Effect of flexible sigmoidoscopy-based screening on incidence and mortality of colorectal cancer: a systematic review and meta-analysis of randomized controlled trials

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

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

Effects of sigmoidoscopy screening (including colonoscopy) on colorectal cancer: A meta-analysis based on randomized controlled trials

Background

This study aimed to investigate the role of endoscopy screening in colorectal cancer (CRC).

Methods

Up to January 2023, databases were searched for studies related to sigmoidoscopy and colonoscopy screening. The incidence of CRC, and/or CRC mortality were the main observation outcomes.

Results

A total of 5 randomized controlled trials (RCTs) published from 2017 to 2022 were included. Among them, four studies used sigmoidoscopy screening and one study involved colonoscopy screening. Statistical results showed that the incidence (RR: 0.78, p < 0.001) and mortality (RR: 0.75, p < 0.001) of CRC were significantly lower in the screening group than in the control group. Further, a subgroup analysis of CRC site indicated that the incidence and mortality of CRC in the screening group were significantly lower than those in the non-screened group, regardless of distal CRC (Incidence: RR: 0.66, p < 0.001; Mortality: RR: 0.62, p < 0.001) or proximal CRC (Incidence: RR: 0.94, p = 0.038; Mortality: RR: 0.89, p = 0.038). In terms of gender, compared with the non-screening group, both males (Incidence: RR: 0.73, p < 0.001; Mortality: RR: 0.68, p < 0.001) and females (Incidence: RR: 0.85, p < 0.001; Mortality: RR: 0.85, p = 0.017), the screening group had a significant decrease in the incidence and mortality of CRC.

Conclusion

This meta-analysis demonstrated that sigmoidoscopy screening (including colonoscopy) could effectively reduce the incidence and mortality of CRC.

An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles

OBJECTIVE

New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers.

DESIGN

A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles.

RESULTS

Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence.

CONCLUSION

New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact.

Evaluation of a Multi-Gene Methylation Blood-Test for the Detection of Colorectal Cancer

Circulating tumour DNA biomarkers are an expanding field in oncology research that offer great potential but are currently often limited in value by overall cost. The aim of this study was to evaluate the efficacy of a novel multi-gene methylation blood test for the identification of colorectal cancer and throughout the spectrum of colorectal disease. Participants were recruited either prior to resection for known CRC or prior to screening colonoscopy after a positive faecal immunochemical test. Blood was collected from participants prior to their procedure being performed. The plasma was separated, and multiplex MethylLight droplet digital PCR was used to analyse for the presence of four methylated genes: SDC2, NPY, IKZF1 and SEPT9. A total of 537 participants underwent analysis. The SDC2/NPY genes showed a sensitivity of 33-54% and a specificity of 72-96%, whilst the IKZF1/SEPT9 genes showed a sensitivity of 19-42% and a specificity of 88-96%. Combining the two tests did not significantly increase the test accuracy. The sensitivity for advanced adenoma was 2-15%. There was a significant difference in the frequency of detectable methylation between the participants with CRC and those without CRC. However, neither the sensitivity nor the specificity was superior to current diagnostic screening tests.

Effect of flexible sigmoidoscopy-based screening on colorectal cancer incidence and mortality: an updated systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Our objective was to estimate the effect of flexible sigmoidoscopy (FS)-based screening on colorectal cancer (CRC) incidence and mortality by conducting an updated meta-analysis of randomized controlled trials (RCTs).

METHODS

PubMed, Web of Science, Embase, and Cochrane Library searched for RCTs from database inception to December 2022. The methodological quality of the RCTs was assessed using the Cochrane Collaboration Risk of Bias Tool. RevMan 5.4 was used for this meta-analysis.

RESULTS

Four RCTs involving 457, 871 patients were included. This meta-analysis revealed that FS-based screening was associated with a 20% relative risk reduction in CRC incidence [RR = 0.80; 95% CI (0.75, 0.86); P < 0.00001], and a 24% reduction in CRC mortality [RR = 0.76; 95% CI (0.70, 0.82); P < 0.00001]. In addition, this meta-analysis revealed that FS-based screening reduced the incidence[RR = 0.68; 95% CI (0.60, 0.77); P < 0.00001] and mortality[RR = 0.64; 95% CI (0.49, 0.83); P = 0.0007] of distal CRC, but had no significant effect on proximal colon cancer.

CONCLUSION

FS-based screening appeared to be effective in reducing distal CRC incidence and mortality in patients at average risk compared to no intervention, but had no significant effect on proximal colon cancer.

Effectiveness of Colorectal Cancer (CRC) Screening on All-Cause and CRC-Specific Mortality Reduction: A Systematic Review and Meta-Analysis

(1) Background: The aim of this study was to pool and compare all-cause and colorectal cancer (CRC) specific mortality reduction of CRC screening in randomized control trials (RCTs) and simulation models, and to determine factors that influence screening effectiveness. (2) Methods: PubMed, Embase, Web of Science and Cochrane library were searched for eligible studies. Multi-use simulation models or RCTs that compared the mortality of CRC screening with no screening in general population were included. CRC-specific and all-cause mortality rate ratios and 95% confidence intervals were calculated by a bivariate random model. (3) Results: 10 RCTs and 47 model studies were retrieved. The pooled CRC-specific mortality rate ratios in RCTs were 0.88 (0.80, 0.96) and 0.76 (0.68, 0.84) for guaiac-based fecal occult blood tests (gFOBT) and single flexible sigmoidoscopy (FS) screening, respectively. For the model studies, the rate ratios were 0.45 (0.39, 0.51) for biennial fecal immunochemical tests (FIT), 0.31 (0.28, 0.34) for biennial gFOBT, 0.61 (0.53, 0.72) for single FS, 0.27 (0.21, 0.35) for 10-yearly colonoscopy, and 0.35 (0.29, 0.42) for 5-yearly FS. The CRC-specific mortality reduction of gFOBT increased with higher adherence in both studies (RCT: 0.78 (0.68, 0.89) vs. 0.92 (0.87, 0.98), model: 0.30 (0.28, 0.33) vs. 0.92 (0.51, 1.63)). Model studies showed a 0.62-1.1% all-cause mortality reduction with single FS screening. (4) Conclusions: Based on RCTs and model studies, biennial FIT/gFOBT, single and 5-yearly FS, and 10-yearly colonoscopy screening significantly reduces CRC-specific mortality. The model estimates are much higher than in RCTs, because the simulated biennial gFOBT assumes higher adherence. The effectiveness of screening increases at younger screening initiation ages and higher adherences.

Aberrant HMGA2 Expression Sustains Genome Instability That Promotes Metastasis and Therapeutic Resistance in Colorectal Cancer

Colorectal cancer (CRC) is one of the most lethal cancers worldwide, accounting for nearly ~10% of all cancer diagnoses and deaths. Current therapeutic approaches have considerably increased survival for patients diagnosed at early stages; however, ~20% of CRC patients are diagnosed with late-stage, metastatic CRC, where 5-year survival rates drop to 6–13% and treatment options are limited. Genome instability is an enabling hallmark of cancer that confers increased acquisition of genetic alterations, mutations, copy number variations and chromosomal rearrangements. In that regard, research has shown a clear association between genome instability and CRC, as the accumulation of aberrations in cancer-related genes provides subpopulations of cells with several advantages, such as increased proliferation rates, metastatic potential and therapeutic resistance. Although numerous genes have been associated with CRC, few have been validated as predictive biomarkers of metastasis or therapeutic resistance. A growing body of evidence suggests a member of the High-Mobility Group A (HMGA) gene family, HMGA2, is a potential biomarker of metastatic spread and therapeutic resistance. HMGA2 is expressed in embryonic tissues and is frequently upregulated in aggressively growing cancers, including CRC. As an architectural, non-histone chromatin binding factor, it initiates chromatin decompaction to facilitate transcriptional regulation. HMGA2 maintains the capacity for stem cell renewal in embryonic and cancer tissues and is a known promoter of epithelial-to-mesenchymal transition in tumor cells. This review will focus on the known molecular mechanisms by which HMGA2 exerts genome protective functions that contribute to cancer cell survival and chemoresistance in CRC.

