Five-year risk of colorectal neoplasia after negative screening colonoscopy

Optimizing Urgent Suspected Colon Cancer Referrals and Reducing Colonoscopy Wait Times in Wales

AIM

To assess recent colonoscopies and CT scans in conjunction with the feacal immunochemical test (FIT) for possibly downgrading urgent suspected cancer (USC) referrals.

METHODS

 A retrospective single-centre study was conducted, including all USC referrals for colonoscopy in 2022, excluding anal cancers. The CT and colonoscopy findings for a two-year period prior to the referral, along with the FIT result (if done), were noted. Combinations of tests were used to ascertain if any such combination would predict a negative colonoscopy (no cancer detected).

RESULTS

 Out of 500 USC referrals made, 160 were positive for colorectal cancer (CRC). Twelve cases had prior negative CT scans and colonoscopies, and none showed cancer (three were FIT and nine FIT not performed). A total of 54 cases had a prior CT with no FIT, four of which showed cancer. Fifteen cases had a prior CT with a negative FIT, and none showed cancer. Sixteen cases had prior negative colonoscopies, and all were negative for cancer (five negative FIT, one positive FIT, and 10 FIT not done ). Combining the categories where no cancer was missed, potentially 40 referrals could have been downgraded safely (8%).

CONCLUSIONS

 The above data indicate that, among the patients being considered for a colorectal USC referral, a combined prior negative colonoscopy and CT scan warrants a downgrading of the referral (irrespective of the FIT result). Referrals with a prior negative CT (abdomen) with a negative FIT or normal colonoscopy within the last two years can be safely downgraded. This will have a positive impact on waiting times and monetary expenditure on the USC pathway, but larger studies would be required to prove the external validity of these findings.

Risk factors for inadequate bowel preparation before colonoscopy: A meta-analysis

OBJECTIVE

This meta-analysis aimed to comprehensively explore the risk factors for inadequate bowel preparation (IBP).

METHODS

We searched the Embase, PubMed, Web of Science, and The Cochrane Library databases up to August 24, 2023, to identify observational studies and randomized controlled trials (RCTs) that examined risk factors for IBP. A random effects model was used to pool the adjusted odds ratios and 95% confidence intervals.

RESULTS

A total of 125 studies (91 observational studies, 34 RCTs) were included. Meta-analyses of observational studies revealed that three preparation-related factors, namely, characteristics of last stool (solid or brown liquid), incomplete preparation intake, and incorrect diet restriction, were strong predictors of IBP. The other factors were moderately correlated with IBP incidence, including demographic variables (age, body mass index, male sex, Medicaid insurance, and current smoking), comorbidities (diabetes, liver cirrhosis, psychiatric disease, Parkinson's disease, previous IBP, poor mobility, inpatient, and Bristol stool form 1/2), medications (tricyclic antidepressants, opioids, antidepressants, narcotics, antipsychotics, and calcium channel blockers), and preparation-related factors (preparation-to-colonoscopy interval not within 3 to 5/6 h, nonsplit preparation, and preparation instructions not followed). No colonoscopy indications were found to be related to IBP. Meta-analyses of RCTs showed that education, constipation, stroke/dementia, and discomfort during preparation were also moderately associated with IBP. Most of the other findings were consistent with the pooled results of observational studies. However, primarily due to imprecision and inconsistency, the certainty of evidence for most factors was very low to moderate.

CONCLUSIONS

We summarized five categories of risk factors for IBP. Compared to demographic variables, comorbidities, medications, and colonoscopy indications, preparation-related elements were more strongly associated with IBP. These findings may help clinicians identify high-risk individuals and provide guidance for IBP prevention.

Elevated Colon Cancer Rates Linked to Prior Appendicitis: A Retrospective Cohort Study Based on Data from German General Practices

Background/Objective: The association between appendicitis and colon cancer is not yet fully understood. Previous studies have shown contradictory results. Currently, no population-based data from Germany are available with regard to the incidence of colon cancer following appendicitis. This study investigated the association between appendicitis and the incidence of colon cancer in Germany. Methods: In this retrospective cohort study, the incidence of colon cancer was compared for patients with appendicitis and patients without appendicitis, matched for age, sex, index year, average annual consultation frequency, and comorbidity. The aim of the study was to explore the relationship between appendicitis and the incidence of colon cancer. The evaluation was carried out using logistic regression analyses. Results: The study included 49,790 people with and without appendicitis, with a median age of 41 years. During a follow-up period of up to 15 years, 1.04% of cases with appendicitis and 0.60% of cases without appendicitis were newly diagnosed with colon cancer, with some 36.4% of colon cancer cases diagnosed within the first six months after appendicitis. Regression analyses revealed a significant association between appendicitis and colon cancer, particularly in men and in the age groups 41-50 (HR: 10.30; 95% CI: 1.03-43.82) and 18-30 years (HR: 8.17; 95% CI: 1.03-64.58). Conclusions: The present retrospective cohort study suggests an association between appendicitis and the incidence of colon cancer in Germany. Based on our results, we recommend offering a colonoscopy or at least a stool test within 12 months after appendicitis, especially for 18-50-year-olds and >60-year-olds in good general health.

The absolute number of small and diminutive adenomas with high-grade dysplasia is substantially higher compared with large adenomas: a retrospective pooled study

Introduction

The risk that a large polyp (≥10 mm) evolves into high-grade dysplasia (HGD) is relatively high compared with that of a small/diminutive polyp (<10 mm). Recently, the detection of small and diminutive polyps has been substantially improved with the advancement of endoscopy. However, further research is needed on the role of the incidence of HGD caused by the co-occurrence of small and diminutive polyps in the progression of HGD. In this study, we aim to investigate whether and how the small and diminutive polyps correlate with the incidence of HGD in the population.

Methods

The pooled data were deeply analyzed from four published randomized controlled trials (RCTs) regarding colon polyp detection. All polyps detected were examined and confirmed by pathologists. The primary outcome was the composition ratio of the HGD polyps in each polyp size category.

Results

Among a total of 3,179 patients with 2,730 polyps identified, there were 83 HGD polyps confirmed, and 68 patients had at least one polyp with HGD. The risk of development of HGD was lower for a single small and diminutive polyp than for one large polyp (2.18% vs. 22.22%, P < 0.0001). On the contrary, the composition ratio for HGD from small and diminutive polyps was significantly higher than that from the large ones (68.67% vs. 31.33%, P < 0.0001). The combined number of HGD presented a trend negatively correlated to size.

Conclusions

Our data demonstrated that the absolute number of HGD significantly derives more from small and diminutive polyps than from the large ones, and the collective number of small and diminutive polyps per patient is indicative of his/her HGD exposure. These findings positively provide novel perspectives on the management of polyps and may further optimize the prevention of colorectal cancer.

Systematic Review Registration

http://www.chictr.org.cn, identifier ChiCTR1900025235, ChiCTR1800017675, ChiCTR1800018058, and ChiCTR1900023086.

Is It Worth Considering Colonic Evaluation After Appendicectomy?

Introduction The association of acute appendicitis with caecal or colorectal cancer is known. One of the proposed theories for acute appendicitis is luminal blockage by mass at the base of the appendix. There have been no national recommendations or guidelines for follow-up with patients aged 40 and older after an emergency appendicectomy. The purpose of this study was to evaluate the prevalence of caecal and colonic cancer or polyps in patients over the age of 40 who have undergone an appendicectomy. This shall enable us to develop the necessary strategies to investigate and diagnose associated caecal and colonic pathology in acute appendicitis to prevent delayed diagnosis of colon cancer. Methods All patients who underwent appendicectomy between October 2011 and October 31, 2021, and who were 40 years of age or older were included in this retrospective cohort study. Patients aged 40 to 54 years old and patients 55 years or older underwent subgroup analyses. We looked at any investigations of the colon (CT pneumocolon or colonoscopy) within three years before the appendicectomy or three years after an appendicectomy. All colorectal cancers diagnosed within five years of the index episode of appendicitis were included in the analysis. Results A total of 1076 appendicectomies were performed on patients aged 40 and older during the study period of 10 years. A total of 769 patients were confirmed to have appendicitis on histology. One hundred and fifty-seven patients had colonic investigations within three years of the diagnosis of acute appendicitis. In our study, 51 of the 769 patients (6.63%) were found to have colorectal neoplasms. Eight patients (8/769, 1.04%) were diagnosed with colorectal cancers, and the occurrence of caecal cancer was 0.26% (2/769). The mortality rate was 75% (6/8) in these patients diagnosed with colorectal cancer. Four out of six died due to advanced metastatic colonic cancer. In comparison to patients aged 40 to 54, patients over the age of 55 had a statistically significant increased risk of caecal pathology (polyp and cancer) (p = 0.07). Conclusion There seems to be an increased risk of significant colorectal neoplasm in patients over the age of 55 who are admitted with acute appendicitis, and there appears to be an increased severity with a poor prognosis of cancer in these individuals. We recommend the use of routine colonoscopy or CT pneumocolon, particularly for those over the age of 55 who present with acute appendicitis or the histology of appendicular neoplasms.

