Impact of sigmoidoscopy and colonoscopy on colorectal cancer incidence and mortality: an evidence-based review of published prospective and retrospective studies

Colorectal cancer screening: A review of current knowledge and progress in research

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide, being the third most commonly diagnosed malignancy and the second leading cause of cancer-related deaths globally. Despite the progress in screening, early diagnosis, and treatment, approximately 20%-25% of CRC patients still present with metastatic disease at the time of their initial diagnosis. Furthermore, the burden of disease is still expected to increase, especially in individuals younger than 50 years old, among whom early-onset CRC incidence has been increasing. Screening and early detection are pivotal to improve CRC-related outcomes. It is well established that CRC screening not only reduces incidence, but also decreases deaths from CRC. Diverse screening strategies have proven effective in decreasing both CRC incidence and mortality, though variations in efficacy have been reported across the literature. However, uncertainties persist regarding the optimal screening method, age intervals and periodicity. Moreover, adherence to CRC screening remains globally low. In recent years, emerging technologies, notably artificial intelligence, and non-invasive biomarkers, have been developed to overcome these barriers. However, controversy exists over the actual impact of some of the new discoveries on CRC-related outcomes and how to effectively integrate them into daily practice. In this review, we aim to cover the current evidence surrounding CRC screening. We will further critically assess novel approaches under investigation, in an effort to differentiate promising innovations from mere novelties.

Antihypertensive medications and risk of colorectal cancer in British Columbia

Introduction: There is conflicting evidence for the association between antihypertensive medications and colorectal cancer risk, possibly reflecting methodological limitations of previously conducted studies. Here, we aimed to clarify associations between commonly prescribed antihypertensive medication classes and colorectal cancer risk in a large, retrospective, cohort study. Methods: Using linked administrative data between 1996 and 2017 from British Columbia, we identified a cohort of 1,693,297 men and women who were 50 years of age or older, initially cancer-free and nonusers of antihypertensive medications. Medication use was parameterized as ever use, cumulative duration, and cumulative dose. Cox proportional hazard models were used to estimate hazard ratios (HRs) and associated 95% confidence intervals (95% CIs) for associations of time-varying medication use [angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), beta-blockers (BBs), calcium channel blockers (CCBs), and diuretics] with colorectal cancer risk. Results: There were 28,460 incident cases of colorectal cancer identified over the follow-up period (mean = 12.9 years). When medication use was assessed as ever/never, diuretics were associated with increased risk of colorectal cancer (HR 1.08, 95% CI 1.04-1.12). However, no similar association was observed with cumulative duration or cumulative dose of diuretics. No significant associations between the other four classes of medications and colorectal cancer risk were observed. Conclusion: No compelling evidence of associations between antihypertensive medications and colorectal cancer were observed.

Using of endoscopic polypectomy in patients with diagnosed malignant colorectal polyp - The cross-sectional clinical study

The aim of this study was to evaluate the efficacy of endoscopic polypectomy as a therapeutic treatment for malignant alteration of colorectal polyps. In a 5-year research, 89 patients were included, who were tested and treated at the University Clinical Center Kragujevac, Kragujevac, Serbia, with the confirmed presence of malignant alteration polyps of the colon by colonoscopy, which were removed using the method of endoscopic polypectomy and confirmed by the histopathological examination of the entire polyp. After that, the same group of patients was monitored endoscopically within a certain period, controlling polypectomy locations and the occurrence of a possible remnant of the polyp, in the period of up to 2 years of polypectomy. We observed that, with an increasing size of polyps, there is also an increase in the percentage of the complexity of endoscopic resection and the appearance of remnant with histological characteristics of the invasive cancer. The highest percentage of incomplete endoscopic resection and the appearance of remnant with histological characteristics of the invasive cancer were shown at malignant altered polyps in the field of tubulovillous adenoma. Eighteen patients in total underwent the surgical intervention. In conclusion, our data support the high efficacy of endoscopic polypectomy for the removal of the altered malignant polyp.

Does Finding Cecal Adenoma Increase the Risk of Discovering More and Advanced Adenomas in the Remainder of the Colon?

OBJECTIVES

Adenomatous polyps are common, occurring in up to 25% of the population older than 50 years of age in the United States. Conflicting data are present in the literature about the impact of specific adenoma locations and the prediction on the number and advanced histology of adenomas elsewhere. With this study we aimed to review the association between cecal adenoma and the risk of discovering more and advanced adenomas in the remainder of the colon.

METHODS

We performed a retrospective study of 1880 patients who received outpatient colonoscopies between June 2012 and December 2014 at the Veterans Affairs Medical Center in Oklahoma City. The data collected included patient demographics, indications for colonoscopy, smoking history, alcohol use, family history of colon cancer, quality of bowel preparation, number of adenomas, location, size of adenomas, and the histology of adenomas and colon cancer.

RESULTS

The mean age of the study population was 61.6 ± 9.4 year, with 95% of the population being men. Cecal adenomas were found in 243 (12.9%) of patients. Patients with cecal adenoma tended to be older (65 ± 7 vs 61 ± 10, P < 0.0001), more likely to be men (97% vs 94%, P = 0.06) and less likely to have a colonoscopy done for screening indication (11% vs. 13%., P = 0.03). After adjusting for age, sex, indication, and quality of bowel preparation, patients with cecal adenoma were found to have a sixfold increase in finding ≥10 other adenomas elsewhere (4.5% vs 0.8% P = 0.0009) and a threefold increase in finding advanced adenomas (17.7% vs 9.9% P = 0.002) in the remainder of the colon. Stratifying by location, the increased risk was more pronounced in the right side (24.7% vs 8.9% P ≤ 0.0001) compared with the left side.

CONCLUSIONS

Cecal adenoma is associated with an increased risk of finding more and advanced adenomas in the remainder of the colon, especially on the right side; therefore, the discovery of a cecal adenoma should prompt a more thorough evaluation of the entire colon, particularly the right colon.

Biomolecular imaging of colorectal tumor lesions using a FITC-labeled scFv-Cκ fragment antibody

For the sensitive diagnosis of colorectal cancer lesions, advanced molecular imaging techniques using cancer-specific targets have emerged. However, issues regarding the clearance of unbound probes and immunogenicity remain unresolved. To overcome these limitations, we developed a small-sized scFv antibody fragment conjugated with FITC for the real-time detection of colorectal cancer by in vivo molecular endoscopy imaging. A small-sized scFv fragment can target colon cancer secreted protein-2 (CCSP-2), highly expressed in colorectal adenocarcinoma tissues; moreover, its full-length IgG probe has been used for molecular imaging previously. To assess the efficacy of anti-CCSP-2 scFv-FITC, surgical specimens were obtained from 21 patients with colorectal cancer for ex vivo molecular fluorescence analysis, histology, and immunohistochemistry. Orthotopic mice were administered with anti-CCSP-2 scFv-FITC topically and intravenously, and distinct tumor lesions were observed by real-time fluorescence colonoscopy. The fluorescence imaging of human colon cancer specimens allowed the differentiation of malignant tissues from non-malignant tissues (p < 0.05), and the CCSP-2 expression level was found to be correlated with the fluorescence intensity. Here, we demonstrated the feasibility and safety of anti-CCSP-2 scFv-FITC for molecular imaging as well as its potential in real-time fluorescence colonoscopy for the differential diagnosis of tumor lesions.

Comparison of the Effects of Diltiazem Gel with Lidocaine Gel on Reducing Pain and Discomfort in Patients Undergoing Rectosigmoidoscopy: A Randomized Double-blinded Clinical Trial

Background:

Flexible rectosigmoidoscopy is an easy and accessible exam to diagnose distal colon diseases, although many patients refuse to undergo it due to pain and discomfort during the procedure. Studies show that the application of local lidocaine, as an analgesic has no effect on pain relief in patients undergoing rectosigmoidoscopy. The current study aims at comparing the effects of diltiazem gel, an antispasmoic drug with local pain-reducing effects, with lidocaine gel in patients undergoing flexible rectosigmoidoscopy.

Materials and Methods:

The current double-blinded, randomized, clinical trial was performed to compare the effect of two topical drugs, lidocaine and diltiazem, on pain relief in patients undergoing rectosigmoidoscopy. A total of 80 patients who were potential candidates for rectosigmoidoscopy were enrolled in the study after obtaining the informed consent and then randomly assigned to one of the lidocaine gel (2 mL) or diltiazem gel (2 mL) group, 10 minutes prior to rectosigmoidoscopy. The level of pain in the patients during the procedure was measured using the visual analogue scale (VAS) and the results were recorded. The data were analyzed using paired samples ttest and independent t-test as well as analysis of covariance (ANOVA) with SPSS version 18. P-value <0.05 was considered the level of significance.

Results:

Of 80 patients, 35 (43.75%) were male and 45 (56.25%) female. The mean age and body mass index (BMI) of the patients were 51.45 ± 15.21 years and 25.95 ± 7.47 kg/m2, respectively, and there was no significant difference between the groups. The most frequent indications for rectosigmoidoscopy were abdominal pain (46.3%) and rectorrhagia (31.3%). The mean VAS score for pain reported by the patients in the lidocaine and diltiazem groups was 3.97 ± 2.89 and 2.60 ± 2.36, respectively. The VAS score for pain in the diltiazem group was significantly lower than lidocaine group (P = 0.023).

Conclusion:

The application of local diltiazem gel around the anus, in spite of no side effects, can effectively reduce the pain and discomfort in patients during rectosigmoidoscopy. Iranian Registry of Clinical Trials (Reg. No 31055).

Prophylactic clipping after endoscopic mucosal resection of large nonpedunculated colorectal lesions: A meta-analysis

BACKGROUND AND AIM

It is not clear whether prophylactic clipping after endoscopic mucosal resection (EMR) of large nonpedunculated colorectal lesions (LNPCLs) prevents delayed bleeding (DB). We aimed to conduct a meta-analysis to clarify the efficacy of prophylactic clipping in prevention of DB following EMR of LNPCLs.