Single CT Appointment for Double Lung and Colorectal Cancer Screening: Is the Time Ripe?

Annual screening of lung cancer (LC) with chest low-dose computed tomography (CT) and screening of colorectal cancer (CRC) with CT colonography every 5 years are recommended by the United States Prevention Service Task Force. We review epidemiological and pathological data on LC and CRC, and the features of screening chest low-dose CT and CT colonography comprising execution, reading, radiation exposure and harm, and the cost effectiveness of the two CT screening interventions. The possibility of combining chest low-dose CT and CT colonography examinations for double LC and CRC screening in a single CT appointment is then addressed. We demonstrate how this approach appears feasible and is already reasonable as an opportunistic screening intervention in 50–75-year-old subjects with smoking history and average CRC risk. In addition to the crucial role Computer Assisted Diagnosis systems play in decreasing the test reading times and the need to educate radiologists in screening chest LDCT and CT colonography, in view of a single CT appointment for double screening, the following uncertainties need to be solved: (1) the schedule of the screening CT; (2) the effectiveness of iterative reconstruction and deep learning algorithms affording an ultra-low-dose CT acquisition technique and (3) management of incidental findings. Resolving these issues will imply new cost-effectiveness analyses for LC screening with chest low dose CT and for CRC screening with CT colonography and, especially, for the double LC and CRC screening with a single-appointment CT.

Colorectal cancer screening knowledge and uptake in lebanon: a national survey

OBJECTIVE

The main aim of this national survey was to identify the levels of colorectal cancer screening knowledge and uptake in Lebanon.

METHODS

A total of 1200 participants were enrolled in this cross-sectional household survey targeting the Lebanese population aged 50 years and above. The sample was recruited using a two-stage stratified cluster sampling approach.

RESULTS

Of the total sample, 38.3% knew about any screening test for colorectal cancer but only 7.5% had ever used any. Thirty-nine percent of the participants rated their risk of getting colorectal cancer as very low or low, and only 53.5% were confident in their ability to undertake a screening test. Almost all participants agreed that medical advice and test reimbursement would encourage them to do a screening test. At the multivariate analysis level, hearing of an awareness campaign in the last two years showed the strongest association with the knowledge of a colorectal cancer screening test with an estimated OR_adj = 5.12 (95%CI: 3.67 - 7.15). Other factors that were significantly associated with this knowledge variable included: a family history of colorectal cancer, a personal history of colorectal illness, having a health coverage, and knowledge of colorectal cancer signs and symptoms.

DISCUSSION

This national study highlights an alarming lack of uptake and low levels of knowledge of colorectal cancer screening tests even though it is among the most prevalent cancers in Lebanon and its prevalence has been continuously increasing in the past years. The evidence suggests that people who had an experience with colorectal cancer diagnostic tests, either personally or through a family member, and those who have heard of an awareness campaign about colorectal cancer in the last two years are more likely to know its screening tests.

CONCLUSION

Colorectal cancer screening knowledge and uptake in Lebanon are limited and justify the need for public health interventions. This study gives evidence that awareness campaigns, coupled with the involvement of medical providers and the reimbursement of screening test fees, would alleviate the burden of colorectal cancer in Lebanon.

Use of Omics Technologies for the Detection of Colorectal Cancer Biomarkers

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers with high mortality rates, especially when detected at later stages. Early detection of CRC can substantially raise the 5-year survival rate of patients, and different efforts are being put into developing enhanced CRC screening programs. Currently, the faecal immunochemical test with a follow-up colonoscopy is being implemented for CRC screening. However, there is still a medical need to describe biomarkers that help with CRC detection and monitor CRC patients. The use of omics techniques holds promise to detect new biomarkers for CRC. In this review, we discuss the use of omics in different types of samples, including breath, urine, stool, blood, bowel lavage fluid, or tumour tissue, and highlight some of the biomarkers that have been recently described with omics data. Finally, we also review the use of extracellular vesicles as an improved and promising instrument for biomarker detection.

Age-Specific Rates and Time-Courses of Gastrointestinal and Nongastrointestinal Complications Associated With Screening/Surveillance Colonoscopy

INTRODUCTION

The rates of serious cardiac, neurologic, and pulmonary events attributable to colonoscopy are poorly characterized, and background event rates are usually not accounted for.

METHODS

We performed a multistate population-based study using changepoint analysis to determine the rates and timing of serious gastrointestinal and nongastrointestinal adverse events associated with screening/surveillance colonoscopy, including analyses by age (45 to <55, 55 to <65, 65 to <75, and ≥75 years). Among 4.5 million persons in the Ambulatory Surgery and Services Databases of California, Florida, and New York who underwent screening/surveillance colonoscopy in 2005-2015, we ascertained serious postcolonoscopy events in excess of background rates in Emergency Department (SEDD) and Inpatient Databases (SID).

RESULTS

Most serious nongastrointestinal postcolonoscopy events were expected based on the background rate and not associated with colonoscopy itself. However, associated nongastrointestinal events predominated over gastrointestinal events at ages ≥65 years, including more myocardial infarctions plus ischemic strokes than perforations at ages ≥75 years (361 [95% confidence intervals {CI} 312-419] plus 1,279 [95% CI 1,182-1,384] vs 912 [95% CI 831-1,002] per million). At all ages, the observed-to-expected ratios for days 0-7, 0-30, and 0-60 after colonoscopy were substantially >1 for gastrointestinal bleeding and perforation, but minimally >1 for most nongastrointestinal complications. Risk periods ranged from 1 to 125 days depending on complication type and age. No excess postcolonoscopy in-hospital deaths were observed.

DISCUSSION

Although crude counts substantially overestimate nongastrointestinal events associated with colonoscopy, nongastrointestinal complications exceed bleeding and perforation risk in older persons. The inability to ascertain modifications to antiplatelet therapy was a study limitation. Our results can inform benefit-to-risk determinations for preventive colonoscopy.

Nanotechnology in Colorectal Cancer for Precision Diagnosis and Therapy

Colorectal cancer (CRC) is the third most frequently occurring tumor in the human population. CRCs are usually adenocarcinomatous and originate as a polyp on the inner wall of the colon or rectum which may become malignant in the due course of time. Although the therapeutic options of CRC are limited, the early diagnosis of CRC may play an important role in preventive and therapeutic interventions to decrease the mortality rate. The CRC-affected tissues exhibit several molecular markers that may be exploited as the novel strategy to develop newer approaches for the treatment of the disease. Nanotechnology consists of a wide array of innovative and astonishing nanomaterials with both diagnostics and therapeutic potential. Several nanomaterials and nano formulations such as Carbon nanotubes, Dendrimer, Liposomes, Silica Nanoparticles, Gold nanoparticles, Metal-organic frameworks, Core-shell polymeric nano-formulations, Nano-emulsion System, etc can be used to targeted anticancer drug delivery and diagnostic purposes in CRC. The light-sensitive photosensitizer drugs loaded gold and silica nanoparticles can be used to diagnose as well as the killing of CRC cells by the targeted delivery of anticancer drugs to cancer cells. This review is focused on the recent advancement of nanotechnology in the diagnosis and treatment of CRC.

Adenoma and Serrated Lesion Detection by Colonoscopy Indication: The ADR-ESS (ADR Extended to all Screening/Surveillance) Score

BACKGROUND

The adenoma detection rate at screening (ADR) predicts interval colorectal cancer. Monitoring other lesion detection rates and colonoscopy indications has been proposed. We developed a comprehensive, automated colonoscopy audit program based on standardized clinical documentation, explored detection rates across indications, and developed the Adenoma Detection Rate - Extended to all Screening / Surveillance (ADR-ESS) score.

