Colorectal cancer screening comes of age

Aetiology and prevalence of post-colonoscopy colorrectal cancer

BACKGROUND

Colonoscopy is the gold standard for the detection and prevention of colorectal cancer (CRC). However, some individuals are diagnosed with CRC soon after a previous colonoscopy.

AIMS

To evaluate the rate of new onset or missed CRC after a previous colonoscopy and to study potential risk factors.

METHODS

Patients in our endoscopy database diagnosed with CRC from March 2004 to September 2011 were identified, selecting those with a colonoscopy performed within the previous 5years. Medical records included age, gender, comorbidities and colonoscopy indication. Tumour characteristics studied were localization, size, histological grade and TNM stage and possible cause. These patients were compared with those diagnosed with CRC at their first endoscopy (sporadic CRC-control group).

RESULTS

A total of 712 patients with CRC were included; 24 patients (3.6%) had undergone colonoscopy within the previous 5 years (50% male, 50% female, mean age 72). Post-colonoscopy CRCs were attributed to: 1 (4.2%) incomplete colonoscopy, 4 (16.6%) incomplete polyp removal, 1 (4.2%) failed biopsy, 8 (33.3%) 'missed lesions' and 10 (41.7%) new onset CRC. Post-colonoscopy CRCs were smaller in size than sporadic CRCs (3.2cm vs. 4.5cm, P<.001) and were mainly located in the proximal colon (63% vs. 35%, P=.006); no difference in histological grade was found (P=.125), although there was a tendency towards a lower TNM stage (P=.053).

CONCLUSIONS

There is a minor risk of CRC development after a previous colonoscopy (3.6%). Most of these (58.4%) are due to preventable factors. Post-colonoscopy CRCs were smaller and mainly right-sided, with a tendency towards an earlier TNM stage.

Choosing the optimal method in programmatic colorectal cancer screening: current evidence and controversies

Colorectal cancer (CRC) is an important health problem all over the world, being the third most common cancer and the second leading cause of cancer-related death in Western countries. The most important strategy for CRC prevention is screening (i.e. secondary prevention). Since it is widely accepted that adenomas and serrated polyps are the precursors of the vast majority of CRC, early detection and removal of these lesions is associated with a reduction of CRC incidence and, consequently, mortality. Moreover, cancers detected by screening are usually diagnosed at early stages and, therefore, curable by endoscopic or surgical procedures. This review will be address CRC screening strategies in average-risk population, which is defined by those individuals, men and women, 50 years of age or older, without any additional personal or familial predisposing risk factor. In order to maximize the impact of screening and ensure high coverage and equity of access, only organized screening programs (i.e. programmatic screening) should be implemented, as opposed to case-finding or opportunistic screening. For that reason and considering that the optimal approach for colorectal screening may differ depending on the scenario, this review will be focused on the advantages and limitations of each screening strategy in an organized setting.

Mandated coverage of preventive care and reduction in disparities: evidence from colorectal cancer screening

OBJECTIVES

We identified correlates of racial/ethnic disparities in colorectal cancer screening and changes in disparities under state-mandated insurance coverage.

METHODS

Using Behavioral Risk Factor Surveillance System data, we estimated a Fairlie decomposition in the insured population aged 50 to 64 years and a regression-adjusted difference-in-difference-in-difference model of changes in screening attributable to mandates.

RESULTS

Under mandated coverage, blood stool test (BST) rates increased among Black, Asian, and Native American men, but rates among Whites also increased, so disparities did not change. Endoscopic screening rates increased by 10 percentage points for Hispanic men and 3 percentage points for non-Hispanic men. BST rates fell among Hispanic relative to non-Hispanic men. We found no changes for women. However, endoscopic screening rates improved among lower income individuals across all races and ethnicities.

CONCLUSIONS

Mandates were associated with a reduction in endoscopic screening disparities only for Hispanic men but may indirectly reduce racial/ethnic disparities by increasing rates among lower income individuals. Findings imply that systematic differences in insurance coverage, or health plan fragmentation, likely existed without mandates. These findings underscore the need to research disparities within insured populations.

Does hyoscine butylbromide really improve polyp detection during colonoscopy? A meta-analysis of randomized controlled trials

AIM: To investigate the benefits of hyoscine butylbromide in polyp detection during colonoscopy by a meta-analysis of available randomized controlled trials (RCTs).

METHODS: Databases, including PubMed, EMBASE, the Cochrane Library, and the Science Citation Index up to September 2013, were searched. The primary outcome was polyp detection rate, and the secondary outcome was adenoma detection rate. The meta-analysis was performed using the free software Review Manager. Differences observed between the treated and the control groups were expressed as odds ratio (OR) with a 95% confidence interval (CI). A fixed-effects model was used to pool data when statistical heterogeneity was absent. If statistical heterogeneity was present (P < 0.05), a random-effects model was used.

