Expected long-term impact of the German screening colonoscopy programme on colorectal cancer prevention: analyses based on 4,407,971 screening colonoscopies

Potential for enhancing efficacy of screening colonoscopy by lowering starting ages and extending screening intervals: A modelling study for Germany

Studies aimed to evaluate the expected impact of alternative screening strategies are essential for optimizing colorectal cancer (CRC) screening offers, but such studies are lacking in Germany, where two screening colonoscopies (CS) 10 years apart are offered for men from age 50 and women from age 55. Our aim was to explore whether and to what extent the efficacy of utilizing two CS could be enhanced by alternative starting ages and screening intervals. We modeled the expected numbers of CRC cases, CRC deaths, years of potential life lost (YPLL), and disability-adjusted life years (DALYs) due to CRC in hypothetical cohorts of 100,000 men and women aged 45-85 using COSIMO, a validated Markov-based multi-state simulation model. Modeled strategies included combinations of starting ages (45/50/55/60) and CS (10/15/20 years). For men, CRC deaths could be slightly reduced by extending the interval to 15 years, with a second CS at 65. YPLL and DALYs would be reduced by decreasing starting age to 45 when combined with a 15-year screening interval. For women, use of two CS at ages 50 and 65 would reduce all CRC burden parameters compared to the current earliest-use offer at 55 and 65 years. Our results suggest that lowering the starting age of screening colonoscopy to 45 for men and 50 for women, combined with extending the CS screening interval to 15 years would have the potential to enable significant reductions in years of potential life lost, and disability-adjusted life years compared to current screening offers in Germany.

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.

Evaluation of a questionnaire to assess the indication for screening colonoscopy for asymptomatic patients

INTRODUCTION

Colorectal cancer is the second most common cause of cancer death worldwide. Screening colonoscopy is a very effective measure to prevent colorectal cancer and can reduce mortality at the population level. However, the participation rates of screening programs are low.To provide easily accessible information on screening colonoscopy and to increase the participation rates of screening programs, we developed a questionnaire for asymptomatic patients based on the German guidelines to assess the indication for screening colonoscopy. We evaluated the questionnaire with reference to the indications given by specialists in gastroenterology.

METHODS

Patients who visited a specialist in gastroenterology in an outpatient clinic of a tertiary hospital for other reasons than a colonoscopy were eligible for the study. A maximum of seven questions to assess the indication for screening colonoscopy were answered by the patients. Afterward, the indication for screening colonoscopy was given or not by a specialist in gastroenterology. The accuracy of the questionnaire was measured in terms of sensitivity, specificity, and predictive values.

RESULTS

In total, 335 patients were included in the analyses, of whom 50 and 285 patients were given and were not given an indication for screening colonoscopy by the specialists, respectively. In 0/50 patients, the questionnaire was false negative and in 8/285 patients false positive. Thus, the questionnaire had a sensitivity of 100% (95% confidence interval: 93-100%), a specificity of 97% (95-99%), a negative predictive value of 100% (99-100%), and a positive predictive value of 86% (75-94%).A subgroup analysis including patients who had never had a colonoscopy (n=109) showed comparable results: sensitivity of 100% (92-100%), specificity of 92% (83-97%), negative predictive value of 100% (94-100%), and positive predictive value of 90% (87-97%).

CONCLUSION

The self-assessment questionnaire for asymptomatic individuals to assess the recommendation for screening colonoscopy is very sensitive and specific compared to a specialist in gastroenterology.The questionnaire can be found at: https://www.interdisziplinaere-endoskopie.mri.tum.de/de/infos-patienten/index.php.

The association between organised colorectal cancer screening strategies and reduction of its related mortality: a systematic review and meta-analysis

BACKGROUND

To assess the long-term association between organised colorectal cancer (CRC) screening strategies and CRC-relate mortality.

METHODS

We systematically reviewed studies on organised CRC screening through PubMed, Ovid Medline, Embase and Cochrane from the inception. We retrieved characteristics of organised CRC screening from included literature and matched mortality (over 50 years) of those areas from the International Agency for Research on Cancer in May 2023. The variations of mortality were reported via the age-standardised mortality ratio. A random-effects model was used to synthesis results.

RESULTS

We summarised 58 organised CRC screening programmes and recorded > 2.7 million CRC-related deaths from 22 countries where rollout screening programmes were performed. The CRC screening strategy with faecal tests (guaiac faecal occult blood test (gFOBT) or faecal immunochemical tests (FIT)) or colonoscopy as the primary screening offer was associated with a 41.8% reduction in mortality, which was higher than those offered gFOBT (4.4%), FIT (16.7%), gFOBT or FIT (16.2%), and faecal tests (gFOBT or FIT) or flexible sigmoidoscopy (16.7%) as primary screening test. The longer duration of screening was associated with a higher reduction in the pooled age-standardised mortality ratio. In particular, the pooled age-standardised mortality ratio became non-significant when the screening of FIT was implemented for less than 5 years.

CONCLUSIONS

A CRC screening programme running for > 5 years was associated with a reduction of CRC-related mortality. Countries with a heavy burden of CRC should implement sustainable, organised screening providing a choice between faecal tests and colonoscopy as a preferred primary test.

