Optimal timing of anticoagulation pre- and post-colonoscopy with polypectomy

Purpose  

An increasing number of patients are treated with anticoagulation for many medical conditions. Our practice is to suspend warfarin 5–7 days, aspirin 3 days, and clopidogrel (Plavix) 7 days prior to colonoscopy that may require polypectomy. Generally, we accept an INR of ≤1.5 as safe. However, there are no published case series documenting when it is safe to resume these medications after polypectomy. Therefore, the management of anticoagulation after polypectomy varies. We sought to evaluate the safety of our practice with regard to anticoagulation and polypectomy.     

Complication and local recurrence rate after endoscopic resection of large high-risk colorectal adenomas of ≥3 cm in size

Purpose

Endoscopic resection is a widely used technique for treatment of large colorectal adenomas, but few data are available including only lesions larger than ≥2 cm. The aim of this study is to evaluate the complication and recurrence rate after endoscopic resection of high-risk colorectal adenomas ≥3 cm in size.

Methods

Retrospective analysis of a prospectively maintained database of patients undergoing polypectomy of large colorectal polyps of ≥3 cm.

Results

In 341 patients, 360 colorectal adenomas with a mean size of 3.9 cm were resected endoscopically. In 25 patients, a complication including 22 delayed bleedings (6.5 %) and three perforations (0.9 %) occurred. Single-variate analysis showed an increasing risk of complications for larger adenomas (3.9 vs. 4.6 cm; p?≤?0.05). Two hundred twelve patients with 224 adenomas had undergone at least one documented follow-up endoscopy with a medium follow-up period of 16 months. In 95 resected lesions (42.4 %), a residual adenoma occurred in the first follow-up colonoscopy (n?=?88, 92.6 %) or a recurrent adenoma occurred after at least one negative follow-up colonoscopy (n?=?7, 7.4 %). In multivariate analysis, risk factors were lesion size, sessile growth pattern, and the performing endoscopist. The complication and recurrence rate correlated inversely between endoscopists.

Conclusions

The present study is the largest study showing complication and recurrence rates after colorectal polypectomy of advanced colorectal adenomas of ≥3 cm in size. Polyp size was identified as the most important risk factor for complications. For the first time, this study shows that the complication rate after colorectal polypectomy of large adenomas is correlated inversely with the residual and/or recurrence rate.

     

Different screening definitions have little impact on polypectomy rate estimates

BACKGROUND:

Polypectomy rate is a surrogate quality indicator for screening colonoscopy. Various methods for identifying screening colonoscopies have been used and it is unclear how different definitions affect the estimated polypectomy rate.

OBJECTIVE:

To estimate polypectomy rates and how they vary according to the definition of a screening colonoscopy, using patient- and endoscopist-reported indications.

METHODS:

A cross-sectional analysis of endoscopists and their patients 50 to 75 years of age who underwent colonoscopy was conducted. Based on questionnaire responses, four patient indications were derived: perceived screening; perceived nonscreening; medical history indicating nonscreening; and combination of the three indications. Endoscopist indication was derived from a questionnaire completed immediately after colonoscopy. Polypectomy status was obtained from provincial physician billing records. Polypectomy rates were computed, while accounting for physician and hospital level clustering, using all four patient indications, endoscopist indication, and the agreement between patient and endoscopist indications. The effect of indications on polypectomy rate was estimated adjusting for age, sex and family history of colorectal cancer.

RESULTS:

A total of 2134 patients and 45 endoscopists were included. The proportion of colonoscopies classified as screening according to the nine indications ranged from 32.2% to 70.9%. Polypectomy rates ranged between 22.6% and 26.2% for screening colonoscopy, and between 27.1% and 30.8% for nonscreening colonoscopy. Adjusted ORs for indication ranged between 0.74 and 0.94.

DISCUSSION:

Although the proportion of colonoscopies identified as screening varied considerably among the indications, the estimated polypectomy rates were similar.

CONCLUSION:

The findings suggest that the way screening is defined does not greatly affect the estimates of polypectomy rate.     

