Clinical practice. Screening for colorectal cancer

Polymorphic variation in the GC and CASR genes and associations with vitamin D metabolite concentration and metachronous colorectal neoplasia

BACKGROUND

Vitamin D levels and calcium intake have been associated with risk of colorectal neoplasia, and genetic variation in vitamin D pathway genes may affect circulating vitamin D metabolite concentrations and/or risk for colorectal lesions. This study evaluated associations between polymorphic variation in the Gc-globulin (GC) and calcium-sensing receptor (CASR) and odds for metachronous colorectal neoplasia and vitamin D metabolite concentrations.

METHODS

Participants from the Ursodeoxycholic Acid (UDCA) and Wheat Bran Fiber (WBF) trials (n = 1,439) were analyzed using a single-nucleotide polymorphism (SNP) tagging approach, with a subset (n = 404) of UDCA trial participants for whom vitamin D metabolite concentrations were also available. A total of 25 GC and 35 CASR tagSNPs were evaluated using multiple statistical methods.

RESULTS

Principal components analyses did not reveal gene-level associations between GC or CASR and colorectal neoplasia; however, a significant gene-level association between GC and 25(OH)D concentrations (P < 0.01) was observed. At the individual SNP level and following multiple comparisons adjustments, significant associations were observed between seven GC (rs7041, rs222035, rs842999, rs1155563, rs12512631, rs16846876, and rs1746825) polymorphisms and circulating measures of 25(OH)D (adjusted P < 0.01) and CASR SNP rs1042636 and proximal colorectal neoplasia (adjusted P = 0.01).

CONCLUSIONS

These results show a possible association between variation in CASR and odds of colorectal neoplasia as well as the potential role of variation in GC with circulating 25(OH)D concentrations.

IMPACT

Additional research is warranted to determine the mechanism of GC genotype in influencing 25(OH)D concentrations and to further elucidate the role of CASR in colorectal neoplasia.

Self-stabilizing colonic capsule endoscopy: pilot study of acute canine models

Video capsule endoscopy (VCE) is a noninvasive method for examining the gastrointestinal tract which has been successful in small intestine studies. Recently, VCE has been attempted in the colon. However, the capsule often tumbles in the wider colonic lumen, resulting in missed regions. Self-stabilizing VCE is a novel method to visualize the colon without tumbling. The aim of the present study was to comparatively quantify the effect of stabilization of a commercially available nonmodified capsule endoscope (CE) MiroCam and its modified self-stabilizing version in acute canine experiments. Two customized MiroCam CEs were reduced in volume at the nonimaging back-end to allow the attachment of a self-expanding, biocompatible stabilizing device. Four mongrel dogs underwent laparotomy and exteriorization of a 15-cm segment of the proximal descending colon. A single CE, either self-stabilizing or nonmodified was inserted through an incision into the lumen of the colon followed by pharmacologically induced colonic peristalsis. The inserted capsule was propelled distally through the colon and expelled naturally through the anus. Novel signal processing method was developed to quantify the video stabilization based on camera tracking a predetermined target point (locale). The average locale trajectory, the average radius movement of the locale, and the maximum rate of change of the locale for sequential images were significantly lower for the stabilized capsules compared to the nonstabilized ones . The feasibility of self-stabilized capsule endoscopy has been demonstrated in acute canine experiments.

Screening for colorectal cancer

March is national colorectal cancer awareness month. It is estimated that as many as 60% of colorectal cancer deaths could be prevented if all men and women aged 50 years or older were screened routinely. In 2000, Katie Couric's televised colonoscopy led to a 20% increase in screening colonoscopies across America, a stunning rise called the "Katie Couric Effect". This event demonstrated how celebrity endorsement affects health behavior. Currently, discussion is ongoing about the optimal strategy for CRC screening, particularly the costs of screening colonoscopy. The current CRC screening guidelines are summarized in Table 2. Debates over the optimum CRC screening test continue in the face of evidence that 22 million Americans aged 50 to 75 years are not screened for CRC by any modality and 25,000 of those lives may have been saved if they had been screened for CRC. It is clear that improving screening rates and reducing disparities in underscreened communities and population subgroups could further reduce colorectal cancer morbidity and mortality. National Institutes of Health consensus identified the following priority areas to enhance the use and quality of colorectal cancer screening: Eliminate financial barriers to colorectal cancer screening and appropriate follow-up of positive results of colorectal cancer screening. Develop systems to ensure the high quality of colorectal cancer screening programs. Conduct studies to determine the comparative effectiveness of the various colorectal cancer screening methods in usual practice settings. Encouraging population adherence to screening tests and allowing patients to select the tests they prefer may do more good (as long as they choose something) than whatever procedure is chosen by the medical profession as the preferred test.