Diagnostic yield of repeat screening colonoscopy ten years after an adenoma-negative index screening endoscopy

In Germany, colonoscopy was introduced as a screening instrument about 20 years ago. Ten years after an adenoma-negative index endoscopy, a second screening colonoscopy can be performed in younger persons, but this approach is based on limited evidence. We therefore prospectively analyzed the diagnostic yield of second screening colonoscopies in clinical routine.Ten years following adenoma-negative screening endoscopy a second screening colonoscopy was performed in 401 persons (210 women and 191 men); mean age was 70 years. A total of 244 benign neoplastic lesions were removed in 135 persons (34%). Eight persons had three or more small tubular adenomas removed; 19 persons had at least one tubular adenoma measuring ≥ 10 mm; 14 persons had adenomas with villous characteristics; 19 persons had serrated adenomas; one person had an adenoma with high grade dysplasia. Thus 61 persons (33 men and 28 women) were classified as bearing a significant risk for the development of colorectal cancer (15%). An additional patient had a low-risk malignant polyp removed endoscopically.We conclude that a significant number of small and advanced adenomas can be identified in a second screening colonoscopy ten years after an adenoma-negative index screening endoscopy, but malignant lesions are rare. Whether or not removal of the benign lesions in a second screening colonoscopy will reduce incidence and mortality of colorectal carcinoma remains to be seen in this elderly group.

Korean Guidelines for Postpolypectomy Colonoscopic Surveillance: 2022 revised edition

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: adenoma ≥10 mm in size; 3 to 5 (or more) adenomas; tubulovillous or villous adenoma; adenoma containing high-grade dysplasia; traditional serrated adenoma; sessile serrated lesion containing any grade of dysplasia; serrated polyp of at least 10 mm in size; and 3 to 5 (or more) sessile serrated lesions. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

[Korean Guidelines for Postpolypectomy Colonoscopic Surveillance: 2022 Revised Edition]

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: 1) adenoma ≥10 mm in size; 2) 3-5 (or more) adenomas; 3) tubulovillous or villous adenoma; 4) adenoma containing high-grade dysplasia; 5) traditional serrated adenoma; 6) sessile serrated lesion (SSL) containing any grade of dysplasia; 7) serrated polyp of at least 10 mm in size; and 8) 3-5 (or more) SSLs. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

[Korean Guidelines for Postpolypectomy Colonoscopic Surveillance: 2022 Revised Edition]

Colonoscopic polypectomy is effective in decreasing the incidence and mortality of colorectal cancer (CRC). Premalignant polyps discovered during colonoscopy are associated with the risk of metachronous advanced neoplasia. Postpolypectomy surveillance is the most important method for managing advanced metachronous neoplasia. A more efficient and evidence-based guideline for postpolypectomy surveillance is required because of the limited medical resources and concerns regarding colonoscopy complications. In these consensus guidelines, an analytic approach was used to address all reliable evidence to interpret the predictors of CRC or advanced neoplasia during surveillance colonoscopy. The key recommendations state that the high-risk findings for metachronous CRC following polypectomy are as follows: 1) adenoma ≥10 mm in size; 2) 3-5 (or more) adenomas; 3) tubulovillous or villous adenoma; 4) adenoma containing high-grade dysplasia; 5) traditional serrated adenoma; 6) sessile serrated lesion (SSL) containing any grade of dysplasia; 7) serrated polyp of at least 10 mm in size; and 8) 3-5 (or more) SSLs. More studies are needed to fully comprehend the patients who are most likely to benefit from surveillance colonoscopy and the ideal surveillance interval to prevent metachronous CRC.

A Novel Convolutional Neural Network Model as an Alternative Approach to Bowel Preparation Evaluation Before Colonoscopy in the COVID-19 Era: A Multicenter, Single-Blinded, Randomized Study

INTRODUCTION

Adequate bowel preparation is key to a successful colonoscopy, which is necessary for detecting adenomas and preventing colorectal cancer. We developed an artificial intelligence (AI) platform using a convolutional neural network (CNN) model (AI-CNN model) to evaluate the quality of bowel preparation before colonoscopy.

METHODS

This was a colonoscopist-blinded, randomized study. Enrolled patients were randomized into an experimental group, in which our AI-CNN model was used to evaluate the quality of bowel preparation (AI-CNN group), or a control group, which performed self-evaluation per routine practice (control group). The primary outcome was the consistency (homogeneity) between the results of the 2 methods. The secondary outcomes included the quality of bowel preparation according to the Boston Bowel Preparation Scale (BBPS), polyp detection rate, and adenoma detection rate.

RESULTS

A total of 1,434 patients were enrolled (AI-CNN, n = 730; control, n = 704). No significant difference was observed between the evaluation results ("pass" or "not pass") of the groups in the adequacy of bowel preparation as represented by BBPS scores. The mean BBPS scores, polyp detection rate, and adenoma detection rate were similar between the groups. These results indicated that the AI-CNN model and routine practice were generally consistent in the evaluation of bowel preparation quality. However, the mean BBPS score of patients with "pass" results were significantly higher in the AI-CNN group than in the control group, indicating that the AI-CNN model may further improve the quality of bowel preparation in patients exhibiting adequate bowel preparation.

DISCUSSION

The novel AI-CNN model, which demonstrated comparable outcomes to the routine practice, may serve as an alternative approach for evaluating bowel preparation quality before colonoscopy.

Comparative Effectiveness of Enhanced Patient Instructions for Bowel Preparation Before Colonoscopy: Network Meta-analysis of 23 Randomized Controlled Trials

Background

Various enhanced patient instructions (EPIs) have been used for bowel preparation (BP) and our previous meta-analysis also demonstrated the efficacy of EPIs in increasing the colonic polyp and adenoma detection rates; however, the optimal method for adequate BP has not yet been developed.

Objective

We performed a network meta-analysis to determine the optimal instructions.

Methods

We searched for randomized controlled trials (RCTs) comparing the effectiveness of EPIs with each other or standard patient instructions (SPIs) for BP. We performed direct and Bayesian network meta-analyses for all instructions and used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria to appraise the quality of evidence.

Results

We included 23 RCTs (7969 patients) comparing 10 different instructions. In direct meta-analyses, most of the EPIs, except visual aids and mobile apps, increased the adequate preparation rate (APR). Network meta-analyses showed that additional explanations were superior to visual aids (odds ratio [OR] 0.35, 95% CI 0.19-0.59), telephone calls (OR 0.62, 95% CI 0.37-0.99), educational videos (OR 0.79, 95% CI 0.5-0.77), and mobile apps (OR 0.33, 95% CI 0.14-0.68) with low-to-high-quality evidence; newly designed booklets (OR 3.28, 95% CI 1.59-6.16), SMS text messaging (OR 2.33, 95% CI 1.28-3.91), telephone calls (OR 1.86, 95% CI 1.03-1.78), educational videos (OR 2.33, 95% CI 1.40-3.65), and social media applications (OR 2.42, 95% CI 1.4-3.93) were superior to visual aids and mobile apps with low-to-high-quality evidence. SMS text messaging, telephone calls, and social media applications increase adherence to and satisfaction with the BP regime. Social media applications reduce the risk of adverse events (AEs). Telephone calls and social media applications increase the polyp detection rate (PDR).

Conclusions

Newly designed booklets, telephone calls, educational videos, and social media applications can improve the quality of BP. Telephone calls and social media applications improve adherence to and satisfaction with the BP regime, reduce the risk of AEs, and increase the PDR.

Trial Registration

INPLASY (International Platform of Registered Systematic Review and Meta-analysis Protocols) INPLASY2020120103; https://inplasy.com/inplasy-2020-12-0103/

Clinical and endoscopic characteristics of post-colonoscopy colorectal cancers detected within 10 years after a previous negative examination

Background and study aims We sometimes encounter colorectal cancer (CRC) that is discovered during the time interval between initial colonoscopy and the recommended follow-up examination. Although several studies reported such cases of CRC, most were based on registry data, which implied that the endoscopic quality was not consistent or guaranteed. We aimed to clarify these clinical and endoscopic characteristics at our high-volume center where a retrospective survey could be precisely performed.

Patients and methods We retrospectively analyzed patients with CRC who underwent endoscopic resection or surgery from April 2002 to December 2010, categorizing them into two groups: a “study group” of patients with a negative colonoscopy during the previous 10 years, and a “control group” of patients without a previous colonoscopy or with a previous colonoscopy more than 10 years prior.

Results A total of 2042 patients had CRC, among which 55 patients were classified into the study group and the remaining 1989 into the control group. The CRC cases in the study group showed a significant association with smaller (< 30 mm) tumor size (odds ratio [OR] 2.3; 95 % confidence interval [CI] 1.3–4.0) and proximal tumor site (OR 1.7; 95 %CI 0.9–2.9). In addition, right-sided and depressed-type T1 CRCs were significantly more common in the study group.