METHODS

We searched PubMed, EMBASE, Web of Science, ScienceDirect, Cochrane Library databases, and ClinicalTrials.gov for studies that compared clipping versus (vs) nonclipping in prevention of DB following EMR of LNPCLs. Pooled odds ratio (OR) was determined using a random effects model. The pooled ORs of DB, perforation, and post-polypectomy syndrome in the clipping group compared with the nonclipping group comprised the outcomes. Subgroup analyses based on study design, polyp location, and completeness of wound closure were performed.

RESULTS

Five studies with a total of 3112 LNPCLs were extracted. Prophylactic clipping reduced the risk of DB compared with nonclipping (3.3% vs 6.2%, OR: 0.494, P = 0.002) following EMR of LNPCLs. In subgroup analysis, prophylactic clipping reduced DB of LNPCLs at proximal location (3.8% vs 9.8%, P = 0.029), but not of them at distal location (P = 0.830). Complete wound closure showed superior efficacy to prevent DB compared with partial closure (2.0% vs 5.4%, P = 0.004). No benefit of clipping for preventing perforation or post-polypectomy syndrome was observed (P = 0.301 and 0.988, respectively).

CONCLUSIONS

Prophylactic clipping can reduce DB following EMR of LNPCLs at proximal location. Besides, complete wound closure showed superior efficacy to prevent DB compared with partial closure. Further cost analyses should be conducted to implement the most cost-effective strategies.

Impact of nonalcoholic fatty liver disease on the risk of metachronous colorectal neoplasia after polypectomy

BACKGROUND/AIMS

Metabolic syndrome has been reported to be a risk factor for metachronous colorectal neoplasia (CRN). However, the impact of nonalcoholic fatty liver disease (NAFLD), a hepatic manifestation of metabolic syndrome, on the development of metachronous CRN after polypectomy has been rarely examined. We evaluated the association between NAFLD and the development of metachronous CRN after polypectomy.

METHODS

Asymptomatic subjects who underwent abdominal ultrasonography and endoscopic removal of ≥ 1 adenomas at the index colonoscopy between 2010 and 2014, and had a follow-up surveillance colonoscopy until 2017 were analyzed.

RESULTS

Of 6,182 participants, 2,642 (42.7%) had NAFLD at the time of the index colonoscopy. Patients with NAFLD had significantly higher cumulative incidence rates of metachronous overall CRN than those without NAFLD in both men (19.4% vs. 18.2% at 3 years and 49.2% vs. 44.0% at 5 years; p = 0.001) and women (18.7% vs. 10.5% at 3 years and 56.1% vs. 29.8% at 5 years; p < 0.001). Even after adjusting for confounders, NAFLD remained independently associated with an increased risk of metachronous overall CRN in both men (adjusted hazard ratio [HR], 1.17; 95% confidence interval [CI], 1.06 to 1.29) and women (adjusted HR, 1.63; 95% CI, 1.27 to 2.07). Additionally, NAFLD was an independent risk factor for metachronous advanced CRN (ACRN) in women (adjusted HR, 2.61; 95% CI, 1.27 to 5.37).

CONCLUSION

NAFLD is related to an increased risk of metachronous CRN after polypectomy. Especially, women with NAFLD are at an increased risk of developing metachronous ACRN. Our results indicate a possible effect of NAFLD on the pathogenesis of CRN.

Metformin Inhibits the Urea Cycle and Reduces Putrescine Generation in Colorectal Cancer Cell Lines

The urea cycle (UC) removes the excess nitrogen and ammonia generated by nitrogen-containing compound composites or protein breakdown in the human body. Research has shown that changes in UC enzymes are not only related to tumorigenesis and tumor development but also associated with poor survival in hepatocellular, breast, and colorectal cancers (CRC), etc. Cytoplasmic ornithine, the intermediate product of the urea cycle, is a specific substrate for ornithine decarboxylase (ODC, also known as ODC1) for the production of putrescine and is required for tumor growth. Polyamines (spermidine, spermine, and their precursor putrescine) play central roles in more than half of the steps of colorectal tumorigenesis. Given the close connection between polyamines and cancer, the regulation of polyamine metabolic pathways has attracted attention regarding the mechanisms of action of chemical drugs used to prevent CRC, as the drug most widely used for treating type 2 diabetes (T2D), metformin (Met) exhibits antitumor activity against a variety of cancer cells, with a vaguely defined mechanism. In addition, the influence of metformin on the UC and putrescine generation in colorectal cancer has remained unclear. In our study, we investigated the effect of metformin on the UC and putrescine generation of CRC in vivo and in vitro and elucidated the underlying mechanisms. In nude mice bearing HCT116 tumor xenografts, the administration of metformin inhibited tumor growth without affecting body weight. In addition, metformin treatment increased the expression of monophosphate (AMP)-activated protein kinase (AMPK) and p53 in both HCT116 xenografts and colorectal cancer cell lines and decreased the expression of the urea cycle enzymes, including carbamoyl phosphate synthase 1 (CPS1), arginase 1 (ARG1), ornithine trans-carbamylase (OTC), and ODC. The putrescine levels in both HCT116 xenografts and HCT116 cells decreased after metformin treatment. These results demonstrate that metformin inhibited CRC cell proliferation via activating AMPK/p53 and that there was an association between metformin, urea cycle inhibition and a reduction in putrescine generation.

High-quality colon cleansing and multiple neoplasia detection with 1L NER1006 versus mid-volume options: Post hoc analysis of phase 3 clinical trials

Background and study aims  Multiple neoplasia increase the risk of colorectal cancer. High-quality cleansing may improve adenoma detection. We assessed whether a new bowel preparation can improve colon cleansing and multiple lesion detection. Patients and methods  This post hoc analysis of two randomized clinical trials in Europe and the US assessed the per study and combined cleansing efficacy of overnight split dosing with (preparation + clear fluids) 1 + 1 L polyethylene glycol (PEG) NER1006 versus 2 + 1 L PEG + ascorbate (2LPEG) or 1 + 2 L oral sulfate solution (OSS) combined. Treatment-blinded central readers assessed cleansing quality using the Harefield Cleansing Scale (HCS). Patients with full segmental scoring were included. HCS segmental scores 0-4 (high-quality = HCS 3-4) were analyzed for NER1006 versus 2LPEG/OSS. Mean number of polyps or adenomas per patient (MPP/MAP) was calculated for treatments in patients with at least one polyp or adenoma. Results  In 1037 patients, NER1006 attained a greater rate of HCS 3 scores (29 % vs. 20 %; P  < 0.001) and HCS 4 scores (20 % vs. 17 %; P  = 0.007) versus 2LPEG/OSS. More polyps (678 versus 585) and adenomas (397 versus 331) were detected with NER1006 (N = 517) versus 2LPEG/OSS (N = 520). In all neoplasia-positive patients, with increasing minimal per-patient neoplasia multiplicity from 1 to 10, NER1006 numerically improved MPP (difference ± SE: 0.48 ± 0.24 to 3.89 ± 3.37) and MAP (0.47 ± 0.26 to 7.50 ± 9.00) versus 2LPEG/OSS. Conclusions  Low-volume NER1006 enhances high-quality cleansing versus medium-volume 2LPEG or OSS, individually and when combined. NER1006 may consequently facilitate the detection of multiple neoplasia in patients.

Improved high-quality colon cleansing with 1L NER1006 versus 2L polyethylene glycol + ascorbate or oral sulfate solution

BACKGROUND & AIMS

Colonoscopy requires bowel cleansing for gut mucosa visualization; high-quality cleansing facilitates lesion detection. NER1006 is a 1L polyethylene glycol (PEG) bowel preparation. This post hoc analysis of two randomized trials investigated cleansing efficacy assessed, as in clinical practice, by site endoscopists.

METHODS

Patients received NER1006, 2L PEG + ascorbate (2LPEG), or oral sulfate solution (OSS) as a 2-day evening/morning regimen (N2D) or NER1006 morning-only dosing (N1D). Treatment-blinded site endoscopists assessed cleansing using the Harefield Cleansing Scale (HCS). Analyses were conducted in a modified full analysis set, including (mFAS; n = 1378) or excluding (mFAS2; n = 1319) imputed failures, and in patients with 100% treatment adherence (mFAS100; n = 1047). Overall cleansing success (HCS grade A/B), overall high-quality cleansing (HCS grade A), and high-quality segments (HCS 3-4) per treatment population were analyzed.

RESULTS

Overall cleansing success was higher with N2D than 2LPEG (92.7-97.5% vs. 87.9-93.0%), and more patients had overall high-quality cleansing with N2D and N1D than 2LPEG (68.0-72.1% and 64.0-68.4% vs. 50.7-56.0%). Without imputed failures, N2D delivered more overall high-quality cleansing than OSS (74.5-77.3% vs. 67.8-69.8%). More high-quality segments were demonstrated with N2D and N1D versus 2 LPEG (82.5-87.1% and 79.4-84.4% vs. 70.4-76.3%) and with N2D versus OSS (82.7-89.5% vs. 78.1-84.4%).

CONCLUSION

When assessed by site endoscopists, NER1006 delivers greater high-quality cleansing than 2LPEG or OSS.

Risk of Developing Metachronous Advanced Colorectal Neoplasia After Polypectomy in Patients With Multiple Diminutive or Small Adenomas

INTRODUCTION

Current post-polypectomy guidelines recommend a 3-year surveillance interval for ≥3 nonadvanced adenomas (NAAs) without discrimination between diminutive (1-5 mm) and small (6-9 mm) adenomas. We compared the risk of metachronous advanced colorectal neoplasia (ACRN) among these groups.