Predictors of delayed-stage colorectal cancer: are we neglecting critical demographic information?

PURPOSE

We sought to distinguish roles of demographic variables and bowel segments as predictors of delayed versus early stage colorectal cancer in California.

METHODS

Demographic and anatomic variables for 66,806 colorectal cancers were extracted from the California Cancer Registry for 2004-2008 and analyzed using logistic regression as delayed versus early stage.

RESULTS

Odds ratios (OR) for binary stage categories comparing age <40 (OR=2.58; 95% CI=2.26-2.94), 40-49 (1.71; 95%=1.60-1.83) and 75+ (1.05; 1.02-1.09) relative to 50-74 years were computed. Compared with non-Hispanic whites, ORs for stage categories were: 1.05; 0.99-1.13 (non-Hispanic blacks), 1.08; 1.02-1.13 (Hispanics), and 1.05; 1.00-1.10 (Asian/others). Females had higher odds of delayed diagnosis (1.09; 1.06-1.13) than males. Descending ORs were measured for successively lower to highest socioeconomic status (SES) quintiles (OR 4:5=1.08; 1.03-1.14, OR 3:5=1.13; 1.08-1.19, OR 2:5=1.18; 1.12- 1.24, and OR 1:5=1.21; 1.14-1.28).

CONCLUSIONS

Younger and older than age 50-74; females; Hispanic ethnicity; bowel segment contrasts (right/left, proximal/distal, cecum plus appendix/distal), and lower SES were independent predictors of delayed diagnosis. Low SES was the most robust predictor of delayed diagnosis, independent of other covariates. Approximately 77% of delayed diagnoses were in non-Hispanic whites and Asian/others. These findings illustrate the value of a community SES index for targeting egalitarian colorectal cancer screening.

Socio-geographical determinants of colonoscopy uptake after faecal occult blood test

BACKGROUND

Survival from colorectal cancer is poorer in patients of lower socioeconomic level, or living far from the cancer reference centre.

AIMS

To evaluate the impact of material deprivation and geographical remoteness on the uptake of colonoscopy after a positive screening faecal occult blood test.

METHODS

Data from two large French average-risk population-based trials comparing two faecal occult blood tests were used. Compliance with colonoscopy after a positive faecal occult blood test was analysed using a logistic model and a Cox model considering time between faecal occult blood test and colonoscopy. Covariates studied were sex, age, distance to nearest gastroenterologist, distance to regional capital, and Townsend's deprivation score.

RESULTS

Amongst 4320 eligible subjects, 4131 were included. The rate of colonoscopy was 83.8%, within a median time of 66.0 days after faecal occult blood test. Distance to regional capital (p-trend=0.02) and study centre (p<0.0001) were independently associated with colonoscopy uptake. Time from positive faecal occult blood test to colonoscopy, was associated only with distance to the regional capital (p<0.0001, multivariate model stratified on study centre).

CONCLUSION

Geographical remoteness but not material deprivation was responsible for lower uptake of colonoscopy. Healthcare decision-makers should focus on geographical remoteness to promote equal access to diagnostic procedures in faecal occult blood test colorectal cancer screening programmes.

Proceedings of a preliminary workshop at Gastro 2009--narrow banding imaging in digestive endoscopy: clinical outcome of classification (Omed-Jges Educational Meeting held on 22 November, 2009)

This publication reports the proceedings of the preliminary meeting of the working party that met at Gastro 2009 during the World Congress in London. The purpose of the preliminary meeting was to consider the areas that require attention, to discuss some of the findings that have already been published and to agree on the way forward. Our reason for publishing these proceedings is to stimulate interest in this venture and to provide the opportunity for input from the endoscopy community worldwide. The next meeting of the working party will be at the JGES Society meeting in Aomori in April 2011 when we hope to prepare a preliminary classification. This will be presented for general discussion and debate at the International Congress of Endoscopy (ICE) in Los Angeles in September 2011.