METHODS

In a prospective cohort study, we calculated overall and advanced adenoma and sessile serrated lesion (SSL) detection rates among 15,253 colonoscopies by 35 endoscopists from 4 endoscopy units across all colonoscopy indications. We explored correlations between detection rates, and the precision and stability of ADR-ESS versus ADR.

RESULTS

The overall "screening, first" ADR was 36.3% (95% confidence interval [CI], 34.5%-38.1%). The adenoma detection rate was lower for "screening, not first" (relative rate [RR], 0.80; 95% CI, 0.74-0.87) and "family history" (RR, 0.84; 95% CI, 0.74-0.96), and higher for "surveillance" (RR, 1.22; 95% CI, 1.15-1.31) and "follow-up, FIT" (RR, 1.21; 95% CI, 1.07-1.37). For "screening, first," the detection rates for advanced adenoma, SSL, and advanced SSL were 6.7% (95% CI, 5.7%-7.7%), 7.2% (95% CI, 6.2%-8.2%), and 2.6% (95% CI, 2.0%-3.2%), respectively. Adenoma and SSL detection were correlated (r = 0.44; P = .008). ADR-ESS had substantially narrower confidence intervals and less period-to-period variability than ADR, and was not improved by weighting for indication volume and correction for detection by indication.

CONCLUSIONS

Comprehensive, automated colonoscopy audit based on standardized clinical documentation is feasible. Adenoma detection is a fair but imperfect proxy for SSL detection. ADR-ESS increases the precision of adenoma detection assessments and emphasizes quality across colonoscopy indications.

Characteristics of colorectal cancers among Alaska Native people before and after implementing programs to promote screening

BACKGROUND

Alaska Native (AN) people have the highest rates of colorectal cancer (CRC) globally. Increasing CRC screening has been effective in reducing CRC-related morbidity and mortality in other populations.

OBJECTIVE

To examine recent descriptive epidemiology and longer-term CRC trends among AN people. To determine any changes in the descriptive epidemiology of CRC among AN people concurrent with increases in screening prevalence.

METHODS

We estimated age-specific CRC incidence and mortality rates 2000-2017. To examine longer-term trends in incidence and mortality 1990-2017, we conducted Joinpoint regression analyses of three-year rolling average incidence and mortality rates. We calculated descriptive statistics for two time-periods: 2000-2008, and 2009-2017. Finally, we examined five-year survival probability.

RESULTS

CRC incidence increased over time (1990-2017) among AN people aged less than 50 years, while there were modest declines in AN people older than 50 years old since 2000. Overall, AN CRC mortality rates declined between 1990 and 2004, but have been increasing steadily since that time. Comparing 2000-2008 with 2009-2017 we observed no difference in CRC incidence and mortality, age at diagnosis, tumor size, tumor location, or stage distribution. Survival analyses indicated no change in hazard of death between 2004-2008 and 2009-2017 (HR 1.02, 95 % CI: 0.74, 1.38, P = 0.93).

CONCLUSIONS

Colorectal cancer prevention and control efforts across the Alaska Tribal Health System have not yet resulted in reduced mortality rates, or induced earlier stage migration.

POLICY SUMMARY STATEMENT

Intensified efforts will be necessary to reduce the burden of CRC among this high-risk population. Continued and increased focus on primary and secondary prevention efforts is warranted.

Detection of advanced colorectal neoplasia and relative colonoscopy workloads using quantitative faecal immunochemical tests: an observational study exploring the effects of simultaneous adjustment of both sample number and test positivity threshold

OBJECTIVE

When screening for colorectal cancer (CRC) using quantitative faecal immunochemical tests (FIT), test parameters requiring consideration are the faecal haemoglobin concentration (f-Hb) positivity cut-off and the number of stools sampled. This observational study explored variation in f-Hb between samples and the relationship between sensitivity for advanced neoplasia (AN, cancer or advanced adenoma) and colonoscopy workload across a range of independently-adjusted parameter combinations.

DESIGN

Quantitative FIT data (OC-Sensor) were accessed from individuals undergoing personalised colonoscopic screening with an offer of 2-sample FIT in the intervening years. We estimated variation in f-Hb between samples in 12 710 completing 2-sample FIT, plus test positivity rates (colonoscopy workload) and sensitivity for AN according to parameter combinations in 4037 instances where FIT was done in the year preceding colonoscopy.

RESULTS

There was large within-subject variability between samples, with the ratio for the second to the first sample f-Hb ranging up to 18-fold for all cases, and up to 56-fold for AN cases. Sensitivity for AN was greatest at lower f-Hb cut-offs and/or using 2-sample FIT. Colonoscopy workload varied according to how parameters were combined. Using different cut-offs for 1-sample FIT and 2-sample FIT to return similar sensitivity, workload was less with 2-sample FIT when the sensitivity goal exceeded 35%.

CONCLUSION

Variation in f-Hb between samples is such that both parameters are crucial determinants of sensitivity and workload; independent adjustment of each should be considered. The 2-sample FIT approach is best for detecting advanced adenomas as well as CRC provided that the colonoscopy workload is feasible.

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.

The Role of p53 Dysfunction in Colorectal Cancer and Its Implication for Therapy

Colorectal cancer (CRC) is one of the most common and fatal cancers worldwide. The carcinogenesis of CRC is based on a stepwise accumulation of mutations, leading either to an activation of oncogenes or a deactivation of suppressor genes. The loss of genetic stability triggers activation of proto-oncogenes (e.g., KRAS) and inactivation of tumor suppression genes, namely TP53 and APC, which together drive the transition from adenoma to adenocarcinoma. On the one hand, p53 mutations confer resistance to classical chemotherapy but, on the other hand, they open the door for immunotherapy, as p53-mutated tumors are rich in neoantigens. Aberrant function of the TP53 gene product, p53, also affects stromal and non-stromal cells in the tumor microenvironment. Cancer-associated fibroblasts together with other immunosuppressive cells become valuable assets for the tumor by p53-mediated tumor signaling. In this review, we address the manifold implications of p53 mutations in CRC regarding therapy, treatment response and personalized medicine.

Effects of Screenings in Reducing Colorectal Cancer Incidence and Mortality Differ by Polygenic Risk Scores

INTRODUCTION

Colorectal cancer (CRC) screening reduces CRC incidence and mortality. However, it is unclear whether the reduction in CRC risk may differ by genetic susceptibility.

METHODS

We evaluated this question in a cohort of 304,740 participants of European descent aged 50 years and older. Genetic susceptibility was measured using a polygenic risk score (PRS) constructed with risk variants identified in genomewide association studies. Cox models were used to estimate hazard ratios and 95% confidence intervals of CRC risk.

RESULTS

Over a median follow-up of 7.0 years, 2,261 incident CRC cases and 528 CRC deaths were identified. CRC screening was associated with a significantly reduced CRC incidence among individuals with a high (hazard ratio, 0.80; 95% confidence interval, 0.71-0.92) and intermediate PRS (0.84, 0.71-0.98) but not among those with a low PRS (1.03, 0.86-1.25; Pinteraction, 0.005). A similar but more evident difference was observed for mortality (Pinteraction, 0.046), with more than 30% reduced mortality observed in the high PRS group (0.69, 0.52-0.91). Among the younger group (age 50-60 years), CRC screenings were associated with a slightly (but nonsignificantly) elevated incidence and mortality in the low PRS group but a reduced risk in the high PRS group (Pinteraction, 0.043 [incidence]; 0.092 [mortality]). No significant interaction was observed in the older group (age > 60 years).

DISCUSSION

Individuals with a higher genetic risk benefited more substantially from CRC screenings than those with a lower risk. Our findings suggest that PRS may be used to develop personalized CRC screening to maximize its effect on CRC prevention.

Colonoscopy screening and surveillance guidelines

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles.

Citrus fruit intake and lung cancer risk: A meta-analysis of observational studies

OBJECTIVE

To explore the hypothesis that Citrus intake may reduce the risk of lung cancer.