RESULTS: The initial search identified nine articles. After screening, five RCTs with a total of 1998 patients were included in this meta-analysis. Of the five studies, all described a comparison of baseline patient characteristics and showed that there was no statistically significant difference between the two groups. Among the 1998 patients, 1006 received hyoscine butylbromide and 992 were allocated to the control group, and the polyp detection rate was reported. There were no significant differences between the treated and the control group (OR = 1.09, 95%CI: 0.91-1.31, P = 0.33). Four RCTs included 1882 patients, of whom 948 received hyoscine butylbromide, and the adenoma detection rate was reported. There were no significant differences between the treated and the control group (OR = 1.13, 95%CI: 0.92-1.38, P = 0.24).

CONCLUSION: The use of hyoscine butylbromide did not significantly improve the polyp detection rate during colonoscopy.

Increased screening colonoscopy rates and reduced racial disparities in the New York Citywide campaign: an urban model

OBJECTIVES

In 2003, in response to low colonoscopy screening rates and significant sociodemographic disparities in colonoscopy screening in New York City (NYC), the NYC Department of Health and Mental Hygiene, together with the Citywide Colon Cancer Control Coalition, launched a multifaceted campaign to increase screening. We evaluated colonoscopy trends among adult New Yorkers aged 50 years and older between 2003 and 2007, the first five years of this campaign.

METHODS

Data were analyzed from the NYC Community Health Survey, an annual, population-based surveillance of New Yorkers. Annual prevalence estimates of adults who reported a timely colonoscopy, one within the past 10 years, were calculated. Multivariate models were used to analyze changes over time in associations between colonoscopy screening and sociodemographic characteristics.

RESULTS

Overall, from 2003 to 2007 the proportion of New Yorkers aged 50 years and older who reported timely colonoscopy screening increased from 41.7% to 61.7%. Racial/ethnic and sex disparities observed in 2003 were eliminated by 2007: prevalence of timely colonoscopy was similar among non-Hispanic whites, non-Hispanic blacks, Hispanics, men, and women. However, Asians, the uninsured, and those with lower education and income continued to lag in receipt of timely colonoscopies.

CONCLUSIONS

The increased screening colonoscopy rate and reduction of racial/ethnic disparities observed in NYC suggest that multifaceted, coordinated urban campaigns can improve low utilization of clinical preventive health services and reduce public-health disparities.

Screening for colorectal cancer

Although there are several methods available for colon cancer screening, none is optimal. This article reviews methods for screening, including fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, CT colonography, capsule endoscopy, and double contrast barium enema. A simple, inexpensive, noninvasive, and relatively sensitive screening test is needed to identify people at risk for developing advanced adenomas or colorectal cancer who would benefit from colonoscopy. It is hoped that new markers will be identified that perform better. Until then we fortunately have a variety of screening strategies that do work.

Primary care provider perceptions of barriers to and facilitators of colorectal cancer screening in a managed care setting

BACKGROUND

Colorectal cancer (CRC) screening tests (e.g., fecal occult blood testing [FOBT], flexible sigmoidoscopy [FS], etc.) are underused. Primary care providers (PCPs) play a critical role in screening, but barriers to and facilitators of screening as perceived by PCPs in managed care settings are poorly understood. The objectives of the current study were to describe current CRC screening practices and to explore determinants of test use by PCPs in a managed care setting.

METHODS

In 2000, a self-administered survey was mailed to a stratified, random sample of 1340 PCPs in a large, network model health maintenance organization in California.

RESULTS

The survey response rate was 67%. PCPs indicated that 79% of their standard-risk patients were screened for CRC. PCP-reported median rates of recommendation for the use of specific screening tests were 90% for FOBT and 70% for FS. In logistic regression models, perceived barriers to the use of FOBT and FS included patient characteristics (e.g., education) and PCP-related barriers (e.g., failure to recall that patients were due for testing). Perceived facilitators of the use of FOBT and FS included interventions targeting certain aspects of the health care system (e.g., reimbursement) and interventions targeting certain aspects of the tests themselves (e.g., provision of evidence of a test's effectiveness). Assignment of high priority to screening, integrated medical group (as opposed to independent practice association) affiliation, and the proportion of patients receiving routine health maintenance examinations were positively associated with reported test use.

