Colon polyps and cancer

Circulating miRNAs and lncRNAs serve as biomarkers for early colorectal cancer diagnosis

BACKGROUND

Colorectal cancer (CRC), the third most prevalent and lethal disease, accounted for approximately 1.9 million new cases and claimed nearly 861,000 lives in 2018. It is imperative to develop a minimally invasive diagnostic technique for early identification of CRC. This would facilitate the selection of patient populations most suitable for clinical trials, monitoring disease progression, assessing treatment effectiveness, and enhancing overall patient care. Utilizing blood as a biomarker source is advantageous due to its minimal discomfort for patients, enabling better integration into clinical and follow-up trials. Recent findings indicate that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are detectable in the blood of cancer patients, proving crucial in diagnosing various malignancies.

METHODS

In this case-control study, we collected plasma samples from 30 patients diagnosed with colorectal cancer (CRC) and 30 healthy volunteers. Following RNA extraction, we measured the expression levels of specific biomolecules, including miR-410, miR-211, miR-139, miR-197, lncRNA UICLM, lncRNA FEZF1-AS1, miR-129, lncRNA CCAT1, lncRNA BBOX1-AS1, and lncRNA LINC00698, using real-time quantitative polymerase chain reaction (RT-qPCR). The obtained data underwent analysis using the Mann-Whitney test for non-parametric data and the T-test for parametric data.

RESULTS

The level of miR-410, miR-211, miR-139, miR-197, lncRNA UICLM, lncRNA FEZF1-AS1 were significantly higher in patients with CRC than healthy controls (p < .05). Meanwhile, the level of miR-129, lncRNA CCAT1, lncRNA BBOX1-AS1, and lncRNA LINC00698 were higher in healthy controls than in CRC patients (p < .05).

CONCLUSION

MicroRNA (miRNA) and long noncoding RNAs (lncRNAs) have recently emerged as detectable entities in the blood of cancer patients, playing crucial roles in diagnosing various malignancies. However, their specific relevance in the diagnosis of colorectal cancer (CRC) remains underexplored. This study aimed to investigate miRNA and lncRNA profiles in the plasma fraction of human blood to discern significant differences in content and expression levels between CRC patients and healthy individuals. Our cohort comprised 30 CRC patients and 30 healthy controls, with no statistically significant differences (p < 0.05) in age or gender observed between the two groups. Noteworthy is the uniqueness of our study, as we identified a panel of three significant microRNAs and one significant lncRNA, providing a more reliable prediction compared to existing molecular markers in diagnosing CRC. The four genes examined, including miR-211, miR-129, miR-197, and lncRNA UICLM, demonstrated impeccable results in terms of sensitivity and specificity, suggesting their potential candidacy for inclusion in diagnostic panels. Further validation in a larger statistical population is recommended to confirm the robustness of these genes as promising markers for colorectal cancer diagnosis.

Using of endoscopic polypectomy in patients with diagnosed malignant colorectal polyp - The cross-sectional clinical study

The aim of this study was to evaluate the efficacy of endoscopic polypectomy as a therapeutic treatment for malignant alteration of colorectal polyps. In a 5-year research, 89 patients were included, who were tested and treated at the University Clinical Center Kragujevac, Kragujevac, Serbia, with the confirmed presence of malignant alteration polyps of the colon by colonoscopy, which were removed using the method of endoscopic polypectomy and confirmed by the histopathological examination of the entire polyp. After that, the same group of patients was monitored endoscopically within a certain period, controlling polypectomy locations and the occurrence of a possible remnant of the polyp, in the period of up to 2 years of polypectomy. We observed that, with an increasing size of polyps, there is also an increase in the percentage of the complexity of endoscopic resection and the appearance of remnant with histological characteristics of the invasive cancer. The highest percentage of incomplete endoscopic resection and the appearance of remnant with histological characteristics of the invasive cancer were shown at malignant altered polyps in the field of tubulovillous adenoma. Eighteen patients in total underwent the surgical intervention. In conclusion, our data support the high efficacy of endoscopic polypectomy for the removal of the altered malignant polyp.

