The Norwegian guidelines for surveillance after polypectomy: 10-year intervals

A Comparison of Risk Classification Systems of Colorectal Adenomas: A Case-Cohort Study

BACKGROUND & AIMS

Because post-polypectomy surveillance uses a growing proportion of colonoscopy capacity, more targeted surveillance is warranted. We therefore compared surveillance burden and cancer detection using 3 different adenoma classification systems.

METHODS

In a case-cohort study among individuals who had adenomas removed between 1993 and 2007, we included 675 individuals with colorectal cancer (cases) diagnosed a median of 5.6 years after adenoma removal and 906 randomly selected individuals (subcohort). We compared colorectal cancer incidence among high- and low-risk individuals defined according to the traditional (high-risk: diameter ≥10 mm, high-grade dysplasia, villous growth pattern, or 3 or more adenomas), European Society of Gastrointestinal Endoscopy (ESGE) 2020 (high-risk: diameter ≥10 mm, high-grade dysplasia, or 5 or more adenomas), and novel (high-risk: diameter ≥20 mm or high-grade dysplasia) classification systems. For the different classification systems, we calculated the number of individuals recommended frequent surveillance colonoscopy and estimated number of delayed cancer diagnoses.

RESULTS

Four hundred and thirty individuals with adenomas (52.7%) were high risk based on the traditional classification, 369 (45.2%) were high risk based on the ESGE 2020 classification, and 220 (27.0%) were high risk based on the novel classification. Using the traditional, ESGE 2020, and novel classifications, the colorectal cancer incidences per 100,000 person-years were 479, 552, and 690 among high-risk individuals, and 123, 124, and 179 among low-risk individuals, respectively. Compared with the traditional classification, the number of individuals who needed frequent surveillance was reduced by 13.9% and 44.2%, respectively, and 1 (3.4%) and 7 (24.1%) cancer diagnoses were delayed using the ESGE 2020 and novel classifications.

CONCLUSIONS

Using the ESGE 2020 and novel risk classifications will substantially reduce resources needed for colonoscopy surveillance after adenoma removal.

Long-term colorectal cancer incidence and mortality after adenoma removal in women and men

BACKGROUND

Women and men with colorectal adenomas are at increased risk of colorectal cancer and colonoscopic surveillance is recommended. However, the long-term cancer risk remains unknown.

AIMS

To investigate colorectal cancer incidence and mortality after adenoma removal in women and men METHODS: We identified all individuals who had adenomas removed in Norway from 1993 to 2007, with follow-up through 2018. We calculated standardized incidence ratios (SIR) and incidence-based mortality ratios (SMR) with 95% confidence intervals (CI) for colorectal cancer in women and men using the female and male population for comparison. We defined high-risk adenomas as ≥2 adenomas, villous component, or high-grade dysplasia.

RESULTS

The cohort comprised 40 293 individuals. During median follow-up of 13.0 years, 1079 women (5.5%) and 866 men (4.2%) developed colorectal cancer; 328 women (1.7%) and 275 men (1.3%) died of colorectal cancer. Colorectal cancer incidence was more increased in women (SIR 1.64, 95% CI 1.54-1.74) than in men (SIR 1.12, 95% CI 1.05-1.19). Colorectal cancer mortality was increased in women (SMR 1.13, 95% CI 1.02-1.26) and reduced in men (SMR 0.79, 95% CI 0.71-0.89). Women with high-risk adenomas had an increased risk of colorectal cancer death (SMR 1.37, 95% CI 1.19-1.57); women with low-risk adenomas (SMR 0.90, 95% CI 0.76-1.07) and men with high-risk adenomas had a similar risk (SMR 0.89, 95% CI 0.76-1.04), while men with low-risk adenomas had reduced risk (SMR 0.70, 95% CI 0.59-0.84).

CONCLUSIONS

After adenoma removal, women had an increased risk of colorectal cancer death, while men had reduced risk, compared to the general female and male populations. Sex-specific surveillance recommendations after adenoma removal should be considered.

Modeling in Colorectal Cancer Screening: Assessing External and Predictive Validity of MISCAN-Colon Microsimulation Model Using NORCCAP Trial Results

BACKGROUND

Microsimulation models are increasingly being used to inform colorectal cancer (CRC) screening recommendations. MISCAN-Colon is an example of such a model, used to inform the Dutch CRC screening program and US Preventive Services Task Force guidelines. Assessing the validity of these models is essential to provide transparency regarding their performance. In this study, we tested the external and predictive validity of MISCAN-Colon.

METHODS

We validated MISCAN-Colon using the Norwegian Colorectal Cancer Prevention (NORCCAP) trial, a randomized controlled trial that examined the effectiveness of once-only flexible sigmoidoscopy (FS) screening. We simulated the study population and design of the NORCCAP trial in MISCAN-Colon and compared 10- to 12-year model-predicted hazard ratios (HRs) for overall and distal CRC incidence and mortality to those observed. In addition, we compared the numbers of screen-detected neoplasia. Finally, we predicted the trial's future results to allow for the assessment of predictive validity.

RESULTS

MISCAN-Colon predicted an HR for overall CRC incidence (0.85), distal CRC incidence (0.82), overall CRC mortality (0.68), and distal CRC mortality (0.62). These were within the limits of the 95% confidence intervals of the NORCCAP trial results. Similar results were observed for the number of screen-detected cancers. The model significantly underestimated the number of screen-detected adenomas. Model-predicted HRs for CRC incidence and mortality up to 15- to 17-year follow-up were 0.84 and 0.72, respectively.