Conclusions Tumor size and location were associated with CRCs detected within 10 years after the negative examination. In addition, depressed-type T1 CRCs were more common. Therefore, we should pay more attention to small, right-sided, or depressed-type tumors in daily colonoscopy.

Colorectal Cancer Incidence After Colonoscopy at Ages 45-49 or 50-54 Years

BACKGROUND & AIMS

Colorectal cancer (CRC) incidence at ages younger than 50 years is increasing, leading to proposals to lower the CRC screening initiation age to 45 years. Data on the effectiveness of CRC screening at ages 45-49 years are lacking.

METHODS

We studied the association between undergoing colonoscopy at ages 45-49 or 50-54 years and CRC incidence in a retrospective population-based cohort study using Florida's linked Healthcare Cost and Utilization Project databases with mandated reporting from 2005 to 2017 and Cox models extended for time-varying exposure.

RESULTS

Among 195,600 persons with and 2.6 million without exposure to colonoscopy at ages 45-49 years, 276 and 4844 developed CRC, resulting in CRC incidence rates of 20.8 (95% CI, 18.5-23.4) and 30.6 (95% CI, 29.8-31.5) per 100,000 person-years, respectively. Among 660,248 persons with and 2.4 million without exposure to colonoscopy at ages 50-54 years, 798 and 6757 developed CRC, resulting in CRC incidence rates of 19.0 (95% CI, 17.7-20.4) and 51.9 (95% CI, 50.7-53.1) per 100,000 person-years, respectively. The adjusted hazard ratios for incident CRC after undergoing compared with not undergoing colonoscopy were 0.50 (95% CI, 0.44-0.56) at ages 45-49 years and 0.32 (95% CI, 0.29-0.34) at ages 50-54 years. The results were similar for women and men (hazard ratio, 0.48; 95% CI, 0.40-0.57 and hazard ratio, 0.52; 95% CI, 0.43-0.62 at ages 45-49 years, and hazard ratio, 0.35; 95% CI, 0.31-0.39 and hazard ratio, 0.29; 95% CI, 0.26-0.32 at ages 50-54 years, respectively).

CONCLUSIONS

Colonoscopy at ages 45-49 or 50-54 years was associated with substantial decreases in subsequent CRC incidence. These findings can inform screening guidelines.

Multidisciplinary prevention and management strategies for colorectal cancer and cardiovascular disease

Colorectal cancer (CRC) and cardiovascular disease (CVD) are leading causes of morbidity and mortality worldwide. Their numerous shared and modifiable risk factors underscore the importance of effective prevention strategies for these largely preventable diseases. Conventionally regarded as separate disease entities, clear pathophysiological links and overlapping risk factors represent an opportunity for synergistic collaborative efforts of oncologists and cardiologists. In addition, current CRC treatment approaches can exert cardiotoxicity and thus increase CVD risk. Given the complex interplay of both diseases and increasing numbers of CRC survivors who are at increased risk for CVD, multidisciplinary cardio-oncological approaches are warranted for optimal patient care from primary prevention to acute disease treatment and long-term surveillance.

Pancreatic Cancer-Associated Diabetes is Clinically Distinguishable From Conventional Diabetes

BACKGROUND

Type 3c diabetes mellitus (T3cDM) is diabetes secondary to other pancreatic diseases such as chronic pancreatitis, pancreatic resection, cystic fibrosis, and pancreatic ductal adenocarcinoma (PDA). Clinically, it may easily be confused with conventional type 2 diabetes mellitus (T2DM). A delay in pancreatic cancer diagnosis and treatment leads to a worse outcome. Therefore, early recognition of PDA-associated T3cDM and distinction from conventional T2DM represents an opportunity improve survival in patients with PDA.

METHODS

Six hundred and sixty four patients with PDA underwent pancreatic resection. Patients were classified as per whether or not they had diabetes. The specific type of diabetes was determined. T3cDM surgical patients (n = 127) were compared with a control group of medical patients with T2DM who did not have PDA (n = 127).

RESULTS

Patients with T3cDM were older (66 versus 61 y, P < 0.001), had lower body mass indices (25.9 versus 32.1, P < 0.001), more favorable hemoglobin A1c levels (7.0 versus 8.8, P < 0.001), higher alanine aminotransferase levels (39 versus 20, P < 0.001), and lower creatinine levels (0.8 versus 0.9 mg/dL, P < 0.001). In addition, they were more likely to be insulin dependent. In a subgroup analysis of surgical patients, T3cDM (versus surgical patients with T2DM and no diabetes) was not associated with surrogate markers of main pancreatic duct obstruction and glandular atrophy.

CONCLUSIONS

PDA-associated T3cDM has a distinctive presenting phenotype compared with medical patients with conventional T2DM. Greater attention to associated signs, symptoms, and biochemical data could identify patients at risk for harboring an underlying pancreatic malignancy and trigger diagnostic pathways leading to earlier PDA diagnosis and treatment.

Diagnostic yield of early repeat colonoscopy after suboptimal bowel preparation in a fecal immunochemical test-based screening program

BACKGROUND

Current guidelines regarding surveillance after screening colonoscopy assume adequate bowel preparation. However, follow-up intervals after suboptimal cleansing are highly heterogeneous. We aimed to determine the diagnostic yield of early repeat colonoscopy in patients with suboptimal bowel preparation in fecal immunochemical test (FIT)-based screening colonoscopy.

METHODS

An observational study including patients who underwent colonoscopy with suboptimal bowel preparation after positive FIT screening and then repeat colonoscopy within 1 year. Suboptimal preparation was defined as a Boston Bowel Preparation Scale (BBPS) score of 1 in any segment. Patients with a BBPS score of 0 in any segment or incomplete examination were excluded. The adenoma detection rate (ADR), advanced ADR (AADR), and colorectal cancer rate were calculated for the index and repeat colonoscopies.

RESULTS

Of the 2474 patients with FIT-positive colonoscopy at our center during this period, 314 (12.7 %) had suboptimal preparation. Of the 259 (82.5 %) patients who underwent repeat colonoscopy, suboptimal cleansing persisted in 22 (9 %). On repeat colonoscopy, the ADR was 38.7 % (95 %CI 32.6 % to 44.8 %) and the AADR was 14.9 % (95 %CI 10.5 % to 19.4 %). The per-adenoma miss rate was 27.7 % (95 %CI 24.0 % to 31.6 %), and the per-advanced adenoma miss rate was 17.6 % (95 %CI 13.3 % to 22.7 %). After repeat colonoscopy, the post-polypectomy surveillance recommendation changed from 10 to 3 years in 14.7 % of the patients with previous 10-year surveillance recommendation.

CONCLUSIONS

Patients with suboptimal bowel preparation on FIT-positive colonoscopy present a high rate of advanced adenomas in repeat colonoscopy, with major changes in post-polypectomy surveillance recommendations.

AGA White Paper: Roadmap for the Future of Colorectal Cancer Screening in the United States

The American Gastroenterological Association's Center for Gastrointestinal Innovation and Technology convened a consensus conference in December 2018, entitled, "Colorectal Cancer Screening and Surveillance: Role of Emerging Technology and Innovation to Improve Outcomes." The goal of the conference, which attracted more than 60 experts in screening and related disciplines, including the authors, was to envision a future in which colorectal cancer (CRC) screening and surveillance are optimized, and to identify barriers to achieving that future. This White Paper originates from that meeting and delineates the priorities and steps needed to improve CRC outcomes, with the goal of minimizing CRC morbidity and mortality. A one-size-fits-all approach to CRC screening has not and is unlikely to result in increased screening uptake or desired outcomes owing to barriers stemming from behavioral, cultural, and socioeconomic causes, especially when combined with inefficiencies in deployment of screening technologies. Overcoming these barriers will require the following: efficient utilization of multiple screening modalities to achieve increased uptake; continued development of noninvasive screening tests, with iterative reassessments of how best to integrate new technologies; and improved personal risk assessment to better risk-stratify patients for appropriate screening testing paradigms.

The efficacy of aspirin and metformin combination therapy in patients with rectal aberrant crypt foci: a double-blinded randomized controlled trial

Background

The incidence and mortality rates of colorectal cancer (CRC) continue to increase worldwide. Therefore, new preventive strategies are needed to lower the burden of this disease. Previous studies reported that aspirin could suppress the development of sporadic colorectal adenoma. In addition, metformin is a biguanide derivative that is long widely used for the treatment of diabetes mellitus and has recently been suggested to have a suppressive effect on carcinogenesis and cancer cell growth. Both drugs exhibit a chemopreventive effect, but their efficacy is limited.

