Colorectal cancers occurring after colonoscopy with polyp detection: sites of polyps and sites of cancers

Outcomes of thin versus thick-wire snares for cold snare polypectomy: a systematic review and meta-analysis

BACKGROUND/AIMS

Cold snare polypectomy (CSP) is commonly used for the resection of colorectal polyps ≤10 mm. Data regarding the influence of snare type on CSP effectiveness are conflicting. Hence, this meta-analysis aimed to compare the outcomes and safety of thin- and thick-wire snares for CSP.

METHODS

A comprehensive search of the literature published between 2000 and 2021 was performed of various databases for comparative studies evaluating the outcomes of thin- versus thick-wire snares for CSP.

RESULTS

Five studies with data on 1,425 polyps were included in the analysis. The thick-wire snare was comparable to the thin-wire snare with respect to complete histological resection (risk ratio [RR], 1.03; 95% confidence interval [CI], 0.97-1.09), overall bleeding (RR, 0.98; 95% CI, 0.40-2.40), polyp retrieval (RR, 1.01; 95% CI, 0.97-1.04), and involvement of submucosa in the resection specimen (RR, 1.28; 95% CI, 0.72-2.28). There was no publication bias and a small study effect, and the relative effects remained the same in the sensitivity analysis.

CONCLUSION

CSP using a thin-wire snare has no additional benefit over thick-wire snares in small colorectal polyps. Factors other than snare design may play a role in improving CSP outcomes.

Recurrence of Colorectal Neoplastic Polyps After Incomplete Resection

BACKGROUND

Incomplete resection of neoplastic polyps is considered an important reason for the development of colorectal cancer. However, there are no data on the natural history of polyps that were incompletely removed.

OBJECTIVE

To examine the risk for metachronous neoplasia during surveillance colonoscopy after documented incomplete polyp resection.

DESIGN

Observational cohort study of patients who participated in the CARE (Complete Adenoma REsection) study (2009 to 2012).

SETTING

2 academic medical centers.

PATIENTS

Patients who had resection of a 5- to 20-mm neoplastic polyp, had a documented complete or incomplete resection, and had a surveillance examination.

MEASUREMENTS

Segment metachronous neoplasia, defined as the proportion of colon segments with at least 1 neoplastic polyp at first surveillance examination, was measured. Segment metachronous neoplasia was compared between segments with a prior incomplete polyp resection (incomplete segments) and those with a prior complete resection (complete segments), accounting for clustering of segments within patients.

RESULTS

Of 233 participants in the original study, 166 (71%) had at least 1 surveillance examination. Median time to surveillance was shorter after incomplete versus complete resection (median, 17 vs. 45 months). The risk for any metachronous neoplasia was greater in segments with incomplete versus complete resection (52% vs. 23%; risk difference [RD], 28% [95% CI, 9% to 47%]; P = 0.004). Incomplete segments also had a greater number of neoplastic polyps (mean, 0.8 vs. 0.3; RD, 0.50 [CI, 0.1 to 0.9]; P = 0.008) and greater risk for advanced neoplasia (18% vs. 3%; RD, 15% [CI, 1% to 29%]; P = 0.034). Incomplete resection was the strongest independent factor associated with metachronous neoplasia (odds ratio, 3.0 [CI, 1.12 to 8.17]).

LIMITATION

Potential patient selection bias due to incomplete follow-up.

CONCLUSION

This natural history study found a statistically significantly greater risk for future neoplasia and advanced neoplasia in colon segments after incomplete resection compared with segments with complete resection.

PRIMARY FUNDING SOURCE

None.

Metachronous Neoplasias Arise in a Higher Proportion of Colon Segments From Which Large Polyps Were Previously Removed, and Can be Used to Estimate Incomplete Resection of 10-20 mm Colorectal Polyps

BACKGROUND & AIMS

Incomplete resection of polyps could be an important cause of post-colonoscopy colorectal cancer. However, it is difficult to study progression of incompletely removed polyps or their clinical importance. We aimed to estimate incomplete polyp resection using risk of metachronous neoplasia per colon segment.

METHODS

We performed a retrospective study of 1031 patients (6186 colon segments) who initially underwent resection of a large (10-20 mm) neoplastic polyp at 2 academic medical centers (from 2000 through 2012) and then underwent a subsequent colonoscopy within 0.5 to 5 years. We determined the proportions of metachronous neoplasia in colon segments from which a single large neoplastic polyp was removed and in segments without prior neoplasia. We then used the absolute difference in proportions between these groups to estimate the rate of incomplete resection. Our analysis assumed that development of metachronous neoplasia in each colon segment was the consequence of a newly grown polyp, a previously missed polyp, or an incompletely removed polyp.