Risk of Metachronous Neoplasia with High-Risk Adenoma and Synchronous Sessile Serrated Adenoma: A Systematic Review and Meta-Analysis

Background: Sessile serrated adenomas are important precursors to colorectal cancers and account for 30% of colorectal cancers. The United States Multi-Society Task Force recommends that patients with sessile serrated adenomas undergo surveillance similar to tubular adenomas. However, the risk of metachronous neoplasia when the high-risk adenoma co-exists with sessile serrated adenomas is poorly defined. Objective: To examine the risk of metachronous neoplasia in the presence of high-risk adenoma and synchronous sessile serrated adenomas compared with isolated high-risk adenoma. Data sources: PubMed, Embase, Scopus, Cochrane Library. Study selection: A literature search for studies evaluating the risk of metachronous neoplasia in patients with high-risk adenoma alone and those with synchronous high-risk adenoma and sessile serrated adenomas during surveillance colonoscopy was conducted on online databases. Main outcome measures: The primary outcome of interest was the presence of metachronous neoplasia. Results: Of the 1164 records reviewed, six (four retrospective and two prospective) studies met inclusion criteria with 2490 patients (1607 males, mean age 59.98 ± 3.23 years). Average follow-up was 47.5 ± 12.5 months. There were 2068 patients with high-risk adenoma on index colonoscopy and 422 patients with high-risk adenoma and synchronous sessile serrated adenomas. Pooled estimates showed a significantly elevated risk for metachronous neoplasia in patients with high-risk adenoma and synchronous sessile serrated adenomas (pooled odds ratio 2.21; 95% confidence intervals 1.65-2.96; p < 0.01). There was low heterogeneity (I² = 11%) among the studies. Sensitivity analysis of the prospective studies alone also showed elevated risk of metachronous neoplasm (pooled odds ratio 2.56; 95%, confidence intervals 1.05-6.23; p = 0.04). Limitations: Inclusion of a small number of retrospective studies. Conclusions: The presence of high-risk adenomas and synchronous sessile serrated adenomas is associated with an increased risk of metachronous neoplasia. Therefore, shorter surveillance intervals may be considered in patients with high-risk adenoma and synchronous sessile serrated adenomas compared to those with high-risk adenoma alone.

Shape-specific characterization of colorectal adenoma growth and transition to cancer with stochastic cell-based models

Colorectal adenoma are precursor lesions on the pathway to cancer. Their removal in screening colonoscopies has markedly reduced rates of cancer incidence and death. Generic models of adenoma growth and transition to cancer can guide the implementation of screening strategies. But adenoma shape has rarely featured as a relevant risk factor. Against this backdrop we aim to demonstrate that shape influences growth dynamics and cancer risk. Stochastic cell-based models are applied to a data set of 197,347 Bavarian outpatients who had colonoscopies from 2006-2009, 50,649 patients were reported with adenoma and 296 patients had cancer. For multi-stage clonal expansion (MSCE) models with up to three initiating stages parameters were estimated by fits to data sets of all shapes combined, and of sessile (70% of all adenoma), peduncular (17%) and flat (13%) adenoma separately for both sexes. Pertinent features of adenoma growth present themselves in contrast to previous assumptions. Stem cells with initial molecular changes residing in early adenoma predominantly multiply within two-dimensional structures such as crypts. For these cells mutation and division rates decrease with age. The absolute number of initiated cells in an adenoma of size 1 cm is small around 103, related to all bulk cells they constitute a share of about 10-5. The notion of very few proliferating stem cells with age-decreasing division rates is supported by cell marker experiments. The probability for adenoma transiting to cancer increases with squared linear size and shows a shape dependence. Compared to peduncular and flat adenoma, it is twice as high for sessile adenoma of the same size. We present a simple mathematical expression for the hazard ratio of interval cancers which provides a mechanistic understanding of this important quality indicator. We conclude that adenoma shape deserves closer consideration in screening strategies and as risk factor for transition to cancer.

Modeling age-specific incidence of colon cancer via niche competition

Cancer development is a multistep process often starting with a single cell in which a number of epigenetic and genetic alterations have accumulated thus transforming it into a tumor cell. The progeny of such a single benign tumor cell expands in the tissue and can at some point progress to malignant tumor cells until a detectable tumor is formed. The dynamics from the early phase of a single cell to a detectable tumor with billions of tumor cells are complex and still not fully resolved, not even for the well-known prototype of multistage carcinogenesis, the adenoma-adenocarcinoma sequence of colorectal cancer. Mathematical models of such carcinogenesis are frequently tested and calibrated based on reported age-specific incidence rates of cancer, but they usually require calibration of four or more parameters due to the wide range of processes these models aim to reflect. We present a cell-based model, which focuses on the competition between wild-type and tumor cells in colonic crypts, with which we are able reproduce epidemiological incidence rates of colon cancer. Additionally, the fraction of cancerous tumors with precancerous lesions predicted by the model agree with clinical estimates. The correspondence between model and reported data suggests that the fate of tumor development is majorly determined by the early phase of tumor growth and progression long before a tumor becomes detectable. Due to the focus on the early phase of tumor development, the model has only a single fit parameter, the time scale set by an effective replacement rate of stem cells in the crypt. We find this effective rate to be considerable smaller than the actual replacement rate, which implies that the time scale is limited by the processes succeeding clonal conversion of crypts.

Cancer development is a multistep process often starting with a single cell turning into a tumor cell whose progeny growths via clonal expansion into a macroscopic tumor with billions of cells. While experimental insight exists on the cellular scale and cancer registries provide statistics on detectable tumors, the complex dynamics leading from the microscopic cellular scale to a macroscopic tumor is still not fully resolved. Models of cancer biology are commonly used to explain incidence rates but usually require the fit of several biological parameters due to the complexity of the incorporated processes. We employ a cell-based model based on the competition in colonic crypts, to reproduce epidemiological age-specific incidence rates of colon cancer. Due to the focus on the early stage of tumor development, only the time scale in the model has to be calibrated. The agreement between theoretical prediction and epidemiological observation suggests that the fate of tumor development is dominated by the early phase of tumor development long before a tumor becomes detectable.