KRAS mutations and their associations with clinicopathological features and survival in Vietnamese non‑polyp colon cancer patients

The aim of the present study was to determine Kirsten Ras sarcoma virus (KRAS) mutations and the associations of KRAS mutations with clinicopathological features and treatment outcomes in Vietnamese non-polyp colon cancer (NPCC) patients. The data in the present study covered 194 patients with non-polyp colon cancers at stages II or III, according to the 8th edition of the American Joint Committee on Cancer staging system, in northern Vietnam from January 2016 to August 2020. All patients underwent radical surgery and adjuvant therapy with FOLFOX4 or XELOX. Subsequently, the recruited patients were followed-up with scheduled hospital exams for diagnosing recurrence. Genomic DNA samples were prepared from dissected tumors and specific sequences of the KRAS gene were amplified by polymerase chain reactions (PCR). The mutations at codons 12, 13, 59, 60, 61, 117 and 146 of the gene were determined. Possible associations of the KRAS mutations with clinicopathological properties and the survival of patients were analysed. The KRAS mutation rate was 47.9% in Vietnamese patients with NPCC, of those, mutations in exon 2 accounted for 91.4% of all detected mutations. The mutated-KRAS patients exhibited a significantly higher rate of anemia. Moreover, the KRAS mutation rate was higher in females (57.1%) than in males (39.8%). The KRAS mutation rate was also higher in patients with right colon cancers. Furthermore, KRAS mutations were an independent prognosis for poor disease-free survival (DFS) and overall survival (OS) in stage II patients. Among left-sided colon patients, mutated KRAS was a significant predictive factor for poor DFS but not for OS. The present study revealed a very high mutation rate of KRAS in Vietnamese patients with NPCC. The data of the present study indicated that the mutation status was associated with female patients and right-sided tumors. The KRAS mutations were a negative factor for the survival of patients with stage II NPCC and patients with left-sided colon cancer.

Artificial intelligence to improve polyp detection and screening time in colon capsule endoscopy

Colon Capsule Endoscopy (CCE) is a minimally invasive procedure which is increasingly being used as an alternative to conventional colonoscopy. Videos recorded by the capsule cameras are long and require one or more experts' time to review and identify polyps or other potential intestinal problems that can lead to major health issues. We developed and tested a multi-platform web application, AI-Tool, which embeds a Convolution Neural Network (CNN) to help CCE reviewers. With the help of artificial intelligence, AI-Tool is able to detect images with high probability of containing a polyp and prioritize them during the reviewing process. With the collaboration of 3 experts that reviewed 18 videos, we compared the classical linear review method using RAPID Reader Software v9.0 and the new software we present. Applying the new strategy, reviewing time was reduced by a factor of 6 and polyp detection sensitivity was increased from 81.08 to 87.80%.

A literature review on large intestinal hyperelastic constitutive modeling

Impacts, traumas and strokes are spontaneously life-threatening, but chronic symptoms strangle patient every day. Colorectal tissue mechanics in such chronic situations not only regulates the physio-psychological well-being of the patient, but also confirms the level of comfort and post-operative clinical outcomes. Numerous uniaxial and multiaxial tensile experiments on healthy and affected samples have evidenced significant differences in tissue mechanical behavior and strong colorectal anisotropy across each layer in thickness direction and along the length. Furthermore, this study reviewed various forms of passive constitutive models for the highly fibrous colorectal tissue ranging from the simplest linearly elastic and the conventional isotropic hyperelastic to the most sophisticated second harmonic generation image based anisotropic mathematical formulation. Under large deformation, the isotropic description of tissue mechanics is unequivocally ineffective which demands a microstructural based tissue definition. Therefore, the information collected in this review paper would present the current state-of-the-art in colorectal biomechanics and profoundly serve as updated computational resources to develop a sophisticated characterization of colorectal tissues.