METHODS

We studied 9,733 patients who underwent ≥1 adenoma removal and follow-up colonoscopic surveillance. Patients were classified based on baseline adenoma characteristics: group 1, 1-2 NAAs (n = 8,051); group 2, ≥3 diminutive NAAs (n = 293); group 3, ≥3 small NAAs (n = 258); and group 4, advanced adenomas (AAs) (n = 1,131).

RESULTS

The mean age of the study population was 45.8 ± 8.2 years. In group 4, most patients (94.5%) had 1 AA. The 3- and 5-year cumulative incidence rates of metachronous ACRN in groups 1, 2, 3, and 4 were 0.9%, 2.8%, 3.5%, and 4.0% and 3.1%, 10.7%, 15.1%, and 8.5%, respectively. Groups 2, 3, and 4 had a higher risk of metachronous ACRN than group 1. Compared with those for group 1, adjusted hazard ratios (95% confidence interval) for metachronous ACRN were 2.07 (1.16-3.68), 3.29 (1.94-5.56), and 2.73 (2.00-3.72) for groups 2, 3, and 4, respectively. However, this relationship was statistically insignificant between groups 2, 3, and 4. Compared with those for group 2, adjusted hazard ratios (95% confidence intervals) for groups 3 and 4 were 1.59 (0.76-3.30) and 1.32 (0.72-2.42), respectively, and 0.83 (0.47-1.46) for group 4 compared with group 3. The results of patients aged ≥50 years were identical to those of all patients.

DISCUSSION

Risk of metachronous ACRN was not different between patients aged ≥50 years who underwent polypectomy of ≥3 diminutive NAAs, ≥3 small NAAs, and AA, thus supporting current guidelines that recommend a uniform surveillance interval for these lesions.

A Randomized Controlled Trial Comparing Colonoscopic Enema With Additional Oral Preparation as a Salvage for Inadequate Bowel Cleansing Before Colonoscopy

GOALS

The goal of this study was to evaluate the noninferiority of colonoscopic enema to additional oral preparation in salvage bowel cleansing for inadequate preparation for a morning colonoscopy.

BACKGROUND

Colonoscopic enema, administering additional cathartics into the right colon through the colonoscope accessory channel, is suggested to rescue poor bowel preparation for a colonoscopy but lacking comparative study.

STUDY

In this prospective, randomized, actively-controlled, parallel group, noninferiority trial, consecutive outpatients and health checkup recipients aged from 19 to 70 years with inappropriate bowel preparation during an elective colonoscopy were enrolled to receive either a colonoscopic enema of 1 L polyethylene glycol (PEG) (enema group) or additional oral intake of 2 L PEG (oral group). The primary endpoint was the proportion of adequate bowel preparation evaluated using the Boston Bowel Preparation Scale.

RESULTS

Overall, 131 participants were randomized. Adequate bowel preparation was achieved in 53% (35/66) of the enema group, which was significantly inferior to the oral group (81.5%; 53/67) with a difference of -28.5% (95% confidence interval, -44.1, -12.9; P=0.001). The largest difference in the proportion of adequate bowel preparation was observed in the right colon (57.8% in the enema group vs. 86.9% in the oral group; P<0.001), followed by the transverse colon (85.9% vs. 98.4%; P=0.017) and the left colon (90.6% vs. 96.7%; P=0.274).

CONCLUSIONS

The colonoscopic enema of 1 L PEG was inferior to the additional oral ingestion of 2 L PEG regarding efficacy as a salvage bowel preparation in adults with inadequate bowel cleansing for colonoscopy.

Impact of obesity and metabolic abnormalities on the risk of metachronous colorectal neoplasia after polypectomy in men

BACKGROUND AND AIM

Obesity and metabolic syndrome are well-known risk factors for the development of metachronous colorectal neoplasia (CRN). However, data on the risks of metachronous CRN among subgroups according to obesity and metabolic status are scarce. Therefore, we aimed to compare the risk of metachronous CRN among men with different obesity and metabolic status.

METHODS

In total, 8059 asymptomatic men who underwent ≥ 1 adenoma removal between 2010 and 2014 and follow-up colonoscopic surveillance until 2017 were categorized into four groups according to obesity and metabolic status: metabolically healthy non-obese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy non-obese (MUNO), and metabolically unhealthy obese (MUO).

RESULTS

Of the 8059 men, 2389 (29.6%), 351 (4.4%), 1986 (24.6%), and 3333 (41.4%) subjects were assigned to the MHNO, MHO, MUNO, and MUO groups, respectively. The mean surveillance interval was 3.5 ± 1.4 years. Compared to the MHNO group, the risk of metachronous advanced CRN was significantly increased in the MUO group (adjusted hazard ratio [HR] = 1.50; 95% confidence interval [CI]: 1.02-2.19), but not in the MHO and MUNO groups, while the risk of metachronous overall CRN significantly increased in the MUNO (adjusted HR = 1.12; 95% CI: 1.01-1.24) and MUO groups (adjusted HR = 1.17; 95% CI: 1.07-1.29), but not in the MHO group.

CONCLUSIONS

Men who had both obesity and poor metabolic health were found to be at an increased risk of metachronous advanced CRN, suggesting that MUO men may need to undergo more intensive surveillance colonoscopy after polypectomy.

Confounders in Adenoma Detection at Initial Screening Colonoscopy: A Factor in the Assessment of Racial Disparities as a Risk for Colon Cancer

Background and Aims

The incidence and mortality of colorectal cancer is persistently highest in Black/African-Americans in the United States. While access to care, barriers to screening, and poverty might explain these findings, there is increased interest in examining biological factors that impact the colonic environment. Our group is examining biologic factors that contribute to disparities in development of adenomas prospectively. In preparation for this and to characterize a potential patient population, we conducted a retrospective review of initial screening colonoscopies in a cohort of patients.

Methods

A retrospective review was performed on initial average risk screening colonoscopies on patients (age 45-75 years) during 2012 at three institutions. Descriptive statistics and multivariable logistic regression models were used to examine the relationship between potential risk factors and the detection of adenomas.

Results

Of the 2225 initial screening colonoscopies 1495 (67.2%) were performed on Black/African-Americans and 566 (25.4%) on Caucasians. Multivariable logistic regression revealed that older age, male sex, current smoking and teaching gastroenterologists were associated with higher detection of adenomas and these were less prevalent among Black/African-Americas except for age. Neither race, ethnicity, BMI, diabetes mellitus, HIV nor insurance were associated with adenoma detection.

Conclusion

In this sample, there was no association between race and adenoma detection. While this may be due to a lower prevalence of risk factors for adenomas in this sample, our findings were confounded by a lower detection rate by consultant gastroenterologists at one institution. The study allowed us to rectify the problem and characterize patients for future trials.

A Comparative Study Evaluating the Incidence of Colorectal Neoplasia(s) in Candidates for Bariatric Surgery by Screening Colonoscopy, 40-49 Versus 50-65 Years Old: a Preliminary Study

INTRODUCTION

Obesity and metabolic syndrome (MetS) are associated with colorectal neoplasia (CRN) and carcinoma (CRC). Whether such subjects must undergo screening colonoscopy (SC) earlier, is unknown. Incidences of CRNs in 40-49- versus 50-65-year-old bariatric patients were compared by SC. No prospective data on SC is available in morbidly obese/MetS.

MATERIAL AND METHODS

Surgical weight loss candidates over 39 years of age, asymptomatic, and average-risk for CRC offered SC. Those giving written informed consent were enrolled. Colonoscopies were done by the same surgeon. Smoking/drinking history, fasting blood glucose (FBG), insulin, C-peptide, triglyceride, high density lipoprotein, vitamin D, HbA1c, and insulin resistance parameters were recorded. CRN rate and the distribution of variables in patients 40-49 years of age were compared with 50-65. Student's t and Chi-square tests were used as appropriate. P < 0.05 was regarded as statistically significant.

RESULTS

Among 168 SCs, 47 had CRNs (27.9%). Including carcinoma, 15 had an advanced CRN (aCRN) (8.9% aCRN and 0.6% CRC). CRN rate was 35.6% in ≥ 50 years old whereas 22.1% in 40-49 (p = 0.053). aCRN rates (8.4% in 40-49 versus 9.6% in 50-65) were similar (p = 0.792). Metabolic parameters and smoking-drinking history were equally distributed between the groups except FBG and HbA1c as their mean levels were slightly higher in the 50-65 age group (p < 0.05).

CONCLUSIONS

Presented results warrant routine SC in the 40-49-year-old morbidly obese and/or MetS patient population with average risk, and in aged > 50, it certainly must be enforced and included in the preoperative check-list if not done before.

Risk of developing metachronous advanced colorectal neoplasia after colonoscopic polypectomy in patients aged 30 to 39 and 40 to 49 years

BACKGROUND AND AIMS

Current guidelines define postpolypectomy surveillance intervals in patients aged ≥50 years. The risk of metachronous colorectal neoplasia (CRN) and the optimal postpolypectomy surveillance interval in patients aged <50 years remain unclear. We compared the risk of metachronous CRN in patients aged 30 to 39, 40 to 49, and ≥50 years.

METHODS

We studied patients who underwent ≥1 adenoma removal between 2010 and 2014 and follow-up colonoscopic surveillance until 2017.

RESULTS

Among 10,014 patients studied, 3242, 4606, and 2166 were 30 to 39, 40 to 49, and ≥50 years old, respectively. After high-risk adenoma removal, the 3-year risk of metachronous advanced CRN (ACRN) in patients aged 30 to 39 and 40 to 49 years was lower than in patients ≥50 years old (1.9% and 3.6% vs 8.1%, respectively; P < .001 and .008). After low-risk adenoma removal, the 5-year risk of metachronous ACRN in patients aged 30 to 39 and 40 to 49 years was lower than in patients ≥50 years old (2.8% and 3.3% vs 5.9%, respectively; P = .010 and .031). The risk of metachronous ACRN or ≥3 adenomas in patients aged 30 to 39 years was significantly lower than in patients aged 40 to 49 years. Age remained significantly associated with the risk of metachronous ACRN despite adjustments for potential confounders.