CONCLUSION

Although the underestimation of screen-detected adenomas requires further investigation, MISCAN-Colon is able to make a valid replication of the CRC incidence and mortality reduction of an FS screening trial, which suggests that it can be considered a useful tool to support decision making on CRC screening.

Long-Term Effectiveness of Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality in Women and Men: A Randomized Trial

BACKGROUND

The long-term effects of sigmoidoscopy screening on colorectal cancer (CRC) incidence and mortality in women and men are unclear.

OBJECTIVE

To determine the effectiveness of flexible sigmoidoscopy screening after 15 years of follow-up in women and men.

DESIGN

Randomized controlled trial. (ClinicalTrials.gov: NCT00119912).

SETTING

Oslo and Telemark County, Norway.

PARTICIPANTS

Adults aged 50 to 64 years at baseline without prior CRC.

INTERVENTION

Screening (between 1999 and 2001) with flexible sigmoidoscopy with and without additional fecal blood testing versus no screening. Participants with positive screening results were offered colonoscopy.

MEASUREMENTS

Age-adjusted CRC incidence and mortality stratified by sex.

RESULTS

Of 98 678 persons, 20 552 were randomly assigned to screening and 78 126 to no screening. Adherence rates were 64.7% in women and 61.4% in men. Median follow-up was 14.8 years. The absolute risks for CRC in women were 1.86% in the screening group and 2.05% in the control group (risk difference, -0.19 percentage point [95% CI, -0.49 to 0.11 percentage point]; HR, 0.92 [CI, 0.79 to 1.07]). In men, the corresponding risks were 1.72% and 2.50%, respectively (risk difference, -0.78 percentage point [CI, -1.08 to -0.48 percentage points]; hazard ratio [HR], 0.66 [CI, 0.57 to 0.78]) (P for heterogeneity = 0.004). The absolute risks for death from CRC in women were 0.60% in the screening group and 0.59% in the control group (risk difference, 0.01 percentage point [CI, -0.16 to 0.18 percentage point]; HR, 1.01 [CI, 0.77 to 1.33]). The corresponding risks for death from CRC in men were 0.49% and 0.81%, respectively (risk difference, -0.33 percentage point [CI, -0.49 to -0.16 percentage point]; HR, 0.63 [CI, 0.47 to 0.83]) (P for heterogeneity = 0.014).

LIMITATION

Follow-up through national registries.

CONCLUSION

Offering sigmoidoscopy screening in Norway reduced CRC incidence and mortality in men but had little or no effect in women.

PRIMARY FUNDING SOURCE

Norwegian government and Norwegian Cancer Society.

Colorectal cancer death after adenoma removal in Scandinavia

OBJECTIVES

Improved understanding of the subsequent risk death from colorectal cancer (CRC) among individuals who had adenomas removed is needed. We aimed to quantify this risk using prospectively collected data from population-based cohorts.

MATERIALS AND METHODS

Using Norwegian and Swedish registries, a cohort of 90,864 individuals with colorectal adenomas removed between 1980 and 2013 was identified. Surveillance was only recommended for high-risk adenomas. The validity of the registry data did not allow classification into low- and high-risk adenomas. Virtually complete follow-up was achieved through linkage to nationwide registers. We calculated incidence-based standardised mortality ratios (SMRs) with 95% confidence intervals (CI).

RESULTS

The median follow-up was 7.2 years; 48,058 individuals were followed for more than 10 years. We observed 819 deaths (0.9%) from CRC and expected 731 CRC deaths (0.8%), corresponding to an absolute excess risk of 88 cases (0.1%) and a relative risk of 12% (SMR 1.12; 95%CI 1.05-1.20). The relative risk of CRC death following adenoma removal was slightly higher in Sweden (SMR 1.22; 95%CI 1.11-1.34) than in Norway (SMR 1.03; 95%CI 0.93-1.14), and higher in women (SMR 1.24; 95%CI 1.12-1.36) than in men (SMR 1.02; 95%CI 0.93-1.13). Among individuals with more than 10 years of follow-up, the estimates were similar to the overall cohort, absolute excess risk 0.1% (SMR 1.15; 95%CI 1.06-1.24).

CONCLUSION

The excess risk of CRC death following adenoma removal is small. Optimal surveillance recommendations should be tested in randomised trials.

The clinical effectiveness of different surveillance strategies to prevent colorectal cancer in people with intermediate-grade colorectal adenomas: a retrospective cohort analysis, and psychological and economic evaluations

BACKGROUND

The UK guideline recommends 3-yearly surveillance for patients with intermediate-risk (IR) adenomas. No study has examined whether or not this group has heterogeneity in surveillance needs.

OBJECTIVES

To examine the effect of surveillance on colorectal cancer (CRC) incidence; assess heterogeneity in risk; and identify the optimum frequency of surveillance, the psychological impact of surveillance, and the cost-effectiveness of alternative follow-up strategies.

DESIGN

Retrospective multicentre cohort study.

SETTING

Routine endoscopy and pathology data from 17 UK hospitals (n = 11,944), and a screening data set comprising three pooled cohorts (n = 2352), followed up using cancer registries.

SUBJECTS

Patients with IR adenoma(s) (three or four small adenomas or one or two large adenomas).