Aberrant crypt foci (ACF), defined as lesions containing crypts that are larger in diameter and stain more darkly with methylene blue than normal crypts, are more prevalent in patients with cancer and adenomas, and considered a reliable surrogate biomarker of CRC. Thus, we designed a prospective trial as a preliminary study prior to a CRC chemoprevention trial to evaluate the chemopreventive effect of aspirin combined with metformin on colorectal ACF formation in patients scheduled for polypectomy.

Methods

This study is a double-blind randomized controlled trial that will be conducted in patients with both colorectal ACF and colorectal polyps scheduled for polypectomy. Eligible patients will be recruited for the study and the number of ACF in the rectum will be counted at the baseline colonoscopy. Then, the participants will be allocated to one of the following two groups; the aspirin plus placebo group or the aspirin plus metformin group. Patients in the aspirin plus placebo group will receive oral aspirin (100 mg) and placebo for 8 weeks, and those in the aspirin plus metformin group will receive oral aspirin (100 mg) and metformin (250 mg) for 8 weeks. After 8 weeks of administration, polypectomy will be performed to evaluate changes in the number of ACF, and the cell-proliferative activity in the normal colorectal mucosa and colorectal polyps.

Discussion

This is the first study proposed that will explore the effect of aspirin combined with metformin on the formation of colorectal ACF in humans.

Trial registration

This trial has been registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000028259. Registered 17 July 2017.

Optimal Colonoscopic Surveillance Interval After Normal Baseline Screening Colonoscopy

The optimal colonoscopic surveillance interval in the Chinese population is unclear. The present study aimed to assess the optimal colonoscopic surveillance interval after normal baseline screening colonoscopy to avoid overuse or underuse of colonoscopy. This retrospective study included individuals with normal baseline colonoscopy who had undergone at least 2 follow-up colonoscopy examinations at the Digestive Endoscopy Center of our hospital between 2000 and 2013. The risk factors for adenoma and the optimal colonoscopic surveillance interval were assessed. A total of 1,005 individuals (419 men; mean age, 49.34 ± 13.29 years) were included in the study. Of these, 169 individuals had adenomas at colonoscopic surveillance (mean, 1.32 ± 0.79 procedures). The mean adenoma diameter was 0.54 ± 0.38 cm, and the mean number of adenomas was 1.76 ± 1.29. The mean adenoma surveillance interval was 4.76 ± 2.89 years. The risk factors for adenoma identification were age more than 50 years and male gender. The optimal colonoscopic surveillance interval was 4.76 years according to an adenoma detection rate of 5%. The optimal colonoscopic surveillance interval is around 5 years for individuals with normal baseline colonoscopy. Age more than 50 years and male gender are risk factors for adenoma identification.

Enhanced Patient Education for Colonic Polyp and Adenoma Detection: Meta-Analysis of Randomized Controlled Trials

Background

To improve patients’ comprehension of bowel preparation instructions before colonoscopy, enhanced patient education (EPE) such as cartoon pictures or other visual aids, phone calls, mobile apps, multimedia education and social media apps have been proposed. However, it is uncertain whether EPE can increase the detection rate of colonic polyps and adenomas.

Objective

This meta-analysis aimed to evaluate the efficacy of EPE in detecting colonic polyps and adenomas.

Methods

We searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials from their inception to June 2019 for the identification of trials comparing the EPE with standard patient education for outpatients undergoing colonoscopy. We used a random effects model to calculate summary estimates of the polyp detection rate (defined as the number of patients with at least one polyp divided by the total number of patients undergoing selective colonoscopy), adenoma detection rate (defined as the number of patients with at least one adenoma divided by the total number of patients undergoing selective colonoscopy), advanced adenoma detection rate (defined as the number of patients with at least one advanced adenoma divided by the total number of patients undergoing selective colonoscopy), sessile serrated adenoma detection rate (defined as the number of patients with at least one sessile serrated adenoma divided by the total number of patients undergoing selective colonoscopy), cancer detection rate (defined as the number of patients with at least one cancer divided by the total number of patients undergoing selective colonoscopy), or adenoma detection rate - plus (defined as the number of additional adenomas found after the first adenoma per colonoscopy). Moreover, we conducted trial sequential analysis (TSA) to determine the robustness of summary estimates of all primary outcomes.

Results

We included 10 randomized controlled trials enrolling 4560 participants for analysis. The meta-analysis suggested that EPE was associated with an increased polyp detection rate (9 trials; 3781 participants; risk ratio [RR] 1.19, 95% CI 1.05-1.35; P<.05; I²=42%) and adenoma detection rate (5 trials; 2133 participants; RR 1.37, 95% CI 1.15-1.64; P<.001; I2=0%), which were established by TSA. Pooled result from the inverse-variance model illustrated an increase in the sessile serrated adenoma detection rate (3 trials; 1248 participants; odds ratio 1.76, 95% CI 1.22-2.53; P<.05; I²=0%). One trial suggested an increase in the adenoma detection rate - plus (RR 4.39, 95% CI 2.91-6.61; P<.001). Pooled estimates from 3 (1649 participants) and 2 trials (1375 participants) generated no evidence of statistical difference for the advanced adenoma detection rate and cancer detection rate, respectively.

Conclusions

The current evidence indicates that EPE should be recommended to instruct bowel preparation in patients undergoing colonoscopy because it can increase the polyp detection rate, adenoma detection rate, and sessile serrated adenoma detection rate. However, further trials are warranted to determine the efficacy of EPE for advanced adenoma detection rate, adenoma detection rate - plus, and cancer detection rate because of limited data.

Reinforced education improves the quality of bowel preparation for colonoscopy: An updated meta-analysis of randomized controlled trials

Background and aims

Inadequate bowel preparation (BP) is an unfavorable factor that influence the success of colonoscopy. Although standard education (SE) given to patients are proved useful to avoid inadequate BP. Studies concerning the effects of reinforced education (RE) on the quality of BP were inconsistent. The aim of this updated meta-analysis of randomized controlled trial was to compare the quality of BP between patients receiving RE in addition to SE and those receiving SE alone.

Methods

MEDLINE, EMBASE, Web of Science and the Cochrane Library were systemically searched to identify the relevant studies published through April 2019. The primary outcome was the rate of adequate BP. Subgroup analyses were conducted. Secondary outcomes included BP score, adenoma detection rate (ADR), polyp detection rate (PDR), insertion time, withdrawal time, adverse events, >80% purgative intake and diet compliance. Dichotomous variables were reported as odds ratio (OR) with 95% confidence interval (CI). Continuous data were reported as mean difference (MD) with 95%CI. Pooled estimates of OR or MD were calculated using a random-effects model. Statistical heterogeneity was accessed by calculating the I2 value. A P value less than 0.05 was considered significant.

Results

A total of 18 randomized controlled trails (N = 6536) were included in this meta-analysis. Patients who received RE had a better BP quality than those only receiving SE (OR 2.59, 95%CI: 2.09–3.19; P<0.001). A higher ADR (OR 1.35; 95%CI: 1.06–1.72; P = 0.020) and PDR (OR 1.24, 95%CI: 1.02–1.50; P = 0.030), shorter insertion (MD -0.76; 95%CI: -1.48-(-0.04); P = 0.040) and withdrawal time (MD -0.83; 95%CI: -1.83-(-0.28); P = 0.003), less nausea/vomiting (OR 0.78; 95%CI: 0.64–0.97; P = 0.020) and abdominal distension (OR 0.72; 95%CI: 0.68–0.92; P = 0.020) were achieved in the RE group. More patients had >80% purgative intake (OR 2.17; 95%CI, 1.09–4.32; P = 0.030) and were compliant with diet restriction (OR 2.38; 95%CI: 1.79–3.17; P<0.001) in the RE group.

Conclusion

RE significantly improved BP quality, increased ADR and PDR, decreased insertion and withdrawal time and adverse events.

Colorectal cancer prevention by a CLEAR principles-based colonoscopy protocol: an observational study

BACKGROUND AND AIMS

Colorectal cancer (CRC) prevention by colonoscopy has been lower than expected. We studied CRC prevention outcomes of a colonoscopy protocol based on Clean the colon, Look Everywhere, and complete Abnormality Removal (CLEAR) principles.

METHODS

This observational follow-up study studied patients provided screening colonoscopy at a free-standing private ambulatory surgery center in South Carolina by 80 endoscopists from October 2001 to December 2014, followed through December 2015. The colonoscopy protocol, optimized for polyp clearance, featured in-person bowel preparation instructions reinforced by phone, polyp search and removal throughout insertion and gradual withdrawal with circumferential tip movements, and a team approach using all personnel present to maximize polyp detection, patient safety, and clear-margin polypectomy including requesting repeat inspection or additional tissue removal. Outcome measures were postscreening lifetime CRC risk relative to Surveillance Epidemiology and End Results (SEER)-18 and interval cancer rate (postcolonoscopy CRCs among cancer-free patients at screening).