CONCLUSIONS

CRC screening tests appear to be underused in the managed care setting examined in the current study. The perceived barriers and facilitators that were identified can be used to guide interventions aimed at increasing recommendations for, as well as actual performance of, CRC screening.

Training general practitioners in flexible sigmoidoscopy to screen for colorectal cancer

BACKGROUND

A screening programme to detect polyps or early carcinoma would significantly reduce the mortality and morbidity of colorectal cancer (CRC). The aims of the present study were to evaluate: (i) the feasibility of training general practitioners in flexible sigmoidoscopy (FS) for CRC screening; (ii) the acceptability of screening by faecal occult blood testing (FOBT) and FS in asymptomatic standard risk Australians aged over 50 years; and (iii) the yield of such screening.

METHODS

Subjects were recruited by general practitioner (GP) referral, newspaper advertisement or by a direct approach to retirement villages. Participants were mailed a FOBT kit and a prescreening questionnaire. Flexible sigmoidoscopy was performed by a GP supervised by an experienced endoscopist. Subjects then completed a second questionnaire. General practitioners were assessed after 50 unassisted procedures.

RESULTS

A total of 264 individuals contacted the study coordinator; 169 were screened. Screening was accepted well by the participants. Fifteen per cent of subjects had polyps and 4% had a positive FOBT. Training in FS was adversely affected by the availability of resources. Three GPs completed 50 unassisted procedures over a 15-month period, but none were able to reliably assess the distal bowel.

CONCLUSIONS

Although the three trainees and their supervisors did not consider that the GPs were adequately trained after 50 unassisted procedures, training was adversely affected by limited resources within the Victorian public hospital system. Screening by FOBT and FS was considered to be acceptable by the patients undergoing these procedures. Existing facilities are not adequate if GPs are to be trained in FS as part of a national CRC screening program.

Indications for performing transanal endoscopic microsurgery (TEM) in rectal cancer patients

OBJECTIVE

The aim of this study was to clarify the application of a local excision using TEM for rectal cancer.

PATIENTS AND METHODS

Fifteen patients were preoperatively diagnosed to have cancer invasion in the submucosa (T1) and thus were treated by TEM, while 13 others were preoperatively diagnosed to have cancer invasion reaching the muscularis propria (T2) and thus were treated by a radical operation. Surgical specimens from all 28 patients were pathologically examined and compared with the preoperative evaluation.

RESULTS

The mean operating time for TEM was 53 min. The accuracy of the preoperative evaluation for the depth of cancer invasion was 68% (19/28). In the 15 patients with preoperative evaluation of T1 cancer, two pathologically showed cancer invasion into muscularis propria. In the 13 patients with a preoperative evaluation of T2 cancer, three pathologically showed cancer invasion within the submucosa.

CONCLUSION

Since some patients with a preoperative evaluation of T2 rectal cancer showed the possibility of a complete cure with a local excision, preoperative T2 stage rectal cancer is considered to be a good candidate for a local excision using TEM.

Fecal occult blood testing for colorectal cancer. Can we afford not to do this?

Current practice guidelines recommend annual fecal occult blood test screening for colorectal cancer in the average-risk population over the age of 50. Efficacy of fecal occult blood test screening is supported by several controlled prospective trials and case-control studies. Implementation of this recommendation, in combination with periodic flexible sigmoidoscopy every 5 years, is feasible, affordable, highly effective, and has the potential for reducing colorectal cancer mortality by at least 50%. With over 50,000 Americans dying of this malignancy each year, we cannot afford not to do this.

Screening for colorectal cancer by immunochemical fecal occult blood testing

Screening for colorectal cancer using the conventional Hemoccult test has been shown to reduce mortality associated with cancer by 33% through a randomized controlled trial. However, the magnitude of effectiveness is small in terms of cost-effectiveness. The recently developed immunochemical fecal occult blood test (IFOBT) provides a potential replacement for the Hemoccult test as a screening test, due to its superior performance characteristics such as higher sensitivity shown in preliminary studies and the fact that it does not require any dietary restriction. The IFOBT method is reviewed, especially in relation to its specificity. In known colorectal cancer subjects, IFOBTs have shown both higher sensitivity and specificity than the Hemoccult test. Similarly, IFOBT has demonstrated a higher sensitivity than Hemoccult for colorectal cancer in an asymptomatic population. A nationwide screening program in Japan has demonstrated the feasibility of this approach for large population screening. However, the positivity rate varied according to the conditions at each screening facility. Therefore, technical factors that influence the positivity rate of IFOBTs in the screening program are discussed. Case-control studies have strongly suggested that screening using IFOBT would reduce mortality from colorectal cancer by 60% or more. Several observational studies have provided support for this estimate. The feasibility and effectiveness of population-based screening by IFOBT are discussed.