Significant decrease of the pathological stage I rectal carcinoma in the era of neoadjuvant therapy-A matter of concern

BACKGROUND

Neoadjuvant treatment (nTx) for rectal cancer is commonly reserved for UICC stages II/III. Patients with stage I tumours (T1-2N0M0) are not candidates for nTx. The accuracy of treatment allocation depends on the precision of clinical staging, which is liable to understaging and overstaging. The study aimed at exploring changes in the proportion of stage pI patients with the introduction of nTx over a 26-year period.

MATERIALS AND METHODS

All consecutive patients with histologically proven rectal cancer excluding carcinoma in situ were retrieved from a prospective database of our colorectal unit. Time periods were defined as per the use of nTx: baseline phase 1994-1997; implementation phase 1998-2005 and guideline phase 2006-2019. Trends over time regarding proportion of applied nTx and stage pI tumours were investigated.

RESULTS

Overall, 1468 patients met the inclusion criteria. There were no major differences in patients' characteristics, especially proportion of synchronous metastases (stage IV) over time. nTx was applied to 1.2% of patients without metastases in the baseline phase, to 29.6% in the implementation phase, and to 59.6% in the guideline phase (p < 0.001). Corresponding proportions for patients with stage pI were 31.0%, 26.3% and 14.2%, respectively (p < 0.001).

CONCLUSION

With a stable proportion of stage IV carcinomas indicating no major changes in the patient cohorts, we could document a significant decrease of stage pI patients with increasing use of nTx. This trend clearly signals overtreatment caused by clinical T- and N-staging. More precise criteria are needed to better select patients with rectal cancer for nTx.

Strongly Divergent Impact of Adherence Patterns on Efficacy of Colorectal Cancer Screening: The Need to Refine Adherence Statistics

INTRODUCTION

The performance of colorectal cancer (CRC) screening programs depends on the adherence to screening offers. However, identical adherence levels may result from varying patterns of the population's screening behavior. We quantified the effects of different adherence patterns on the long-term performance of CRC screening for annual fecal immunochemical testing and screening colonoscopy at 10-year intervals.

METHODS

Using a multistate Markov model, we simulated scenarios where, while at the same overall adherence level, a certain proportion of the population adheres to all screening offers (selective adherence) or the entire population uses the screening offers at some point(s) of time, albeit not in the recommended frequency (sporadic adherence). Key outcomes for comparison were the numbers of prevented CRC cases and prevented CRC deaths after 50 simulated years.

RESULTS

For screening with annual fecal immunochemical testing at adherence levels of 10%-50%, ratios of prevented CRC cases (CRC deaths) resulting from a sporadic vs a selective pattern ranged from 1.8 to 4.4 (1.9-5.3) for men and from 1.7 to 3.6 (1.8-4.4) for women, i.e., up to 4-5 times more CRC cases and deaths were prevented when the population followed a sporadic instead of a selective adherence pattern. Comparisons of simulated scenarios for screening colonoscopy revealed similar patterns.

DISCUSSION

Over a lifelong time frame, large numbers of irregular screening attendees go along with much larger preventive effects than small numbers of perfectly adhering individuals. In clinical practice, efforts to reach as many people as possible at least sporadically should be prioritized over efforts to maximize adherence to repeat screening offers.

Effects of screening for colorectal cancer: Development, documentation and validation of a multistate Markov model

Simulation models are a powerful tool to overcome gaps of evidence needed to inform medical decision-making. Here, we present development and application of COSIMO, a Markov-based Colorectal Cancer (CRC) Multi-state Simulation Model to simulate effects of CRC screening, along with a thorough assessment of the model's ability to reproduce real-life outcomes. Firstly, we provide a comprehensive documentation of COSIMO's development, structure and assumptions. Secondly, to assess the model's external validity, we compared model-derived cumulative incidence and prevalences of colorectal neoplasms to (a) results from KolosSal, a study in German screening colonoscopy participants, (b) registry-based estimates of CRC incidence in Germany, and (c) outcome patterns of randomized sigmoidoscopy screening studies. We found that (a) more than 90% of observed prevalences in the KolosSal study were within the 95% confidence intervals of the model-predicted neoplasm prevalences; (b) the 15-year cumulative CRC incidences estimated by simulations for the German population deviated by 0.0% to 0.2% units in men and 0.0% to 0.3% units in women when compared to corresponding registry-derived estimates; and (c) the time course of cumulative CRC incidence and mortality in the modeled intervention group and control group closely resembles the time course reported from sigmoidoscopy screening trials. Overall, COSIMO adequately predicted colorectal neoplasm prevalences and incidences in a German population for up to 25 years, with estimated patterns of the effect of screening colonoscopy resembling those seen in registry data and real-world studies. This suggests that the model may represent a valid tool to assess the comparative effectiveness of CRC screening strategies.

Colonoscopic screening is associated with reduced Colorectal Cancer incidence and mortality: a systematic review and meta-analysis

It is the great priority to detect colorectal cancer (CRC) as early as possible, finally to reduce the incidence and mortality of CRC. However, although colonoscopy is recommended in many consensuses, yet no one systematic review is conducted to figure out how colonoscopy could change the incidence and mortality. In our study, we conducted a comprehensive meta-analysis to evaluate the association between colonoscopy screening and the incidence or mortality of CRC. PubMed, EMBASE, and PMC database were systematically searched from their inception to June 2020. A total of 13 cohort and 16 case-control studies comprising 4,713,778 individuals were obtained in this review. Our results showed that colonoscopy was associated with a 52% RR reduction in incidence of CRC (RR: 0.48, 95% CI: 0.46-0.49) and 62% RR reduction in mortality of CRC (RR: 0.38, 95% CI: 0.36-0.40). Subgroup analysis of different interventions, study design, country, sample size, age or sex showed that the incidence and mortality reduction remained consistent, and colonoscopy screening had the same effect on people below and above 50. Our study indicated that colonoscopy could significantly reduce the incidence and mortality of CRC.