PRIMARY OUTCOMES

Advanced adenoma (AA) and CRC detected at follow-up visits, and CRC incidence after baseline and first follow-up.

METHODS

The effects of surveillance on long-term CRC incidence and of interval length on findings at follow-up were examined using proportional hazards and logistic regression, adjusting for patient, procedural and polyp characteristics. Lower-intermediate-risk (LIR) subgroups and higher-intermediate-risk (HIR) subgroups were defined, based on predictors of CRC risk. A model-based cost-utility analysis compared 13 surveillance strategies. Between-group analyses of variance were used to test for differences in bowel cancer worry between screening outcome groups (n = 35,700). A limitation of using routine hospital data is the potential for missed examinations and underestimation of the effect of interval and surveillance.

RESULTS

In the hospital data set, 168 CRCs occurred during 81,442 person-years (pys) of follow-up [206 per 100,000 pys, 95% confidence interval (CI) 177 to 240 pys]. One surveillance significantly lowered CRC incidence, both overall [hazard ratio (HR) 0.51, 95% CI 0.34 to 0.77] and in the HIR subgroup (n = 9265; HR 0.50, 95% CI 0.34 to 0.76). In the LIR subgroup (n = 2679) the benefit of surveillance was less clear (HR 0.62, 95% CI 0.16 to 2.43). Additional surveillance lowered CRC risk in the HIR subgroup by a further 15% (HR 0.36, 95% CI 0.20 to 0.62). The odds of detecting AA and CRC at first follow-up (FUV1) increased by 18% [odds ratio (OR) 1.18, 95% CI 1.12 to 1.24] and 32% (OR 1.32, 95% CI 1.20 to 1.46) per year increase in interval, respectively, and the odds of advanced neoplasia at second follow-up increased by 22% (OR 1.22, 95% CI 1.09 to 1.36), after adjustment. Detection rates of AA and CRC remained below 10% and 1%, respectively, with intervals to 3 years. In the screening data set, 32 CRCs occurred during 25,745 pys of follow-up (124 per 100,000 pys, 95% CI 88 to 176 pys). One follow-up conferred a significant 73% reduction in CRC incidence (HR 0.27, 95% CI 0.10 to 0.71). Owing to the small number of end points in this data set, no other outcome was significant. Although post-screening bowel cancer worry was higher in people who were offered surveillance, worry was due to polyp detection rather than surveillance. The economic evaluation, using data from the hospital data set, suggested that 3-yearly colonoscopic surveillance without an age cut-off would produce the greatest health gain.

CONCLUSIONS

A single surveillance benefited all IR patients by lowering their CRC risk. We identified a higher-risk subgroup that benefited from further surveillance, and a lower-risk subgroup that may require only one follow-up. A surveillance interval of 3 years seems suitable for most IR patients. These findings should be validated in other studies to confirm whether or not one surveillance visit provides adequate protection for the lower-risk subgroup of intermediate-risk patients.

STUDY REGISTRATION

Current Controlled Trials ISRCTN15213649.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Risk stratification and detection of new colorectal neoplasms after colorectal cancer screening with faecal occult blood test: experiences from a Danish screening cohort

BACKGROUND

Limited data exist on adenoma surveillance as recommended in the European guidelines for quality assurance in colorectal cancer (CRC) screening and diagnosis after faecal occult blood test (FOBT) screening.

OBJECTIVE

To assess the European guidelines for adenoma surveillance after CRC screening with FOBT.

MATERIALS AND METHODS

This was a population-based cohort-study of 176 782 Danish individuals aged 50-74 years invited for CRC screening in 2005-2006. Adenoma patients were stratified into risk groups (low A, medium B, high C) in accordance with the European guidelines and followed up for recurrence of new neoplasms until the end of 2011. Risk ratios (RR) between the risk groups were calculated to assess differences in the recurrence rates of neoplasms.

RESULTS

Among 84 803 screening participants, 2059 had positive FOBT, of whom 1861 underwent colonoscopy, and 709 patients had screen-detected adenomas. During a median follow-up period of 72.7 months, detection of new advanced adenomas (B+C) was significantly higher in risk group C than group A (RR 2.25, 95% confidence interval: 1.13-4.48). Nine patients were diagnosed with CRC: one in risk group A, two in B and six in C. The detection rate of CRC was higher in risk group C than A (RR 5.20, 95% confidence interval: 0.63-42.58), but not statistically significant. In risk group C, half of new advanced adenomas were detected within the first year and four of nine CRC were detected within 3 years.

CONCLUSION

Risk stratification of adenoma patients, as recommended by the European guidelines, is appropriate for postpolypectomy surveillance after FOBT screening.

Long-term risk of colorectal cancer in individuals with serrated polyps

OBJECTIVE

Although serrated polyps may be precursors of colorectal cancer (CRC), prospective data on the long-term CRC risk in individuals with serrated polyps are lacking.

DESIGN

In a population-based randomised trial, 12,955 individuals aged 50-64 years were screened with flexible sigmoidoscopy, while 78 220 individuals comprised the control arm. We used Cox models to estimate HRs with 95% CIs for CRC among individuals with ≥1 large serrated polyp (≥10 mm in diameter), compared with individuals with adenomas at screening, and to population controls, and multivariate logistic regression to assess polyp risk factors for CRC.