Long-term follow-up of patients with malignant pedunculated colon polyps after colonoscopic polypectomy

BACKGROUND:

Previously published studies have suggested that patients with resected colon cancer have an increased risk for early metachronous colon cancer. Current screening guidelines recommend intense surveillance by colonoscopy for the initial five years after the initial colon cancer has been resected. Information regarding endoscopically removed malignant polyps is limited.

METHODS:

In the present study, 25 consecutive patients (14 male, 11 female) with malignant pedunculated colon polyps treated with snare cautery polypectomy were followed for more than one decade up to 20 years. Five patients required an additional resection to ensure that removal of the original cancer was complete. Annual colonoscopies were planned for five years. If an adenoma was detected in the fifth year, colonoscopy was performed annually until no adenomas were detected. Otherwise, colonoscopy was planned every three years after five years.

RESULTS:

In the present study, there was no mortality from colon cancer and no patient developed either recurrent colon cancer or an early metachronous colon cancer during the initial five-year period of surveillance. Two patients (one male, one female) ultimately developed late cecal cancers almost one decade after the original colon cancers were resected. One had an early stage cancer that was resected, while the other had an infiltrating mucinous carcinoma complicating a small tubulovillous adenoma with extension to a single lymph node. After surgical removal and adjuvant chemotherapy, no further neoplastic disease has been detected.

CONCLUSIONS:

Overall, patients with malignant pedunculated polyps do extremely well if appropriately managed at the time of the initial polypectomy. Short-term outcomes after removal of a malignant polyp(s) appear to be similar to those with a nonmalignant polyp. However, late metachronous colon cancer may still occur. Long-term follow-up should be considered in each patient, assuming reasonable life expectancy, because risk of additional adenomas and metachronous colon cancer persists even after the initial five years of currently recommended surveillance. Patients with resected malignant polyps may represent a special patient subgroup that requires surveillance for more extended periods than current guidelines have recommended.     

Number of aberrant crypt foci in the rectum is a useful surrogate marker of colorectal adenoma recurrence

Aim: Endoscopic screening and removal of colorectal adenomas can reduce the incidence of colorectal cancer. However, given the possibility of adenoma recurrence, surveillance colonoscopy is currently recommended after the initial screening and removal of colorectal adenomas. Aberrant crypt foci (ACF) have been shown to serve as a reliable surrogate marker of colorectal carcinogenesis. In this study, the relationship between the number of ACF at the initial endoscopic polypectomy and the likelihood of colorectal adenoma recurrence after polypectomy were investigated. Methods: High‐magnification chromoscopic colonoscopy was performed in 82 subjects who underwent endoscopic polypectomy to identify ACF in the lower rectum. Surveillance colonoscopy was then performed 3 years after the baseline polypectomy at Yokohama City University Hospital. Results: The number of ACF was greater in patients who showed adenoma recurrence (7.88 ± 6.35) than in those who did not (2.19 ± 2.95) (P < 0.001). Receiver–operating curve analysis showed that the number of ACF was a highly specific predictor of the risk of adenoma recurrence. Conclusions: This is the first study conducted to investigate the relationship between the number of ACF after endoscopic polypectomy and the likelihood of recurrence of colorectal adenomas. These results suggest that the number of ACF is a useful predictor of the likelihood of colorectal adenoma recurrence.     

Post-traumatic stress disorder is associated with a higher rate of polypectomy independent of an increased frequency of colonoscopy in Australian veterans: a retrospective review

Background

Post-traumatic stress disorder (PTSD) is associated with extensive physical comorbidities, including lower gastrointestinal symptoms. Diagnostic uncertainty and poor therapeutic responses may result in more frequent colonoscopies than clinically necessary. Polypectomy is standard practice when polyps are identified, and if PTSD is a risk factor for polyp formation, one would expect a higher rate of polyp detection and removal in veterans with PTSD than those without PTSD.

Aim

To determine the association between PTSD and the rate of colonoscopy and polypectomy in Australian veterans.

Methods

Diagnostic and therapeutic colonoscopy rates in Australian male Veterans aged ≥50 years were examined by reviewing case records of veterans who accessed Department of Veterans' Affairs funded health services between 1 January 2013 and 31 December 2018.