Issues related to colorectal cancer and colorectal cancer screening practices in women

Studies have shown that colorectal cancer (CRC) incidence is equal between men and women. However, several studies have demonstrated lower adenoma detection rates in women than in men. Many questions arise about differences in adenomas, CRC, and screening practices between men and women: should screening be the same for both sexes, are there differences in risk factors in the formation of colon cancer, should special groups of women be screened differently from the general population, are colonoscopies tolerated differently in women and why, and what determines if a woman will undergo colonoscopy? This article reviews these issues.

Deep sedation compared with moderate sedation in polyp detection during colonoscopy: a randomized controlled trial

AIM

The detection rate of adenomas is one of the current quality indicators in high-quality colonoscopy. We compared the performance of colonoscopy for the detection of polyps in patients sedated with deep and moderate sedation. Secondary objectives included the patient's and the endoscopist's satisfaction, recovery time and the adverse events related to sedation between the two groups.

METHOD

Five hundred and twenty patients submitted for colonoscopy were prospectively randomized into a deep sedation group (DS group, n = 258) and a moderate sedation (MS group, n = 262) group. In both, sedation and analgesia were performed using midazolam with pethidine.

RESULTS

There were no differences between the two groups in the following three areas: (1) The overall detection of polyps (DS, 1 [0-20]; MS, 1 [0-15]; P = 0.67), (2): polyp size ≥ 10 mm (DS, 0.00 [0-7]; MS, 0.00 [0-6]; P = 0.30), and (3) polyp size < 10 mm (DS, 0.00 [0-20]; MS, 0.00 [0-13]; P = 0.83). There was no significant difference in the rate of adenoma detection (DS, 1 [0-10]; MS, 1 [0-9]; P = 0.99).

CONCLUSION

The study demonstrated no difference in the detection of polyps by colonoscopy using deep or moderate sedation.

Colorectal cancer screening: the effectiveness of education on its barriers and acceptability

To assess the awareness and acceptability of colorectal cancer (CRC) screening in noncompliant Singaporeans and to determine if their barriers can be overcome by education. A questionnaire developed from thematic analysis of open-ended interviews with 72 subjects was administered to 580 residents in a local high-rise housing estate. Participants aware of CRC screening were assessed for barriers and acceptability of CRC screening. All participants were subsequently educated about CRC screening and reassessed for barriers and acceptance. Those keen for fecal occult blood testing (FOBT) were offered FOBT kits and followed up. CRC screening awareness was poor. Having no symptoms was the most common barrier. More barriers to FOBT than to colonoscopy were reduced with education. After education, acceptability toward FOBT increased but rejection rates rose even higher. FOBT is probably Singapore's most acceptable screening modality. Education is limited by barriers, which need to be overcome by alternative measures.

Identification of biomarkers for colorectal cancer through proteomics-based approaches

The early detection of colorectal cancer is one of the great challenges in the battle against this disease. However, owing to its heterogeneous character, single markers are not likely to provide sufficient diagnostic power to be used in colorectal cancer population screens. This review provides an overview of recent studies aimed at the discovery of new diagnostic protein markers through proteomics-based approaches. It indicates that studies that start with the proteomic analysis of tumor tissue or tumor cell lines (near the source) have a high potential to yield novel and colorectal cancer-specific biomarkers. In the next step, the diagnostic accuracy of these candidate markers can be assessed by a targeted ELISA assay using serum from colorectal cancer patients and healthy controls. Instead, direct proteomic analysis of serum yields predominantly secondary markers composed of fragments of abundant serum proteins that may be associated with tumor-associated protease activity, and alternatively, immunoproteomic analysis of the serum antibody repertoire provides a valuable tool to identify the molecular imprint of colorectal cancer-associated antigens directly from patient serum samples. The latter approach also allows a relatively easy translation into targeted assays. Eventually, multimarker assays should be developed to reach a diagnostic accuracy that meets the stringent criteria for colorectal cancer screening at the population level.