RESULTS

A total of 103 individuals had large serrated polyps, of which 81 were included in the analyses. Non-advanced adenomas were found in 1488 individuals, advanced adenomas in 701. Median follow-up was 10.9 years. Compared with the control arm, the HR for CRC was 2.5 (95% CI 0.8 to 7.8) in individuals with large serrated polyps, 2.0 (95% CI 1.3 to 2.9) in individuals with advanced adenomas and 0.6 (95% CI 0.4 to 1.1) in individuals with non-advanced adenomas. A large serrated polyp was an independent risk factor for CRC, adjusted for histology, size and multiplicity of concomitant adenomas (OR 3.3; 95% CI 1.3 to 8.6). Twenty-three large serrated polyps found at screening were left in situ for a median of 11.0 years. None developed into a malignant tumour.

CONCLUSIONS

Individuals with large serrated polyps have an increased risk of CRC, comparable with individuals with advanced adenomas. However, this risk may not be related to malignant growth of the serrated polyp.

TRIAL REGISTRATION NUMBER

The Norwegian Colorectal Cancer Screening trial is registered at clinicaltrials.gov (NCT00119912).

Long-term colorectal-cancer mortality after adenoma removal

BACKGROUND

Although colonoscopic surveillance of patients after removal of adenomas is widely promoted, little is known about colorectal-cancer mortality among these patients.

METHODS

Using the linkage of the Cancer Registry and the Cause of Death Registry of Norway, we estimated colorectal-cancer mortality among patients who had undergone removal of colorectal adenomas during the period from 1993 through 2007. Patients were followed through 2011. We calculated standardized incidence-based mortality ratios (SMRs) using rates for the Norwegian population at large for comparison. Norwegian guidelines recommended colonoscopy after 10 years for patients with high-risk adenomas (adenomas with high-grade dysplasia, a villous component, or a size ≥10 mm) and after 5 years for patients with three or more adenomas; no surveillance was recommended for patients with low-risk adenomas. Polyp size and exact number were not available in the registry. We defined high-risk adenomas as multiple adenomas and adenomas with a villous component or high-grade dysplasia.

RESULTS

We identified 40,826 patients who had had colorectal adenomas removed. During a median follow-up of 7.7 years (maximum, 19.0), 1273 patients were given a diagnosis of colorectal cancer. A total of 398 deaths from colorectal cancer were expected and 383 were observed, for an SMR of 0.96 (95% confidence interval [CI], 0.87 to 1.06) among patients who had had adenomas removed. Colorectal-cancer mortality was increased among patients with high-risk adenomas (expected deaths, 209; observed deaths, 242; SMR, 1.16; 95% CI, 1.02 to 1.31), but it was reduced among patients with low-risk adenomas (expected deaths, 189; observed deaths, 141; SMR, 0.75; 95% CI, 0.63 to 0.88).

CONCLUSIONS

After a median of 7.7 years of follow-up, colorectal-cancer mortality was lower among patients who had had low-risk adenomas removed and moderately higher among those who had had high-risk adenomas removed, as compared with the general population. (Funded by the Norwegian Cancer Society and others.).

Effect of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: a randomized clinical trial

IMPORTANCE

Colorectal cancer is a major health burden. Screening is recommended in many countries.

OBJECTIVE

To estimate the effectiveness of flexible sigmoidoscopy screening on colorectal cancer incidence and mortality in a population-based trial.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial of 100,210 individuals aged 50 to 64 years, identified from the population of Oslo city and Telemark County, Norway. Screening was performed in 1999-2000 (55-64-year age group) and in 2001 (50-54-year age group), with follow-up ending December 31, 2011. Of those selected, 1415 were excluded due to prior colorectal cancer, emigration, or death, and 3 could not be traced in the population registry.

INTERVENTIONS

Participants randomized to the screening group were invited to undergo screening. Within the screening group, participants were randomized 1:1 to receive once-only flexible sigmoidoscopy or combination of once-only flexible sigmoidoscopy and fecal occult blood testing (FOBT). Participants with positive screening test results (cancer, adenoma, polyp ≥10 mm, or positive FOBT) were offered colonoscopy. The control group received no intervention.

MAIN OUTCOMES AND MEASURES

Colorectal cancer incidence and mortality.

RESULTS

A total of 98,792 participants were included in the intention-to-screen analyses, of whom 78,220 comprised the control group and 20,572 comprised the screening group (10,283 randomized to receive a flexible sigmoidoscopy and 10,289 to receive flexible sigmoidoscopy and FOBT). Adherence with screening was 63%. After a median of 10.9 years, 71 participants died of colorectal cancer in the screening group vs 330 in the control group (31.4 vs 43.1 deaths per 100,000 person-years; absolute rate difference, 11.7 [95% CI, 3.0-20.4]; hazard ratio [HR], 0.73 [95% CI, 0.56-0.94]). Colorectal cancer was diagnosed in 253 participants in the screening group vs 1086 in the control group (112.6 vs 141.0 cases per 100,000 person-years; absolute rate difference, 28.4 [95% CI, 12.1-44.7]; HR, 0.80 [95% CI, 0.70-0.92]). Colorectal cancer incidence was reduced in both the 50- to 54-year age group (HR, 0.68; 95% CI, 0.49-0.94) and the 55- to 64-year age group (HR, 0.83; 95% CI, 0.71-0.96). There was no difference between the flexible sigmoidoscopy only vs the flexible sigmoidoscopy and FOBT screening groups.