Effects of Alternative Offers of Screening Sigmoidoscopy and Colonoscopy on Utilization and Yield of Endoscopic Screening for Colorectal Neoplasms: Protocol of the DARIO Randomized Trial

BACKGROUND

Flexible sigmoidoscopy and colonoscopy are recommended screening options for colorectal cancer (CRC). Despite colonoscopy being offered for CRC screening in Germany, the uptake of this offer has been very limited.

OBJECTIVE

The objective of this study was to assess the potential for increasing use of endoscopic CRC screening and the detection of advanced colorectal neoplasms by offering the choice between use of flexible sigmoidoscopy and colonoscopy.

METHODS

The DARIO study includes a cross-sectional study (part I), followed by a prospective 2-arm randomized controlled intervention trial (part II) with an associated biobank study (part III). Participation is possible in part I of the DARIO study only, parts I and II, or all 3 study parts. After obtaining informed consent from the municipalities, 12,000 people, aged 50-54 years, from the Rhine-Neckar region in Germany were randomly selected from residential lists of the responsible population registries and invited to complete a standardized questionnaire to investigate the nature, frequency, timing, and results of previous CRC screening and eventual diagnostic colonoscopies. In study part II participants from study part I with no colonoscopy in the preceding 5 years are randomized into 2 arms: arm A offering screening colonoscopy only, and arm B offering both options, either screening colonoscopy or screening sigmoidoscopy. The primary endpoint is the proportion of participants in whom colorectal neoplasms >0.5 cm are detected and removed at screening endoscopy. The secondary endpoints are the detection rate of any neoplasm and use of any endoscopic screening. Part III of the study will use samples from participants in study part II to construct a liquid and tissue biobank for the evaluation of less invasive methods of early detection of colon cancer and for the more detailed characterization of the detected neoplasms. Blood, urine, stool, and saliva samples are taken before the endoscopy. Tissue samples are obtained from the neoplasms removed during endoscopy.

RESULTS

A total of 10,568 from 12,000 randomly selected women and men aged 50-54 years living in the Rhine-Neckar-Region of Germany have been invited for participation. The remaining 1432 (11.93%) could not be invited because they reached the age of 55 at the time of contact. Of those invited, 2785/10,568 (26.35%) participated in study part I; 53.60% (1493/2785) of these participants were female. Study parts II and III are ongoing.

CONCLUSIONS

This study will answer the question if alternative offers of either screening sigmoidoscopy or screening colonoscopy will increase utilization and effectiveness of endoscopic CRC screening compared with an exclusive offer of screening colonoscopy. In addition, alternative noninvasive screening tests will be developed and validated.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00018932; https://www.drks.de/drks_web/navigate.do? navigationId=trial.HTML&TRIAL_ID=DRKS00018932.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/17516.

Age-specific sequence of colorectal cancer screening options in Germany: A model-based critical evaluation

BACKGROUND

The current organized screening program for colorectal cancer in Germany offers both sexes 5 annual fecal immunochemical tests (FITs) between ages 50 and 54 years, followed by a first screening colonoscopy at age 55 years if all of these FITs were negative. We sought to assess the implications of this approach for key parameters of diagnostic performance.

METHODS AND FINDINGS

Using a multistate Markov model, we estimated the expected detection rates of advanced neoplasms (advanced adenomas and cancers) and number needed to scope (NNS) to detect 1 advanced neoplasm at a first screening colonoscopy conducted at age 55 after 5 preceding negative FITs and compared them with the corresponding estimates for a first screening colonoscopy at age 55 with no preceding FIT testing. In individuals with 5 consecutive negative FITs undergoing screening colonoscopy at age 55, expected colonoscopy detection rate (NNS) was 3.7% (27) and 0.10% (1,021) for any advanced neoplasm and cancer, respectively, in men, and 2.1% (47) and 0.05% (1,880) for any advanced neoplasm and cancer, respectively, in women. These NNS values for detecting 1 advanced neoplasm are approximately 3-fold higher, and the NNS values for detecting 1 cancer are approximately 8-fold higher, than those for a first screening colonoscopy at age 55 without prior FITs. This study is limited by model simplifying assumptions and uncertainties related to input parameters.

CONCLUSIONS

Screening colonoscopy at age 55 after 5 consecutive negative FITs at ages 50-54, as currently offered in the German cancer early detection program, is expected to have very low positive predictive value. Our results may inform efforts to enhance the design of screening programs.

Characteristics and attitudes of first round invitees in the Irish National Colorectal Cancer Screening Programme

BACKGROUND/OBJECTIVE

Colorectal cancer (CRC) screening is proven to reduce CRC-related mortality. Faecal immunochemical testing (FIT)-positive clients in the Irish National CRC Screening Programme underwent colonoscopy. Round 1 uptake was 40.2%. We sought to identify barriers to participation by assessing knowledge of CRC screening and examining attitudes towards FIT test and colonoscopy.

METHODS

Questionnaires based on a modified Champion's Health Belief Model were mailed to 3500 invitees: 1000 FIT-positive, 1000 FIT-negative and 1500 non-participants. 44% responded: 550 (46%) FIT-positive, 577 (48%) FIT-negative and 69 (6%) non-responders (NR).

RESULTS

25% of respondents (n=286) did not perceive a personal risk of cancer, did not perceive CRC to be a serious disease and did not perceive benefits to screening. These opinions were more likely to be expressed by men (p=0.035). One-fifth (n=251) found screening stressful. Fear of cancer diagnosis and test results were associated with stress. FIT-positive clients, women and those with social medical insurance were more likely to experience stress.