Piwil2 is reactivated by HPV oncoproteins and initiates cell reprogramming via epigenetic regulation during cervical cancer tumorigenesis

The human papillomavirus (HPV) oncoproteins E6 and E7 are risk factors that are primarily responsible for the initiation and progression of cervical cancer, and they play a key role in immortalization and transformation by reprogramming differentiating host epithelial cells. It is unclear how cervical epithelial cells transform into tumor-initiating cells (TICs). Here, we observed that the germ stem cell protein Piwil2 is expressed in pre-cancerous and malignant lesions of the cervix and cervical cancer cell lines with the exception of the non-HPV-infected C33a cell line. Knockdown of Piwil2 by shRNA led to a marked reduction in proliferation and colony formation, in vivo tumorigenicity, chemo-resistance, and the proportion of cancer stem-like cells. In contrast, Piwil2 overexpression induced malignant transformation of HaCaT cells and the acquisition of tumor-initiating capabilities. Gene-set enrichment analysis revealed embryonic stem cell (ESC) identity, malignant biological behavior, and specifically, activation targets of the cell reprogramming factors c-Myc, Klf4, Nanog, Oct4, and Sox2 in Piwil2-overexpressing HaCaT cells. We further confirmed that E6 and E7 reactivated Piwil2 and that E6 and E7 overexpression resulted in a similar gene-set enrichment pattern as Piwil2 overexpression in HaCaT cells. Moreover, Piwil2 overexpression or E6 and E7 activation induced H3K9 acetylation but reduced H3K9 trimethylation, which contributed to the epigenetic reprogramming and ESC signature maintenance, as predicted previously. Our study demonstrates that Piwil2, reactivated by the HPV oncoproteins E6 and E7, plays an essential role in the transformation of cervical epithelial cells to TICs via epigenetics-based cell reprogramming.

Colorectal Cancer Detection Using Targeted LC-MS Metabolic Profiling

Colorectal cancer (CRC) is one of the most commonly diagnosed malignancies and causes of cancer death. While the mortality rates from CRC have steadily declined, 50,000 individuals in the USA (and many times this number worldwide) still succumb to this illness every year. Early detection of CRC is the most critical need for improving 5-year survival and cure rates. Currently available CRC diagnostic techniques often miss early stage disease such that only 40% of newly diagnosed CRC patients are treated for local disease, Therefore, development of new screening methods that are highly sensitive, specific, noninvasive and easily accessible are critically desired for the early diagnosis and significant reduction in death rate from CRC. In this chapter we describe a targeted LC-MS based metabolic profiling approach used for the discovery of CRC metabolite biomarker candidates, based on highly reproducible hydrophilic interaction liquid chromatography coupled to triple-quadrupole mass spectrometry (HILIC-LC-QQQ-MS). A partial least squares-discriminant analysis (PLS-DA) model was able to differentiate CRC patients from both healthy controls and polyp patients, as well as to distinguish CRC patients based on the cancer stage.

KRAS and BRAF somatic mutations in colonic polyps and the risk of metachronous neoplasia

Background & aims

High-risk features of colonic polyps are based on size, number, and pathologic characteristics. Surveillance colonoscopy is often recommended according to these findings. This study aimed to determine whether the molecular characteristics of polyps might provide information about the risk of metachronous advanced neoplasia.

Methodology

We retrospectively included 308 patients with colonic polyps. A total of 995 polyps were collected and tested for somatic BRAF and KRAS mutations. Patients were classified into 3 subgroups, based on the polyp mutational profile at baseline, as follows: non-mutated polyps (Wild-type), at least one BRAF-mutated polyp, or at least one KRAS-mutated polyp. At surveillance, advanced adenomas were defined as adenomas ≥ 10 mm and/or with high grade dysplasia or a villous component. In contrast, advanced serrated polyps were defined as serrated polyps ≥ 10 mm in any location, located proximal to the splenic flexure with any size or with dysplasia.

Results

At baseline, 289 patients could be classified as wild-type (62.3%), BRAF mutated (14.9%), or KRAS mutated (22.8%). In the univariate analysis, KRAS mutations were associated with the development of metachronous advanced polyps (OR: 2.36, 95% CI: 1.22–4.58; P = 0.011), and specifically, advanced adenomas (OR: 2.42, 95% CI: 1.13–5.21; P = 0.023). The multivariate analysis, adjusted for age and sex, also showed associations with the development of metachronous advanced polyps (OR: 2.27, 95% CI: 1.15–4.46) and advanced adenomas (OR: 2.23, 95% CI: 1.02–4.85).

Conclusions

Our results suggested that somatic KRAS mutations in polyps represent a potential molecular marker for the risk of developing advanced neoplasia.