CONCLUSIONS

The risk of metachronous ACRN was lower in patients aged <50 years than in those aged ≥50 years; thus, the postpolypectomy surveillance interval may be extendable to >3 and 5 years in high-risk and low-risk adenoma groups, respectively, in patients aged <50 years.

Patients' Preferences for Primary Colorectal Cancer Screening: A Survey of the National Colorectal Cancer Screening Program in Korea

Background/Aims

The adoption of colonoscopy as a primary colorectal cancer (CRC) screening technique has been argued for in Korea, without evidence of patient preferences. This study aimed to investigate patients’ preferences for the primary CRC screening test for the National Cancer Screening Program (NCSP).

Methods

Between June and August 2016, 414 individuals aged ≥50 years who participated in the NCSP were prospectively invited to complete a questionnaire regarding their preferences for the primary CRC screening test and the reasons for their selection.

Results

Among the 396 respondents who completed the questionnaire, 124 individuals (31.3%) preferred the fecal immunochemical test (FIT), whereas 272 individuals (68.7%) preferred colonoscopy. Elderly participants preferred the FIT (p<0.001), whereas participants with a higher education level (p=0.030), a higher income level (p=0.009), or individuals with a family member (p=0.028) or acquaintance (p=0.013) with a history of CRC preferred colonoscopy. Only 12.9% of participants had a bad experience with a previous FIT; however, 39.3% of participants had a bad experience with a previous colonoscopy.

Conclusions

Colonoscopy was preferred to FIT in a 2.2:1 ratio as the primary CRC screening test for the NCSP. Patients’ preference for colonoscopy should be considered for the NCSP in Korea.

Characteristics of right-sided colonic neoplasia and colonoscopy barriers limiting their early detection and prognosis: a review of the literature

Colonoscopy provides less protection from colorectal cancer in the right colon than the left. Areas covered: This review examines patient outcomes and colonoscopy success rates to identify factors that limit the protective effect of colonoscopy in the right colon. The MEDLINE and Embase databases were searched for literature from 2000 onwards, on the long-term outcomes and differences in screening practice between the right and left colon. In total, 12 systematic reviews (including nine meta-analyses) and 44 primary data records were included. Differences in patient outcomes and colonoscopy practice were identified between the right and left colon, suggesting that several factors, many of which disproportionally affect the right colon, impact lesion detection rates. Shorter withdrawal times reduce detection rates, while longer times significantly increase detection; mostly of adenomas in the right colon. Colonoscope attachments often only show a significant improvement in detection rates in the right colon, suggesting detection is more challenging due to visibility of the right colonic mucosa. Higher bowel cleansing grades significantly improve detection rates in the right colon compared to the left. Expert commentary: These findings confirm the need for continued improvement of colonoscopy effectiveness, and obligatory quality assessment, overall and especially in the right colon.

Right Versus Left Colon Cancer: Resectable and Metastatic Disease

OPINION STATEMENT

Colorectal cancer does not represent a single anatomic entity and side of origin has a key impact on prognosis and response to different systemic therapies. Compared to tumours arising in left colon, right colorectal cancers rely on the activation of different molecular pathways (e.g. BRAF mutation and MSI status). From a clinical point of view, this results in a different response to anti-EGFR agents. Current guidelines suggest the use of cetuximab or panitumumab in RAS wild-type disease and left colon cancer especially for cytoreduction/conversion purposes, since the expected benefit in right colon cancer is absent or clinically modest. The prognostic role of microbiota in colorectal cancer disease deserves more clarification before being considered in common clinical practice. Screening policies could also be affected by these new acquisitions. At the moment, sidedness should be considered as a strong prognostic variable and a surrogate predictor of different activity of anti-EGFR agents in the metastatic setting. Its role in early stages of resected disease is still uncertain.

Postoperative adjuvant chemotherapy is associated with a lower incidence of colorectal adenomas in patients with previous colorectal cancer

BACKGROUND AND AIMS

The effects of chemotherapeutic agents on the development of colorectal adenomas in patients with previous colorectal cancer (CRC) are not defined. Therefore, we evaluated the potential effect of adjuvant chemotherapy on the incidence of colorectal adenomas in patients with previous CRC.

METHODS

We selected patients with low-risk stage II CRC with or without postoperative 5-fluorouracil-based adjuvant chemotherapy to reduce selection bias. Among 1808 patients with stage II CRC who underwent colonoscopic surveillance after curative resection of CRC between 2006 and 2013, 192 patients were retrospectively enrolled in this study after matching for age and sex. The patients were divided into 96 patients receiving and 96 patients not receiving 5-fluorouracil-based chemotherapy.

RESULTS

Forty patients (41.7%) exhibited colorectal adenomas among 96 patients who received adjuvant chemotherapy, compared with 50 patients (52.1%) with colorectal adenomas among 96 patients who received surgery only. The incidence rate of advanced adenoma was significantly lower in the chemotherapy group than in the nonchemotherapy group (3.1% vs 10.4%, P = .044). After adjustment for clinically relevant factors such as body mass index, aspirin use, metformin use, number of follow-up colonoscopies, and operation type, adjuvant chemotherapy was found to be associated with a decreased incidence of advanced adenoma (odds ratio, .151; 95% confidence interval, .035-.653; P = .011) in patients with stage II CRC.

CONCLUSIONS

The results showed that chemotherapy in patients with CRC may be associated with a lower risk of colorectal advanced adenoma development.

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.

The risk of colorectal neoplasia can be different according to the types of family members affected by colorectal cancer

BACKGROUND AND AIM

A family history of colorectal cancer (CRC) is an important risk factor for CRC, but more detailed data are needed to prepare effective screening guidelines. We aimed to evaluate the risk of colorectal neoplasia (CRN) among individuals with different relatives affected by CRC (the first-degree relatives [FDRs] or the second-degree relatives or the first cousins) and to assess the effects of family histories according to age groups (30-39, 40-49, and ≥ 50 years).

METHODS

A cross-sectional study was performed on 98 562 asymptomatic examinees aged ≥ 30 years who underwent colonoscopy as part of a health checkup.

RESULTS

Mean age of the study population was 41.4 years, and the prevalence of CRN was 15.7%. Participants with ≥ 1 FDRs and ≥ 2 FDRs affected by CRC had a higher risk of CRN than those with no family history of CRC, while those with ≥ 1 second-degree relatives or first cousins affected did not. In the 30-39 and 40-49 years age groups, a family history of CRC in parents was a risk factor for CRN and advanced CRN, but not in siblings. By contrast, in the ≥ 50 age group, participants with affected siblings (reference group) had a significantly higher risk for advanced CRN than those with affected parents (adjusted odds ratio; 95% confidence interval: 0.39; 0.16-0.94 in father and 0.43; 0.18-0.995 in mother).

CONCLUSIONS

The risk of CRN can be different according to the types of family members affected, and the impact of such family histories can be different according to age.

Prospective analysis of delayed colorectal post-polypectomy bleeding

BACKGROUNDS/AIMS

Although post-polypectomy bleeding is the most frequent complication after colonoscopic polypectomy, only few studies have investigated the incidence of bleeding prospectively. The aim of this study was to investigate the incidence of delayed post-polypectomy bleeding and its associated risk factors prospectively.

METHODS

Patients who underwent colonoscopic polypectomy at Kangbuk Samsung Hospital from January 2013 to December 2014 were prospectively enrolled in this study. Trained nurses contacted patients via telephone 7 and 30 days after polypectomy and completed a standardized questionnaire regarding the development of bleeding. Delayed post-polypectomy bleeding was categorized as minor or major and early or late bleeding. Major delayed bleeding was defined as a > 2-g/dL drop in the hemoglobin level, requiring hospitalization for control of bleeding or blood transfusion; late delayed bleeding was defined as bleeding occurring later than 24 h after polypectomy.

RESULTS

A total of 8175 colonoscopic polypectomies were performed in 3887 patients. Overall, 133 (3.4%) patients developed delayed post-polypectomy bleeding. Among them, 90 (2.3%) and 43 (1.1%) patients developed minor and major delayed bleeding, respectively, and 39 (1.0%) patients developed late delayed bleeding. In the polyp-based multivariate analysis, young age (< 50 years; odds ratio [OR] 2.10; 95% confidence interval [CI] 1.18-3.68), aspirin use (OR 2.78; 95% CI 1.23-6.31), and polyp size of > 10 mm (OR 2.45; 95% CI 1.38-4.36) were significant risk factors for major delayed bleeding, while young age (< 50 years; OR 2.6; 95% CI 1.35-5.12) and immediate bleeding (OR 3.3; 95% CI 1.49-7.30) were significant risk factors for late delayed bleeding.

CONCLUSIONS

Young age, aspirin use, polyp size, and immediate bleeding were found to be independent risk factors for delayed post-polypectomy bleeding.

Clinical risk stratification model for advanced colorectal neoplasia in persons with negative fecal immunochemical test results

OBJECTIVES

The fecal immunochemical test (FIT) has low sensitivity for detecting advanced colorectal neoplasia (ACRN); thus, a considerable portion of FIT-negative persons may have ACRN. We aimed to develop a risk-scoring model for predicting ACRN in FIT-negative persons.

MATERIALS AND METHODS

We reviewed the records of participants aged ≥40 years who underwent a colonoscopy and FIT during a health check-up. We developed a risk-scoring model for predicting ACRN in FIT-negative persons.