RESULTS

Of 25,862 patients (mean age, 58.1 years; 52% black; 205,522 person-years of observation), 159 had CRC at screening and 67 patients developed interval CRC. The interval CRC rate was 3.34 per 10,000 person-years of observation, 5.79 and 2.24 among patients with and without adenomas, respectively. The rate was similar among older patients (mean age 68.5 years at screening) and with prolonged follow-up. Postscreening lifetime CRC risk was 1.6% (bootstrap 95% confidence interval, 1.3%-1.8%) versus 4.7% in SEER-18, 67% lower. Subgroups with mean screening ages of 50 and 68.5 years showed risk reductions of 80% and 72%, respectively. The adverse event rate was less than usually reported rates: perforation 2.6 per 10,000, bleeding with hospitalization 2.4 per 10,000, and no deaths.

CONCLUSIONS

A colonoscopy protocol optimized for polyp clearance prevented 67% of CRC compared with a SEER-18 population given ongoing population screening.

Risk stratification of advanced colorectal neoplasia after baseline colonoscopy: Cohort study of 17 Japanese community practices

BACKGROUND AND AIM

In Japan, risk stratification after baseline colonoscopy is not widely accepted. We investigated the findings of baseline colonoscopies at 17 community practices and evaluated the risk of the incidence of advanced neoplasia over a 5-year period.

METHODS

This retrospective cohort study enrolled 3115 subjects over 40 years of age who underwent baseline colonoscopies and had at least one repeated colonoscopy within 5 years. Each group was classified based on the endoscopic findings of the baseline colonoscopy: no neoplasia/diminutive polyp <5 mm (N/D); small adenoma <10 mm; advanced adenoma; invasive cancer, respectively. We examined the incidence of advanced neoplasia during these 5 years and investigated the relationship between the surveillance colonoscopy and newly detected advanced neoplasia.

RESULTS

The small adenoma group did not show any significant increased risk as compared to the N/D group (hazard ratio [HR]: 0.799. 95% CI 0.442-1.443). There was a significantly increased risk in the advanced adenoma and invasive cancer groups (HR: 4.996, 95% CI 2.940-8.491, HR: 3.737, 95% CI 1.309-10.666). Cancer incidences during the study period were 0.18% in the N/D group, and 1.9% in the invasive cancer group, respectively. Undergoing surveillance colonoscopies twice within 5 years decreased the risk of advanced neoplasia.

CONCLUSIONS

There was a close relationship between the endoscopic findings of baseline colonoscopies and subsequent advanced neoplasia development. Risk stratification for advanced neoplasia based on the baseline findings can serve as a useful index for determining the optimal interval and frequency of colonoscopies over a 5-year period.

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.

Colorectal Cancer Outcomes in a Large Negative Computed Tomography Colonography Screening Cohort

Introduction

At our institution, the most common cohort of individuals having computed tomography colonography (CTC) are those that require primary screening for colorectal cancer and were unable to tolerate or failed optical colonoscopy (OC). CTC is an efficient method for detecting polyps, masses, flat-lesions, and overt colorectal cancer, serving as a viable alternative to colonoscopy. This study follows patients with negative CTC results to evaluate the number of clinically significant lesions that may have been potentially missed by CTC. We suspect this number will be exceedingly low given the high sensitivity of this technique.

Methods

All patients with negative CTC screening (n = 509) in the Eastern Health Medical Health Region, located in Newfoundland and Labrador, Canada were included. An electronic medical record review was undertaken, encompassing provider, colonoscopy, imaging, and histopathology reports. Subjects were also checked through the Newfoundland Cancer Clinic Registry Database. All incidents of colorectal cancer were recorded.

Results

The study cohort comprised 509 subjects. These subjects were followed for an average of 7.88 years. Two colorectal adenocarcinomas in this cohort were identified representing a crude cancer incidence rate of 0.49 cancers per 1000 patient years, and a rate of 0.39% following a normal CTC.

Conclusions

Colorectal cancer presenting clinically is rare in the 7.88 years following a negative CTC, suggesting CTC is equally effective for colorectal screening compared to OC. Furthermore, current guidelines that recommend interval CTC screening every 5 years is conservative, and interval screening can likely be recommended over a longer time frame.

Microsimulation Modeling in Oncology

PURPOSE

Microsimulation is a modeling technique that uses a sample size of individual units (microunits), each with a unique set of attributes, and allows for the simulation of downstream events on the basis of predefined states and transition probabilities between those states over time. In this article, we describe the history of the role of microsimulation in medicine and its potential applications in oncology as useful tools for population risk stratification and treatment strategy design for precision medicine.

METHODS

We conducted a comprehensive and methodical search of the literature using electronic databases-Medline, Embase, and Cochrane-for works published between 1985 and 2016. A medical subject heading search strategy was constructed for Medline searches by using a combination of relevant search terms, such as "microsimulation model medicine," "multistate modeling cancer," and "oncology."

RESULTS

Microsimulation modeling is particularly useful for the study of optimal intervention strategies when randomized control trials may not be feasible, ethical, or practical. Microsimulation models can retain memory of prior behaviors and states. As such, it allows an explicit representation and understanding of how various processes propagate over time and affect the final outcomes for an individual or in a population.

CONCLUSION

A well-calibrated microsimulation model can be used to predict the outcome of the event of interest for a new individual or subpopulations, assess the effectiveness and cost effectiveness of alternative interventions, and project the future disease burden of oncologic diseases. In the growing field of oncology research, a microsimulation model can serve as a valuable tool among the various facets of methodology available.

Update in Surveillance Recommendations in Individuals With Conventional Adenomas

PURPOSE OF REVIEW

Conventional adenomas, which are precursors to almost 70% of colorectal carcinomas, are found in more than one-third of screening colonoscopies. Surveillance recommendations, based on adenoma size, histology, and number, have evolved over the years and are currently reflective of index adenoma categorization as either low-risk (LRA) or high-risk (HRA). In this review, recent guideline recommendations as well as primary data that have helped to shape these recommendations are presented.

RECENT FINDINGS

Recent data have demonstrated that individuals with HRA on index exams may be at increased risk for CRC while those with LRA may have a minimal long-term risk for CRC, similar to those adults with normal index exams. Furthermore, the quality of the index exams is important for minimizing CRC risk. While individuals with HRA may require close surveillance intervals of 3 years, those with LRA or normal exams may need longer such as 10-year follow-up.

Risk factors associated with the detection and missed diagnosis of colorectal flat adenoma: a Chinese multicenter observational study

OBJECTIVES

Flat colorectal adenomas have a high risk of malignancy; however, their detection is often difficult due to their flat morphology. In this retrospective, large-scale study, we investigated the prevalence and characteristics of flat adenomas in a population in China.

METHODS

We analyzed the data collected for 16951 consecutive patients who underwent colonoscopy at four participating hospitals between September 2013 and September 2015. All colonoscopies were performed without magnification.

RESULTS

Among the 1,6951 patients, 2938 (17.3%) had adenoma and 796 (4.7%) had flat adenomas. The detection of flat adenoma showed a weak correlation with the detection of adenoma (r = 0.666). Multivariable logistic regression analysis revealed the following independent factors influencing the detection of flat adenomas: patient-related factors of age, presence of warning symptoms, history of adenomas and bowel preparation as well as endoscopist-related factors of endoscopist's level of proficiency, number of colonoscopy operators and withdrawal time.

CONCLUSIONS

The prevalence of flat adenomas in our study on Chinese patients was consistent with that reported from other countries. Factors conducive to the detection of flat adenomas were patient age of > 60 years, warning symptoms, history of adenoma, good bowel preparation, experienced endoscopist, single-operator colonoscopy and colonoscopy withdrawal time of >6 min.

Long-term performance of colorectal cancerscreening programmes based on the faecal immunochemical test

BACKGROUND

The long-term performance of colorectal cancer (CRC) screening programmes based on a 2-year faecal immunochemical test (FIT) is still unclear.

METHODS

In a sample of 50 to 69-year-olds repeatedly screened with the FIT (OC-Hemodia latex agglutination test; cut-off: 20 µg haemoglobin/g faeces), we examined: (1) the FIT positivity rate, the CRC and advanced adenoma detection rate and the FIT's positive predictive value (PPV) for advanced neoplasia, at each round of screening and (2) the cumulative CRC and advanced adenoma detection rate after five rounds of FIT.

RESULTS

Over 12 years (2002-2014), 123 347 individuals were administered the FIT up to six times, and 781 CRCs and 4713 advanced adenomas were diagnosed. The CRC and advanced adenoma detection rates declined substantially from the first to the third (rate ratio (RR) 0.25, 95% CI 0.20 to 0.32) and second (RR 0.51, 95% CI 0.47 to 0.56) rounds, respectively, and then remained stable. The PPV for advanced neoplasia dropped by 18% in the second round (RR 0.82, 95% CI 0.77 to 0.89), with no further reduction thereafter due to a concomitant decline in the FIT positivity rate (RR first to sixth rounds: 0.56, 95% CI 0.53 to 0.60).The cumulative CRC and advanced adenoma detection rates over five consecutive rounds were 8.5‰ (95% CI 7.8 to 9.2), and 58.9‰ (95% CI 56.9 to 61.0), respectively.