DESIGN

Meta-analyses of Dichotomy and dose-response relationship.

DATA SOURCES

We searched online literature databases including PubMed, Embase, and Cochrane Library to screen relevant articles available up to 27 July 2020. Search terms included (i) Citrus, Fruit, Diet, Dietary; (ii) cancer, neoplasm, tumor (iii)lung; (iv)case-control, cohort, prospective.

STUDY SELECTION

The selection of studies and the meta-analysis were carried out by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The following inclusion criteria were chosen: (i) epidemiological studies with case-control or cohort design; (ii) human participants; (iii) studies investigated the relationship between Citrus fruit intake and lung cancer risk; (iv) if data were duplicated in more than two studies, we brought the most recent or all-sided study into this analysis. We collected all full-text articles that met the inclusion criteria. We applied the following exclusion criteria to the full-text articles, including possible articles listed by manual search: (i) there was no represented odds ratio (OR) or relative risk (RR) estimate and its corresponding 95 % confidence interval (95 % CI) (or data to calculate them) for the highest versus lowest levels of Citrus fruit consumption (ii) reviews, systematic reviews and meta-analyses; (iii) there was no data of Citrus fruit intake at the individual level.

DATA EXTRACTION

Two reviewers independently performed the extraction of data from eligible studies.

STATISTICAL METHODS

Adjusted odds ratios (ORs) and 95 % CIs were combined and weighted by the method of "Dersimonian and Laird" to produce pooled ORs using a random-effects model. Moreover, we utilized the method reported by "Longnecker and Greenland" to evaluate linear trends and 95 % CIs by the ORs' natural logs and corresponding CIs from categories of Citrus intake. Finally, we evaluated the risk of publication bias and selection bias by inspecting for asymmetry in the pre-specified funnel plots of the study OR against the standard error of the OR's logarithm and by "Egger's test".

RESULTS

We included twenty-one studies in the final review. Pooled analyses suggested that those with the highest Citrus fruit intake compared to the lowest intake had a 9% reduction in lung cancer risk [OR 0.91 (95 % CI 0.84-0.98)]. We found a nonlinear association between Citrus intake and lung cancer risk in the dose-response analysis (p = 0.0054) and that the risk reached the minimum (OR = 0.91) around 60 g/d. However, no obvious dose-response association was observed with intakes above 80 g/d.

CONCLUSION

We found that Citrus fruit intake was negatively associated with the risk of lung cancer. Besides, there was a nonlinear dose-response relationship between Citrus intake and lung cancer risk within a certain range.

Implementation of long-term non-participant reminders for flexible sigmoidoscopy screening

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Long-term self-referral reminders increased uptake by 4.1%.

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13% of those who self-referred had pre-cancerous lesions detected.

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The biggest effects were seen in the most deprived areas.

The clinical effectiveness of screening is highly dependent on uptake. Previous randomised controlled trials suggest that non-participant reminders, which highlight the opportunity to re-book an appointment, can improve participation. The present analysis examines the impact of implementing these reminders within the English Flexible Sigmoidoscopy (FS) Screening Programme, which offers once-only FS screening to adults aged 55–59 years.

We assessed the screening status of 26,339 individuals invited for once-only FS screening in England. A total of 10,952 (41.6%) had attended screening, and were subsequently ineligible. The remaining 15,387 had not attended screening, and were selected to receive a reminder, 1–2 years after their invitation. Descriptive statistics were used to assess the increase in uptake and the adenoma detection rate (ADR) of those who self-referred, six months after the delivery of the final reminder. Pearson’s Chi-Square was used to compare the ADR between those who attended when invited and those who self-referred.

Of the 15,387 adults eligible to receive a reminder, 13,626 (88.6%) were sent a reminder as intended (1,761 were not sent a reminder, due to endoscopy capacity). Of these, 8.0% (n = 1,086) booked and attended an appointment, which equated to a 4.1% increase in uptake from 41.6% at baseline, to 45.7% at follow-up. The ADR was significantly higher for those who self-referred, compared with those who attended when invited (13.3% and 9.5%, respectively; X² = 16.138, p = 0.000059).

The implementation of non-participant reminders led to a moderate increase in uptake. Implementing non-participant reminders could help mitigate the negative effects of COVID-19 on uptake.

The association between hypertension and colorectal cancer: a meta-analysis of observational studies

The relationship between hypertension and risk of colorectal cancer (CRC) is unclear. This meta-analysis aims to explore the association between them. Six databases were searched for studies published before August 2019. The pooled relative risk (RR) and 95% confidence intervals (CIs) were calculated to estimate the association between the hypertension and CRC risk. A total of 2841 potentially relevant articles were obtained, and 25 studies with a pooled 1.95 million participants were finally included in the meta-analysis. These results suggested a positive association between hypertension and risk of CRC with a pooled RR of 1.15 (95% CI: 1.08, 1.23). Male patients with hypertension had a 13% (95% CI: 1.06, 1.20) increased risk of CRC. The risk of colon cancer and rectal cancer in male patients was 1.17 (95% CI: 1.01, 1.36) and 1.35 (95% CI: 1.04, 1.74), respectively, while no association between hypertension and the risk of CRC in females was elucidated. This meta-analysis demonstrated that a positive association between hypertension and CRC exists, with male patients having a higher risk of developing CRC than female patients.

An Electronic Clinical Decision-Making Tool for Patients with Suspected Colorectal Cancer-Preliminary Evaluation in Patients Presenting with Rectal Bleeding

Background and Objectives

The CarePath-CRC electronic clinical decision-making application was designed to assist physicians with evaluation of patients with suspected colorectal cancer (CRC). The physician completes an interactive checklist of evidence-based clinical parameters, and a recommended referral urgency is generated based on the post-test probability of CRC. This study aimed toward validation of the tool in symptomatic patients presenting with rectal bleeding.

Methods

The medical records of a sample of patients with histologically confirmed CRC from 2010 to 2014 were reviewed. The CarePath-CRC tool was applied retrospectively to all patients who initially presented with rectal bleeding, to determine its sensitivity for detecting CRC in this population. A generated recommendation of ‘immediate referral’ (referral ≤24 hours, expected endoscopy ≤2 weeks) or ‘urgent referral’ (expected consultation and endoscopy ≤4 and ≤8 weeks) was considered a positive test result. An a priori sensitivity of 90% was deemed adequate, based on test characteristics of the tool’s individual clinical criteria.

Results

The tool was applied to 281 patients. A total of 69 (24.6%) and 211 (75.1%) patients met criteria for immediate and urgent referral, respectively. The remaining patient (0.4%) met criteria for ‘possible priority referral’, while none met criteria for ‘no specific action recommended’. This resulted in a calculated sensitivity of 99.6% (95% confidence interval 98.0 to 99.9%).

Conclusions

The CarePath-CRC tool is sensitive in the prediction of CRC in patients presenting with rectal bleeding. A prospective cohort study is being designed to allow for acquisition of comprehensive test performance characteristics and full validation of the instrument.

Association Between Age and Complications After Outpatient Colonoscopy

IMPORTANCE

There are insufficient data describing the incidence and risk factors of postcolonoscopy complications in older individuals.

OBJECTIVE

To assess the association between older age (≥75 years) and the risk of postcolonoscopy complications.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study included adults (≥50 years) undergoing outpatient colonoscopy between April 2008 and September 2017, identified from Ontario administrative databases. Individuals with inflammatory bowel disease and hereditary colorectal cancer syndromes were excluded. The study population was subdivided into a colorectal cancer screening-eligible cohort (patients aged 50-74 years) and an older cohort (patients aged ≥75 years). The statistical analysis was conducted from December 2018 to September 2019.

EXPOSURES

Older age (≥75 years).