Results

A total of 138 471 veterans was included, of whom 28 018 had a diagnosis of PTSD; 56.4% were aged ≥65 years. Twenty-one percent of the entire cohort underwent at least one colonoscopy during the study period. Increased rates of diagnostic colonoscopy and polypectomy were associated with the presence of PTSD across all age brackets. The effect was empirically large as veterans with PTSD experience colonoscopy rates 76–81% greater than those without PTSD. Similarly, veterans with PTSD experienced polypectomy rates 76–81% greater than veterans without PTSD, and this increase persisted when controlling for the increased number of diagnostic colonoscopies they undergo.

Conclusion

The presence of PTSD has a marked impact on colonoscopy rates in Australian veterans. The increased polypectomy rate independent of increased colonoscopy rate suggests that PTSD is a risk factor for colonic polyp formation.     

Rate of serious complications of colonoscopy in Quebec

BACKGROUND

The rate of serious complications is one marker of the quality of colonoscopy services.

OBJECTIVE:

To estimate the rate of serious complications of colonoscopy according to colonoscopy indication and polypectomy status.

METHODS:

A prospective cohort study of patients scheduled for colonoscopy who were recruited from seven endoscopy facilities across Montreal (Quebec) was conducted. Before colonoscopy, patients completed a brief questionnaire and provided their health insurance numbers. Colonoscopy indication was based on patient-reported medical history. Polypectomy status was obtained from provincial physician billing records (Régie de l’assurance maladie du Québec). Diagnoses and procedures associated with hospitalization in the 30 days following colonoscopy were obtained from the provincial hospitalization database (MedEcho).

RESULTS:

Of the 2134 patients enrolled (mean age 60.9 years, 50.1% male), 33 (1.55% [95% CI 1.06% to 2.16%]) were hospitalized within 30 days. One patient experienced bleeding following a colonoscopy that involved polypectomy and was diagnosed with carcinoma in situ of the rectum. Based on self-reported rectal bleeding in the previous six months, the colonoscopy was nonscreening. The provincial hospitalization data showed no occurrences of perforation, diverticulitis, myocardial infarction/stroke or death; thus, the rate of serious colonoscopy complications was 0.05% (95% CI 0.00% to 0.26%).

DISCUSSION:

The rate of serious colonoscopy complications requiring hospitalization was low and comparable with what is reported in the literature. The serious complication occurred subsequent to polypectomy and in a nonscreening colonoscopy.

CONCLUSION:

The findings support the relative safety of screening colonoscopy in persons without large bowel diseases and symptoms. However, future research to determine the rate of serious complications not requiring hospitalization is warranted to reassure decision makers of the safety of colonoscopy for colorectal cancer screening.     

Colonoscopy surveillance after polypectomy

The goal of surveillance examinations after polypectomy is to detect new adenomas and missed synchronous adenomas, as well as preventing adenomas from becoming invasive or cancerous. The first colonoscopy surveillance program reported was the National Polyp Study from the United States in 1997, with an update in 2003. First screening colonoscopy and polypectomy have been shown to produce the greatest effects in reducing the incidence of colorectal cancer in patients with adenomatous polyps. However, a large number of adenomas are being discovered as a result of the increased use of colorectal cancer screening, particularly with the dramatic increase in screening colonoscopy and surveillance. Increased efficiency of surveillance colonoscopy practices is therefore needed to decrease the cost, risk, and overuse of medical resources. In developing surveillance programs, studying miss rates and incidences and performing separate evaluations are important, along with accurately assessing incidence. This is because the recurrence rate or apparent incidence after colonoscopic polypectomy includes the true incidence of new polyp formation plus the incidence of missed polyps from the initial colonoscopy. Many studies have indicated the number of adenomas on initial examination as the most significant predictor for missed adenoma and incidence of adenoma on surveillance colonoscopy. In Japan, many facets of colonoscopic examination differ from those in Western countries. Further studies are recommended to establish an appropriate and original Japanese colonoscopy surveillance program for use after polypectomy, based on guidelines from the United States.     

A Prospective Randomized Study on Computed Virtual Chromoendoscopy Versus Conventional Colonoscopy for the Detection of Small Colorectal Adenomas

Background  

Colonoscopy is considered to be the standard diagnostic test for detecting colonic neoplasia, particularly for small lesions. However, recent publications have suggested that 15–27% of small adenomas might be missed during conventional colonoscopy.     