CONCLUSIONS

Repeated FIT significantly reduces the burden of colorectal disease while facilitating an efficient use of colonoscopy resources. The cumulative detection rate after five rounds of FIT is similar to primary screening with colonoscopy, supporting the need to account for the cumulative sensitivity of repeated FITs when evaluating the test's efficacy.

Risk of Metachronous Advanced Neoplasia in Patients With Multiple Diminutive Adenomas

OBJECTIVES

Individuals with advanced adenomas or three or more adenomas have a higher risk of metachronous advanced neoplasia (AN) and are recommended to undergo surveillance colonoscopy at shorter intervals. However, it is questionable whether patients with multiple (three or more) non-advanced diminutive adenomas should be considered as high-risk.

METHODS

We analyzed 5482 patients diagnosed with one or more adenomas during their first colonoscopy screening and who underwent a follow-up colonoscopy. Patients were categorized into four groups based on adenoma characteristics at baseline: Group 1, 1-2 non-advanced adenomas; Group 2, ≥3 non-advanced, diminutive (1 to 5 mm) adenomas; Group 3, ≥3 non-advanced, small (6-9 mm) adenomas; and Group 4, advanced adenomas.

RESULTS

During a median follow-up of 38 months, the incidence of metachronous AN at surveillance colonoscopy was 5.6%. The incidence of AN was 3.9% in group 1, 5.9% in group 2, 10.6% in group 3, and 22.1% in group 4. The adjusted hazard ratios (HRs) [95% confidence intervals (CIs)] for metachronous AN between group 2, group 3, and group 4, and low risk group 1 were 1.71 (0.99-2.94), 2.76 (1.72-4.44), and 5.23 (3.57-7.68), respectively. Compared with group 4, the adjusted HRs (95% CIs) for group 1, group 2, and group 3 were 0.19 (0.13-0.28), 0.32 (0.18-0.59), and 0.52 (0.31-0.89), respectively.

CONCLUSIONS

We found that patients with three or more non-advanced diminutive adenomas had a borderline increased risk of metachronous AN compared with patients with low risk adenomas.

Risk of Malignancy in Adenomas Detected During Screening Colonoscopy

BACKGROUND & AIMS

A higher incidence of proximal interval cancers after colonoscopy has been reported in several follow-up studies. One possible explanation for this might be that proximally located adenomas have greater malignant potential. The aim of the present study was to assess the risk of malignancy in proximal versus distal adenomas in patients included in a large screening colonoscopy database; adenoma shape and the patients' age and sex distribution were also analyzed.

METHODS

Data for 2007-2012 from the German National Screening Colonoscopy Registry, including 594,614 adenomas identified during 2,532,298 screening colonoscopies, were analyzed retrospectively. The main outcome measure was the rate of high-grade dysplasia (HGD) in adenomas, used as a surrogate marker for the risk of malignancy. Odds ratios (ORs) for the rate of HGD found in adenomas were analyzed in relation to patient- and adenoma-related factors using multivariate analysis.

RESULTS

HGD histology was noted in 20,873 adenomas (3.5%). Proximal adenoma locations were not associated with a higher HGD rate. The most significant risk factor for HGD was adenoma size (OR 10.36 ≥1 cm vs <1 cm), followed by patient age (OR 1.26 and 1.46 for age groups 65-74 and 75-84 vs 55-64 years) and sex (OR 1.15 male vs female). In comparison with flat adenomas as a reference lesion, sessile lesions had a similar HGD rate (OR 1.02) and pedunculated adenomas had a higher rate (OR 1.23). All associations were statistically significant (P ≤ .05).

CONCLUSIONS

In this large screening database, it was found that the rates of adenomas with HGD are similar in the proximal and distal colon. The presence of HGD as a risk marker alone does not explain higher rates of proximal interval colorectal cancer. We suggest that certain lesions (flat, serrated lesions) may be missed in the proximal colon and may acquire a more aggressive biology over time. A combination of endoscopy-related factors and biology may therefore account for higher rates of proximal versus distal interval colorectal cancer.

Young patients with sporadic colorectal adenomas: current endoscopic surveillance practices and outcomes

BACKGROUND AND AIMS

For young individuals (age <40 years) without strong family histories that would put them at risk for genetic colorectal cancer syndromes, it is unclear if national Multi-Society Task Force surveillance recommendations apply or if endoscopists follow these guideline recommendations when such patients are incidentally found to have adenoma(s) on colonoscopy.

METHODS

We reviewed records on young (age <40 years) patients, with either no family history or only a moderate family history (1 first-degree family member with colorectal cancer at age ≥50), who were found to have neoplastic polyp(s) on their index colonoscopy. We assessed the pattern of endoscopist surveillance recommendations, whether endoscopist recommendations complied with national guidelines, and compliance with surveillance recommendations.

RESULTS

One hundred forty-one subjects were included, of whom 19 (13.5%) had a moderate family history of colorectal cancer. For patients with non-high-risk findings, 27.7% were asked to repeat their colonoscopy in ≤3 years and 99.0% within 5 years. Endoscopist surveillance recommendation compliance rates with national guidelines were >65.0% for low-risk neoplasia but lower for high-risk (40.0%), nonpolypoid (44.2%), and serrated neoplasia (54.2%, P < .001 for all). Subjects whose endoscopist recommendations were noncompliant with guidelines were usually recalled too early (96%). Only 24.7% of subjects were actually compliant with endoscopist surveillance recommendations.

CONCLUSIONS

For young patients with neoplastic polyp(s) but no strong family history, most endoscopists complied with national guidelines and recommended repeat colonoscopy in 3 to 5 years. However, relatively few patients were compliant with repeat colonoscopy recommendations. For most cases that were noncompliant with guidelines, patients were recalled too early as opposed to too late.

Cap-assisted endoscopy: Do we have enough evidence?

So, is there enough evidence to incorporate CC in clinical practice? If we interpret the literature and the meta-analysis by Nutalapati et al., the answer for the clinically-focused endoscopist, with regard to adenoma detection rate (ADR), at present, may be "no". Significant differences do not necessarily imply clinical benefits and translation into clinical practice. The answer for the improvement of cecal intubation frequency and intubation time by the cap depends on the focus of training commitment, because these effects of the cap may be beneficial, especially for unexperienced endoscopists. It is obvious that further studies are needed. In this line, it is interesting to know, that in a recent meta-analysis of prospective studies, the length of the transparent cap had opposite effects on investigation time and polyp detection rate. Whereas, the anal to cecal time was significantly shortened by a cap length of > 7 mm and a polyp detection rate was significantly improved by a cap length of < 4 mm.

Colorectal cancer after negative colonoscopy in fecal immunochemical test-positive participants from a colorectal cancer screening program

Background and study aims  Colorectal cancer (CRC) risk after a positive fecal immunochemical test (FIT) and negative colonoscopy is unknown. We aimed to ascertain the cumulative incidence of post-colonoscopy colorectal cancer (PCCRC) and the manifestation of other lesions that could explain the test positivity in individuals with a negative colonoscopy in a population screening program. Patients and method  Observational study in participants from the first round of a CRC screening program (2010 - 2012) with positive-FIT (≥ 20 μg/g of feces) and negative colonoscopy (without neoplasia). A 42- to 76-month follow-up was performed searching in the National Health Service database and by a brief structured telephonic interview. Results  Of 2659 FIT-positive individuals who underwent colonoscopy, 811 (30.5 %) had a negative colonoscopy. Three PCCRC (0.4 %) were detected within 11 - 28 months and accelerated carcinogenesis was ruled out. Among those with normal colonoscopy, 32 (5 %) relevant lesions were detected at follow-up. One-third of them (11/32) were significant neoplasias: a gastric cancer, a small-bowel lymphoma, six advanced colorectal adenomas, and the three PCCRC. The 21 remaining lesions were inflammatory, vascular disorders, or non-advanced colorectal adenomas. Conclusions  The vast majority (95 %) of individuals did not present any subsequent lesion that could explain the FIT positivity. The very low incidence (0.4 %) and characteristics of PCCRC observed in our cohort reinforce the concept that, although a positive FIT preselects high risk individuals, a high quality colonoscopy is the paramount factor in preventing PCCRC. Improving quality standards of colonoscopy are required to strengthen the current CRC screening strategies.