MAIN OUTCOMES AND MEASURES

The primary outcome was postcolonoscopy complications, defined as the composite of hospitalization or emergency department visits in the 30-day period after the outpatient colonoscopy. Secondary outcomes included incidence of surgically treated colorectal cancer and all-cause mortality at 30 days. Independent variables associated with postcolonoscopy complications were also assessed.

RESULTS

The study sample included 38 069 patients; the mean (SD) age was 65.2 (10.1) years, there were 19 037 women (50.0%), and 27 831 patients (73.1%) underwent a first colonoscopy. The cumulative incidence of complications was 3.4% (1310 patients) in the overall population, and it was higher in individuals aged 75 years or older (515 of 7627 patients [6.8%]) than in screening-eligible cohort (795 of 30 443 patients [2.6%]) (P < .001). Independent risk factors for postcolonoscopy complications were age 75 years or older (odds ratio [OR], 2.3; 95% CI, 2.0-2.6), anemia (OR, 1.4; 95% CI, 1.2-1.7), cardiac arrhythmia (OR, 1.7; 95% CI, 1.2-2.2), congestive heart failure (OR, 3.4; 95% CI, 2.5-4.6), hypertension (OR, 1.2; 95% CI, 1.0-1.5), chronic kidney disease (OR, 1.8; 95% CI, 1.1-3.0), liver disease (OR, 4.7; 95% CI, 3.5-6.5), smoking history (OR, 3.2; 95% CI, 2.4-4.3), and obesity (OR, 2.3; 95% CI, 1.2-4.2). The number of previous colonoscopies was associated with a lower risk of complications (OR, 0.9; 95% CI, 0.7-1.0). The incidence of surgically treated colorectal cancer was higher in the older cohort than the screening-eligible cohort (119 patients [1.6%] vs 144 patients [0.5%]; P < .001). All-cause mortality rates were 0.1% overall (39 patients) and 0.1% (19 patients) for individuals aged 50 to 74 years and 0.2% (20 patients) for those aged 75 years and older (P < .001).

CONCLUSIONS AND RELEVANCE

In this population-based cohort study of individuals living in southern Ontario, age of 75 years and older was associated with a higher risk of 30-day postprocedure complications after outpatient colonoscopy. These findings suggest that the decision to perform a colonoscopy should be carefully considered in patients older than 75 years, especially in the presence of comorbidities. Further studies are needed to better understand the benefits of invasive procedures as opposed to less invasive approaches for colorectal cancer screening and surveillance among older patients.

Challenges and Approaches to Measuring Repeat Fecal Immunochemical Test for Colorectal Cancer Screening

BACKGROUND

Colorectal cancer screening with fecal immunochemical testing (FIT) can reduce colorectal cancer-related mortality. Effectiveness of FIT may be compromised when patients do not adhere to a regular schedule. However, having no standard measure of repeat FIT presents challenges for assessing effectiveness across populations and settings. We compared three measures of repeat FIT in a large, integrated health care system in Dallas, Texas.

METHODS

We identified 18,257 patients age-eligible (50-60 years) for FIT in January 1-December 31, 2010 and followed over four rounds of screening. Measures included: (i) repeat FIT in prior screeners, or completion of FIT within 9-15 months of the previous; (ii) yes-no patterns, whereby patients were assigned yes or no in 9-15 month windows; and 3) proportion of time covered (PTC), or the amount of time patients were up-to-date with screening relative to time eligible.

RESULTS

Repeat FIT varied by measure. Using a prior screeners measure, 15.8% of patients with a normal FIT in round 1 completed repeat FIT in round 2. Repeat FIT was notably higher (52.3%) using PTC. The most common yes-no pattern was YNNN or "one-and-done," and only 9.4% of patients completed two consecutive FITs across all rounds (YYNN).

CONCLUSIONS

Different measures of repeat FIT yielded a range of estimates, making comparison across studies difficult. Researchers should weigh the advantages and disadvantages of each measure and select the most appropriate to their research question.

IMPACT

Our study highlights the need for future research of repeat FIT measures that best approximate screening effectiveness.

Targeting of oncogenic signaling pathways by berberine for treatment of colorectal cancer

Studies indicate that inhibiting a single signaling pathway or one single product of a gene is insufficient for the prevention and treatment of cancer. This is due to the fact that dysregulation must occur in more than 500 genes in order to produce a cancerous phenotype. Despite this evidence, available drugs used for cancer treatment focus on a single target. Meanwhile, berberine as a nutraceutical is capable of targeting various processes involved in tumor development including proliferation, invasion, angiogenesis, and metastasis. In comparison with synthetic agents, berberine is cheaper, safer, and more available. Berberine has shown anti-inflammatory properties which make it an ideal option in order to prevent inflammation-associated cancers. Colorectal cancer is one of the most common cancers all over the world and its incidence is increasing each day. Therefore, further investigations about berberine could be helpful in the discovery of novel agents for preventing and/or treating colorectal cancer. This review emphasizes the studies investigating the roles of berberine in colorectal cancer such as controlling cell signaling pathways, inducing apoptosis, regulating microRNAs, attenuating oxidative stress, and affecting inflammation.

Multiple treatment lines and prognosis in metastatic colorectal cancer patients

The proportion of patients with metastatic colorectal cancer (mCRC) receiving second or further lines of treatment has not been widely studied. To shed light on this issue, we retrospectively analysed the treatments administered for metastatic disease, and investigated prognostic factors after a diagnosis of metastases, in a consecutive cohort of mCRC patients. Three hundred forty-six mCRC patients were enrolled: 173 were stage II or III (metachronous group), and 173 stage IV (synchronous group) at diagnosis. Survival was calculated between the date of metastatic disease and the date of death or last follow-up. Patients with synchronous lesions more frequently had multiple disease sites, peritoneal carcinomatosis and massive liver deposits, whereas significantly more patients with metachronous lesions developed lung metastases as the sole disease site. 97.4% patients received at least one, 62.4% two, 41.9% three and 23.7% four treatment lines. Patients with metachronous metastases more frequently underwent surgery of metastases in first-line treatment (48.5 versus 24.8%), and more of them were progression-free at the time of the analysis (44 versus 34.9%). At univariate analysis, age > 70 years, multiple disease sites and peritoneal carcinomatosis were associated with significantly decreased survival, whereas surgery of metastases and isolated lung metastases predicted better survival. At multivariate analysis, only peritoneal carcinomatosis and surgery of metastases independently affected survival. The percentage of patients who received an active treatment decreased going from first- to fourth-line treatment. However, the proportion of patients who received efficacious treatment in advanced line remained high. Surgery of metastases was the most important prognostic factors.

Economic evaluation of colorectal cancer screening programs: Affordability for the health service

OBJECTIVES

To estimate the cost-effectiveness of the public colorectal cancer screening program in the Abruzzo region, Italy.

METHODS

Cost-effectiveness was analysed using a two-armed Markov model comparing: (1) Abruzzo screening program based on biennial faecal immunochemical occult blood testing, with colonoscopy as second level test for individuals with positive results, with (2) Treatment of symptomatic patients according to the stage of the neoplasm. Transition probabilities were adjusted for accuracy of tests and incidence of colorectal cancer. Diagnosis-related groups' charges and field collected data were used to estimate costs. Costs and benefits were discounted by 3.5%. Monte Carlo simulation confirmed the robustness of the model results.

RESULTS

Assuming a compliance rate of 64.7%, the incremental cost-effectiveness ratio for the current colorectal screening program was €433.06/quality adjusted life year gained, considerably lower than conventional thresholds (around €30,000).

CONCLUSION

Early detection and intervention programs help to avoid a large number of highly debilitating and expensive cancer treatments. These results show that the screening program currently implemented in Abruzzo should be considered as a good investment in health.

Clinical and Economic Impact of Tailoring Screening to Predicted Colorectal Cancer Risk: A Decision Analytic Modeling Study

BACKGROUND

Global increases in colorectal cancer risk have spurred debate about optimal use of screening resources. We explored the potential clinical and economic impact of colorectal cancer screening tailored to predicted colorectal cancer risk.