Risk and cause of interval colorectal cancer after colonoscopic polypectomy

Background: To investigate the cause and risk of interval colorectal cancer (ICC) in patients undergoing surveillance colonoscopy within 5 years after colonoscopic polypectomy. Patients and Methods: We retrospectively analyzed data (endoscopy, pathology, demography) of patients who received surveillance colonoscopy within 5 years after colonoscopic polypectomy. Results: Among 1,794 patients undergoing surveillance colonoscopy within 5 years after colonoscopic polypectomy, 14 suffered from ICC. The mean follow-up time was 2.67 years and the incidence density of ICC was 2.9 cases per 1,000 person-years. 50% of ICCs were found in patients in whom adenomas had been incompletely removed by endoscopic therapy, 36% were missed cancers, and 14% were new cancers. Age >60 years (OR 2.97, 95% CI 2.31-3.82) was significantly associated with interval cancer on the surveillance colonoscopy as were advanced adenoma (OR 1.28, 95% CI 1.01-1.62), the presence of villous (HR 1.38, 95% CI 1.03-1.85) and high-grade dysplasia (OR 1.61, 95% CI 1.07-2.42). Conclusions: Among patients undergoing surveillance colonoscopy within 5 years after polypectomy, the incidence density of ICC was 2.9 cases per 1,000 person-years. The majority of interval cancers originated from incomplete resection of advanced adenomas and missed cancers, which can be prevented by improving endoscopic techniques and selecting an appropriate follow-up time interval.     

Resection rates and safety profile of cold vs. hot snare polypectomy in polyps sized 5–10 mm and 11–20 mm

Background and aims

Hot snare (HS) is widely used for the resection of adenomas >5?mm. The cold snare (CS) has a better safety profile and is more cost-effective. The aims of this study were to evaluate effectiveness and safety of CS polypectomy (CSP) compared to HS polypectomy (HSP) for adenomas sized 5–10?mm and 11–20?mm.

Point-of-care, peer-comparator colonoscopy practice audit: The Canadian Association of Gastroenterology Quality Program--Endoscopy

BACKGROUND

Point-of-care practice audits allow documentation of procedural outcomes to support quality improvement in endoscopic practice.

OBJECTIVE

To evaluate a colonoscopists’ practice audit tool that provides point-of-care data collection and peer-comparator feedback.

METHODS

A prospective, observational colonoscopy practice audit was conducted in academic and community endoscopy units for unselected patients undergoing colonoscopy. Anonymized colonoscopist, patient and practice data were collected using touchscreen smart-phones with automated data upload for data analysis and review by participants. The main outcome measures were the following colonoscopy quality indicators: colonoscope insertion and withdrawal times, bowel preparation quality, sedation, immediate complications and polypectomy, and biopsy rates.

RESULTS

Over a span of 16 months, 62 endoscopists reported on 1279 colonoscopy procedures. The mean cecal intubation rate was 94.9% (10th centile 84.2%). The mean withdrawal time was 8.8 min and, for nonpolypectomy colonoscopies, 41.9% of colonoscopists reported a mean withdrawal time of less than 6 min. Polypectomy was performed in 37% of colonoscopies. Independent predictors of polypectomy included the following: endoscopy unit type, patient age, interval since previous colonoscopy, bowel preparation quality, stable inflammatory bowel disease, previous colon polyps and withdrawal time. Withdrawal times of less than 6 min were associated with lower polyp removal rates (mean difference −11.3% [95% CI −2.8% to −19.9%]; P=0.01).

DISCUSSION

Cecal intubation rates exceeded 90% and polypectomy rates exceeded 30%, but withdrawal times were frequently shorter than recommended. There are marked practice variations consistent with previous observations.

CONCLUSION

Real-time, point-of-care practice audits with prompt, confidential access to outcome data provide a basis for targeted educational programs to improve quality in colonoscopy practice.     