Affibody-functionalized gold-silica nanoparticles for Raman molecular imaging of the epidermal growth factor receptor

The affibody functionalization of fluorescent surface-enhanced Raman scattering gold-silica nanoparticles as multimodal contrast agents for molecular imaging specific to epidermal growth factor receptor (EGFR) is reported. This nanoparticle bioconjugate reports EGFR-positive A431 tumors with a signal nearly 35-fold higher than EGFR-negative MDA-435S tumors. The low-level EGFR expression in adjacent healthy tissue is 7-fold lower than in the positive tumors. Validation via competitive inhibition reduces the signal by a factor of six, and independent measurement of EGFR via flow cytometry correlates at R(2) = 0.92.

MicroRNA dysregulation in colorectal cancer: a clinical perspective

Recent researches have shed light on the biological importance of microRNAs (miRNAs) in colorectal cancer (CRC) genesis, progression and response to treatments. The potential utility of miRNAs in the preclinical stage have been explored and investigated. In this review, we explored the literature and reviewed the cutting edge progress in the discovery of noninvasive plasma and faecal miRNAs for CRC early diagnosis, as well as their measurability and predictability. We also discussed the utility of miRNAs as novel prognostic and predictive markers, and their association with CRC clinical phenotypes including recurrence, metastasis and therapeutic outcomes. Finally, we summarised miRNA-related single-nucleotide polymorphisms and their potential influence on sporadic CRC susceptibility and therapeutic response. In conclusion, the use of miRNAs as biomarker for CRC is still in its infancy and need further characterisation and evaluation.

MicroRNA dysregulation in colorectal cancer: a clinical perspective

Recent researches have shed light on the biological importance of microRNAs (miRNAs) in colorectal cancer (CRC) genesis, progression and response to treatments. The potential utility of miRNAs in the preclinical stage have been explored and investigated. In this review, we explored the literature and reviewed the cutting edge progress in the discovery of noninvasive plasma and faecal miRNAs for CRC early diagnosis, as well as their measurability and predictability. We also discussed the utility of miRNAs as novel prognostic and predictive markers, and their association with CRC clinical phenotypes including recurrence, metastasis and therapeutic outcomes. Finally, we summarised miRNA-related single-nucleotide polymorphisms and their potential influence on sporadic CRC susceptibility and therapeutic response. In conclusion, the use of miRNAs as biomarker for CRC is still in its infancy and need further characterisation and evaluation.

Online "spaced education progress-testing" of students to confront two upcoming challenges to medical schools

PURPOSE

U.S. medical students will soon complete only one licensure examination sequence, given near the end of medical school. Thus, schools are challenged to identify poorly performing students before this high-stakes test and help them retain knowledge across the duration of medical school. The authors investigated whether online spaced education progress-testing (SEPT) could achieve both aims.

METHOD

Participants were 2,648 students from four U.S. medical schools; 120 multiple-choice questions and explanations in preclinical and clinical domains were developed and validated. For 34 weeks, students randomized to longitudinal progress-testing alone (LPTA) received four new questions (with answers/ explanations) each week. Students randomized to SEPT received the identical four questions each week, plus two-week and six-week cycled reviews of the questions/explanations. During weeks 31-34, the initial 40 questions were re-sent to students to assess longer-term retention.

RESULTS

Of the 1,067 students enrolled, the 120-question progress-test was completed by 446 (84%) and 392 (74%) of the LPTA and SEPT students, respectively. Cronbach alpha reliability was 0.87. Scores were 39.9%, 51.9%, 58.7%, and 58.8% for students in years 1-4, respectively. Performance correlated with Step 1 and Step 2 Clinical Knowledge scores (r = 0.52 and 0.57, respectively; P < .001) and prospectively identified students scoring below the mean on Step 1 with 75% sensitivity, 77% specificity, and 41% positive predictive value. Cycled reviews generated a 170% increase in learning retention relative to baseline (P < .001, effect size 0.95).

CONCLUSIONS

SEPT can identify poorly performing students and improve their longer-term knowledge retention.