RESULTS

Metachronous neoplasia was detected in 177 of 757 segments (23.4%) with a single large polyp, and in 438 of 4232 segments (10.3%) without any neoplasia at baseline colonoscopy (P < .001). Resections were therefore estimated to be incomplete in 13.0% of segments (95% CI, 9.8-16.2). This proportion was greater for sections with non-pedunculated polyps (18.3%; 95% CI, 14.2-22.5) than pedunculated polyps (3.5%; 95% CI, -0.7 to -11.3; P < .001). A higher proportion of piecemeal resections appeared to be incomplete (28.0%; 95% CI, 20.2-35.7) than of en bloc resections (9.2%; 95% CI, 5.9-12.5) (P < .001). No differences in incomplete resection were associated with polyp histology.

CONCLUSION

Metachronous neoplasia arises in a significantly higher proportion of colon segments from which a polyp was previously removed. Based on these data, we estimate that 13% of all large polyps are incompletely resected and 18% of large non-pedunculated polyps are incompletely resected. These findings indicate that incomplete resection could be a risk factor for later development of neoplasia. Segment metachronous neoplasia might be used as a marker of resection quality.

Racial and Ethnic Disparities in Interval Colorectal Cancer Incidence: A Population-Based Cohort Study

BACKGROUND

Interval colorectal cancer (CRC) accounts for 3% to 8% of all cases of CRC in the United States. Data on interval CRC by race/ethnicity are scant.

OBJECTIVE

To examine whether risk for interval CRC among Medicare patients differs by race/ethnicity and whether this potential variation is accounted for by differences in the quality of colonoscopy, as measured by physicians' polyp detection rate (PDR).

DESIGN

Population-based cohort study.

SETTING

Medicare program.

PARTICIPANTS

Patients aged 66 to 75 years who received colonoscopy between 2002 and 2011 and were followed through 2013.

MEASUREMENTS

Kaplan-Meier curves and adjusted Cox models were used to estimate cumulative probabilities and hazard ratios (HRs) of interval CRC, defined as a CRC diagnosis 6 to 59 months after colonoscopy.

RESULTS

There were 2735 cases of interval CRC identified over 235 146 person-years of follow-up. A higher proportion of black persons (52.8%) than white persons (46.2%) received colonoscopy from physicians with a lower PDR. This rate was significantly associated with interval CRC risk. The probability of interval CRC by the end of follow-up was 7.1% in black persons and 5.8% in white persons. Compared with white persons, black persons had significantly higher risk for interval CRC (HR, 1.31 [95% CI, 1.13 to 1.51]); the disparity was more pronounced for cancer of the rectum (HR, 1.70 [CI, 1.25 to 2.31]) and distal colon (HR, 1.45 [CI, 1.00 to 2.11]) than for cancer of the proximal colon (HR, 1.17 [CI, 0.96 to 1.42]). Adjustment for PDR did not alter HRs by race/ethnicity, but differences between black persons and white persons were greater among physicians with higher PDRs.

LIMITATION

Colonoscopy and polypectomy were identified by using billing codes.

CONCLUSION

Among elderly Medicare enrollees, the risk for interval CRC was higher in black persons than in white persons; the difference was more pronounced for cancer of the distal colon and rectum and for physicians with higher PDRs.

PRIMARY FUNDING SOURCE

American Cancer Society.

Estimating the Effect of Targeted Screening Strategies: An Application to Colonoscopy and Colorectal Cancer

Supplemental Digital Content is available in the text.

Screening behavior depends on previous screening history and family members’ behaviors, which can act as both confounders and intermediate variables on a causal pathway from screening to disease risk. Conventional analyses that adjust for these variables can lead to incorrect inferences about the causal effect of screening if high-risk individuals are more likely to be screened. Analyzing the data in a manner that treats screening as randomized conditional on covariates allows causal parameters to be estimated; inverse probability weighting based on propensity of exposure scores is one such method considered here. I simulated family data under plausible models for the underlying disease process and for screening behavior to assess the performance of alternative methods of analysis and whether a targeted screening approach based on individuals’ risk factors would lead to a greater reduction in cancer incidence in the population than a uniform screening policy. Simulation results indicate that there can be a substantial underestimation of the effect of screening on subsequent cancer risk when using conventional analysis approaches, which is avoided by using inverse probability weighting. A large case–control study of colonoscopy and colorectal cancer from Germany shows a strong protective effect of screening, but inverse probability weighting makes this effect even stronger. Targeted screening approaches based on either fixed risk factors or family history yield somewhat greater reductions in cancer incidence with fewer screens needed to prevent one cancer than population-wide approaches, but the differences may not be large enough to justify the additional effort required. See video abstract at, http://links.lww.com/EDE/B207.