Adenoma incidence decreases under the effect of polypectomy

AIM:To investigate whether,under the influence of pol-ypectomy,the incidence of adenoma decreases with age.METHODS:Consecutive patients with colonic adenomas identified at index colonoscopy were retrospectively selected if they had undergone three or more complete colonoscopies,at least 24 mo apart.Patients who had any first-degree relative with colorectal cancer were excluded.Data regarding number of adenomas at each colonoscopy,their location,size and histological classification were recorded.The monthly incidence density of adenomas after the index examination was estimated for the study population,by using the person-years method.Baseline adenomas were excluded from incidence calculations but their characteristics were correlated with recurrence at follow-up,using the χ 2 test.RESULTS:One hundred and fifty-six patients were included(109 male,mean age at index colonoscopy 56.8 ± 10.3 years),with follow-up that ranged from 48 to 232 mo.No significant correlations were observed between the number,the presence of villous component,or the size of adenomas at index colonoscopy and the presence of adenomas at subsequent colonoscopies(P = 0.49,0.12 and 0.78,respectively).The incidence of colonic adenomas was observed to decay from 1.4% person-months at the beginning of the study to values close to 0%,at 12 years after index colonoscopy.CONCLUSION:Our results suggest the sporadic formation of adenomas occurs within a discrete period and that,when these adenomas are removed,all neoplasia-prone clones may be extinguished.     

High-Definition White-Light (HDWL) Colonoscopy and Higher Adenoma Detection Rate and the Potential for Paradoxical Over Surveillance

Background

Patients undergoing high-definition white-light colonoscopy by a high adenoma detector may have a lower risk of interval adenoma detection on follow-up colonoscopy and may require less frequent follow-up but may paradoxically be assigned to more frequent surveillance when more adenomas are detected.

Aims

To evaluate whether high-definition white-light colonoscopy (vs. standard-definition white-light colonoscopy) and endoscopist adenoma detection rate (ADR) at index colonoscopy are associated with increased likelihood of adenomas at follow-up.

Methods

Longitudinal follow-up of prior cross-section cohort study of patients who underwent colonoscopy at baseline with at least one detected adenoma was included. Associations of type of white-light at index colonoscopy and the ADR of the endoscopist at index colonoscopy (high vs. low adenoma detector) were evaluated with various adenoma and polyp detection endpoints. Eighteen endoscopists were classified as high and low adenoma detectors based on the median ADR of 0.255.

Results

There were no significant differences in subsequent interval adenoma or polyp detection endpoints with regard to whether baseline exam was performed with high-definition white-light or standard-definition white-light colonoscopy nor between high and low ADR after adjusting for multiple testing (P ≤ 0.0029 considered significant). Prior to multiple testing adjustment, there was a significantly lower detection rate of hyperplastic polyps in the left colon (24 vs. 35 %, OR: 0.56, P = 0.033) at follow-up colonoscopy when baseline exam was performed with high-definition white-light index colonoscopy.

Conclusions

The results of this study do not support adjusting colonoscopy surveillance guidelines based on type of colonoscopy performed or the endoscopist’s ADR.     

A prospective, partly randomized study of the effectiveness of repeated examination of the colon after polypectomy and radical surgery for cancer

Results of 629 colonoscopies and 130 double-contrast examinations, performed during the first 2 years of a prospective, partly randomized cancer prophylactic programme, are reported. The patients were not more than 75 years old and had no previous diagnosis of adenoma or cancer. Repeated colonoscopy 3 months after polypectomy in 80 patients increased the chance of obtaining a complete colonoscopy from 70% to 86%, and the hepatic flexure was reached in a further 9%. Thirteen had polypectomy during the second colonoscopy. The gain in number of patients with adenomas was highest in those with sessile villous adenomas, carcinoma in situ, and mucosal carcinoma. Repeated colorectal examinations every 6 months in these resulted in recurrence rates of 13 of 33, 3 of 23, and 2 of 15 (18 months), respectively. The same figures for patients with stalked polyps, allocated to examination every 6 months, were 3 of 34, 1 of 21, and 2 of 14. Colonoscopy was also performed within 3 months of radical surgery for colorectal cancer, and 35 of 142 patients had polypectomy. Repeated examinations every 6 months resulted in recurrence rates for adenomas of 11 of 85, 3 of 46, and 1 of 34. One new cancer after 12 months could be treated radically. Five uncomplicated laparotomies were performed after the 629 colonoscopies because of perforation or bleeding.     