Fecal DNA for noninvasive diagnosis of colorectal cancer in immunochemical fecal occult blood test-positive individuals

BACKGROUND

We aimed to define the potential of the fecal DNA assay as an alternative or in addition to the currently used immunochemical fecal occult blood test (iFOBT) for the early diagnosis of colorectal cancer.

METHODS

A total of 560 individuals aged 50 to 69 years with a positive iFOBT were recruited from an Italian FOBT regional screening program. Twenty-six were diagnosed with adenocarcinoma, 264 with high-risk adenoma, and 54 with low-risk adenoma, whereas 216 subjects did not have premalignant or malignant lesions. Fecal DNA integrity was analyzed blindly by the fluorescence long DNA (FL-DNA) test.

RESULTS

iFOBT and FL-DNA were largely independent variables (rs = 0.036, P = 0.42), with values ranging from 101 to 5,826 ng/mL and from 0 to 515 ng, respectively. Median values of both variables were significantly higher in cancer patients than in patients with noncancerous lesions or in healthy individuals. Moreover, iFOBT and FL-DNA values were individually associated with a number of pathologic parameters. Sequential use of the diagnostic iFOBT and FL-DNA methods showed that fecal DNA provided more accurate diagnostic information and was able to identify subgroups at different risk of cancer in iFOBT-positive individuals.

CONCLUSIONS

A combined approach based on FL-DNA and iFOBT evaluation could help to better identify colorectal cancers and to determine a patient's risk of harboring a preneoplastic or neoplastic lesion. Further evaluation in a screening setting is needed to confirm this hypothesis.

IMPACT

Fecal DNA could be a useful tool to better predict cancer risk in FOBT-positive individuals.

Colorectal cancer: what should patients and families be told to lower the risk of colorectal cancer?

Colorectal cancer (CRC) is the second most common cause of cancer-related death in the United States. CRC, however, is potentially preventable, and several strategies may be employed to decrease the incidence of and mortality from CRC. Understanding of individual risk and adherence to screening and surveillance recommendations undoubtedly will reduce CRC-associated deaths. Several natural and synthetic chemopreventive agents may prove effective for both primary and secondary CRC chemoprevention. Finally, dietary modifications (ie, increased dietary fiber, fruits and vegetables, and decreased red meat) and other lifestyle changes (i.e., increased physical activity, weight maintenance, avoidance of smoking, and moderation of alcohol intake) also may lower the risk of developing CRC.

Use of faecal markers in screening for colorectal neoplasia: a European group on tumor markers position paper

Several randomized controlled trials have shown that population-based screening using faecal occult blood testing (FOBT) can reduce mortality from colorectal neoplasia. Based on this evidence, a number of countries have introduced screening for colorectal cancer (CRC) and high-risk adenoma and many others are considering its introduction. The aim of this article is to critically review the current status of faecal markers as population-based screening tests for these neoplasia. Most of the available faecal tests involve the measurement of either occult blood or a panel of DNA markers. Occult blood may be measured using either the guaiac faecal occult blood test (gFOBT) or a faecal immunochemical test (iFOBT). Although iFOBT may require a greater initial investment, they have several advantages over gFOBT, including greater analytical sensitivity and specificity. Their use results in improved clinical performance and higher uptake rates. Importantly for population screening, some of the iFOBTs can be automated and provide an adjustable cutoff for faecal haemoglobin concentration. However, samples for iFOBT, may be less stable after collection than for gFOBT. For new centres undertaking FOBT for colorectal neoplasia, the European Group on Tumour Markers recommends use of a quantitative iFOBT with an adjustable cutoff point and high throughput analysis. All participants with positive FOBT results should be offered colonoscopy. The panel recommends further research into increasing the stability of iFOBT and the development of improved and affordable DNA and proteomic-based tests, which reduce current false negative rates, simplify sample transport and enable automated analysis.