Predictors of inadequate bowel preparation for colonoscopy: a systematic review and meta-analysis

The aim of this study was to investigate factors contributing to poor bowel preparation in patients undergoing colonoscopy procedures. We used a reproducible search strategy to identify studies, searching 10 medical databases, including PubMed, Ovid, Medline, and Cochrane Library Database for reports published between 2000 and 2016. Fully published studies, evaluating risk factors for inadequate bowel preparation, were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. Pooling was conducted with both fixed-effects and random-effects models; results were presented from the random effects model when heterogeneity was significant. Odds ratios (OR) estimates with 95% confidence interval were calculated. Heterogeneity was assessed by I statistics. Twenty-four studies with a total of 49 868 patients met the inclusion criteria. Age (OR: -1.20), male sex (OR: 0.85), inpatient status (OR: 0.57), diabetes mellitus (OR: 0.58), hypertension (OR: 0.58), cirrhosis (OR: 0.49), narcotic use (OR: 0.59), constipation (OR: 0.61), stroke (OR; 0.51), and tricyclic antidepressant (TCA) use (0.51), were associated with inadequate bowel preparation. In our sensitivity analysis comparing Western and Asian countries, we found that diabetes, cirrhosis, male sex, history of stroke and TCA use were stronger risk factors for inadequate bowel preparation in Western countries than in Asian countries. We also found that history of stroke, TCA use, and race were risk factors for inadequate bowel preparation in patients receiving conventional bowel preparation compared with those receiving split-dose bowel preparation. Multiple risk factors affect the quality of bowel preparation and specific risk factors can be intervened upon, in different populations, to optimize preparation.

Bowel preparation quality scales for colonoscopy

Colorectal cancer (CRC) is the third most common cancer and second leading cause of cancer-related death in the United States. Colonoscopy is widely preferred for CRC screening and is the most commonly used method in the United States. Adequate bowel preparation is essential for successful colonoscopy CRC screening. However, up to one-quarter of colonoscopies are associated with inadequate bowel preparation, which may result in reduced polyp and adenoma detection rates, unsuccessful screens, and an increased likelihood of repeat procedure. In addition, standardized criteria and assessment scales for bowel preparation quality are lacking. While several bowel preparation quality scales are referred to in the literature, these differ greatly in grading methodology and categorization criteria. Published reliability and validity data are available for five bowel preparation quality assessment scales, which vary in several key attributes. However, clinicians and researchers continue to use a variety of bowel preparation quality measures, including nonvalidated scales, leading to potential confusion and difficulty when comparing quality results among clinicians and across clinical trials. Optimal clinical criteria for bowel preparation quality remain controversial. The use of validated bowel preparation quality scales with stringent but simple scoring criteria would help clarify clinical trial data as well as the performance of colonoscopy in clinical practice related to quality measurements.

Bowel preparation quality scales for colonoscopy

Colorectal cancer (CRC) is the third most common cancer and second leading cause of cancer-related death in the United States. Colonoscopy is widely preferred for CRC screening and is the most commonly used method in the United States. Adequate bowel preparation is essential for successful colonoscopy CRC screening. However, up to one-quarter of colonoscopies are associated with inadequate bowel preparation, which may result in reduced polyp and adenoma detection rates, unsuccessful screens, and an increased likelihood of repeat procedure. In addition, standardized criteria and assessment scales for bowel preparation quality are lacking. While several bowel preparation quality scales are referred to in the literature, these differ greatly in grading methodology and categorization criteria. Published reliability and validity data are available for five bowel preparation quality assessment scales, which vary in several key attributes. However, clinicians and researchers continue to use a variety of bowel preparation quality measures, including nonvalidated scales, leading to potential confusion and difficulty when comparing quality results among clinicians and across clinical trials. Optimal clinical criteria for bowel preparation quality remain controversial. The use of validated bowel preparation quality scales with stringent but simple scoring criteria would help clarify clinical trial data as well as the performance of colonoscopy in clinical practice related to quality measurements.

Incidence and Classification of Postcolonoscopy Colorectal Cancers in Inflammatory Bowel Disease: A Dutch Population-Based Cohort Study

BACKGROUND AND AIMS

Patients with inflammatory bowel disease [IBD] colitis are at increased risk for colorectal cancer [CRC]. We examined the proportion and most likely aetiology of potentially preventable postcolonoscopy CRCs [PCCRCs] in a population-based cohort. Furthermore, adherence to IBD surveillance guidelines was evaluated in both PCCRCs and the remainder of prevalent CRCs.

METHODS

All IBD patients diagnosed from 1991 to 2011 in the South Limburg region of The Netherlands [i.e. IBDSL cohort] were included. CRC cases were cross-checked with the Dutch pathology database and cancer registry. PCCRCs were defined as cancers diagnosed within 6-60 months after a colonoscopy and were classified as attributable to 'inappropriate surveillance interval', 'inadequate bowel examination', 'incomplete resection', 'missed lesion' or 'newly developed cancer'.

RESULTS

Twenty CRC cases were identified during 25,931 patient years of follow-up in 2,801 patients. The proportion of PCCRCs was 45.0%. Of these, 55.6% could be considered a 'missed lesion', while other possible aetiologies occurred only once. Considering both PCCRCs [n=9] and prevalent CRCs [n=11], ten were detected after publication of the surveillance guideline, but only three patients were enrolled. Moreover, 6 CRCs [30.0%] were detected before the recommended start of surveillance.

CONCLUSIONS

In the IBDSL cohort, 45.0% of all CRCs were considered to be PCCRCs, mainly classified as missed lesions. Additionally, a large proportion of CRCs in our cohort were observed before a surveillance endoscopy was performed. Therefore, stringent adherence to IBD surveillance guidelines, improving endoscopy techniques and adjusting the surveillance program may lead to a decrease in CRC incidence.

Individual invitation letters lead to significant increase in attendance for screening colonoscopies: Results of a pilot study in Northern Hesse, Germany

Background

Colorectal cancer (CRC) is the second most common cancer in Germany. Screening colonoscopies are considered an effective tool for early detection and prevention of CRC and are recommended in Germany for citizens over the age of 55. To increase the participation rate for screening colonoscopies, an invitation procedure was initiated in parts of Germany for patients between the ages of 55 and 75 who had never undergone a screening colonoscopy before.

Methods

We examined the number of participating patients before, during, and after the invitation procedure and compared the number of the participating patients who received a cover letter with the participating patients from the control group. Additionally, we classified the findings of the colonoscopies including CRC, advanced adenomas, and polyps.

Results

During the invitation period, the participation rate of the invitation group increased from 220 patients to 531 patients compared to 1256 to 1693 in the control group. The increase was significantly greater in patients with cover letters (+141% vs.+35%, p < 0.0001). Also, significantly more polyps and adenomas were found in patients from the invitation letter group (254 (+102%) vs. 679 (-9%), p < 0.0001).

Conclusions

Our study clearly indicates that personal invitation letters are an effective measure to increase overall participation rates in screening colonoscopies.

Risk of metachronous neoplasia on surveillance colonoscopy in young patients with colorectal neoplasia

BACKGROUND AND AIMS

Few prior reports exist that address the appropriate colonoscopy surveillance interval for individuals <50 years old. We compared the risk of metachronous neoplasia between younger (20-49 years) and older (50-54 years) cohorts.

METHODS

This multicenter retrospective cohort study compared the incidence of metachronous neoplasia in younger and older cohorts according to baseline risk stratification. Subjects were eligible if they underwent their first colonoscopy between June 2006 and May 2010 and had at least 1 or more surveillance colonoscopy up to June 2015.

RESULTS

Among a total of 10,477 subjects who underwent baseline colonoscopy, 9722 were eligible after excluding 755 subjects. Of those 9722 subjects, 43% underwent surveillance colonoscopy. In the baseline high-risk adenoma group (n = 840), the 3-year risk of metachronous advanced neoplasia was 10.7% in the younger patients on screening colonoscopy and 8.9% in the older patients (P > .1). In the baseline low-risk adenoma group (n = 1869), the 5-year risk of metachronous advanced neoplasia was 4.9% in the younger patients on screening colonoscopy and 5.1% in the older patients (P > .1). Similarly, in the baseline no neoplasia group (n = 7013), the 5-year risk of metachronous advanced neoplasia was 4.1% in the younger patients on screening colonoscopy and 5.6% in the older patients (P > .1).

CONCLUSIONS

Considering the similar risk of metachronous advanced neoplasia in younger and older individuals, we suggest a 3-year surveillance interval for high-risk adenoma and a 5-year surveillance interval for low-risk adenoma in young individuals without a strong family history.

Adenoma detection rate influences the risk of metachronous advanced colorectal neoplasia in low-risk patients

BACKGROUND AND AIMS

In individuals with either no or 1 to 2 nonadvanced adenomas, future risks of advanced colorectal neoplasia (AN) vary according to clinical risk factors. However, little is known about the association between the adenoma detection rate (ADR) and the risk for metachronous AN in patients with low-risk adenomas.

METHODS

We identified 7171 participants with no or 1 to 2 nonadvanced adenomas at first-time screening colonoscopy. The risk of metachronous AN was investigated at surveillance colonoscopy, according to clinical characteristics and the ADR.