CONCLUSIONS

The CRC screening process causes stress to one-fifth of participants. Greater use of media and involvement of healthcare professionals in disseminating information on the benefits of screening may lead to higher uptake in round 2.

Older age, symptoms, or anemia: Which factors increase colorectal cancer risk with a positive fecal immunochemical test?

BACKGROUND AND AIM

Fecal immunochemical tests (FIT) are used to screen asymptomatic individuals aged 50-74 years for colorectal cancer (CRC) within the Australian screening program. Gastrointestinal symptoms or iron deficiency anemia (IDA) may also drive primary care physicians to request a FIT. This study aimed to examine factors that may increase neoplasia risk associated with a positive FIT, specifically age, gastrointestinal symptoms, or IDA.

METHODS

A retrospective audit was performed on colonoscopies performed in a single hospital in South Australia for a positive FIT (from all referral sources) between 2014 and 2017. Patients aged < 50 years, or who had a colonoscopy in the preceding 5 years, were excluded. A subgroup (n = 198) was evaluated to assess whether age ≥ 75 years, symptoms, or IDA, as well as other demographics, comorbidities, and medications, were associated with risk of neoplasia. Features found to be associated with risk for CRC or high-risk adenoma were examined in the entire cohort using multivariate analysis.

RESULTS

Colonoscopies (750/4221, 17.8%) were completed in patients ≥ 50 years for a positive FIT. Of these, 7.6% (n = 57) also had gastrointestinal symptoms, 5.5% (n = 41) IDA, and 13.1% (n = 98) were ≥ 75 years. At colonoscopy, 2.8% (n = 21) were diagnosed with CRC and 23.2% (n = 174) with high-risk adenoma. CRC was more prevalent in ≥ 75 years compared with 50-74 years (7.1% vs 2.1%, P = 0.005), and associated with symptoms (15.8% vs 1.7%, P < 0.001), and IDA (14.6% vs 2.1%, P < 0.001). Multivariate analysis showed that IDA (odds ratio 7.68, P < 0.001) and symptoms (odds ratio 10.37, P < 0.001), but not age, were independent risk factors for CRC.

CONCLUSION

The presence of gastrointestinal symptoms or IDA, independent of age, is associated with an increased risk for CRC following a positive FIT.

Colorectal Cancer Incidence and Mortality After Removal of Adenomas During Screening Colonoscopies

BACKGROUND & AIMS

Recommendation of surveillance colonoscopy should be based on risk of colorectal cancer and death after adenoma removal. We aimed to develop a risk classification system based on colorectal cancer incidence and mortality following adenoma removal.

METHODS

We performed a multicenter population-based cohort study of 236,089 individuals (median patient age, 56 years; 37.8% male) undergoing screening colonoscopies with adequate bowel cleansing and cecum intubation at 132 centers in the Polish National Colorectal Cancer Screening Program, from 2000 through 2011. Subjects were followed for a median 7.1 years and information was collected on colorectal cancer development and death. We used recursive partitioning and multivariable Cox models to identify associations between colorectal cancer risk and patient and adenoma characteristics (diameter, growth pattern, grade of dysplasia, and number of adenomas). We developed a risk classification system based on standardized incidence ratios, using data from the Polish population for comparison. The primary endpoints were colorectal cancer incidence and colorectal cancer death.

RESULTS

We identified 130 colorectal cancers in individuals who had adenomas removed at screening (46.5 per 100,000 person-years) vs 309 in individuals without adenomas (22.2 per 100,000 person-years). Compared with individuals without adenomas, adenomas ≥20 mm in diameter and high-grade dysplasia were associated with increased risk of colorectal cancer (adjusted hazard ratios 9.25; 95% confidence interval [CI] 6.39-13.39, and 3.58; 95% CI 1.96-6.54, respectively). Compared with the general population, colorectal cancer risk was higher or comparable only for individuals with adenomas ≥20 mm in diameter (standardized incidence ratio [SIR] 2.07; 95% CI 1.40-2.93) or with high-grade dysplasia (SIR 0.79; 95% CI 0.39-1.41), whereas for individuals with other adenoma characteristics the risk was lower (SIR 0.35; 95% CI 0.28-0.44). We developed a high-risk classification based on adenoma size ≥20 mm or high-grade dysplasia (instead of the current high-risk classification cutoff of ≥3 adenomas or any adenoma with villous growth pattern, high-grade dysplasia, or ≥10 mm in diameter). Our classification system would reduce the number of individuals classified as high-risk and requiring intensive surveillance from 15,242 (36.5%) to 3980 (9.5%), without increasing risk of colorectal cancer in patients with adenomas (risk difference per 100,000 person-years, 5.6; 95% CI -10.7 to 22.0).

CONCLUSIONS

Using data from the Polish National Colorectal Cancer Screening Program, we developed a risk classification system that would reduce the number of individuals classified as high risk and require intensive surveillance more than 3-fold, without increasing risk of colorectal cancer in patients with adenomas. This system could optimize the use of surveillance colonoscopy.

Outcomes at follow-up of negative colonoscopy in average risk population: systematic review and meta-analysis

OBJECTIVE

To review and summarise the evidence on the prevalence of colorectal adenomas and cancers at a follow-up screening colonoscopy after negative index colonoscopy, stratified by interval between examinations and by sex.

DESIGN

Systematic review and meta-analysis of all available studies.

DATA SOURCES

PubMed, Web of Science, and Embase. Two investigators independently extracted characteristics and results of identified studies and performed standardised quality ratings.

ELIGIBILITY CRITERIA

Studies assessing the outcome of a follow-up colonoscopy among participants at average risk for colorectal cancer with a negative previous colonoscopy (no adenomas).