CONCLUSIONS AND RELEVANCE

In Norway, once-only flexible sigmoidoscopy screening or flexible sigmoidoscopy and FOBT reduced colorectal cancer incidence and mortality on a population level compared with no screening. Screening was effective both in the 50- to 54-year and the 55- to 64-year age groups.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00119912.

Long-term effectiveness of endoscopic screening on incidence and mortality of colorectal cancer: A randomized trial

BACKGROUND

Due to few randomized trials, there is uncertainty about the long-time effect of endoscopic screening on colorectal cancer (CRC) incidence and mortality.

AIM

To evaluate the long-term effect of endoscopic screening on CRC incidence and mortality, we performed a population-based randomized controlled trial in Norway.

MATERIALS AND METHODS

In 1983, 799 Norwegian men and women, age 50-59 years were drawn from the population registry and randomly assigned to flexible sigmoidoscopy screening (400 individuals), or no screening (399 individuals). Colonoscopy surveillance was offered after two and six years for all polyp-bearers in the screening group. In 1996, both groups were offered colonoscopy. Only individuals with advanced adenomas at colonoscopy in 1996 were recommended surveillance. All individuals were followed through Norwegian registries until 2008. Hazard ratios (HR) for CRC incidence, and CRC and overall mortality rates were calculated.

RESULTS

During 26 years of follow up (17,327 person-years), 26 colorectal cancers were observed: seven in the screening group and 19 in the control group (HR in screening group 0.40, 95% CI 0.17-0.95, p = 0.04). Eight individuals died of colorectal cancer; one in the screening group and seven in the control group (HR 0.16, 95% CI 0.02-1.28, p = 0.08).

CONCLUSIONS

This first randomized trial on the long-term effect of endoscopic screening shows reduced CRC incidence and mortality if screening is combined with rigorous surveillance for individuals with polyps. Colonoscopy screening without such surveillance may not be effective.

Quality assurance as an integrated part of the electronic medical record - a prototype applied for colonoscopy

OBJECTIVE

Electronic medical records (EMRs) have not developed much beyond the days of typewritten journals when it comes to facilitating extraction of data for quality assurance (QA) and improvement of health-care performance.

MATERIAL AND METHODS

Based on 5 years' experience from the Norwegian Gastronet QA programme, we have developed a highly QA-profiled EMR for colonoscopy. We used a three-tier solution (client, server and database) written in the Java programming language using a number of open-source libraries. QA principles from the Norwegian paper-based Gastronet QA programme formed the basis for development of the ColoReg software. ColoReg is developed primarily for colonoscopy reporting in a screening trial, but may be used in routine clinical work. The QA module in ColoReg is well suited for intervention towards suboptimal performance in both settings.

RESULTS

We have developed user-friendly software dominated by clickable boxes and curtain menus reducing free text to a minimum. The software gives warnings when illogical registrations are entered and reasons have to be given for divergence from software recommendations for work-up and surveillance. At any time, defined performance quality parameters are readily accessible in tabular form with the named, logged-in endoscopist being compared with all other anonymized endoscopists in the database.

CONCLUSION

The ColoReg software is developed for use in an international, multicentre trial on colonoscopy screening. It is user-friendly and secures continuous QA of the endoscopist's performance. The principles used are applicable to development of EMRs in general.

Risk of colorectal cancer seven years after flexible sigmoidoscopy screening: randomised controlled trial

OBJECTIVE

To determine the risk of colorectal cancer after screening with flexible sigmoidoscopy.

DESIGN

Randomised controlled trial.

SETTING

Population based screening in two areas in Norway-city of Oslo and Telemark county (urban and mixed urban and rural populations).

PARTICIPANTS

55 736 men and women aged 55-64 years.

INTERVENTION

Once only flexible sigmoidoscopy screening with or without a single round of faecal occult blood testing (n=13 823) compared with no screening (n=41 913).

MAIN OUTCOME MEASURES

Planned end points were cumulative incidence and mortality of colorectal cancer after 5, 10, and 15 years. This first report from the study presents cumulative incidence after 7 years of follow-up and hazard ratio for mortality after 6 years.

RESULTS

No difference was found in the 7 year cumulative incidence of colorectal cancer between the screening and control groups (134.5 v 131.9 cases per 100 000 person years). In intention to screen analysis, a trend towards reduced colorectal cancer mortality was found (hazard ratio 0.73, 95% confidence interval 0.47 to 1.13, P=0.16). For attenders compared with controls, a statistically significant reduction in mortality was apparent for both total colorectal cancer (hazard ratio 0.41, 0.21 to 0.82, P=0.011) and rectosigmoidal cancer (0.24, 0.08 to 0.76, P=0.016).

CONCLUSIONS

A reduction in incidence of colorectal cancer with flexible sigmoidoscopy screening could not be shown after 7 years' follow-up. Mortality from colorectal cancer was not significantly reduced in the screening group but seemed to be lower for attenders, with a reduction of 59% for any location of colorectal cancer and 76% for rectosigmoidal cancer in per protocol analysis, an analysis prone to selection bias.

TRIAL REGISTRATION

Clinical trials NCT00119912.

Impact of a colonoscopic screening examination for colorectal cancer on later utilization of distal GI endoscopies

BACKGROUND

Colonoscopic screening for colorectal cancer is being implemented in an increasing number of countries. This might lead to a demand for colonoscopies that could outstrip supply.