Association between the location of colon polyps at baseline and surveillance colonoscopy - A retrospective study

INTRODUCTION

Several factors are used to stratify the probability of polyp recurrence. However, there are no studies correlating the location of the initial polyps and the recurrent ones. The aim of this study was to verify whether the polyp location at the surveillance colonoscopy was correlated with the location of the previously excised polyps at the baseline colonoscopy.

METHODS

A retrospective study of patients submitted to colonoscopy with presence and excision of all polyps, followed by a surveillance colonoscopy. Polyp location was divided into proximal/distal to splenic flexure and rectum. Characteristics and recurrent rates at the same colon location were also evaluated.

RESULTS

Out of the 346 patients who underwent repeated colonoscopy, 268 (77.4%) had at least 1 polyp detected. For all the segments there was an increased risk of recurrent polyps in the same location and it was about four times higher in proximal (OR 3.5; CI 2.1-6.0) and distal colon segments (OR 3.8; CI 2.1-6.8), followed by three times higher in the rectum (OR 2.6; CI 1.5-4.6). No difference was found between the rates of recurrence at the same segment, taking into consideration the polyp morphology, size, polypectomy technique employed and histological classification.

CONCLUSION

There seems to be a significant association between polyp location at baseline and surveillance colonoscopy.

Effects of first-dose volume and exercise on the efficacy and tolerability of bowel preparations for colonoscopy in Chinese people

Aim

This study was designed to compare the efficacy and tolerability of bowel preparations with and without the higher first-dose volume of polyethylene glycol (PEG) solution or exercise after drinking PEG solution in Chinese people.

Methods

A total of 330 participants who had a colonoscopy done in Peking Union Medical College Hospital were randomly and evenly assigned to three groups. Participants in Group A ingested 1 L PEG solution and then ingested 2 L PEG solution at a rate of 250 mL every 15 minutes. Participants in Group B ingested 3 L PEG solution at a rate of 250 mL every 15 minutes and then exercised more than 10 minutes after ingesting each liter of PEG solution. Participants in Group C ingested 3 L PEG solution at a rate of 250 mL every 15 minutes. Experienced gastrointestinal endoscopists rated the efficacy of bowel preparations based on the Boston Bowel Preparation Scale score. A questionnaire regarding participants’ symptoms associated with bowel preparations was administered to evaluate participants’ tolerability.

Results

The three groups had insignificant difference in the percentages of participants’ symptoms including dizziness, nausea, stomach ache, bloating, and asthenia. However, the percentages of participants having hunger sensation, sleep disturbance, and anal discomfort were significantly higher in groups with the higher first-dose volume of PEG solution or exercise after drinking PEG solution than without them. The three groups had insignificant difference in the Boston Bowel Preparation Scale score.

Conclusion

Whether to add the higher first-dose volume of PEG solution and exercise after drinking PEG solution or not, all participants achieved a similar quality of bowel preparations. Bowel preparations without the additional first-dose volume of PEG solution or exercise after drinking PEG solution showed the advantage of high participant tolerability.

Factors associated with reclassification of hyperplastic polyps after pathological reassessment from screening and surveillance colonoscopies

INTRODUCTION

A substantial interobserver variation in the differential diagnosis of hyperplastic polyps (HPs) and sessile or traditional serrated adenomas (SSAs/TSAs) has been described.

METHODS

The aim of this study is to determine the magnitude of reclassification of HPs and associated factors after pathological reassessment of specimens from screening and surveillance colonoscopies, and to estimate its consequences for follow-up recommendations.

RESULTS

Among 1694 screening and surveillance colonoscopies, a total of 536 polyps were initially diagnosed as HPs and remained unchanged in 88.5% (n = 474), whereas 7.6 (n = 41) and 1.1% (n = 6) were reclassified as SSA and TSA, respectively. Compared to definite HPs, SSAs were found more frequently in men than in women (82.9 vs. 61.2%, p < 0.05), and in individuals ≥65.0 years (51.2 vs. 31.6%, p = 0.05). Also, more SSAs were >5 mm in size (36.6 vs. 6.3%, p < 0.05) and were localized in the proximal colon (31.7 vs. 11.8%, p < 0.05). In a mixed model analysis, age ≥65.0 years (OR 4.13, 95% CI 1.22-14.2), snare polypectomy (OR 23.6, 95% CI 4.86-115), and coincident advanced adenomas (OR 7.56, 95% CI 1.31-43.5) were significantly (p < 0.05) associated with reclassification to SSAs. Only 0.53% of patients had received false recommendations for follow-up visits based on the incorrect HP diagnosis. A c.1799T>A, p.V600E BRAF mutation was detected in 21.9 % (n = 9) of reclassified SSAs.