RESULTS

28 studies were identified, including 22 cohort studies, five cross sectional studies, and one case-control study. Findings for an interval between colonoscopies of one to five, five to 10, and more than 10 years were reported by 17, 16, and three studies, respectively. Summary estimates of prevalences of any neoplasm were 20.7% (95% confidence interval 15.8% to 25.5%), 23.0% (18.0% to 28.0%), and 21.9% (14.9% to 29.0%) for one to five, five to 10, and more than 10 years between colonoscopies. Corresponding summary estimates of prevalences of any advanced neoplasm were 2.8% (2.0% to 3.7%), 3.2% (2.2% to 4.1%), and 7.0% (5.3% to 8.7%). Seven studies also reported findings stratified by sex. Summary estimates stratified by interval and sex were consistently higher for men than for women.

CONCLUSIONS

Although detection of any neoplasms was observed in more than 20% of participants within five years of a negative screening colonoscopy, detection of advanced neoplasms within 10 years was rare. Our findings suggest that 10 year intervals for colonoscopy screening after a negative colonoscopy, as currently recommended, may be adequate, but more studies are needed to strengthen the empirical basis for pertinent recommendations and to investigate even longer intervals.

STUDY REGISTRATION

Prospero CRD42019127842.

Invitation to Screening Colonoscopy in the Population at Familial Risk for Colorectal Cancer

BACKGROUND

Screening colonoscopy can lower the incidence of colorectal cancer (CRC), yet participation rates are low even in groups at high risk. The goal of this study was to double the rate of participation in screening colonoscopy among persons at familial risk and then to determine the frequency of neoplasia in this risk group.

METHODS

In a nationwide, cluster-randomized, multicenter study, first-degree relatives (FDR) of patients with CRC across Germany received written informational materials concerning the familial risk of CRC, along with an invitation to undergo colonoscopy. Participants in the intervention group were additionally counseled by nurses over the telephone. The primary endpoint of the study was colonoscopy uptake within 30 days.

RESULTS

The participants' mean age was 50.8 years. The colonoscopy uptake rates were 99/125 (79%) in the intervention group and 97/136 (71%) in the control group (RR = 1.11; 95% confidence interval [0.97; 1.28]). A polypectomy was performed in 72 of 196 asymptomatic persons (37%). In 13 cases (7%), an advanced neoplasia was detected; two of these persons had colon cancer (stages T0 and T1). 42% of the participants expressed barriers against colonoscopy. 22 reported mild side effects; there were no serious side effects.

CONCLUSION

Additional counseling by nurses over the telephone does not increase the participation rate. Approaching patients who have CRC is an opportunity to increase the participation of their first-degree relatives in screening colonoscopy. The frequency of neoplasia that was found in this study underscores the need to screen relatives even before they reach the usual age threshold for screening.

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.

Should Screening Colonoscopy Be Offered From Age 50?

BACKGROUND

The introduction of colonoscopic screening in 2002 for persons aged 55 and older was followed by a marked decline in the incidence of colon cancer in the corresponding age groups in Germany. The prevalence of colorectal neoplasia among persons aged 50 to 54 has remained unknown until now. Expert committees currently recommend colonoscopic screening for persons aged 50 and older. This option has been offered since 2014 by the AOK Baden-Württemberg and by Bosch BKK in the framework of their specialized medical care program.

METHODS

In April 2014 and 2015, 84 726 insurees aged 50-54 were invited by mail to participate in colonoscopic screening. The utilization and results of colonoscopic screening were studied. A questionnaire about risks was additionally sent to half of the participants, who were selected at random (study registration: DRKS00006268).

RESULTS

Within one year, 1.9% of persons to whom invitations had been sent took up the offer of colonoscopic screening; these persons included 3.3% of those already enrolled in the specialized medical care program. The 1396 colonoscopies that were performed revealed advanced neoplasia (colon cancer or advanced adenoma) in 6.8% of cases. The prevalence of advanced neoplasia among men aged 50 to 54 was nearly twice as high as that among women in the same age group (8.6% vs. 4.5%, p = 0.0027). It was also higher than the prevalences documented in the German nationwide cancer registry for women aged 55 to 79. The additional sending of a risk questionnaire along with the invitation had no effect on the rate of detection of relevant findings or on the rate of participation in colonoscopic screening.

CONCLUSION

These findings lend support to the demand that the offer of colonoscopic screening should be extended at least to men aged 50 and above.

Patient-rated importance of key information on screening colonoscopy in Germany: a survey of statutory health insurance members

BACKGROUND

Primary colonoscopic screening is considered to be of great benefit but also has the potential to cause severe harm. Thus, eligible subjects should be supported in making an informed choice whether to participate.

OBJECTIVES

To identify information on screening colonoscopy that colonoscopy-naïve subjects rate as particularly important for decision making.

DESIGN

Survey of German statutory health insurance members using a written questionnaire in November 2015.

STUDY POPULATION

Colonoscopy-naïve individuals aged 50 to 65 years.

MAIN OUTCOME MEASURES

Importance of key information about screening colonoscopy, including potential risks and benefits, baseline risk of colorectal cancer/polyps and practical aspects of the procedure, as well as associations between participants' characteristics and their judgement of information as to being 'very important'.

RESULTS

Of 1871 respondents (overall response rate: 31%), a subgroup of 370 colonoscopy-naïve subjects was eligible for inclusion (average age: 55 years, 47% male). Information on the risks was rated as very important by most respondents, unimportant by 6%. Information on the benefits was considered unimportant by 26%. Regression analysis showed that less educated persons regarded most items to be more often relevant than highly educated subjects. A greater proportion of women than men rated details regarding pain and practical aspects as very important. Subjects with a low educational level living alone were identified as the group with the least interest in information on risks.