METHODS

We compared screening tailored to predicted risk versus uniform screening in a validated decision analytic model, considering the average risk population's actual colorectal cancer risk distribution, and a risk-prediction tool's discriminatory ability and cost. Low, moderate, and high risk tiers were identified as colorectal cancer risk after age 50 years of ≤3%, >3 to <12%, and ≥12%, respectively, based on threshold analyses with willingness-to-pay <$50,000/quality-adjusted life-year (QALY) gained. Tailored colonoscopy (once at age 60 years for low risk, every 10 years for moderate risk, and every 5 years for high risk) was compared with colonoscopy every 10 years for all. Tailored fecal immunochemical testing (FIT)/colonoscopy (annual FIT for low and moderate risk, colonoscopy every 5 years for high risk) was compared with annual FIT for all.

RESULTS

Assuming no colorectal cancer risk misclassification or risk-prediction tool costs, tailored screening was preferred over uniform screening. Tailored colonoscopy was minimally less effective than uniform colonoscopy, but saved $90,200-$889,000/QALY; tailored FIT/colonoscopy yielded more QALYs/person than annual FIT at $10,600-$60,000/QALY gained. Relatively modest colorectal cancer risk misclassification rates or risk-prediction tool costs resulted in uniform screening as the preferred approach.

CONCLUSIONS

Current risk-prediction tools may not yet be accurate enough to optimize colorectal cancer screening.

IMPACT

Uniform screening is likely to be preferred over tailored screening if a risk-prediction tool is associated with even modest misclassification rates or costs.

Association of Race and Socioeconomic Status With Colorectal Cancer Screening, Colorectal Cancer Risk, and Mortality in Southern US Adults

IMPORTANCE

Colorectal cancer (CRC) screening is rarely studied in populations who may face additional barriers to participate in cancer screening, such as African American individuals and individuals with low socioeconomic status (SES).

OBJECTIVE

To examine the associations of CRC screening and modalities with CRC incidence and mortality by race and SES.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the Southern Community Cohort Study, which enrolled more than 85 000 participants from community health centers or stratified random sampling of the general population in 12 states in the southeastern United States. The present study included data from cohort members who were eligible for CRC screening as recommended by expert organizations based on age and family history. Participants completed questionnaires from 2002 to 2009 and were contacted again from 2008 to 2012. Linkages to state cancer registries and the National Death Index as of December 31, 2016, identified incident CRC and vital status. Data analysis was performed from January 1, 2018, to October 30, 2019.

MAIN OUTCOMES AND MEASURES

Incident CRC (n = 632) and mortality (n = 10 003). Cox proportional hazards regression models evaluated associations between screening modalities and CRC risk and mortality. Information on fecal occult blood test use was only obtained on the follow-up questionnaire. Self-identified race was measured as African American/black, white, or other, and SES was defined by household income.

RESULTS

This study included 47 596 participants (median baseline age, 54 years [interquartile range, 10 years]; 32 185 [67.6%] African American; 28 884 [60.7%] female; and 26 075 [54.8%] with household income <$15 000). A total of 24 432 participants (63.9%) had never undergone CRC testing at baseline. The CRC testing assessed at baseline and follow-up interviews was associated with significant CRC risk reduction (hazard ratio [HR], 0.55; 95% CI, 0.44-0.70 for ever colonoscopy at baseline). Results were similar in analyses stratified by race (African American: HR, 0.65; 95% CI, 0.50-0.85; white: HR, 0.44; 95% CI, 0.27-0.70) and household income (<$15 000: HR, 0.63; 95% CI, 0.46-0.86, ≥$15 000: HR, 0.49; 95% CI, 0.35-0.69). Ever sigmoidoscopy at baseline was associated with CRC risk reduction (HR, 0.66; 95% CI, 0.51-0.87), and undergoing fecal occult blood test in the interval between baseline and follow-up interview was associated with CRC risk reduction (HR, 0.75; 95% CI, 0.57-0.98). Inverse associations were also observed between CRC mortality and receipt of colonoscopy (HR for women, 0.39; 95% CI, 0.21-0.73; HR for men, 0.69; 95% CI, 0.40-1.18) and sigmoidoscopy (HR for women, 0.37; 95% CI, 0.16-0.85; HR for men, 0.82; 95% CI, 0.46-1.47); however, the association did not extend to fecal occult blood test (HR for women, 1.02; 95% CI, 0.62-1.70; HR for men, 1.03; 95% CI, 0.55-1.93).

CONCLUSIONS AND RELEVANCE

In this study, CRC test rates were low among African American individuals and those with low SES. The findings suggest that screening, particularly with colonoscopy, is significantly associated with reduced risk of CRC and mortality. The CRC disparities experienced by individuals with low SES and African American individuals may be lessened by improving access to and uptake of CRC screening.

Diagnostic Accuracy Of Fecal Occult Blood Tests For Detecting Proximal Versus Distal Colorectal Neoplasia: A Systematic Review And Meta-Analysis

Objective

We conducted a systematic review and meta-analysis aimed at evaluating the differences of diagnostic performance of fecal occult blood tests (FOBTs) in detecting advanced colorectal neoplasms located in the proximal versus distal colorectum.

Methods

PubMed, Embase, Cochrane Library, and Web of Science were searched for eligible articles published before August 17, 2018. Two independent reviewers conducted study assessment and data extraction. Diagnosis-related indicators of FOBT for detecting proximal and distal colorectal neoplasms were summarized, and further stratified by the type of FOBT (guaiac-based FOBT (gFOBT) and immunochemical FOBT (iFOBT)). Pooled sensitivities and specificities were calculated using a random effect model. Summary receiver operating characteristic curves were plotted and area under the curves were calculated.

Results

Overall, 31 studies meeting the inclusion criteria were included in this review. For gFOBT, we found no site-specific difference (proximally vs distally located) of pooled sensitivities observed in the colorectal cancer (CRC), advanced adenomas, and advanced neoplasms groups. As for iFOBT, pooled sensitivities for detecting CRC located in the distal colon/rectum were comparable with that in the proximal colon (proximal vs distal, 0.67, 95% CI 0.62-0.72 vs 0.72, 95% CI 0.68-0.75), while higher pooled sensitivities for detecting advanced adenomas and advanced neoplasms located in the distal colon/rectum than for detecting those in the proximal colon were observed for iFOBT with the values of 0.24 (95% CI 0.22-0.25) vs 0.32 (95% CI 0.30-0.34) and 0.25 (95% CI 0.23-0.28) vs 0.38 (95% CI 0.36-0.40), respectively. Summary receiver operating characteristic curve analyses showed similar patterns for both types of FOBT regarding the diagnostic accuracy for detecting colorectal neoplasms according to the anatomical sites of the colorectum.

Conclusion

iFOBT had higher sensitivity for detecting advanced adenomas and advanced neoplasia located in the distal colon/rectum than that for those in the proximal colon.

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.

Reviewing the Evidence that Polypectomy Prevents Cancer

Colonoscopic polypectomy is fundamental to effective prevention of colorectal cancer. Polypectomy reduces colorectal cancer incidence and mortality by altering the natural history and progression of precancerous precursor polyps. Epidemiologic data from the United States, where colorectal cancer rates have been steadily declining in parallel with screening efforts, provide indisputable evidence about the effectiveness of polypectomy. Randomized controlled trials of fecal occult blood tests and flexible sigmoidoscopy, and observational colonoscopy studies, provide additional support. Longitudinal studies have shown variable levels of protection after polypectomy, highlighting the central importance of high quality and adequate surveillance of higher-risk patients.