CONCLUSION

Considering these factors may be helpful in serrated lesions that are difficult to allocate. Incorrect recommendations regarding control colonoscopy intervals due to misdiagnosed HPs can explain only a small fraction of interval colorectal cancers.

Ideal colonoscopic surveillance intervals to reduce incidence of advanced adenoma and colorectal cancer

BACKGROUND AND AIMS

There is limited information about the interplay between multiple risk factors contributing to the risk of advanced neoplasia. We determined the actual risk for advanced neoplasia in relation to lapsed time between colonoscopies in people enrolled in a structured surveillance program. This risk information can be used to guide the selection of optimal surveillance intervals.

METHODS

Patients were recruited into programs at two major tertiary hospitals, with a personal or family history of advanced neoplasia. Five thousand one hundred forty-one patients had an index and one or more surveillance colonoscopies. Fifty-one percent had a family history of colorectal neoplasia while the remainder had a personal history.

RESULTS

Patients with an immediately prior colonoscopy result (prior result) of advanced adenoma had a risk for advanced neoplasia 7.1 times greater than those with a normal prior result. Cancer as a prior result did not confer a greater risk than either a hyperplastic polyp or a nonadvanced adenoma. Being female reduced risk, age increased risk. Only a family history of a first-degree relative diagnosed under 55, or definite or suspected hereditary nonpolyposis colorectal cancer (HNPCC) conferred an increased risk over a personal history of advanced neoplasia.

CONCLUSIONS

Most family history categories did not confer excess risk above personal history of advanced neoplasia. A prior cancer poses less of a risk than a prior advanced adenoma. Based on our models, a person with an advanced adenoma should be scheduled for colonoscopy at 3 years, corresponding to a 15% risk of advanced neoplasia for a male aged under 56. Guidelines should be updated that uses a 15% risk as a benchmark for calculating surveillance intervals.

3-L split-dose is superior to 2-L polyethylene glycol in bowel cleansing in Chinese population: a multicenter randomized, controlled trial

Large volume (4 L) of polyethylene glycol (PEG) solution would ensure a better quality of bowel cleansing but might be poorly tolerated. Due to the smaller body size, lower body weight, and different diet habits, the large volume of 4-L PEG might be poorly tolerated by the Chinese population. In view of this, a balance should be made between the volume and effectiveness. This study aimed to compare the effectiveness, compliance, and safety between 3-L split-dose and 2-L PEG in Chinese population. Consecutive patients scheduled for colonoscopy were recruited from 5 tertiary medical centers in South China between April and July, 2014. Patients were prospectively randomized into 2 groups: 3-L split-dose PEG (3L-group) and 2 L PEG (2L-group). The primary endpoint was bowel cleansing and was defined according to Ottawa Bowel Preparation Scale (OBPS). The safety and compliance were also evaluated. A total of 318 patients were included in the analysis. The mean total OBPS score was significantly higher in 2L-group than in 3L-group (4.4 ± 2.7 vs 2.9 ± 2.4, P < 0.001). Both the intention-to-treat and per-protocol analysis found that rates of successful and excellent bowel preparation were much higher in 3L-group (89.9% and 78.0%) than 2L-group (79.2% and 48.4%), respectively (P < 0.001). The average cecum intubation time was significantly shorter in 3L-group (8.2 ± 3.7 min) than in 2L-group (10.3 ± 4.2 min) (P = 0.04). Adenoma detection rate in right colon was slightly higher in 3L-group than in 2L-group (17.6% vs 12.6%, P = 0.21). The safety and compliance including the taste, smell, and dosage of PEG were similar between 2 groups (P > 0.05). 3-L split-dose PEG is superior to 2-L PEG by better bowel cleansing, improved safety and compliance, shorter cecum intubation time, and potentially higher adenoma detection rate in rightward colon in Chinese population.

Colorectal cancer prevention in Europe: burden of disease and status of screening programs

Colorectal cancer is a major public health challenge worldwide. In Europe it is the first malignancy in terms of incidence and the second in terms of mortality in both genders. Despite evidence indicating that removal of premalignant and early-stage cancer lesion scan greatly reduce mortality, remarkable differences are still found among countries both in terms of organized screening programs and of the tests used. In 2003 the European Council recommended that priority be given to activation of organized cancer screening programs, and various states have been making significant efforts to adopt effective prevention programs with international quality standards and centralizing screening organization and result evaluation. After a 2008 European Union report on the state of screening program, activation highlighted that little more than 50% (12/22) of Member States had colorectal cancer screening programs, Screening programs have been adopted or earlier pilot projects have been extended nationwide. This paper examines the state of activation and the screening strategies of colorectal cancer screening programs in EU States as of July 2013.