RESULTS

Of 11,873 FIT-negative participants, 255 (2.1%) had ACRN. On the basis of the multivariable logistic regression model, point scores were assigned as follows among FIT-negative persons: age (per year from 40 years old), 1 point; current smoker, 10 points; overweight, 5 points; obese, 7 points; hypertension, 6 points; old cerebrovascular attack (CVA), 15 points. Although the proportion of ACRN in FIT-negative persons increased as risk scores increased (from 0.6% in the group with 0-4 points to 8.1% in the group with 35-39 points), it was significantly lower than that in FIT-positive persons (14.9%). However, there was no statistical difference between the proportion of ACRN in FIT-negative persons with ≥40 points and in FIT-positive persons (10.5% vs. 14.9%, P = 0.321).

CONCLUSIONS

FIT-negative persons may need to undergo screening colonoscopy if they clinically have a high risk of ACRN. The scoring model based on age, smoking habits, overweight or obesity, hypertension, and old CVA may be useful in selecting and prioritizing FIT-negative persons for screening colonoscopy.

Association Between Low Relative Muscle Mass and the Risk of Colorectal Neoplasms

GOALS

We aimed to ascertain whether low relative muscle mass is associated with colorectal neoplasm (CRN) risk.

BACKGROUND

CRN and sarcopenia have common pathophysiological mechanisms such as insulin resistance, chronic inflammation, and physical inactivity. However, the direct relationship between the 2 diseases has not been investigated.

STUDY

A cross-sectional study was performed on 81,885 examinees who underwent colonoscopy as part of a health check-up. The skeletal muscle mass index (SMI) [SMI (%)=total skeletal muscle mass (kg)/body weight (kg)×100] was estimated using a bioelectrical impedance analyzer.

RESULTS

Of 81,885 participants, 52,272 were men and 29,613 were women. The prevalence rate of CRN in subjects in quartiles 1, 2, 3, and 4 of SMI was 22.8%, 20.5%, 18.2%, and 14.9% among men, and 14.8%, 11.8%, 9.7%, and 8.2% among women, respectively (Ptrend<0.001). In a multivariable-adjusted model, the inverse associations between SMI and prevalence of CRN remained significant. In men, the adjusted odds ratios (95% confidence interval) for overall CRN comparing each of the quartiles 1, 2, and 3 of SMI with the quartile 4 were 1.41 (1.32 to 1.52), 1.24 (1.16 to 1.33), and 1.12 (1.04 to 1.20), and those for advanced CRN were 1.64 (1.34 to 2.01), 1.38 (1.12 to 1.70), and 1.12 (0.90 to 1.40), respectively (all Ptrend<0.001). In women, those for overall CRN were 1.18 (1.04 to 1.33), 1.15 (1.01 to 1.30), and 1.05 (0.93 to 1.20), respectively (Ptrend=0.006).

CONCLUSIONS

Relative muscle mass was negatively associated with CRN prevalence, supporting low muscle mass as an independent risk factor for CRN. Our results may provide a novel insight into the mechanisms linking low muscle mass and CRN.

Molecular Imaging of Colorectal Tumors by Targeting Colon Cancer Secreted Protein-2 (CCSP-2)

A versatile biomarker for detecting colonic adenoma and colon cancer has yet to be developed. Colon cancer secreted protein-2 (CCSP-2) is a protein specifically expressed and secreted in colon adenomas and cancers. We developed a fluorescent imaging method based on CCSP-2 targeting for a more sensitive and specific detection of colorectal tumors. CCSP-2 expression was evaluated in human colon adenoma and colorectal specimens. Anti–CCSP-2 antibody was labeled with a near-infrared fluorescent dye, FPR-675, and molecular imaging of surgical human colorectal tumors was performed. Immunohistochemistry identified CCSP-2 expression in 87.0% of colorectal cancer specimens and 89.5% of colon adenoma specimens. Fluorescence imaging of surgical human colon specimens after spraying treatment with the probe permitted a clear distinction of cancer from paired normal colon tissue (target-to-background ratio, 4.09 ± 0.42; P < .001). CCSP-2 targeting imaging was also evaluated in patient-derived colon cancer xenograft mouse and liver metastasis murine models. CCSP-2–positive colon cancer xenografts and liver metastases were visualized by near-infrared fluorescence imaging after intravenous injection of the probe, which showed significantly higher fluorescence. Our results show that CCSP-2 is a promising marker for colorectal tumor detection in clinical settings and that a CCSP-2–targeting molecular imaging strategy might improve the diagnosis of colorectal tumors in metastatic or recurrent cancers and aid in early colonoscopic detection of premalignant lesions.

Prospective Analysis of Minor Adverse Events After Colon Polypectomy

BACKGROUND

The risks of minor adverse events (MAEs) such as abdominal pain and bloating after colon polypectomy (CP) are less clearly documented than major adverse events. However, these complications may cause significant discomfort during the performance of normal activities. We aimed to estimate the incidence of MAE, associated risk factors, and healthcare resource utilization after CP.

METHODS

Patients who underwent CP were prospectively enrolled in this study. Trained nurses contacted patients by telephone at 7 and 30 days after the CP and administered a standardized questionnaire to obtain information regarding the development of complications. MAEs were defined as any discomfort the patient experienced after CP excluding major bleeding, perforation, and post-polypectomy coagulation syndrome.

RESULTS

Among a total of 2716 patients, 2253 patients completed the interview at 7 and 30 days. MAEs occurred in 263 patients (11.7%) before day 7, among which the most common were abdominal pain (4.5%), rectal bleeding (2.8%), and bloating (2.6%). Cumulative incidence of MAEs was in 267 patients (11.9%) at 30 days. On multivariate analysis, female sex (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.58-3.18) and use of meperidine (OR 1.54, 95% CI 1.04-2.27) were risk factors for the occurrence of MAEs. Two patients (0.7%) required hospital admission, 117 patients (43.8%) were treated medically in the outpatient clinic, and the majority at 148 patients (55.4%) experienced resolution of symptoms after observation.

CONCLUSIONS

The post-CP MAE rate was as low as 11.8%. The MAEs occurred mainly in the first seven postoperative days and resulted in little use of healthcare resources.

Risk factors of missed colorectal lesions after colonoscopy

Several studies have reported a significant rate of missed colorectal polyps during colonoscopy. This study aimed to determine the variables that affect the miss rate of colorectal polyps.We performed a retrospective observational study of patients who, between January 2007 and December 2014, had undergone a second colonoscopy within 6 months of their first. In all patients, the first colonoscopy constituted a screening or surveillance colonoscopy as part of a health check-up, and the patients were referred to the endoscopic clinic if there were meaningful polyps. The miss rate of colorectal polyps was evaluated, as were the variables related to these missed lesions.Among 659 patients (535 men), the miss rate of colorectal polyps was 17.24% (372/2158 polyps), and 38.69% of patients (255/659 patients) had at least 1 missed polyp. The most common site for missed polyps was the ascending colon (29.8%), followed by the sigmoid colon (27.8%). The miss rate of polyps was higher in men [odds ratio (OR) = 1.611, 95% confidence interval (95% CI) = 1.024-2.536], patients with multiple polyps at their first colonoscopy (OR = 1.463, 95% CI = 0.992-2.157), and patients who had a history of polyps (OR = 23.783, 95% CI = 3.079-183.694). Multiple missed polyps were more frequently located in the right colon (OR = 2.605, 95% CI = 1.458-4.657), and the risk of sessile serrated adenoma/polyp was greater in the right colon (OR = 10.418, 95% CI = 2.073-52.353).Endoscopists should pay careful attention in patients who have multiple polyps and in those who have a history of polyps, because such patients are at a high risk of missed polyps in colonoscopy.

Risk factors of nonadherence to colonoscopy surveillance after polypectomy and its impact on clinical outcomes: a KASID multicenter study

BACKGROUND

An optimal surveillance program is important to prevent advanced colorectal neoplasm. In this context, we have evaluated the cumulative risk of high-risk adenoma (HRA) or colorectal cancer (CRC) according to surveillance interval time after polypectomy. In addition, we assessed risk factors for late surveillance to determine whether late surveillance can impact the risk of subsequent advanced colorectal neoplasm.

METHODS

This was a multicenter retrospective cohort study involving 3562 subjects who had undergone removal of at least one adenoma at the index colonoscopy and who subsequently underwent a surveillance colonoscopy. The subjects were classified into an early, appropriate or late group depending on the timing of the surveillance colonoscopy, performed using modified U.S.

RESULTS

With 3% of the study population with LRA and HRA at the index colonoscopy going on to develop HRA or CRC, the estimated surveillance intervals calculated would be 6.3 [95% confidence interval (CI) 5.42-7.10] years and 3.1 (95% CI 2.61-4.45) years, respectively. The predictors of late surveillance were female gender [odd ratio (OR) 1.21; 95% CI 1.04-1.40], having undergone the procedure in small-to-medium-sized cities (OR 1.92; 95% CI 1.36-2.72) and HRA at index colonoscopy (OR 1.37; 95% CI 1.19-1.59). The risk factors for subsequent HRA or CRC were late surveillance (OR 1.34; 95% CI 1.03-1.74), male gender (OR 2.13; 95% CI 1.54-2.95), having undergone the procedure in small-to-medium-sized cities (OR 1.63; 95% CI 1.11-2.40) and HRA at index colonoscopy (OR 2.60; 95% CI 2.04-3.33).

CONCLUSIONS

Women, having undergone the procedure in small-to-medium-sized cities and the presence of an HRA at the index colonoscopy were found to be independent risk factors for late surveillance colonoscopy. Late surveillance is significantly predictive of subsequent HRA or CRC.