Anthropometric factors in adulthood and risk of colorectal adenomas: The French E3N-EPIC prospective cohort

Anthropometric factors have been associated with colorectal cancer and adenomas but with conflicting results in women or regarding adenoma characteristics. The authors aimed to explore associations between anthropometric factors (height, weight, body mass index, waist and hip circumferences, and weight changes) and adenoma risk. They analyzed the 17,391 women of the French Etude épidémiologique des femmes de la Mutuelle Générale de l'Education Nationale (E3N)-European Prospective Investigation into Cancer and Nutrition (EPIC) cohort who underwent a colonoscopy during follow-up (1993-2002), including 1,408 who developed a first colorectal adenoma. In Cox multivariate proportional hazard regression models, obesity was associated with an increased colorectal adenoma risk (hazard ratio = 1.53, 95% confidence interval: 1.21, 1.94). This association was restricted to left colon adenomas (P(homogeneity) = 0.05 and 0.01 for colon vs. rectum and right vs. left colon, respectively), with a dose-effect relation observed from 22 kg/m². A high waist circumference was also associated with left colon adenoma risk (hazard ratio = 1.81, 95% confidence interval: 1.36, 2.41). Mean weight gain over 0.5 kg/year was associated with a 23% increased colorectal adenoma risk. Associations did not differ between advanced and nonadvanced adenomas. In conclusion, study findings suggest that obesity and weight gain are associated with early colorectal carcinogenesis in women, and specifically regarding the distal colon.

Proteomic serum biomarkers and their potential application in cancer screening programs

Early diagnosis of cancer is of pivotal importance to reduce disease-related mortality. There is great need for non-invasive screening methods, yet current screening protocols have limited sensitivity and specificity. The use of serum biomarkers to discriminate cancer patients from healthy persons might be a tool to improve screening programs. Mass spectrometry based proteomics is widely applied as a technology for mapping and identifying peptides and proteins in body fluids. One commonly used approach in proteomics is peptide and protein profiling. Here, we present an overview of profiling methods that have the potential for implementation in a clinical setting and in national screening programs.

Maximizing the value of colonoscopy in community practice

Gastroenterologists who understand future reimbursement and health care trends are already preparing their practice infrastructure to meet new challenges of transparency and bundled payments. Market-based pressures derived from quality and cost transparency will be sufficient to drive change. Robust measurement and public reporting of results are firmly embedded in some regions of the country and will spread nationally within the next few years. The path is clear for those who study these issues; monitor process measures for internal improvement, push resource efficiency, connect to national registries to demonstrate quality externally, and constantly try to provide a service with the highest health value.

Predictors of serious complications associated with lower gastrointestinal endoscopy in a major city-wide health region

BACKGROUND

There are limited data regarding complications associated with colonoscopy and flexible sigmoidoscopy in usual clinical practice in Canada.

OBJECTIVE

To determine the risk factors for lower gastrointestinal (GI) endoscopy-associated complications in usual clinical practice.

METHODS

All outpatient lower GI endoscopies performed in Winnipeg (Manitoba) between April 1, 2004 and March 31, 2006, were identified from the provincial physicians' claims database. All subsequent hospital admissions within 30 days that documented potential complications associated with lower GI endoscopies were identified from the electronic hospital discharges database and reviewed. Multivariate generalized estimating equation regression analysis was performed to determine independent factors (patient, endoscopist and procedure) associated with the risk of developing complications.

RESULTS

There were 29,990 outpatient lower GI endoscopies performed in Winnipeg during the years studied. Seventy-seven (0.26%) procedures were associated with complications requiring hospitalization within 30 days of the index procedure. Stricture dilation (rate ratio [RR] 23.14; 95% CI 6.70 to 76.51), polypectomy (RR 5.93; 95% CI 3.66 to 9.62), increasing patient age (for each year increase in age, RR 1.03; 95% CI 1.01 to 1.05) and performance of endoscopy by low-volume endoscopists (fewer than 200 procedures per year, RR 2.28; 95% CI 1.18 to 4.42) and family physicians (RR 2.23; 95% CI 1.39 to 3.58) were independently associated with complications.

CONCLUSIONS

The results of the present study suggest that increasing patient age, complex procedures and performance of the index procedure by low-volume endoscopists are independent risk factors for lower GI endoscopy-associated complications in usual clinical practice. This suggests that it may be time to consider implementing minimum volume requirements for endoscopists performing non-screening lower GI endoscopies.

Colorectal cancer screening

PURPOSE OF REVIEW

The review will summarize the state of the art in colon cancer screening. Recently published screening guidelines will be reviewed so physicians can understand them and how to deal with the differences. Each screening modality presently in use will then be reviewed with emphasis on efficacy and problems.