OBJECTIVE

We wanted to investigate whether undergoing a colonoscopic examination for colorectal cancer would affect the utilization of later distal GI endoscopies for other indications than follow-up of the findings at the screening examination (usual-care endoscopies).

DESIGN

Prospective case control study.

PATIENTS

In 1996, a screening group of 634 individuals, aged 63 to 72 years, randomly drawn from the official population registry, was invited to a "once only" colonoscopic screening examination for colorectal cancer. A total of 451 individuals (71%) attended. An age- and sex-matched control group of 634 individuals was enrolled from the same registry. Both groups belonged to the encatchment area of a single hospital.

MAIN OUTCOME MEASUREMENTS

Distal endoscopies performed in the 2 groups from January 1996 to November 2004 were registered by investigating medical records.

RESULTS

A total of 1268 individuals (52.4% women) were followed for 9 years. Sixty-three individuals (9.9%) in the screening group and 110 (17.4%) individuals in the control group (odds ratio 0.53, 95% confidence interval 0.38-0.73) had had a total of 85 and 169 usual-care distal endoscopies, respectively (P < .001).

CONCLUSIONS

Undergoing a colonoscopic examination for colorectal cancer seems to reduce the utilization of later usual-care endoscopic examinations. This finding could have an impact on the estimation of endoscopic resources needed for colorectal cancer screening.

Colorectal cancer risk in adenoma patients: a nation-wide study

Colorectal cancer incidence after adenoma removal has been studied in selected populations of adenoma patients. Our study estimates the trend in colorectal cancer incidence after adenoma removal in actual clinical practice. From PALGA, a nationwide network and registry of histo- and cytopathology in the Netherlands, we extracted data of all patients diagnosed with colorectal adenomas between 1 January 1988 and 1 October 1998. The data were used to calculate population-based colorectal cancer incidence rates after adenoma removal. A total of 78,473 adenoma patients were followed for a mean of 4.5 years after the first adenoma removal. The colorectal cancer incidence ratio compared with the general population matched by age and gender was 38.4 (37.3-39.5) in the first year after adenoma removal and 1.5 (95% confidence interval (CI): 1.4-1.6) after Year 1. The incidence ratio decreased from 2.8 (2.5-3.1) in Year 2 to 0.9 (0.6-1.2) in Years 9-11. This time trend is the opposite of the upward time trend that was expected after adenoma removal. Adenoma patients in the Netherlands are at increased risk for colorectal cancer compared to the general population. The high cancer incidence in Years 1-5 after polypectomy can be explained by a colonoscopic sensitivity for cancer of approximately 90%.

Screening, prevention and socioeconomic costs associated with the treatment of colorectal cancer

Colorectal cancer (CRC), the third most prevalent cancer worldwide, imposes a significant economic and humanistic burden on patients and society. One study conservatively estimated the annual expenditures for colorectal cancer to be approximately dollars US 5.3 billion in 2000, including both direct and indirect costs. However, other investigators estimated inpatient costs alone incurred in the US in 1994 to be around dollars US 5.14 billion. Therefore, the economic burden of colorectal cancer in the US could be projected to be somewhere in the range of dollars US 5.5-6.5 billion by considering that inpatient costs approximate 80% of total direct costs. No worldwide data have been published, but assuming that the US represents 25-40% of total expenditures in oncology, as seen for breast and lung cancers, a rough estimate for colorectal cancer would be in the range of dollars US 14-22 billion. Screening helps increase patient survival by diagnosing colorectal cancer early. The ideal method among the four tests most used (faecal occult blood test, flexible sigmoidoscopy, colonoscopy and double contrast barium enema) has not been identified. Economic studies of colorectal cancer screening are complex because of the many variables involved, as well as the fact that the outcomes must be followed for many years, and the lack of consensus on screening guidelines. Intuitively, modelling colorectal cancer is one way to overcome these hurdles; published modelling studies predict colorectal cancer screening programs to be within the threshold of dollars US 40000 per life-year saved. The faecal occult blood test appears to be the only clearly effective test, both from a clinical and an economic viewpoint. Important limitations are the invasiveness and inconvenience of the screening procedures, except faecal occult blood test. Patients' comfort and satisfaction are essential in improving compliance with screening recommendations, which appears to be low even in the US (35% of the general population aged over 40 years and 60% of the high-risk population), the country with the highest awareness and compliance in the world. Since colorectal cancer is generally a disease of the elderly, its economic burden is expected to grow in the near future, mainly due to population aging. Potential avenues to pursue in order to contain or reduce the economic burden of colorectal cancer would be the design and implementation of efficient screening programmes, the improvement of patient awareness and compliance with screening guidelines, the development of appropriate prevention programs (i.e. primary and secondary), and earlier diagnosis.

Computed tomography colonography (virtual colonoscopy): review

Computed tomography examination of the colon performed after bowel cleansing and distension of the lumen with gas goes by several different names--CT colonography (CTC) and CT colography perhaps being the most common. Strictly, the term 'virtual colonoscopy' (VC), should be reserved for the process of examining 3-D, simulated endoluminal images with a capability to navigate through the bowel using appropriate software. Computed tomography colonography appears to be the name that has gained favour among radiologists, although it is suspected that 'virtual colonoscopy' will persist as a generic term due to its attractive 'high-tech' connotations for non-radiological medical and lay persons. Whatever the name, the technique has been made possible through the advent of fast helical CT scanners which allow acquisition of a volume of data, and of proprietary software which enables multiplanar reformatting and 3-D endoluminal reconstructions. It is evident that if CTC/VC can be shown to be acceptable to patients, safe, affordable and accurate, it has enormous potential as a diagnostic and screening tool for colorectal neoplasia.