The risk of advanced neoplasia after polypectomy of one to two non-advanced adenomas less than 5 mm in size vs. normal colonoscopy

BackgroundCurrent guidelines are inconsistent regarding the follow-up of patients with 1–2 diminutive (1–5 mm) non-advanced adenomas (DNAAs).AimsTo evaluate the risk of metachronous advanced neoplasia (AN), defined as cancer or advanced adenoma (AA), among patients with either normal colonoscopy or 1–2 DNAAs.MethodsA retrospective cohort study. Cohort I included 2,347 subjects with normal colonoscopy and 483 subjects with polypectomy of 1–2 DNAAs followed by colonoscopy. Cohort II included 11,881 subjects with normal colonoscopy and 1,342 subjects with 1–2 DNAAs followed through the cancer registry.ResultsIn cohort I, the rate of AN, cancer and AA among the polypectomy group vs. normal colonoscopy was 5.0% vs. 2.5%, Hazard Ratio (HR) 2.96 (95%CI [Confidence Interval]1.86–4.78) for AN; 0.6% vs. 0.3%, HR 3.32 (95%CI 0.85–13) for cancer; 4.3% vs. 2.2% HR 2.91 (95%CI 1.75–4.86) for AA. In cohort II, cancer occurred in 0.4% of the polypectomy group and 0.2% of the normal colonoscopy group, HR 2.27 (95% CI 0.56–9.19).ConclusionCompared to subjects with normal colonoscopy, subjects with polypectomy of 1–2 DNAAs, are at increased risk for AA when followed by colonoscopy, while the risk for cancer is non-significantly increased. Our findings suggest that patients with 1–2 DNNAs should be followed more tightly than patients with normal colonoscopy.     

Colorectal cancer surveillance after index colonoscopy: Guidance from the Canadian Association of Gastroenterology

BACKGROUND:

Differences between American (United States [US]) and European guidelines for colonoscopy surveillance may create confusion for the practicing clinician. Under- or overutilization of surveillance colonoscopy can impact patient care.

METHODS:

The Canadian Association of Gastroenterology (CAG) convened a working group (CAG-WG) to review available guidelines and provide unified guidance to Canadian clinicians regarding appropriate follow-up for colorectal cancer (CRC) surveillance after index colonoscopy. A literature search was conducted for relevant data that postdated the published guidelines.

RESULTS:

The CAG-WG chose the 2012 US Multi-Society Task Force (MSTF) on Colorectal Cancer to serve as the basis for the Canadian position, primarily because the US approach was the simplest and comprehensively addressed the issue of serrated polyps. Aspects of other guidelines were incorporated where relevant. The CAG-WG recommendations differed from the US MSTF guidelines in three main areas: patients with negative index colonoscopy should be followed-up at 10 years using any of the appropriate screening tests, including colonos-copy, for average-risk individuals; among patients with >10 adenomas, a one-year interval for subsequent colonoscopy is recommended; and for long-term follow-up, patients with low-risk adenomas on both the index and first follow-up procedures can undergo second follow-up colonos-copy at an interval of five to 10 years.

DISCUSSION:

The CAG-WG adapted the US MSTF guidelines for colonoscopy surveillance to the Canadian health care environment with a few modifications. It is anticipated that the present article will provide unified guidance that will enhance physician acceptance and encourage appropriate utilization of recommended surveillance intervals.     

Benefits and Limitations of Cap-Fitted Colonoscopy in Screening Colonoscopy

Background

Colonoscopy is widely used to detect colorectal cancer and to remove precancerous lesions to reduce the risk of colonic cancer.

Aims

To examine the benefits and limitations of cap-fitted colonoscopy compared to conventional colonoscopy in terms of technical performance and colorectal adenoma detection rate.

Methods

Screening colonoscopies performed from 2009 to 2010 with or without a transparent cap were retrospectively examined to compare the rate of successful intubation, cecal intubation time, and number, size, shape, and location of adenomas detected. An inclusion criterion was visualization of >95 % of the right colon.