CAC1 knockdown reverses drug resistance through the downregulation of P-gp and MRP-1 expression in colorectal cancer

CDK2-associated cullin domain 1 (CAC1) is as a novel cell cycle regulator widely expressed in colorectal cancer (CRC). However, its expression and function in drug resistant CRC cells remains elusive. Therefore, the present study aimed to assess the biochemical function and relevance of CAC1 in drug resistant CRC cells, and detect the potential mechanism. For this purpose, a total of 83 CRC cases were collected for the immunohistochemical analysis of CAC1 expression. Functional studies (stable transfection, flow cytometry, colony formation, and invasion and migration assays) were performed in SW480, LoVo and their corresponding 5-FU resistant cells. In addition, a nude mice xenograft model was established for further observation in vivo. In the present study, CAC1 protein expression was higher in CRC tissues than that in normal tissues (P<0.05). Furthermore, CAC1 protein expression was higher in SW480/5-FU cells than in SW480 cells. CAC1 knockdown arrested 5-FU resistant cells at the G1/S phase and increased the sensitivity of 5-FU resistant cells to 5-FU by inducing apoptosis. In addition, CAC1 reduced the invasive and migration ability of SW480/5-FU and LoVo/5-FU cells in vitro, and reduced their tumorigenicity and metastatic ability in vivo. Finally, CAC1 knockdown resulted in decreased P-glycoprotein and MRP-1 protein expression. Based on these results, it can be concluded that CAC1 plays an important role in the occurrence and promotion of drug resistance in CRC. Therefore, the knockdown of CAC1 may be considered as a new strategy for the development of CRC drug resistance treatments in the future.

[Current evidence and development of colorectal cancer screening in Germany]

Colon cancer is currently the third leading cause of cancer death in men and women in Germany, with a total of about 25,000 deaths per year. Established methods for early detection of colorectal cancer include lower gastrointestinal endoscopy and fecal occult blood testing. For both procedures, there is evidence of a reduction in colorectal cancer-specific mortality and for endoscopy a reduction of colorectal cancer incidence has been shown.In Germany, the guaiac test for fecal occult blood has been offered since 1977. Additionally, screening colonoscopy has been offered since 2002 and in 2016, the guaiac test was replaced by the immunological fecal occult blood test, which has an improved diagnostic performance. Overall, participation rates have been low over the past decades and differed between men, women, and age groups.Personal invitations are expected to be sent out starting in 2019 as part of the introduction of an organized colorectal cancer screening program in Germany. The program also provides for measures to systematically monitor and improve the quality of colorectal cancer screening. It remains to be seen which effects these changes will have and whether the trend towards declining colon cancer incidence and mortality that has been observed in Germany will continue in the coming years.

Cost-Effectiveness and National Effects of Initiating Colorectal Cancer Screening for Average-Risk Persons at Age 45 Years Instead of 50 Years

BACKGROUND & AIMS

The American Cancer Society has recommended initiating colorectal cancer (CRC) screening at age 45 years instead of 50 years. We estimated the cost effectiveness and national effects of adopting this recommendation.

METHODS

We compared screening strategies and alternative resource allocations in a validated Markov model. We based national projections on screening participation rates by age and census data.

RESULTS

Screening colonoscopy initiation at age 45 years instead of 50 years in 1000 persons averted 4 CRCs and 2 CRC deaths, gained 14 quality-adjusted life-years (QALYs), cost $33,900/QALY gained, and required 758 additional colonoscopies. These 758 colonoscopies could instead be used to screen 231 currently unscreened 55-year-old persons or 342 currently unscreened 65-year-old persons, through age 75 years. These alternatives averted 13-14 CRC cases and 6-7 CRC deaths and gained 27-28 discounted QALYs while saving $163,700-$445,800. Improving colonoscopy completion rates after abnormal results from a fecal immunochemical test yielded greater benefits and savings. Initiation of fecal immunochemical testing at age 45 years instead of 50 years cost $7700/QALY gained. Shifting current age-specific screening rates to 5 years earlier could avert 29,400 CRC cases and 11,100 CRC deaths over the next 5 years but would require 10.7 million additional colonoscopies and cost an incremental $10.4 billion. Improving screening rates to 80% in persons who are 50-75 years old would avert nearly 3-fold more CRC deaths at one third the incremental cost.

CONCLUSIONS

In a Markov model analysis, we found that starting CRC screening at age 45 years is likely to be cost effective. However, greater benefit, at lower cost, could be achieved by increasing participation rates for unscreened older and higher-risk persons.

Reduction of faecal immunochemical test false-positive results using a signature based on faecal bacterial markers

BACKGROUND

Colorectal cancer is the second commonest cause of cancer mortality. Some countries are implementing colorectal cancer screening to detect lesions at an early stage using non-invasive tools like the faecal immunochemical test. Despite affordability, this test shows a low sensitivity for precancerous lesions and a low positive predictive value for colorectal cancer, resulting in a high false-positive rate.

AIM

To develop a new, non-invasive colorectal cancer screening tool based on bacterial faecal biomarkers, which in combination with the faecal immunochemical test, could allow a reduction in the false-positive rate. This tool is called risk assessment of intestinal disease for colorectal cancer (RAID-CRC).

METHODS

We performed both the faecal immunochemical test and the bacterial markers analysis (RAID-CRC test) in stool samples from individuals with normal colonoscopy (167), non-advanced adenomas (88), advanced adenomas (30) and colorectal cancer (48). All the participants showed colorectal cancer-associated symptoms.

RESULTS

Performance of the faecal immunochemical test for advanced neoplasia (ie advanced adenoma and colorectal cancer) was determined by using the cut-off value established in Catalonia (20 µg haemoglobin/g of faeces) for a population-based screening approach. Sensitivity and specificity values of 83% and 80%, respectively, and positive and negative predictive values of 56% and 94%, respectively, were obtained. When both the immunological and the biological analysis were combined, the corresponding values were 80% and 90% for sensitivity and specificity, respectively, and 70% and 94% for positive and negative predictive values, respectively, resulting in a 50% reduction of the false-positive rate.

CONCLUSIONS

RAID-CRC test allows a substantial reduction in the faecal immunochemical test false-positive results (50%) in a symptomatic population. Further validation is indicated in a colorectal cancer-screening scenario.

Colorectal Cancer in the Young: Does Screening Make Sense?

PURPOSE OF REVIEW

Colorectal cancer (CRC) screening is recommended to reduce CRC mortality. This review outlines key factors to consider when recommending screening, including disease burden, screening benefits and harms, and remaining knowledge gaps.

RECENT FINDINGS

In response to increasing rates of CRC incidence among younger (age < 50 years) adults, the American Cancer Society published guidelines in May 2018 recommending average-risk CRC screening beginning at age 45 (vs. 50) years. Rates of young-onset CRC have increased in the USA since the early 1990s. However, there is very little empirical evidence of screening effectiveness in younger adults, and few studies have reported harms of routine screening in this age group. Further, we know little about the natural history of CRC in younger adults. Uncertainty surrounding the efficacy of CRC screening in younger adults suggests the benefits may be small. Precision cancer screening-or modified screening regimens based on risk-may improve the balance of screening benefits and harms beyond conventional age-based strategies.

The detection of interval colorectal cancers following screening by fecal immunochemical test may predict worse outcomes and prompt ethical concerns: a 6-year population-based cohort study in a full district

The rates of colorectal cancer (CRC) interval surveyed in screen-detected patients using a fecal immunochemical test (FIT) are not negligible. The aim of this study was to assess the effect of interval cancer on outcomes compared with a population with cancer diagnosed after a positive test result. All patients between 50 and 71 years of age, who were residents of the Mantua district, affected by CRC and operated on from 2005 to 2010 were reviewed. Other than patient-related, disease-related, and treatment-related factors and tumor location, this population was differentiated as either participating or not to screening and then into populations developing interval cancer after a negative FIT result. Mortality was investigated by univariate analysis and by overall survival rates. The mean age of the 975 patients enrolled was 62 years (61.7% males). Most patients (n=575, 59%) were not screen detected, and 400 (41%) were screen detected. Fifty-six (5.7%) patients in the latter group, representing 14% of the participants, developed interval cancer after a negative FIT result. Their cancer was mostly localized in the right colon (41.1%) instead of the left colon and rectum (P=0.02). They also showed higher stages (P=0.001), a moderate degree of differentiation (P=0.001), and overall higher mortality rates than patients with cancer diagnosed after a positive test result (P=0.001). The effect of interval CRC after screening with FIT resulted in worse outcomes compared with the FIT-positive group. With such findings, patients who had negative results for FIT should be informed of the risk of developing cancer within the rounds of screening to independently gain educational skills in the area of health prevention.

