.28 to 5.74). Thirteen CRCs occurred.

Conclusion

We provide evidence for excess risk of colorectal adenomas and CRCs among childhood cancer survivors. Adenoma risk factors include AP-RT, TBI, cisplatin, and procarbazine. Hepatoblastoma (familial adenomatous polyposis-associated) and family history of early-onset CRC were confirmed as strong risk factors. A full benefit-vs-harm evaluation of CRC screening among high-risk childhood cancer survivors warrants consideration.

Colonoscopy and Sigmoidoscopy Use among the Average-Risk Population for Colorectal Cancer: A Systematic Review and Trend Analysis

Monitoring population-level colonoscopy and sigmoidoscopy use is crucial to estimate the future burden of colorectal cancer and guide screening efforts. We conducted a systematic literature search on colonoscopy and sigmoidoscopy use, published between November 2016 and December 2018 in the databases PubMed and Web of Science to update previous reviews and analyze time trends for various countries. In addition, we used data from the German and European Health Interview Surveys and the National Health Interview Survey to explore recent time trends for Germany and the US, respectively. The literature search yielded 23 new articles: fourteen from the US and nine from Australia, Canada, England, Germany, Saudi Arabia, and South Korea. Colonoscopy use within 10 years was highest and, apart from the youngest age groups eligible for colorectal cancer screening, kept increasing to levels close to 60% in the US and Germany. A recent steep increase was also observed for South Korea. Limited data were available on sigmoidoscopy use; regional studies from the US suggest that sigmoidoscopy has become rarely used. Despite high uptake and ongoing increase in the US, Germany, and South Korea, use of colonoscopy and sigmoidoscopy has either remained low or essentially unknown for the majority of countries.

Optimal age for screening colonoscopy: a modeling study

BACKGROUND AND AIMS

Recent guidelines on colorectal cancer (CRC) screening recommend starting screening earlier than before. We performed a simulation study to examine and compare the optimal ages to have once-only screening colonoscopy and repeated colonoscopies.

METHODS

A Markov model was set up using data from the German national screening colonoscopy registry to simulate the natural history of the adenoma-carcinoma process. CRC deaths and years of potential life lost (YPLL) for a hypothetical unscreened 50-year-old German population were estimated for a single screening colonoscopy or 2 or 3 screening colonoscopies with 10-year intervals at various ages.

RESULTS

One single screening colonoscopy performed between 50 and 65 years of age was expected to reduce CRC death by 49% to 69% and YPLL by 51% to 68%. An inverted U-shaped association was found between screening age and proportion of CRC deaths or YPLL prevented. The optimal age for once-only colonoscopy that yielded the highest reductions in YPLL was around 54 years for men and 56 years for women. Estimates were approximately 6 to 8 years higher when proportions of CRC deaths prevented were examined. For 2 or 3 screening colonoscopies, the optimal starting age fell to around 50 years or even younger for both genders.

CONCLUSIONS

Based on the YPLL estimates, in a high CRC incidence and high life expectancy country like Germany, the optimal age for once-only screening colonoscopy is around 55 years and possibly slightly younger for men than for women. When 2 or more screening colonoscopies are offered with 10-year intervals, screening should start at age 50 at the latest or possibly even younger for both genders.

Analysis of population-based colorectal cancer screening in Guangzhou, 2011-2015

Objective

To analyze the detection rates of colorectal cancer (CRC) and polyps by population‐based screening in Guangzhou.

Methods

From January 2011 to December 2015, the residents aged 30‐79 were selected for CRC screening. The residents were conducted Questionnaires and/or FOBT to assess high‐risk groups, the free colonoscopy examination was recommended, and the results were evaluated in detail.

Results

There were 98 927 residents involving screening, 5306 high‐risk residents identified (males 1859 and females 3447), and 4713 subjects underwent colonoscopy (males 1690 and females 3023). CRC was seen in 55 individuals (males 28 and females 27), and the detection rates in male were higher than in female (P = 0.019). And the detection rates increasing with age, for people over 60 years old, were obviously higher than those younger (x² = 18.64, P = 0.000924).

The polyps were seen in 1458 (30.94%) cases， and 1420 subjects received pathological examination (adenomas 971 and non‐adenomatous polyps 449). Advanced adenomas were seen in 462 cases (males 240 and females 222) and 509 cases of non‐advanced adenomas (males 255 and females 254). For advanced adenomas, the detection rates in male were higher than female (14.20% vs 7.34%, P = 2.64 × 10⁻¹⁴). For the detection rates of adenomas or advanced adenomas by age, the people over 40 years were higher than younger (20.91% vs 3.61% P = 7.87 × 10⁻⁶; 9.94% vs 2.41%, P = 0.009).

Conclusions

For Guangzhou residents, the detection rates of CRC and adenoma were 1.17% and 20.60%. The detection rates of CRC increasing with age, for people over 60 years old, were obviously higher than those younger. But for people over 40 years, the detection rate of adenoma and advanced adenoma was higher than younger. So for people over 40 years, the CRC screening is recommended.

Should We Resect and Discard Low Risk Diminutive Colon Polyps

Diminutive colorectal polyps <5 mm are very common and almost universally benign. The current strategy of resection with histological confirmation of all colorectal polyps is costly and may increase the risk of colonoscopy. Accurate, optical diagnosis without histology can be achieved with currently available endoscopic technologies. The American Society of Gastrointestinal Endoscopy Preservation and Incorporation of Valuable endoscopic Innovations supports strategies for optical diagnosis of small non neoplastic polyps as long as two criteria are met. For hyperplastic appearing polyps <5 mm in recto-sigmoid colon, the negative predictive value should be at least 90%. For diminutive low grade adenomatous appearing polyps, a resect and discard strategy should be sufficiently accurate such that post-polypectomy surveillance recommendations based on the optical diagnosis, agree with a histologically diagnosis at least 90% of the time. Although the resect and discard as well as diagnose and leave behind approach has major benefits with regard to both safety and cost, it has yet to be used widely in practice. To fully implement such as strategy, there is a need for better-quality training, quality assurance, and patient acceptance. In the article, we will review the current state of the science on optical diagnose of colorectal polyps and its implications for colonoscopy practice.