Results

Data from 2,301 colonoscopies (1,165 with cap-fitted colonoscopy, 1,136 without the transparent cap) were retrospectively analyzed. Procedures were performed by four experienced endoscopists. The subjects’ demographic characteristics and technical performances were similar between the two methods. The only significant difference in the technical performance between the two techniques was a shorter cecal intubation time with cap-fitted colonoscopy (5.3 vs. 6.6 min; p = 0.045) by one endoscopist. The total number of adenomas detected was significantly higher with cap-fitted colonoscopy than without the cap (586 vs. 484, respectively; p < 0.0001). Adenoma detection with cap-fitted endoscopy was significantly higher in the right colon than in the left colon (19 vs. 12 %, respectively; p = 0.0001).

Conclusion

Cap-fitted colonoscopy did not improve the technical aspects of colonoscopy but significantly increased adenoma detection, especially in the right colon. It did not increase the detection rate of flat or depressed adenomas.     

Incidence and recurrence rates of colorectal adenomas estimated by annually repeated colonoscopies on asymptomatic Japanese

BACKGROUND: Whereas high recurrence rates of colorectal adenomas after polypectomy are widely recognised, little is known of the natural incidence in those with no neoplastic lesions initially. It is also known that single colonoscopy has a significant miss rate. AIMS: To elucidate the incidence and recurrence rates of colorectal neoplasms from a large cohort of asymptomatic Japanese patients on the basis of annually repeated colonoscopies. METHODS: A total of 6225 subjects (4659 men and 1566 women) participating in an annual colonoscopic screening programme and completing three or more colonoscopies were analysed during the 14 year period between 1988 and 2002. Patients were divided into three groups according to the findings of the initial two colonoscopies: 4084 subjects with no neoplasm, 1818 with small adenomas <10 mm, and 323 with advanced lesions, including carcinoma in situ, severe dysplasia, or large adenomas > or =10 mm. Mean age at the second colonoscopy was 48.8 years. RESULTS: For all types of colorectal neoplasms, the incidence rate in those with no initial neoplasm was 7.2%/year whereas recurrence rates in those with small adenomas and advanced lesions were 19.3% and 22.9%/year, respectively. For advanced colorectal lesions, the incidence rate was 0.21%/year whereas recurrence rates in those with small adenomas and advanced lesions were 0.64% and 1.88%/year, respectively. Colorectal neoplasms were in general more likely to develop in males and older subjects. CONCLUSIONS: Although recurrence rates after polypectomy were elevated, the incidence rates in subjects with no neoplastic lesions initially were quite high.     

The effect of attending a flexible sigmoidoscopic screening program on the prevalence of colorectal adenomas at 13-year follow-up

OBJECTIVES: Understanding the epidemiology of colorectal adenomas is a prerequisite for designing follow-up programs after polypectomy. The aim of the study was to investigate the effect of polypectomy on the long-term prevalence of adenomas. METHODS: In 1983, a total of 799 men and women aged 50-59 yr were drawn from the general population register. Of these, 400 comprised a screening group and 399 a matched control group. The screenees were invited to undergo a once-only flexible sigmoidoscopy. Persons with polyps had a baseline colonoscopy with follow-ups in 1985 and 1989. In 1996, both the screenees and the controls were invited to a colonoscopic examination. RESULTS: In 1996, a total of 451 (71%) individuals attended. Adenomas were found in 78 (37%) individuals in the screening group and 103 (43%) in the control group, relative risk (95% confidence interval): 0.9 (0.7-1.1), p = 0.3, and high-risk adenomas (severe dysplasia, adenomas > or = 10 mm, villous components) were found in 16 (8%) and 32 (13%), respectively; relative risk (95% confidence interval): 0.6 (0.3-1.0), p = 0.07. CONCLUSIONS: There was no significant difference in adenoma prevalence between the group after the screening program and the controls after the usual care. There was a trend toward more high-risk adenomas in the control group. This suggests a very limited effect of one-time screening sigmoidoscopy with surveillance colonoscopy on the prevalence of adenomas, but a preventive effect on the development of high-risk adenomas consistent with the reported effect on cancer prevention.