RESULTS

In multivariate analysis the risk for metachronous AN was strongly associated with increasing age, male sex, increasing number of adenomas, and the ADR of the endoscopist. With the ADR modeled as a continuous variable, each 1.0% increase in the rate of ADR predicted a 3.0% decrease in the risk of metachronous AN (adjusted odds ratio [OR], .97; 95% confidence interval [CI], .95-.99). With the ADR modeled using a binary cut-off (32%), the risk of metachronous AN was reduced in patients of endoscopists with an ADR ≥32% (adjusted OR, .53; 95% CI, .35-.83). Moreover, the risk of metachronous AN was reduced (adjusted OR, .66; 95% CI, .46-.95) in patients of endoscopists with an ADR in the highest tertile, compared with patients of endoscopists with ADRs in the lowest tertile. The impact of ADR on metachronous AN was significant for patients with low-risk adenomas rather than patients with no adenoma.

CONCLUSIONS

In patients with low-risk adenomas, the ADR of the endoscopist was inversely associated with the risk of metachronous AN.

Neoplasia at 10-year follow-up screening colonoscopy in a private U.S. practice: comparison of yield to first-time examinations

BACKGROUND AND AIMS

Prior studies assessing the yield of a second screening colonoscopy performed 10 years after an initial screening colonoscopy with negative results did not include a control group of persons undergoing a first screening colonoscopy during the same time interval. Our aim was to describe the incidence of neoplasia at a second screening colonoscopy (performed at least 8 years after the first colonoscopy) in average-risk individuals and compare it with the yield of first screening examinations performed during the same time interval.

METHODS

Review of a database of outpatient screening colonoscopies performed between January 2010 and December 2015 in an Atlanta private practice.

RESULTS

A total of 2105 average-risk individuals underwent screening colonoscopy, including 470 individuals (53.6% female; mean age ± standard deviation [SD] 64.0 ± 3.9 years) who underwent a second screening examination. In those undergoing second screening, the mean (± SD) interval between examinations was 10.4 years (± 1.1 years, range 8-15 years). At second screening, the polyp detection rate, adenoma detection rate, and advanced neoplasm rate were 44.7%, 26.6%, and 7.4%, respectively. Of 40 advanced neoplasms in 35 individuals, 33 (82.5%) were proximal to the sigmoid colon, and there were no cancers. During the same interval, 1635 individuals (49.4% female; mean age [± SD] 52.6 ± 3.4 years) underwent a first screening colonoscopy. The polyp detection rate, adenoma detection rate, and advanced neoplasm detection rate were 53.5%, 32.2%, and 11.7%, respectively. Of 243 advanced neoplasms in 192 individuals, 152 (62.6%) were proximal to the sigmoid colon, and there were no cancers. After adjustment for age, sex, body mass index, and endoscopist, polyp detection rate, adenoma detection rate, and advanced neoplasm detection rate were all lower at the second screening colonoscopies than at first-time colonoscopies (all P < .001).

CONCLUSIONS

Despite being 10 years older, persons with a screening colonoscopy with negative results 10 years earlier had lower rates of adenoma and advanced neoplasm at the second screening examination compared with patients in the same practice undergoing a first screening colonoscopy, and they had no cancers. The fraction of advanced neoplasms that were proximal to the sigmoid colon was high in both first and second screenings. These results support the safety of the recommended 10-year interval between colonoscopies in average-risk persons with an initial examination with negative results.

Metformin and Colorectal Cancer

Colorectal Cancer (CRC) is one of the most frequently encountered neoplasms in humans. The incidence of CRC has been increasing and new strategies for prevention, including chemoprevention, are required to lower its incidence and associated mortality. Metformin is a biguanide compound commonly used for the treatment of diabetes mellitus. Many recent basic research, epidemiological and clinical trial studies have indicated that metformin has benefits not only in diabetes treatment, but also in lowering the risk of developing cancer (including CRC). These studies indicate that metformin may be a candidate chemoprevention agent for CRC. This review article shall discuss the present evidence of metformin treatment and CRC, as well as outline our challenge in the investigation of metformin use in chemoprevention therapy for colorectal tumors.

Role of baseline adenoma characteristics for adenoma recurrencein patients with high-risk adenoma

Background/aim: The present observational study aimed to determine the predictive value of 3-year recurrence adenoma characteristics at baseline conventional colonoscopy in patients with high-risk adenoma.Materials and methods: A total of 47 patients with high-risk adenoma at baseline colonoscopy were followed up and underwent a surveillance colonoscopy at 3 years. Correlations between adenoma recurrence and baseline adenoma characteristics (size, number, histological features, and location) were analyzed.Results: Among 135 patients with high-risk adenoma, 47 patients (35%) who underwent surveillance colonoscopy at 3 years following baseline colonoscopy were included in the study. In these 47 patients, at least one new adenoma was detected in 19 (40.4%) patients, and new advanced adenomas were detected in 5 (10.6%) patients during the surveillance colonoscopy. No significant difference was found in patients who had adenoma recurrence versus those who did not in terms of size of adenomas (P = 0.143), number of adenomas (P = 0.562), histological properties of adenomas (P = 0.658), or locations of adenomas (P = 0.567).Conclusion: Baseline adenoma characteristics were not associated with the recurrence of adenomas or advanced adenomas in patients with high-risk adenoma.

A novel antibody against cancer stem cell biomarker, DCLK1-S, is potentially useful for assessing colon cancer risk after screening colonoscopy

DCLK1 expression is critically required for maintaining growth of human colon cancer cells (hCCCs). Human colorectal tumors (CRCs) and hCCCs express a novel short isoform of DCLK1 (DCLK1-S; isoform 2) from β-promoter of hDCLK1 gene, while normal colons express long isoform (DCLK1-L; isoform 1) from 5'(α)-promoter, suggesting that DCLK1-S, and not DCLK1-L, marks cancer stem cells (CSCs). Even though DCLK1-S differs from DCLK1-L by only six amino acids, we succeeded in generating a monospecific DCLK1-S-Antibody (PS41014), which does not cross-react with DCLK1-L, and specifically detects CSCs. Subcellular localization of S/L-isoforms was examined by immune-electron-microscopy (IEM). Surprisingly, besides plasma membrane and cytosolic fractions, S/L also localized to nuclear/mitochondrial fractions, with pronounced localization of S-isoform in the nuclei and mitochondria. Sporadic CRCs develop from adenomas. Screening colonoscopy is used for detection/resection of growths, and morphological/pathological criteria are used for risk assessment and recommendations for follow-up colonoscopy. But, these features are not precise and majority of the patients will never develop cancer. We hypothesized that antibody-based assay(s), which identify CSCs, will significantly improve prognostic value of morphological/pathological criteria. We conducted a pilot retrospective study with PS41014-Ab, by staining archived adenoma specimens from patients who developed (high-risk), or did not develop (low-risk) adenocarcinomas within 10-15 years. PS41014-Ab stained adenomas from initial and follow-up colonoscopies of high-risk patients, at significantly higher levels (three to fivefold) than adenomas from low-risk patients, suggesting that PS41014-Ab could be used as an additional tool for assessing CRC risk. CRC patients, with high DCLK1-S-expressing tumors (by qRT-PCR), were reported to have worse overall survival than low expressers. We now report that DCLK1-S-specific Ab may help to identify high-risk patients at the time of index/screening colonoscopy.

Colonoscopy reduces colorectal cancer mortality: A multicenter, long-term, colonoscopy-based cohort study

Background

There are limited colonoscopy-based cohort data concerning the effectiveness of colonoscopy in reducing colorectal cancer deaths. The aim of this study was to clarify whether colonoscopy reduces colorectal cancer mortality.

Methods

A cohort of 18,816 patients who underwent colonoscopy without a diagnosis of colorectal cancer between 2001 and 2010 at high colonoscopy procedure volume centers was selected. Patient characteristics and colonoscopy findings were assessed. The main endpoint was colorectal cancer death (all, right-sided, and left-sided cancers), and data were censored at the time of the final visit or the final colonoscopy. The standardized all colorectal, colon, and rectal cancer mortality rates were estimated with reference to those of the general Japanese population. Additional outcome was all- cause death and the standardized all-cause mortality rate was also estimated.

Results

The total observed person-year mortality for colorectal cancer was 67,119. Of these, 4, 3, and 1 patients died from colorectal, colon, and rectal cancers, respectively; these values were significantly lower than the number of expected deaths in the general population, estimated to be 53.1, 34.0, and 19.1, respectively. The standardized mortalities for all colorectal, colon, and rectal cancers were 0.08 (95% confidence interval (CI), 0.02–0.17), 0.09 (95% CI, 0.02–0.22), and 0.05 (95% CI, 0.0002–0.21), respectively. There were 586 all-cause deaths (3.11%) during the observation period. The standardized all-cause mortality ratios were 0.22 (95% CI, 0.206–0.23).

Conclusions

The colorectal cancer mortality of patients who received colonoscopy without colorectal cancer diagnosis decreased significantly compared with that of individuals in the general population. These results were compatible even in patients with right-sided colon cancer.