Accounting for misclassification in electronic health records-derived exposures using generalized linear finite mixture models

Exposures derived from electronic health records (EHR) may be misclassified, leading to biased estimates of their association with outcomes of interest. An example of this problem arises in the context of cancer screening where test indication, the purpose for which a test was performed, is often unavailable. This poses a challenge to understanding the effectiveness of screening tests because estimates of screening test effectiveness are biased if some diagnostic tests are misclassified as screening. Prediction models have been developed for a variety of exposure variables that can be derived from EHR, but no previous research has investigated appropriate methods for obtaining unbiased association estimates using these predicted probabilities. The full likelihood incorporating information on both the predicted probability of exposure-class membership and the association between the exposure and outcome of interest can be expressed using a finite mixture model. When the regression model of interest is a generalized linear model (GLM), the expectation-maximization algorithm can be used to estimate the parameters using standard software for GLMs. Using simulation studies, we compared the bias and efficiency of this mixture model approach to alternative approaches including multiple imputation and dichotomization of the predicted probabilities to create a proxy for the missing predictor. The mixture model was the only approach that was unbiased across all scenarios investigated. Finally, we explored the performance of these alternatives in a study of colorectal cancer screening with colonoscopy. These findings have broad applicability in studies using EHR data where gold-standard exposures are unavailable and prediction models have been developed for estimating proxies.

Metformin use and the risk of colorectal adenoma: A systematic review and meta-analysis

BACKGROUND AND AIM

Although it is known that metformin can reduce risk of colorectal cancer, it is unclear whether it protects against colorectal adenoma.

METHODS

This study conducted a systematic literature search on MEDLINE, EMBASE, and the Cochrane Library using the primary keywords "colorectal," "colon," "rectal," "rectum," "adenoma," "polyp," "neoplasia," "neoplasm," "metformin," and "diabetes." Studies were included if they evaluated the association between metformin use and colorectal adenoma and reported odds ratios (ORs) or provided data from which these could be estimated.

RESULTS

Ten studies and a total of 8726 patients were evaluated. Across all studies, a median of 32.1% (range: 15.2-53.0%) of patients taking metformin also had adenoma; a median of 43.5% (range: 20.5-59.6%) of those not taking metformin had adenoma. In our meta-analysis, metformin use reduced the risk of adenoma (pooled OR = 0.76, 95% confidence interval [CI] = 0.63-0.92, I²  = 60%). Upon subgroup analyses, metformin use tended to reduce risk of adenoma in a high-risk population consisting of patients with a history of colorectal neoplasia (CRN) (pooled OR = 0.61, 95% CI = 0.34-1.10, I²  = 79%). In addition, metformin reduced the risk of adenoma in a high-risk population consisting of patients with diabetes mellitus (pooled OR = 0.75, 95% CI = 0.62-0.91, I²  = 57%).

CONCLUSION

Metformin use seemed to be associated with a reduced risk of colorectal adenoma, especially in high-risk populations consisting of patients with diabetes mellitus or a history of CRN, although statistical power was not achieved in patients with a history of CRN.

Identifying the optimal strategy for screening of advanced colorectal neoplasia

BACKGROUND AND AIM

To guide selection of optimal screening strategies for advanced colorectal neoplasia (ACRN), we evaluated the screening performances of sigmoidoscopy, fecal immunochemical test (FIT), and the Asia-Pacific Colorectal Screening (APCS) system, as well as combinations of these techniques.

METHODS

We reviewed the records of participants who had undergone a colonoscopy and FIT as part of a comprehensive health-screening program. Results of sigmoidoscopy were estimated from lesions under colonoscopic examination. The screening strategies were classified as sigmoidoscopy-based, FIT-based, and APCS-based. The sensitivity and reduction of number needed to colonoscope (NNScope) of each screening strategy were assessed.

RESULTS

Of 23 023 participants, 398 (1.7%) had ACRN. To predict the presence of ACRN, sigmoidoscopy was the most effective method (odds ratio [OR]: 22.96, 95% confidence interval [CI]: 18.26-29.07), followed by FIT (OR: 7.18, 95% CI: 5.28-9.68) and APCS (high risk [≥4] OR: 2.59, 95% CI: 1.87-3.58; moderate risk [2-3] OR: 1.66, 95% CI: 1.28-2.17). Regarding sigmoidoscopy-based strategies, "sigmoidoscopy positive alone" and "sigmoidoscopy positive or APCS ≥4" were optimal strategies (reduction of NNScope: 79-86%; sensitivity: 73-78%). In the case of FIT-based strategies, "FIT positive or APCS ≥4" was the optimal strategy (reduction of NNScope: 72%; sensitivity: 37%). With regard to the APCS system only, "APCS ≥2" and "APCS ≥4" were recommended as sensitivity-preferred and reduction in NNScope-preferred strategies, respectively.

CONCLUSIONS

The performance in ACRN prediction differs among screening methods (sigmoidoscopy, FIT, and APCS). Among the various single or combined screening strategies, several specific strategies can be chosen depending on medical resources, financial budgets, and screenee preference.

Parameters of Glucose and Lipid Metabolism Affect the Occurrence of Colorectal Adenomas Detected by Surveillance Colonoscopies

PURPOSE

Limited data are available regarding the associations between parameters of glucose and lipid metabolism and the occurrence of metachronous adenomas. We investigated whether these parameters affect the occurrence of adenomas detected on surveillance colonoscopy.

MATERIALS AND METHODS

This longitudinal study was performed on 5289 subjects who underwent follow-up colonoscopy between 2012 and 2013 among 62171 asymptomatic subjects who underwent an initial colonoscopy for a health check-up between 2010 and 2011. The risk of adenoma occurrence was assessed using Cox proportional hazards modeling.

RESULTS

The mean interval between the initial and follow-up colonoscopy was 2.2±0.6 years. The occurrence of adenomas detected by the follow-up colonoscopy increased linearly with the increasing quartiles of fasting glucose, hemoglobin A1c (HbA1c), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and triglycerides measured at the initial colonoscopy. These associations persisted after adjusting for confounding factors. The adjusted hazard ratios for adenoma occurrence comparing the fourth with the first quartiles of fasting glucose, HbA1c, insulin, HOMA-IR, and triglycerides were 1.50 [95% confidence interval (CI), 1.26-1.77; p(trend)<0.001], 1.22 (95% CI, 1.04-1.43; p(trend)=0.024), 1.22 (95% CI, 1.02-1.46; p(trend)=0.046), 1.36 (95% CI, 1.14-1.63; p(trend)=0.004), and 1.19 (95% CI, 0.99-1.42; p(trend)=0.041), respectively. In addition, increasing quartiles of low-density lipoprotein-cholesterol and apolipoprotein B were associated with an increasing occurrence of adenomas.

CONCLUSION

The levels of parameters of glucose and lipid metabolism were significantly associated with the occurrence of adenomas detected on surveillance colonoscopy. Improving the parameters of glucose and lipid metabolism through lifestyle changes or medications may be helpful in preventing metachronous adenomas.

Risk Factors for False Fecal Immunochemical Test Results in Colorectal Cancer Screening

GOALS

We investigated the factors associated with false fecal immunochemical test (FIT) results for advanced colorectal neoplasm (ACRN).

BACKGROUND

Data on whether certain subgroups of patients have an increased risk of inaccurate FIT results are extremely limited.

STUDY

This was a retrospective study conducted in a university hospital in Korea from June 2013 to May 2015. Out of 34,547 participants who had an FIT completed, we analyzed a total of 3990 subjects aged 50 years and above who underwent colonoscopy.

RESULTS

The rates of false-negative and false-positive results were 58.0% and 15.7%, respectively. Elevated fasting blood glucose [adjusted odds ratio (AOR), 0.59; 95% confidence interval (CI), 0.36-0.97], the presence of high-grade dysplasia (AOR, 0.49; 95% CI, 0.25-0.95), 3 or more adenomas (AOR, 0.56; 95% CI, 0.35-0.89), cancer (AOR, 0.20; 95% CI, 0.11-0.38), and distal ACRN (AOR, 0.61; 95% CI, 0.39-0.96) were associated with a lower risk of false-negative FIT results. The presence of proximal ACRN (AOR, 1.59; 95% CI, 1.01-2.51) and adenoma ≥10 mm (AOR, 4.38; 95% CI, 2.17-8.87) were associated with a higher risk of false-negative results. Older age (70 y and above; AOR, 1.67; 95% CI, 1.29-2.17), diverticulum (AOR, 1.94; 95% CI, 1.45-2.58), and hemorrhoid (AOR, 1.63; 95% CI, 1.32-2.01) were associated with false-positive results.

CONCLUSIONS

Subjects with a higher risk of false-negative results should be prioritized for earlier colonoscopy and subjects with inaccurate results should be more cautiously considered for screening by using modalities other than FIT. Our findings will contribute to individualization of screening programs.

Clinicopathological Features and Prognostic Factors of Colorectal Neuroendocrine Neoplasms

Background. Limited research is available regarding colorectal NENs and the prognostic factors remain controversial. Materials and Methods. A total of 68 patients with colorectal NENs were studied retrospectively. Clinical characteristics and prognosis between colonic and rectal NENs were compared. The Cox regression models were used to evaluate the predictive capacity. Results. Of the 68 colorectal NENs patients, 43 (63.2%) had rectal NENs, and 25 (36.8%) had colonic NENs. Compared with rectal NENs, colonic NENs more frequently exhibited larger tumor size (P < 0.0001) and distant metastasis (P < 0.0001). Colonic NENs had a worse prognosis (P = 0.027), with 5-year overall survival rates of 66.7% versus 88.1%. NET, NEC, and MANEC were noted in 61.8%, 23.5%, and 14.7% of patients, respectively. Multivariate analyses revealed that tumor location was not an independent prognostic factor (P = 0.081), but tumor size (P = 0.037) and pathological classification (P = 0.012) were independent prognostic factors. Conclusion. Significant differences exist between colonic and rectal NENs. Multivariate analysis indicated that tumor size and pathological classification were associated with prognosis. Tumor location was not an independent factor. The worse outcome of colonic NENs observed in clinical practice might be due not only to the biological differences, but also to larger tumor size in colonic NENs caused by the delayed diagnosis.