CONCLUSION

Cultivating awareness around the central meaning of the (quantitative) benefits of screening in informed decision making should be focused on more in future information materials. The high requirement of less educated people to become more informed provides a strong motivation for further efforts to develop evidence-based information that adequately informs this group. Tailoring information according to gender-specific needs may be warranted in light of the observed differences in information preferences between women and men.

Expected long-term impact of screening endoscopy on colorectal cancer incidence: a modelling study

BACKGROUND & AIMS

Screening endoscopy reduces colorectal cancer (CRC) incidence but the time course and magnitude of effects beyond 10 years after screening are unknown. We aimed to estimate the expected time course and magnitude of long-term impact of screening endoscopy on CRC incidence.

METHODS

We used Markov models based on the natural history of the disease along with data from the German national screening colonoscopy registry to derive the expected impact of screening colonoscopy at age 55 or 60 on cumulative CRC incidence according to time of follow-up over a period of up to 25 years.

RESULTS

After a single screening colonoscopy, cumulative CRC incidence is expected to be increased for approximately 4 to 5 years. This transient increase is expected to be followed by a steadily increasing reduction in cumulative CRC incidence for at least 25 years. Less than one third of this long-term reduction is expected to be seen within 10-12 years of follow-up, the length of follow-up reported on in RCTs on flexible sigmoidoscopy screening and in most cohort studies on both sigmoidoscopy and colonoscopy screening. In relative terms, risk reduction is expected to reach its maximum approximately 15 years after a single screening colonoscopy and 20-25 years after the initial screening colonoscopy in case of repeat screening colonoscopy after 10 years.

CONCLUSIONS

The long-term impact of screening endoscopy on CRC prevention is expected to be much stronger than suggested by currently available evidence from RCTs and cohort studies with limited length of follow-up.

Public health impact of colonoscopy use on colorectal cancer mortality in Germany and the United States

BACKGROUND AND AIMS

Colonoscopy has been demonstrated to be effective in reducing colorectal cancer (CRC) incidence and mortality and has been widely used for primary CRC screening in Germany and the United States. We performed a population-based analysis to evaluate and compare the public health impact of recent colonoscopy use on CRC deaths among adults aged 55 to 79 years in Germany and the United States from 2008 to 2011.

METHODS

The epidemiologic metrics of attributable fraction and prevented fraction as well as the impact numbers were calculated using colonoscopy utilization data from nationally representative health surveys, relative risk estimates from medical literature, and CRC death registry data.

RESULTS

Overall, 36.6% (95% credible interval [CrI], 27.3%-45.5%) of CRC deaths in Germany were estimated to be attributable to nonuse of colonoscopy, compared with the U.S. estimates of 38.2% (95% CrI, 28.6%-47.1%) and 33.6% (95% CrI, 24.8%-42.2%) for years 2008 to 2009 and 2010 to 2011, respectively. The proportion of CRC deaths theoretically prevented by colonoscopy use within 10 years was 30.7% (95% CrI, 24.8%-35.7%) in Germany, whereas in the United States this proportion ranged from 29.0% (95% CrI, 23.4%-33.6%) for 2008 to 2009 to 33.9% (95% CrI, 27.4%-39.2%) for 2010 to 2011.

CONCLUSIONS

Recent colonoscopy use is likely to have prevented a considerable fraction of CRC mortality in both countries, and more deaths could be avoided by increasing colonoscopy use in the target population. Attributable and prevented fraction can provide valuable information on the public health impact of colonoscopy use and guide policymaking.

Towards personalized medicine of colorectal cancer

Efforts in colorectal cancer (CRC) research aim to improve early detection and treatment for metastatic stages which could translate into better prognosis of this disease. One of the major challenges that hinder these efforts is the heterogeneous nature of CRC and involvement of diverse molecular pathways. New large-scale 'omics' technologies are making it possible to generate, analyze and interpret biological data from molecular determinants of CRC. The developments of sophisticated computational analyses would allow information from different omics platforms to be integrated, thus providing new insights into the biology of CRC. Together, these technological advances and an improved mechanistic understanding might allow CRC to be clinically managed at the level of the individual patient. This review provides an account of the current challenges in CRC management and an insight into how new technologies could allow the development of personalized medicine for CRC.

How significant is the association between metabolic syndrome and prevalence of colorectal neoplasia?

The incidence and prevalence of metabolic syndrome (MS) and colorectal cancer (CRC) has been rising in developed countries. The association between these two diseases has been widely studied and reported. Less evidence is available about the relationship between MS and CRC precancerous lesions (adenomatous polyps, adenomas). The aim of this paper is to present an overview of our scientific understanding of that topic and its implication in clinical practice. One of the principal goals of current CRC secondary prevention efforts is to detect and remove the precancerous lesions in individuals with an average CRC risk to prevent the development of invasive cancer. MS is not currently considered a high-risk CRC factor and is therefore not included in the guidelines of organized screening programs. However, in light of growing scientific evidence, the approach to patients with MS should be changed. Metabolic risk factors for the development of adenomas and cancers are the same - obesity, impaired glucose tolerance, dyslipidemia, hypertension, cardiovascular diseases and diabetes mellitus type 2. Therefore, the key issue in the near future is the development of a simple scoring system, easy to use in clinical practice, which would identify individuals with high metabolic risk of colorectal neoplasia and would be used for individual CRC secondary prevention strategies. Currently, such scoring systems have been published based on Asian (Asia-Pacific Colorectal Screening Score; APCS) and Polish populations.