RECENT FINDINGS

During the past two decades research has clearly demonstrated colon cancer screening to be effective. New modalities such as virtual colonoscopy and stool DNA screening have been introduced and are recommended by some organizations but not others. Ages to discontinue screening have also been suggested. Fecal immunochemical testing exhibits some advantages over guaiac-based testing. Problematic issues with the effectiveness of colonoscopy have arisen, particularly in the proximal colon. Both technical and biological reasons have been suggested for this decrease in effectiveness.

SUMMARY

Colon cancer screening is effective and continues to improve. Refinements of guidelines as well as refinements in each screening modality have occurred. Several screening tools are newly available and quality studies and efforts for present and new tests are imperative.

Fecal MicroRNAs as novel biomarkers for colon cancer screening

INTRODUCTION

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths, but currently available noninvasive screening programs have achieved only a modest decrease in mortality. MicroRNAs (miRNA) play an important role in a wide array of biological processes and are commonly dysregulated in neoplasia. We aimed to evaluate the feasibility of fecal miRNAs as biomarkers for colorectal neoplasia screening.

MATERIALS AND METHODS

Total RNA was extracted from freshly collected stool samples from 8 healthy volunteers and 29 samples collected via fecal occult blood testing from subjects with normal colonoscopies, colon adenomas, and CRCs. miRNA expression analyses were done with TaqMan quantitative reverse transcription-PCR for a subset of miRNAs. Illumina miRNA microarray profiling was done to evaluate the differences in expression patterns between normal colonic mucosa tissues and stool samples from healthy subjects.

RESULTS

We efficiently extracted miRNAs from stool specimens using our developed protocol. Data from independent experiments showed high reproducibility for miRNA extraction and expression. miRNA expression patterns were similar in stool specimens among healthy volunteers, and reproducible in stool samples that were collected serially in time from the same individuals. miRNA expression profiles from 29 patients showed higher expression of miR-21 and miR-106a in patients with adenomas and CRCs compared with individuals free of colorectal neoplasia.

CONCLUSION

Our data indicate that miRNAs could be extracted from stool easily and reproducibly. The stools of patients with colorectal neoplasms have unique and identifiable patterns of miRNA expression.

IMPACT

Fecal miRNAs may be an excellent candidate for the development of a noninvasive screening test for colorectal neoplasms.

Meta-analysis shows colon capsule endoscopy is effective in detecting colorectal polyps

BACKGROUND & AIMS

Colon capsule endoscopy (CCE) is a noninvasive and painless technique used to explore the colon without sedation or air insufflation. We performed a systematic review and meta-analysis to assess the accuracy of CCE in detecting colorectal polyps.

METHODS

The MEDLINE, EMBASE, and SCOPUS databases were searched, from 2006 to 2009, for the terms "colon capsule" and "Pillcam colon"; searches included abstracts. Studies were included that focused on detecting colorectal polyps with CCE and that were verified using within-subject reference colonoscopy. The risk of bias within each study was ascertained according to Quality Assessment of Diagnostic Accuracy in Systematic Reviews recommendations. The per-patient sensitivity and specificity were calculated for polyps of any size and for significant findings (polyps, > or =6 mm in size or >3 in number). Forest plots were produced based on random-effect models. The risk of bias across studies was assessed using the interstudy heterogeneity statistic, meta-regression, and the Egger test.

RESULTS

Eight studies provided data on 837 patients; the prevalences of polyps and significant findings were 57% and 27.4%, respectively. CCE sensitivity for polyps of any size and significant findings were 71% and 68%, respectively. CCE specificity for polyps of any size and significant findings were 75% and 82%, respectively. High levels of heterogeneity (interstudy heterogeneity, >75%) were not detected. Moderate heterogeneity partially was explained by the different design of individual studies. CCE identified 16 of the 21 cancerous lesions detected by colonoscopy (pooled sensitivity, 76%).

CONCLUSIONS

CCE sensitivity for polyps and significant findings compares favorably with other noninvasive colorectal cancer screening strategies. CCE specificity is likely to be underestimated because reference colonoscopy examination results are blinded.