Adenoma detection with Endocuff colonoscopy versus conventional colonoscopy: a multicentre randomised controlled trial

BACKGROUND AND AIMS

Colonoscopy is the current reference standard for the detection of colorectal neoplasia, but nevertheless adenomas remain undetected. The Endocuff, an endoscopic cap with plastic projections, may improve colonic visualisation and adenoma detection. The aim of this study was to compare the mean number of adenomas per patient (MAP) and the adenoma detection rate (ADR) between Endocuff-assisted colonoscopy (EAC) and conventional colonoscopy (CC).

METHODS

We performed a multicentre, randomised controlled trial in five hospitals and included fecal immonochemical test (FIT)-positive screening participants as well as symptomatic patients (>45 years). Consenting patients were randomised 1:1 to EAC or CC. All colonoscopies were performed by experienced colonoscopists (≥500 colonoscopies) who were trained in EAC. All colonoscopy quality indicators were prospectively recorded.

FINDINGS

Of the 1063 included patients (52% male, median age 65 years), 530 were allocated to EAC and 533 to CC. More adenomas were detected with EAC, 722 vs 621, but the gain in MAP was not significant: on average 1.36 per patient in the EAC group versus 1.17 in the CC group (p=0.08). In a per-protocol analysis, the gain was 1.44 vs 1.19 (p=0.02), respectively. In the EAC group, 275 patients (52%) had one or more adenomas detected versus 278 in the CC group (52%; p=0.92). For advanced adenomas these numbers were 109 (21%) vs 117 (22%). The adjusted caecal intubation rate was lower with EAC (94% vs 99%; p<0.001), however when allowing crossover from EAC to CC, they were similar in both groups (98% vs 99%; p value=0.25).

INTERPRETATION

Though more adenomas are detected with EAC, the routine use of Endocuff does not translate in a higher number of patients with one or more adenomas detected. Whether increased detection ultimately results in a lower rate of interval carcinomas is not yet known.

TRIAL REGISTRATION NUMBER

http://www.trialregister.nl Dutch Trial Register: NTR3962.

Identification of patients at risk for colorectal cancer in primary care: an explorative study with routine healthcare data

BACKGROUND

Early diagnosis of colorectal cancer (CRC) is likely to reduce burden of disease and improve treatment success. Estimation of the individual patient risk for CRC diagnostic determinants in a primary care setting has not been very successful as yet. The aim of our study is to improve prediction of CRC in patients selected for colonoscopy in the primary healthcare setting using readily available routine healthcare data.

PATIENTS AND METHODS

A cross-sectional study was carried out in the Julius General Practitioners' Network database. Patients referred for colonoscopy by their general practitioner (GP) between 2007 and 2012 were selected. We evaluated the association between long-term registered patient characteristics, symptoms and conditions, and colonoscopy test results with multivariable logistic regression.

RESULTS

Two per cent (2787/140 000) of the patients between 30 and 85 years were found to be newly referred for colonoscopy by their GP, of whom 57 (2%) were diagnosed with CRC. Age 50 years or over, hypertension and the absence of preceding consultations for abdominal pain were independent predictors for CRC and/or high-risk adenomas, with an area under the curve of 0.65.

CONCLUSION

Three factors in routine care data combined might prove valuable in future strategies to improve the prediction of CRC risk in primary care. Improvement in quality and availability of routine care data for research and risk stratification is needed to optimize its usability for prediction purposes in daily practice.

IMPACT

Only referring patients at the highest risk for colonoscopy by the GP could decrease superfluous colonoscopies.

Importance of reporting segmental bowel preparation scores during colonoscopy in clinical practice

AIM: To evaluate the impact of reporting bowel preparation using Boston Bowel Preparation Scale (BBPS) in clinical practice.

METHODS: The study was a prospective observational cohort study which enrolled subjects reporting for screening colonoscopy. All subjects received a gallon of polyethylene glycol as bowel preparation regimen. After colonoscopy the endoscopists determined quality of bowel preparation using BBPS. Segmental scores were combined to calculate composite BBPS. Site and size of the polyps detected was recorded. Pathology reports were reviewed to determine advanced adenoma detection rates (AADR). Segmental AADR’s were calculated and categorized based on the segmental BBPS to determine the differential impact of bowel prep on AADR.