Rapid review of factors associated with flexible sigmoidoscopy screening use

Flexible sigmoidoscopy (FS) screening has been shown to reduce colorectal cancer (CRC) incidence and mortality among screened adults. The aim of this review was to identify patient-related factors associated with the screening test's use. We searched PubMed for studies that examined the association between FS screening use and one or more factors. To determine the eligibility of studies, we first reviewed titles, then abstracts, and finally the full paper. We started with a narrow search, which we expanded successively (by adding 'OR' terms) until the number of new publications eligible after abstract review was <1% of the total number of publications. We then abstracted factors from eligible papers and reported the number of times each was found to be positively or negatively associated with FS screening use. We identified 42 papers, most of which reported studies conducted in the United States of America (n = 21, 50%) and the United Kingdom (n = 13, 31%). Across studies, a wide range of factors were examined (n = 123), almost half of which were found to be associated with FS screening use at least once (n = 60). Sociodemographic and health and lifestyle factors that were frequently positively associated with FS screening use included: male gender, higher socioeconomic status and a family history of CRC. Frequently positively associated psychosocial factors included low perceived barriers and high perceived benefits. Findings suggest that future research should focus on developing a theoretical framework of cancer screening behaviour to allow a greater level of consistency and specificity in measuring key constructs.

Cancer Mortality Trend in Central Italy: Focus on A "Low Rate of Land Use" Area from 1982 to 2011

The aim of the present study was to estimate total cancer mortality trends from 1982 to 2011 in a “low rate of land use” province of the Latium region (Rieti, central Italy) characterized by a low degree of urbanization, a high prevalence of elderly, and a low number of births. Mortality data of the studied period, provided by the Italian National Institute of Statistics, were used for calculating standardized cancer mortality rates. Trends in mortality were analyzed using Joinpoint regression analysis. Results showed that total standardized cancer mortality rates decreased in the monitored area over the study period. A comparison with other provinces of the same region evidenced that the studied province presented the lowest cancer mortality. The three systems/apparatuses affected by cancer that mainly influenced cancer mortality in the monitored province were the trachea-bronchus-lung, colorectal-anus, and stomach. These findings could be attributed to the implement of preventive initiatives performed in the early 2000s, to healthier environmental scenario, and to lower levels of carcinogenic pollutants in air, water, and soil matrices. Thus, our results indicate that the studied area could be considered a “healthy” benchmark for studies in oncological diseases.

Evaluation of the combined effect of factors influencing bowel preparation and adenoma detection rates in patients undergoing colonoscopy

Background

Colonoscopy is a commonly used modality for screening and surveillance of colorectal cancer (CRC). Therefore, it is essential to have adequate bowel preparation (prep) for the procedure which depends on type of bowel regimens, diet before colonoscopy and timing of the procedure.

Aims

The purpose of this study is to analyse the effect of multiple factors on adenoma detection rate (ADR) and prep quality of colonoscopy. This is the also the first study determining outcomes based on various combinations of diet, timing of the procedure and bowel prep regimens.

Methods

This is a retrospective single-centre observational study. Data about diet before procedure, bowel prepprep regimen and timing of the procedure was collected for patients coming for screening colonoscopy.

Results

Patients with split prep had higher good prep rates (73.8% vs 56.2%) and higher ADRs (34.2 % vs 29.9%) as compared with non-split prep. The good prep quality (65.8% vs 62.1%) and ADRs (31.9% vs 31.5%) were comparable in patients who received clear liquid diet as compared with low residue diet. The good results of bowel prep were obtained with split prep with either clear liquids or low residue diet irrespective of the timing of procedure. The poor prep was noticed in patients who underwent procedure in afternoon, with a low restrictive diet and non-split bowel regimen.

Conclusions

The current study adds to our knowledge about the combined effect of multiple variables affecting the bowel prep quality and ADR. It is imperative to opt for the best combination required for colonoscopy, as this will influence the effectiveness of colonoscopies regarding timely cancer detection and prevention.

Preventing colorectal cancer or early diagnosis: Which is best? A re-analysis of the U.S. Preventive Services Task Force Evidence Report

Flexible sigmoidoscopy (FS) is the only cancer screening test to lower the risk of death compared to usual care in randomized controlled trials (RCTs). We hypothesize that this unique death reduction is more attributable to prevention of colorectal cancer (CRC) than to early diagnosis. The systematic review of the 2016 US Preventive Services Task Force Evidence Report for CRC Screening was used for selection of RCT studies. A random-effects meta-analysis of five FS trials (N = 458,002) and four fecal occult blood test (FOBT) trials (N = 328,767) was performed using intention-to-screen outcomes for death, CRC incidence, and death attributed to CRC; correlation and linear regression analyses explored the relationships between these outcomes. At 10.5-11.9 years of follow-up FS reduces death (relative risk [RR], 0.975; 95% CI, 0.958-0.992 and reduces CRC incidence (RR, 0.79; 95% CI, 0.74-0.84). Within the FS trials death reduction shows a strong linear correlation with CRC incidence reduction (r, 0.95; 95% CI 0.42-0.99). At 15.6-30.0 years of follow-up FOBT does not reduce death (RR, 1.001; 95% CI, 0.992-1.010) or CRC incidence (RR, 0.96; 95% CI, 0.89-1.02) but does reduce deaths attributed to CRC (RR, 0.84; 95% CI, 0.78-0.91). Clinical trials of screening FS display a dose-response relationship between the magnitude of CRC prevention and the magnitude of death reduction. Prevention of CRC appears to be the major (or sole) mechanism of action for death reduction by FS in clinical trials. Conversely, early diagnosis of CRC does not appear to reduce death.

Contrasting Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening Under Commercial Insurance vs. Medicare

OBJECTIVES

Most cost-effectiveness analyses of colorectal cancer (CRC) screening assume Medicare payment rates and a lifetime horizon. Our aims were to examine the implications of differential payment levels and time horizons for commercial insurers vs. Medicare on the cost-effectiveness of CRC screening.

METHODS

We used our validated Markov cohort simulation of CRC screening in the average risk US population to examine CRC screening at ages 50-64 under commercial insurance, and at ages 65-80 under Medicare, using a health-care sector perspective. Model outcomes included discounted quality-adjusted life-years (QALYs) and costs per person, and incremental cost/QALY gained.

RESULTS

Lifetime costs/person were 20-44% higher when assuming commercial payment rates rather than Medicare rates for people under 65. Most of the substantial clinical benefit of screening at ages 50-64 was realized at ages ≥65. For commercial payers with a time horizon of ages 50-64, fecal occult blood testing (FOBT) and fecal immunochemical testing (FIT) were cost-effective (<$61,000/QALY gained), but colonoscopy was costly (>$185,000/QALY gained). Medicare experienced substantial clinical benefits and cost-savings from screening done at ages <65, even if screening was not continued. Among those previously screened, continuing FOBT and FIT under Medicare was cost-saving and continuing colonoscopy was highly cost-effective (<$30,000/QALY gained), and initiating any screening in those previously unscreened was highly effective and cost-saving.

CONCLUSIONS

Modeling suggests that CRC screening is highly cost-effective over a lifetime even when considering higher payment rates by commercial payers vs. Medicare. Screening may appear relatively costly for commercial payers if only a time horizon of ages 50-64 is considered, but it is predicted to yield substantial clinical and economic benefits that accrue primarily at ages ≥65 under Medicare.