[Screening for cancer]

A low birth rate in addition to an increasing life expectancy within the context of an aging population characterize the current demographic situation in Germany. Cancer is primarily a disease of old age and the frequency increases with an expanding older population. In 2013, cancer was the second most common cause of death in Germany. With the aid of screening examinations cancer should be detected in the early stages so that suitable therapeutic measures can be initiated. In Germany, screening is currently offered for breast, cervical, colorectal, skin and prostate cancer and is covered by the statutory health insurance. Mammography screening is the only organized screening program in Germany. Eligible women are regularly invited to attend this program, which is not the case for the other types of cancer screening. In accordance with the Cancer Screening and Registry Act (KFRG) of 2013, colorectal and cervical cancer screening will also be implemented as organized screening programs in the future. As is the case in the mammography screening program, those eligible to participate will receive an invitation letter and the new programs are to be continually monitored, documented and evaluated.

Colonoscopy Reduces Colorectal Cancer Incidence and Mortality in Patients With Non-Malignant Findings: A Meta-Analysis

OBJECTIVES

Observational studies have shown that colonoscopy reduces colorectal cancer (CRC) incidence and mortality in the general population. We aimed to conduct a meta-analysis quantifying the magnitude of protection by colonoscopy, with screening and diagnostic indications, against CRC in patients with non-malignant findings and demonstrating the potentially more marked effect of screening over diagnostic colonoscopy.

METHODS

PubMed, EMBASE, and conference abstracts were searched through 30 April 2015. The primary outcomes were overall CRC incidence and mortality. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random-effect models.

RESULTS

Eleven observational studies with a total of 1,499,521 individuals were included. Pooled analysis showed that colonoscopy was associated with a 61% RR reduction in CRC incidence (RR: 0.39; 95% CI: 0.26-0.60; I(2)=93.6%) and a 61% reduction in CRC mortality (RR: 0.39; 95% CI: 0.35-0.43; I(2)=12.0%) in patients with non-malignant findings, although there was high heterogeneity for the outcome of CRC incidence. After excluding one outlier study, there was low heterogeneity for the outcome of incidence (I(2)=44.7%). Subgroup analysis showed that the effect of screening colonoscopy was more prominent, corresponding to an 89% reduction in CRC incidence (RR: 0.11; 95% CI: 0.08-0.15), in comparison with settings involving diagnostic colonoscopy (RR: 0.51; 95% CI: 0.43-0.59; P<0.001).

CONCLUSIONS

On the basis of this meta-analysis of observational studies, CRC incidence and mortality in patients with non-malignant findings are significantly reduced after colonoscopy. The effect of screening colonoscopy on CRC incidence is more marked than diagnostic colonoscopy.

Declining Bowel Cancer Incidence and Mortality in Germany

BACKGROUND

In October 2002, screening colonoscopy from age 55 onward was introduced as part of the German national statutory cancer screening program. Screening colonoscopy is intended to lower both the mortality and the incidence of bowel cancer by enabling the detection and removal of precursor lesions.

METHODS

The authors studied trends in bowel cancer incidence and mortality in Germany from 2003 to 2012 on the basis of data from the epidemiological cancer registries and from cause-of-death statistics.

RESULTS

Over the period of investigation, the age-standardized incidence of bowel cancer (with the European population as a standard) fell from 66.1 to 57.0 cases per 100 000 persons per year (-13.8%) in men and from 42.6 to 36.5 per 100 000 persons per year (-14.3%) in women. In parallel with these changes, the age-standardized mortality from bowel cancer fell by 20.8% in men and by 26.5% in women. In the age groups 55-64, 65-74, and 75-84 years, the cumulative risk of receiving a diagnosis of bowel cancer fell by 17-26%; in persons under age 55, this risk fell by only 3% in men, but increased by 14% in women. Long-term data from the cancer registry in the German federal state of Saarland revealed that the incidence of bowel cancer, but not its mortality, had risen over the decades preceding the study; it was only during the period of investigation that the trend reversed itself.

CONCLUSION

Within 10 years of the introduction of screening colonoscopy in Germany, the incidence of bowel cancer in persons over age 55 fell by 17-26%, after having risen steadily over the preceding decades.

Evaluation of a 5-Marker Blood Test for Colorectal Cancer Early Detection in a Colorectal Cancer Screening Setting

PURPOSE

In initial studies that included colorectal cancer patients undergoing diagnostic colonoscopy, we had identified a serum marker combination able to detect colorectal cancer with similar diagnostic performance as fecal immunochemical test (FIT). In this study, we aimed to validate the results in participants of a large colorectal cancer screening study conducted in the average-risk, asymptomatic screening population.

EXPERIMENTAL DESIGN

We tested serum samples from 1,200 controls, 420 advanced adenoma patients, 4 carcinoma in situ patients, and 36 colorectal cancer patients with a 5-marker blood test [carcinoembryonic antigen (CEA)+anti-p53+osteopontin+seprase+ferritin]. The diagnostic performance of individual markers and marker combinations was assessed and compared with stool test results.

RESULTS

AUCs for the detection of colorectal cancer and advanced adenomas with the 5-marker blood test were 0.78 [95% confidence interval (CI), 0.68-0.87] and 0.56 (95% CI, 0.53-0.59), respectively, which now is comparable with guaiac-based fecal occult blood test (gFOBT) but inferior to FIT. With cutoffs yielding specificities of 80%, 90%, and 95%, the sensitivities for the detection of colorectal cancer were 64%, 50%, and 42%, and early-stage cancers were detected as well as late-stage cancers. For osteopontin, seprase, and ferritin, the diagnostic performance in the screening setting was reduced compared with previous studies in diagnostic settings while CEA and anti-p53 showed similar diagnostic performance in both settings.

CONCLUSIONS

Performance of the 5-marker blood test under screening conditions is inferior to FIT even though it is still comparable with the performance of gFOBT. CEA and anti-p53 could contribute to the development of a multiple marker blood-based test for early detection of colorectal cancer.