Randomized trial comparing oral sulfate solution with 4-L polyethylene glycol administered in a split dose as preparation for colonoscopy

BACKGROUND AND AIM

The present study aimed to evaluate the non-inferiority of low-volume oral sulfate solution (OSS) to 4-L polyethylene glycol (PEG) solutions administered in a split-dose regimen as bowel preparation for colonoscopy. The safety and tolerability were also compared between the two regimens.

METHODS

In this prospective, randomized, single-blind, active-control, parallel group, and non-inferiority trial, consecutive outpatients and health checkup recipients aged 19-65 years undergoing elective colonoscopy were enrolled to receive OSS or 4-L PEG in a split-dose regimen. The quality of bowel preparation was evaluated using the Boston Bowel Preparation Scale. The occurrence of any adverse events, acceptance, compliance, and satisfaction during bowel preparation were evaluated by participant interviews.

RESULTS

Overall, 210 participants were randomized, and 199 were administered by the study agents. Adequate bowel preparation was achieved in 98.0% (97/99) of the OSS group, which was non-inferior to the PEG group (96%; 96/100) with a difference of +2.8% (95% confidence interval; -2.8, +6.8). There were no differences in the incidence of adverse events except for abdominal pain, which was more frequent in the OSS (7.1%, 7/99) than in the PEG (1.0%, 1/100; P = 0.035) group. Acceptance, compliance, and satisfaction were significantly higher in the OSS than in the PEG group (all P < 0.05).

CONCLUSIONS

Split-dose OSS was non-inferior to split-dose 4-L PEG with regard to bowel preparation efficacy before colonoscopy in adult outpatients or screening colonoscopy recipients aged ≤65 years with acceptable safety and superior tolerability.

Are Hemorrhoids Associated with False-Positive Fecal Immunochemical Test Results?

PURPOSE

False-positive (FP) results of fecal immunochemical tests (FITs) conducted in colorectal cancer (CRC) screening could lead to performing unnecessary colonoscopies. Hemorrhoids are a possible cause of FP FIT results; however, studies on this topic are extremely rare. We investigated whether hemorrhoids are associated with FP FIT results.

MATERIALS AND METHODS

A retrospective study was conducted at a university hospital in Korea from June 2013 to May 2015. Of the 34547 individuals who underwent FITs, 3946 aged ≥50 years who underwent colonoscopies were analyzed. Logistic regression analysis was performed to determine factors associated with FP FIT results.

RESULTS

Among 3946 participants, 704 (17.8%) showed positive FIT results and 1303 (33.0%) had hemorrhoids. Of the 704 participants with positive FIT results, 165 had advanced colorectal neoplasia (ACRN) and 539 had no ACRN (FP results). Of the 1303 participants with hemorrhoids, 291 showed FP results, of whom 81 showed FP results because of hemorrhoids only. Participants with hemorrhoids had a higher rate of FP results than those without hemorrhoids (291/1176, 24.7% vs. 248/2361, 10.5%; p<0.001). Additionally, the participants with hemorrhoids as the only abnormality had a higher rate of FP results than those experiencing no such abnormalities (81/531, 15.3% vs. 38/1173, 3.2%; p<0.001). In multivariate analysis, the presence of hemorrhoids was identified as an independent predictor of FP results (adjusted odds ratio, 2.76; 95% confidence interval, 2.24-3.40; p<0.001).

CONCLUSION

Hemorrhoids are significantly associated with FP FIT results. Their presence seemed to be a non-negligible contributor of FP results in FIT-based CRC screening programs.

Polyp Genetics

The genetic events involved in the transformation of normal colonic epithelium to neoplastic polyps to invasive carcinoma, as initially proposed by Fearon and Vogelstein, form the foundation of our understanding of colorectal cancer. The identification of the polyp as the precursor lesion to colorectal cancer is the basis of many of our current practices for screening, surveillance, and prevention. The last three decades have seen a veritable explosion in our understanding of the molecular events involved in the pathogenesis of colorectal cancer. It is now clear that there are multiple genetic pathways in the polyp to carcinoma sequence. Some polyps previously thought to be nonneoplastic have now been shown to have malignant potential. Finally, increased understanding of the sequence of genetic events has led to the development of targeted therapeutics. The clinical translation of these scientific advances has made a significant impact on the management of patients with colorectal cancer. Accordingly, it is imperative that all clinicians caring for these patients have an understanding of the genetics of colorectal polyps and cancer. In this article, we review the etiology and genetic pathways to carcinoma associated with a range of polyps of the colon and rectum.

A wide variation of the quality of colonoscopy reporting system in the real clinical practice in southeastern area of Korea

Background/Aims

Establishment of a colonoscopy reporting system is a prerequisite to determining and improving quality. This study aimed to investigate colonoscopists' opinions and the actual situation of a colonoscopy reporting system in a clinical practice in southeastern area of Korea and to assess the factors predictive of an inadequate reporting system.

Methods

Physicians who performed colonoscopies in the Daegu-Gyeongbuk province of Korea and were registered with the Korean Society of Gastrointestinal Endoscopy (KSGE) were interviewed via mail about colonoscopy reporting systems using a standardized questionnaire.

Results

Of 181 endoscopists invited to participate, 125 responded to the questionnaires (response rate, 69%). Most responders were internists (105/125, 84%) and worked in primary clinics (88/125, 70.4%). Seventy-one specialists (56.8%) held board certifications for endoscopy from the KSGE. A median of 20 colonoscopies (interquartile range, 10–47) was performed per month. Although 88.8% of responders agreed that a colonoscopy reporting system is necessary, only 18.4% (23/125) had achieved the optimal reporting system level recommended by the Quality Assurance Task Group of the National Colorectal Cancer Roundtable. One-third of endoscopists replied that they did not use a reporting document for the main reasons of "too busy" and "inconvenience." Non-endoscopy specialists and primary care centers were independent predictive factors for failure to use a colonoscopy reporting system.

Conclusions

The quality of colonoscopy reporting systems varies widely and is considerably suboptimal in actual clinical practice settings in southeastern Korea, indicating considerable room for quality improvements in this field.

External Validation of the Endoscopic Features of Sessile Serrated Adenomas in Expert and Trainee Colonoscopists

Background/Aims

It is unclear whether the endoscopic features of sessile serrated adenomas (SSAs) would be useful to trainee colonoscopists to predict SSA. Therefore, the present study aimed to identify features that expert and trainee colonoscopists can use to independently and reliably predict SSA by using high-resolution white-light endoscopy.

Methods

Endoscopic images of 81 polyps (39 SSAs, 22 hyperplastic polyps, and 20 tubular adenomas) from 43 patients were retrospectively evaluated by 10 colonoscopists (four experts and six trainees). Eight endoscopic features of SSAs were assessed for each polyp.

Results

According to multivariable analysis, a mucous cap (odds ratio [OR], 10.44; 95% confidence interval [CI], 5.72 to 19.07), indistinctive borders (OR, 4.21; 95% CI, 2.74 to 7.16), dark spots (OR, 3.64; 95% CI, 1.89 to 7.00), and cloud-like surface (OR, 2.43; 95% CI, 1.27 to 4.668) were independent predictors of SSAs. Among these, a mucous cap, indistinctive borders, and cloud-like surface showed moderate interobserver agreement (mean κ >0.40) among experts and trainees. When ≥1 of the three predictors was observed, the sensitivity and specificity for diagnosing SSAs were 79.0% and 81.4%, respectively.

Conclusions

Colonoscopy trainees and experts can use several specific endoscopic features to independently and reliably predict SSAs.

Weight Change and Obesity Are Associated with a Risk of Adenoma Recurrence

BACKGROUND

Obesity is reportedly a risk factor for colorectal adenoma. However, the influence of weight change and obesity on colorectal adenoma recurrence is unclear.

AIM

To investigate whether weight change and obesity are associated with recurrence and development of colorectal adenoma.

PATIENTS AND METHODS

Of 62,171 asymptomatic subjects who underwent a colonoscopy for a heath checkup between 2010 and 2011, this longitudinal study was performed with the 5297 subjects who underwent another colonoscopy between 2012 and 2013. The risk of recurrence or development of adenoma according to quartiles of weight change (<-1.6, -1.6 to 0.1, 0.2-1.8, and ≥1.9 kg) and baseline BMI categories (<25, 25-29, and ≥30 kg/m(2)) was assessed using Cox proportional hazards modeling.

RESULTS

The average period between visits 1 and 2 was 2.2 ± 0.6 years. Among the 2176 subjects with adenomas, the risk of recurrence of any adenoma increased with increasing weight change quartiles (p for trend = 0.030), whereas the risk of recurrence of advanced adenoma was not associated with weight change (p for trend = 0.852). The risk of recurrence of advanced adenoma increased with increasing baseline BMI categories (p for trend = 0.029). Among 3121 subjects with no adenoma, the risk of developing any adenoma increased with increasing baseline BMI categories (p for trend <0.001). However, the risk of developing any or advanced adenoma was not associated with weight change.

CONCLUSIONS

Weight change over 2.2 years affected adenoma recurrence and obesity was related to advanced adenoma recurrence and adenoma development.

Comparison of Efficacy of Prophylactic Endoscopic Therapies for Postpolypectomy Bleeding in the Colorectum: A Systematic Review and Network Meta-Analysis

OBJECTIVES

Although various endoscopic therapies have been suggested for preventing bleeding after colorectal polypectomy, the optimal therapy has yet to be fully clarified. We assessed the comparative efficacy of prophylactic therapies for postpolypectomy bleeding through a network meta-analysis combining direct and indirect comparisons.