Colorectal cancer: future population screening for early colorectal cancer

Colorectal cancer (CRC) is one of the most frequent cancers in Western countries. The identification of individuals at risk and the early diagnosis of CRC are of critical importance since a large proportion can be prevented or cured by surgical removal before metastasis has occurred. With increasing understanding of the genetic basis of hereditary and sporadic (non-hereditary) CRC, it becomes feasible to detect genetic alterations by molecular techniques. Familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC), as well as early stages of spontaneous CRC, can be diagnosed by molecular characterisation of the adenomatous polyposis coli (APC) gene, the RAS oncogene and other genes in DNA from peripheral blood, stool or intestinal biopsies. With a better understanding of the genetic events leading to malignant transformation, molecular population screening should allow us to identify individuals at risk as well as patients with an early and potentially curable CRC. At present, careful patient and family history, physical examination and testing for occult blood as well as colonoscopy are still the key elements for clinical patient management. Molecular diagnosis will hopefully soon complement these analyses and should result in a reduction of morbidity and mortality from CRC.

Reduction in risk of mortality from colorectal cancer by fecal occult blood screening with immunochemical hemagglutination test. A case-control study

Fecal occult blood testing by immunochemical hemagglutination has been shown to be superior to the Hemoccult test, both in sensitivity and in specificity. The test has been widely used as a tool for population screening in Japan, but there has been no study to evaluate the efficacy of screening using this test. A case-control study to evaluate the screening was conducted in study areas where no previous and no other concomitant colorectal cancer screening had been performed. Case series in the study were 193 cases who died of colorectal cancer. Three controls were selected randomly from the list of individuals who were alive at the time of diagnosis of the corresponding case and had been living in the same area as the case, matched by gender and by age. Odds ratios (OR) of dying of colorectal cancer for those screened within 1, 2 and 3 years of case diagnosis vs. those not screened were 0.40 [95% confidence interval (CI) 0.17-0.92], 0.41 (95% CI 0.20-0.82), and 0.48 (95% CI 0.25-0.92), respectively. OR increased towards 1.0 as the duration during which screening histories were compared was extended, and showed similar tendencies when analyzed by number of years since the most recent screening history. These results suggest that colorectal cancer screening by the immunochemical fecal occult blood test would reduce mortality from colorectal cancer.

Laboratory study on occult gastrointestinal bleedings: differential diagnostic method for the parallel study of intact and fragmented hemoglobin

The authors produced various degradation products of human hemoglobin. With the aid of immune sera raised against native hemoglobin and their fragments, we examined the antigenicity of the intact molecule and fragments as well as the specificity and reactivity of the immune sera used. Since conventional guaiac-type reactions make no distinction between the different hemoglobin molecules and the methods described in recent years' publications only with immune sera raised against native intact hemoglobin, the demonstration of occult fecal blood has not reached the desired rate of efficacy in clinical practice. The authors recommend the introduction of a simple differential diagnostic methods suitable for the parallel examination of intact and fragmented hemoglobin.

Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup

BACKGROUND

The current practice of removing adenomatous polyps of the colon and rectum is based on the belief that this will prevent colorectal cancer. To address the hypothesis that colonoscopic polypectomy reduces the incidence of colorectal cancer, we analyzed the results of the National Polyp Study with reference to other published results.

METHODS

The study cohort consisted of 1418 patients who had a complete colonoscopy during which one or more adenomas of the colon or rectum were removed. The patients subsequently underwent periodic colonoscopy during an average follow-up of 5.9 years, and the incidence of colorectal cancer was ascertained. The incidence rate of colorectal cancer was compared with that in three reference groups, including two cohorts in which colonic polyps were not removed and one general-population registry, after adjustment for sex, age, and polyp size.

RESULTS

Ninety-seven percent of the patients were followed clinically for a total of 8401 person-years, and 80 percent returned for one or more of their scheduled colonoscopies. Five asymptomatic early-stage colorectal cancers (malignant polyps) were detected by colonoscopy (three at three years, one at six years, and one at seven years). No symptomatic cancers were detected. The numbers of colorectal cancers expected on the basis of the rates in the three reference groups were 48.3, 43.4, and 20.7, for reductions in the incidence of colorectal cancer of 90, 88, and 76 percent, respectively (P < 0.001).

CONCLUSIONS

Colonoscopic polypectomy resulted in a lower-than-expected incidence of colorectal cancer. These results support the view that colorectal adenomas progress to adenocarcinomas, as well as the current practice of searching for and removing adenomatous polyps to prevent colorectal cancer.