The role of CT colonography in a colorectal cancer screening program

Computed tomography colonography (CTC) has the potential to become a major component of colorectal cancer (CRC) screening programs and to have a significant effect on CRC prevention. This article describes the potential role of CTC within the framework of colorectal cancer screening. Current screening recommendations and traditional screening tests are reviewed, followed by a summary of recent study results on the use of CTC as a screening tool. Several factors that are affecting the acceptance and adoption of CTC are outlined. Although CTC is valuable and holds considerable promise as a way to increase the use of CRC screening, these issues need to be addressed before CTC becomes more widely disseminated as a screening modality.

Monoclonal antibodies MC3 and MC5 can be used as a tool for screening colorectal cancer

MC3 and MC5 are both colorectal cancer-specific MAbs previously prepared in our laboratory that can detect colorectal cancer with high sensitivity and specificity. Thus far the distribution of MC3-Ag and MC5-Ag in colorectal cancer remains largely unknown. In the present study, we have firstly found that the expression of MC3-Ag and MC5-Ag was higher in moderate-differentiated and poor-differentiated colorectal cancer tissue than that in well-differentiated colorectal cancer tissue by immunohistochemistry. The expression of MC5-Ag in colorectal cancer tissue without metastasis was found to be significantly less than that in tissue accompanied with metastasis. However, the expression of MC3-Ag in colorectal cancer tissue without metastasis was found similar to that in tissue accompanied with metastasis. The results showed that MC3-Ag and MC5-Ag might play important roles in colorectal carcinogenesis and that MC3 and MC5 could be used as a tool for screening colorectal cancer.

Colorectal cancer screening in Europe

Colorectal cancer (CRC) is the second most frequent malignant disease in Europe. Every year, 412 000 people are diagnosed with this condition, and 207 000 patients die of it. In 2003, recommendations for screening programs were issued by the Council of the European Union (EU), and these currently serve as the basis for the preparation of European guidelines for CRC screening. The manner in which CRC screening is carried out varies significantly from country to country within the EU, both in terms of organization and the screening test chosen. A screening program of one sort or another has been implemented in 19 of 27 EU countries. The most frequently applied method is testing stool for occult bleeding (fecal occult blood test, FOBT). In recent years, a screening colonoscopy has been introduced, either as the only method (Poland) or the method of choice (Germany, Czech Republic).

Relevance of biologic markers in colorectal carcinoma: a comparative study of a broad panel

BACKGROUND

Although pathologic stage is currently the main prognostic indicator for patients with colorectal carcinoma (CRC), mounting evidence suggests that, in its current form, it is insufficient to predict clinical outcome. To assess biologic markers of primary CRC that may improve clinical staging and provide useful information for the application of novel therapeutic strategies, the authors investigated a panel of markers that included transforming growth factor alpha (TGF alpha), epithelial growth factor receptor (EGF-R; the protein product of the c-erb B2/HER-2 oncogene), matrix metalloproteinase 2 (MMP-2), insulin-like growth factor II (IGF-II), vascular endothelial growth factor (VEGF), and angiogenesis, as evaluated by microvessel density (MVD).

METHODS

Two groups of CRC were studied: 1) surgical samples from patients who achieved a disease free survival of at least 6 years (CRC-M0) and 2) surgical specimens of both primary tumors and synchronous or metachronous liver metastases (CRC-M1).

RESULTS

Chi-square analysis revealed that expression levels of TGF-alpha, c-erb B2/HER-2, MMP-2, IGF-II, VEGF, and MVD (but not EGF-R) were significantly higher in CRC-M1 samples compared with CRC-M0 samples (P < 0.001, P < 0.05, P < 0.001, P < 0.001, P < 0.01, and P < 0.001, respectively). Logistic regression analysis showed that TGF-alpha, IGF-II, and MMP-2 had significantly greater expression in CRC-M1 samples independent of the other variables (including tumor classification, histologic grade, and patient age). If all three markers had > or = 25% expression, then the probability of developing liver metastasis was 99.5%.

CONCLUSIONS

Based on the evidence of this study, TGF-alpha MMP-2, and IGF-II seem suitable candidates for a selective panel of markers designed to provide significant additional information with respect to the current pathologic staging system for patients with colorectal carcinoma.