Computed tomography colonography

Computed tomography colonography (virtual colonoscopy) is an exciting technique that continues to evolve but promises to be a valuable tool for diagnosis of and screening for colorectal neoplasia.

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.

Surveillance colonoscopy or chemoprevention with COX-2 inhibitors in average-risk post-polypectomy patients: a decision analysis

OBJECTIVES

Clinical trials are currently underway evaluating the efficacy of COX-2 inhibitors in decreasing the incidence of adenomas and colorectal carcinoma in 'average' risk individuals.

AIM

To use decision analysis to compare the cost-effectiveness of celecoxib to surveillance colonoscopy in 'average' risk patients who had undergone prior adenoma resection.

METHODS

A model of the natural history of adenomas after endoscopic polypectomy was constructed using probabilities from the literature. Cost estimates were obtained from available Medicare reimbursement rates and supplemented by the literature. Three strategies were evaluated: (i) no surveillance; (ii) colonoscopic surveillance; and (iii) celecoxib chemoprevention. We compared total costs and performed cost-effectiveness analysis between these strategies. The outcome measures were years of life saved and 'high-grade' adenoma prevented. Sensitivity analyses were performed on selected variables.

RESULTS

Our base-case analysis assumed a 50% risk reduction in the incidence of adenomas among patients using celecoxib. No surveillance was associated with a cost of $1014 per patient, and colonoscopic surveillance with a cost of $1572 per patient, whereas celecoxib use was associated with a total cost of $11,503. Ten years after the index colonoscopy, 15% of patients in the no surveillance strategy developed 'high-grade' lesions compared to 13% of patients in the colonoscopic surveillance group and 6% in the celecoxib group. There was a small gain in years of life saved (0.006) favouring celecoxib over colonoscopic surveillance. The incremental cost-effectiveness ratio of celecoxib vs. colonoscopy was $141 871 per 'high-grade' adenoma prevented and $1,715,199 per year of life saved. The most important variables in determining the cost-effectiveness of celecoxib were its cost and its efficacy.

CONCLUSION

Chemoprevention with COX-2 inhibitors in 'average-risk' postpolypectomy patients is a more expensive strategy compared to colonoscopic surveillance.

Medical-legal risks of incident cancers after clearing colonoscopy

Colonoscopy and polypectomy effectively reduce the incidence and mortality of colorectal cancer, but some patients present with fully developed cancers within 1-4 yr of a colonoscopy that apparently cleared the colon of neoplasia. These events may result in medical-legal action against colonoscopists, generally based on an assumption of negligent technical performance of the procedure. Alternative explanations for the development of interval cancers include variable growth rates of colorectal cancers, the inherent miss rate of the procedure even when optimal examination techniques are used, and the possibility of flat lesions that are not readily detected by standard colonoscopic techniques. This paper discusses issues relevant to reduction of medical-legal risks associated with interval cancers after clearing colonoscopy. These issues include informed consent, documentation of cecal intubation, appropriate description of preparation, documentation of examination time and technique, and attention to potential atypical neoplasms.

Colonic screening and surveillance

Screening for colorectal cancer has not obtained worldwide acceptance in spite of its proven survival benefit for average-risk persons and some high-risk groups. The incidence of and mortality from colorectal cancer are worrying in Europe as well as in the USA, Australia and Japan. The best evidence-based studies are those published on screening using faecal occult blood tests, endoscopic methods and different tumour markers having been evaluated to a lesser degree. Feasibility studies are necessary before massive screening can be undertaken because the results obtained from randomized studies may not be reproduced to a satisfactory degree in average- as well as high-risk populations. Primary prevention by dietary intervention and drugs has been studied in great detail, so far without any major breakthrough. This chapter will address different screening methods in populations with a varying risk of colorectal cancer, together with providing a short review of prevention and intervention strategies.

Significance of a normal surveillance colonoscopy in patients with a history of adenomatous polyps

PURPOSE

The aim of this study was to determine the appropriate surveillance for patients with a history of adenomatous polyps whose last colonoscopic examination was normal.

METHODS

This was a retrospective review of a database of 7,677 colonoscopies (1990 to 1996). In patients under colonoscopic surveillance, we reviewed cases of patients who had received three colonoscopies (an index (initial) colonoscopy positive for adenomas and 2 follow-up colonoscopies (interim and final)). The risk of adenomas and cancers at final follow-up colonoscopy was compared between patients having a normal interim colonoscopy and those with a positive interim colonoscopy. The risk at final colonoscopy was also stratified by time interval and the size and number of adenomas at the initial index colonoscopy.

RESULTS

Two hundred four patients undergoing surveillance for adenomas met inclusion criteria. At index colonoscopy the median polyp size was 1 cm and median frequency was three polyps. At all follow-up colonoscopies, we detected 493 adenomas and one cancer (median follow-up, 55 months). At 36 months patients with a normal interim colonoscopy (n = 91) had significantly fewer polyps than patients with a positive interim colonoscopy (n = 113; 15 vs. 40 percent; P = 0.0001). By 40 months, adenomas were detected in more than 40 percent of patients in both groups. The risk after a normal interim colonoscopy was not affected by time interval or number or size of polyps. Adenomas found subsequent to a normal interim colonoscopy were dispersed throughout the colon in 28 patients and isolated to the rectosigmoid in 6 patients.