METHODS

We searched for all relevant randomized controlled trials published up until January 2016 examining the effects of prophylactic therapy for bleeding after colorectal polypectomy. The types of prophylactic therapy were classified as mechanical therapy, epinephrine-saline injection therapy, coagulation therapy, combined therapy, or no prophylactic therapy. Combined therapy was defined as a combination of two or more types of therapy including mechanical therapy, epinephrine-saline injection therapy, and coagulation therapy. We performed a Bayesian network meta-analysis for all prophylactic therapies.

RESULTS

Fifteen studies with 3,462 patients were included in the meta-analysis. Compared with no prophylactic therapy, both epinephrine-saline injection and mechanical therapy showed superiority for preventing early postpolypectomy bleeding with a moderate quality of evidence (injection therapy, risk ratio (RR; 95% credible interval (CrI))=0.32 (0.11-0.67); mechanical therapy, RR (95% CrI)=0.13 (0.03-0.37)). Combined therapy did not show a statistically significant difference for decreasing the risk of early bleeding compared with injection or mechanical therapies, respectively (combined vs. injection therapy: RR (95% CrI)=0.35 (0.10-1.00); combined vs. mechanical therapy: RR (95% CrI)=0.88 (0.23-3.00)). In cases of delayed bleeding, no type of prophylactic therapy decreased the risk of bleeding compared with no prophylactic therapy.

CONCLUSIONS

Either mechanical therapy or injection therapy reduced the risk of early postpolypectomy bleeding. As for delayed bleeding, none of the prophylactic therapies was associated with a lower risk of bleeding compared with no prophylactic therapy.

Metabolic syndrome is a risk factor for adenoma occurrence at surveillance colonoscopy: A single-center experience in Korea

We investigated the risk factors for adenoma occurrence at surveillance colonoscopy, especially focusing on patient characteristics, including metabolic factors.Surveillance colonoscopy intervals depend on baseline adenoma characteristics. However, patients' characteristics may also influence the occurrence of adenomas.Of 62,171 asymptomatic subjects who underwent colonoscopy for a health check-up between 2010 and 2011, 4869 subjects who underwent follow-up colonoscopy between 2012 and 2013 were included in this longitudinal study. The risk of adenoma occurrence was assessed using Cox proportional hazards modeling.Of 4869 subjects, 2827 (58.1%), 1619 (33.3%), and 423 (8.7%) were assigned to the normal, low-risk, and high-risk groups, respectively, according to baseline adenoma characteristics. The mean interval between initial and follow-up colonoscopy was 2.2 ± 0.6 years. Certain patient factors, including older age (≥50 years; adjusted hazard ratio [aHR], 2.08; 95% CI, 1.73-2.49), male sex (aHR, 1.69; 95% CI, 1.30-2.19), metabolic syndrome (MetS) (aHR, 1.28; 95% CI, 1.09-1.51), obesity (aHR, 1.17; 95% CI, 1.02-1.34), elevated fasting blood glucose levels (aHR, 1.37; 95% CI, 1.19-1.58), and elevated triglyceride levels (aHR, 1.19; 95% CI, 1.03-1.37), as well as baseline adenoma characteristics, were associated with a higher risk of adenoma occurrence at follow-up colonoscopy. The cumulative incidence of adenoma occurrence in the high-risk group was higher than that in the low-risk group, whereas the incidence in the high-risk group without MetS was comparable with that in the low-risk group with MetS.Patient characteristics, such as MetS, obesity, older age, and male sex, in addition to adenoma characteristics, were independent risk factors for adenoma occurrence at surveillance colonoscopy. These patient characteristics may be considered in surveillance colonoscopy intervals.

Comparison of adenoma detection rate and adenoma per colonoscopy as a quality indicator of colonoscopy

BACKGROUND

Although adenoma detection rate (ADR) has been proposed as a quality indicator of colonoscopies, adenomas per colonoscopy (APC) is a promising alternative to ADR, as it reflects inspection over the entire length of the colon. This study investigated the correlation between ADR and APC, and compared the efficacy of ADR and APC based on the correlation of each with the advanced adenoma detection rate (AADR).

STUDY

Two prospectively collected databases, including the 1142 subjects who underwent screening colonoscopies by 28 colonoscopists, were retrospectively reviewed. AADR1 were definded as the proportion of participants having advanced neoplasms, and AADR2 were definded as the proportion of participants having advanced neoplasms or three or more adenomas. Pearson correlation and Steiger's z-test was used to evaluate the relationship between ADR-APC, ADR-AADR and APC-AADR.

RESULTS

The ADRs ranged from 16.67 to 66.67% (mean, 37.29%) and APCs ranged from 0.22 to 1.28 (mean, 0.65). The ADR and APC showed a significant correlation (R = 0.82; p < 0.001). The screening ADR was significantly correlated with AADR1/AADR2 (R = 0.60; p = 0.001 and R = 0.64; p < 0.001, respectively). APC was also significantly correlated with AADR1/AADR2 (R = 0.65; p < 0.001 and R = 0.77; p < 0.001, respectively). The correlation coefficient for APC-AADR2 was higher than ADR-AADR2 (0.77 versus 0.64, p = 0.04).

CONCLUSIONS

Colonoscopists' ADRs and APC were significantly correlated. Moreover, as the correlation coefficient for AADR was higher with APC than it was with ADR, APC might be a better quality indicator of colonoscopy than ADR.

Fecal hemoglobin concentration is useful for risk stratification of advanced colorectal neoplasia

BACKGROUND

Although a fecal immunochemical test (FIT) allows quantitation of fecal hemoglobin (f-Hb), it is typically used as a binary result to identify subjects above a predetermined cut-off concentration.

AIMS

To investigate whether f-Hb concentration is useful for risk stratification of advanced colorectal neoplasia (CRN).

METHODS

This was a retrospective study conducted in a university hospital in Korea. Of 34,547 participants who underwent FIT from June 2013 to May 2015, 1532 (4.4%) showed positive results (≥100ng Hb/ml). Of participants with positive results, 738 subjects aged ≥50 years who underwent colonoscopy were analyzed.

RESULTS

Increasing quartile of f-Hb concentration (Q4 vs. Q1; odds ratio, 3.87; 95% confidence interval, 2.36-6.34), as well as older age, male sex, smoking, and metabolic syndrome (MetS), was significantly associated with a higher prevalence of advanced CRN. Risk for advanced CRN increased 5.13-, 4.27-, 5.12-, and 7.15-fold, respectively, among individuals with f-Hb in the fourth quartile who had risk factors such as age ≥70 years, male sex, smoking, and MetS compared with individuals with first quartile levels of f-Hb who did not have those risk factors.

CONCLUSION

In addition to age, sex, smoking status, and MetS, f-Hb concentration in individuals with positive results from FIT can be used to stratify the probability of detection of advanced CRN.

Risk of Advanced Colorectal Neoplasia According to the Number of High-Risk Findings at Index Colonoscopy: A Korean Association for the Study of Intestinal Disease (KASID) Study

BACKGROUND

Data regarding outcomes for patients with multiple findings for high-risk adenomas are scarce.

AIM

To compare the risk for colorectal neoplasm (CRN) recurrence according to the number of high-risk findings.

METHODS

This was a retrospective and multicenter study. Patients who had one or more high-risk adenomas at the index colonoscopy and underwent follow-up colonoscopy 2.5 or more years after the index colonoscopy were included. The number of high-risk findings was defined as follows: number of adenomas larger than 1 cm + number of adenomas with HGD + number of adenomas with a villous component + existence (counted as 1) or nonexistence (counted as 0) of three or more adenomas.

RESULTS

A total of 1646 patients were included, and the mean duration between index and follow-up colonoscopy was approximately 4 years. The cumulative incidence rate of recurrent advanced CRN in patients with three or more high-risk findings was higher than that in patients with one or two high-risk findings (p < 0.001). However, the difference in 3-year cumulative incidence rates of recurrent advanced CRN between the two groups was not great, although it was statistically significant (4.8 vs. 2.3 %, p = 0.039).

CONCLUSIONS

A 3-year surveillance interval for patients with multiple high-risk findings, regardless of the number of high-risk findings, appears reasonable.

The Polyp Manager: a new tool for optimal polyp documentation during colonoscopy. A pilot study

BACKGROUND AND STUDY AIMS

Conventional reporting of polyps is often incomplete. We tested the Polyp Manager (PM), a new software application permitting the endoscopist to document polyps in real time during colonoscopy. We studied completeness of polyp descriptions, user-friendliness and the potential time benefit.

PATIENTS AND METHODS

In two Dutch hospitals colonoscopies were performed with PM (as a touchscreen endoscopist-operated device or nurse-operated desktop application). Completeness of polyp descriptions was compared to a historical group with conventional reporting (CRH). Prospectively, we compared user-friendliness (VAS-scores) and time benefit of the endoscopist-operated PM to conventional reporting (CR) in one hospital. Duration of colonoscopy and time needed to report polyps and provide a pathology request were measured. Provided that using PM does not prolong colonoscopy, the sum of the latter two was considered as a potential time-benefit if the PM were fully integrated into a digital reporting system.

RESULTS

A total of 144 regular colonoscopies were included in the study. Both groups were comparable with regard to patient characteristics, duration of colonoscopy and number of polyps. Using the PM did reduce incomplete documentation of the following items in CRH-reports: location (96 % vs 82 %, P = 0.01), size (95 % vs 89 %, P = 0.03), aspect (71 % vs 36 %, P < 0.001) and completeness of removal (61 % vs 37 %, P < 0.001). In the prospective study 23 PM-colonoscopies where compared to 28 CR-colonoscopies. VAS-scores were significantly higher in the endoscopist-operated PM group. Time to report was 01:27 ± 01:43 minutes (median + interquartile range) in the entire group (PM as CR), reflecting potential time benefit per colonoscopy.

CONCLUSIONS

The PM is a user-friendly tool that seems to improve completeness of polyp reporting. Once integrated with digital reporting systems, it is probably time saving as well.