CONCLUSIONS

In patients with a history of adenomas, a normal follow-up colonoscopy is associated with a statistically but not clinically significant reduction in the risk of subsequent colonic neoplasms. These patients require follow-up surveillance colonoscopy at a four-year to five-year interval.

The natural history of isolated rectosigmoid adenomatous polyps: is flexible sigmoidoscopy a safe alternative for surveillance?

PURPOSE

Colonoscopic surveillance is recommended for patients with adenomatous polyps. Significant cost savings would result from identification of subgroups of patients in whom less costly surveillance would suffice. This study was performed to determine the natural history of patients undergoing removal of isolated rectosigmoid adenomas and to establish whether flexible sigmoidoscopy might be adequate for follow-up.

METHODS

A retrospective review of a database of 7,677 colonoscopies, from 1990 to 1996, identified patients who had a minimal follow-up of two years after removal of adenomatous polyps isolated to the rectosigmoid. Polyps detected on surveillance colonoscopy were categorized as distal (< or =60 cm from anal verge), proximal (>60 cm from anal verge), and diffuse (proximal plus distal). The risk of polyp formation was determined by actuarial analysis using the Kaplan-Meier method.

RESULTS

Sixty-two patients undergoing surveillance for adenomas met inclusion criteria. At the index colonoscopy, 124 isolated rectosigmoid polyps were identified. The median polyp size was 1 cm and median frequency was one polyp. The median follow-up time for the entire cohort (N = 62) was 53 months. At follow-up surveillance colonoscopy, 105 additional adenomas were discovered and removed in 40 patients. No malignant polyps were detected. The pattern of polyps detected were proximal (n = 19), rectosigmoid (n = 16), and diffuse (n = 5).

CONCLUSIONS

The majority (65 percent) of patients with isolated rectosigmoid polyps have additional polyps on long-term surveillance, and 60 percent of patients will have these polyps located proximal to the reach of a sigmoidoscope. Therefore, flexible sigmoidoscopy is not a safe alternative for surveillance of patients with isolated rectosigmoid polyps.

Frequency of advanced neoplasia in the proximal colon without an index polyp in the rectosigmoid

PURPOSE

Screening endoscopy has the potential to reduce colorectal cancer mortality. However, the efficacy of screening flexible sigmoidoscopy compared with colonoscopy strongly depends on the frequency of advanced proximal neoplasms without an index polyp in the rectosigmoid. We have therefore determined this frequency in our endoscopy population.

METHODS

Endoscopic and histologic data were analyzed from all patients on whom integral colonoscopy was performed between 1980 and 1995. Advanced neoplasia was defined as cancer or adenomas >10 mm in diameter, adenomas with a villous component, or severe dysplasia. Patients with polyposis syndrome or inflammatory bowel disease were excluded.

RESULTS

Colonoscopy was performed on 11,760 patients. 2,272 (19.3 percent) had at least one colorectal neoplasm, of which 39 percent had the neoplasm above the rectosigmoid. Twenty-two percent of all patients with neoplasia had no index polyp in the rectosigmoid and 16 percent of these had no index polyp, but at least one advanced proximal neoplasm.

CONCLUSIONS

Although 39 percent of patients had neoplasms above the rectosigmoid, only 16 percent had an advanced proximal neoplasm without an index polyp in the rectosigmoid. This gives a figure on which to base the evaluation of screening sigmoidoscopy programs against those of screening colonoscopy.

The psychologic effect of attending a screening program for colorectal polyps

BACKGROUND

Participation in screening programs for malignant disease may have negative psychologic health effects that could outweigh the beneficial effects of the screening itself. The present study was designed to investigate the psychologic effect of attending a screening program for detection and removal of colorectal adenomas, which are precursors to colorectal cancer.

METHOD

In 1983 a prospective. controlled screening study using flexible sigmoidoscopy to detect adenomas was started in Telemark County, Norway. Four hundred individuals were enrolled as a screening group and 399 as a control group. In 1996 survivors in both groups were invited to have a colonoscopic screening examination for detection and removal of polyps. Four hundred and fifty-one individuals (71%) attended; their mean age was 67.2 years (range, 63-72 years), and 48% were women. Fourteen days and 3 and 17 months after the examination the attendees received by mail a questionnaire composed of Goldberg's General Health Questionnaire (GHQ-28) and the Hospital Anxiety and Depression Scale (HADS). The questionnaire was also mailed to an age- and sex-matched group not enrolled in the endoscopic screening study. Four hundred and nine (95%), 395 (92%), and 389 (91%), respectively, returned the questionnaire. Of the controls 314 (70%) returned filled-in questionnaires.

RESULTS

The scores for both GHQ-28 and HADS were lower, indicating a lower level of psychiatric morbidity among those attending the examination in 1996 than among the controls. There was a trend towards higher scores with increasing time after the examination in the screened group.

CONCLUSION

During the first 17 months after screening the attendees, as a group, did not appear to have developed untoward psychologic effects as judged by HADS and GHQ questionnaires.