RESULTS: Three hundred and sixty subjects were enrolled in the study with a mean age of 59.2 years, 36.3% males and 63.8% females. Four subjects with incomplete colonoscopy due BBPS of 0 in any segment were excluded. Based on composite BBPS subjects were divided into 3 groups; Group-0 (poor bowel prep, BBPS 0-3) n = 26 (7.3%), Group-1 (Suboptimal bowel prep, BBPS 4-6) n = 121 (34%) and Group-2 (Adequate bowel prep, BBPS 7-9) n = 209 (58.7%). AADR showed a linear trend through Group-1 to 3; with an AADR of 3.8%, 14.8% and 16.7% respectively. Also seen was a linear increasing trend in segmental AADR with improvement in segmental BBPS. There was statistical significant difference between AADR among Group 0 and 2 (3.8% vs 16.7%, P < 0.05), Group 1 and 2 (14.8% vs 16.7%, P < 0.05) and Group 0 and 1 (3.8% vs 14.8%, P < 0.05). χ² method was used to compute P value for determining statistical significance.

CONCLUSION: Segmental AADRs correlate with segmental BBPS. It is thus valuable to report segmental BBPS in colonoscopy reports in clinical practice.

A plasma microRNA panel for early detection of colorectal cancer

Colonoscopy remains the standard screening method for detecting colorectal cancer (CRC) at an early stage. However, many people avoid having a colonoscopy because of the fear for its potential complications. Our study aimed to identify plasma microRNAs for preliminarily screening CRC in general population, so that some unnecessary colonoscopies can be avoided. We investigated plasma microRNA expression in three independent cohorts including the discovery (n = 80), training (n = 112), and validation (n = 49) phases recruited at two medical centers. Microarrays were used for screening 723 microRNAs in 80 plasma samples to identify candidate microRNAs. Quantitative reverse-transcriptase PCR was performed on the 161 training and validation plasma samples to evaluate the candidate microRNAs discovered from microarrays. A logistic regression model was constructed based on the training cohort and then verified by using the validation dataset. Area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic accuracy. We identified a panel of miR-409-3p, miR-7, and miR-93 that yielded high diagnostic accuracy in discriminating CRC from healthy group (AUC: 0.866 and 0.897 for training and validation dataset, respectively). Moreover, the diagnostic performance of the microRNA panel persisted in nonmetastasis CRC stages (Dukes' A-B, AUC: 0.809 and 0.892 for training and validation dataset, respectively) and in metastasis CRC stages (Dukes' C-D, AUC: 0.917 and 0.865 for training and validation dataset, respectively). In conclusion, our study reveals a plasma microRNA panel that has potential clinical value in early CRC detection and would play a critical role on preliminarily screening CRC in general population.

Colorectal cancer detection using targeted serum metabolic profiling

Colorectal cancer (CRC) is one of the most prevalent and deadly cancers in the world. Despite an expanding knowledge of its molecular pathogenesis during the past two decades, robust biomarkers to enable screening, surveillance, and therapy monitoring of CRC are still lacking. In this study, we present a targeted liquid chromatography-tandem mass spectrometry-based metabolic profiling approach for identifying biomarker candidates that could enable highly sensitive and specific CRC detection using human serum samples. In this targeted approach, 158 metabolites from 25 metabolic pathways of potential significance were monitored in 234 serum samples from three groups of patients (66 CRC patients, 76 polyp patients, and 92 healthy controls). Partial least-squares-discriminant analysis (PLS-DA) models were established, which proved to be powerful for distinguishing CRC patients from both healthy controls and polyp patients. Receiver operating characteristic curves generated based on these PLS-DA models showed high sensitivities (0.96 and 0.89, respectively, for differentiating CRC patients from healthy controls or polyp patients), good specificities (0.80 and 0.88), and excellent areas under the curve (0.93 and 0.95). Monte Carlo cross validation was also applied, demonstrating the robust diagnostic power of this metabolic profiling approach.

Competition in Colon Cancer Screening? What Is the Role of Colonoscopy?

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the Western world. The incidence could be reduced if this cancer were to be diagnosed at an early stage of disease. A competition has started between the existing screening methods to be the most efficient in detecting premalignant conditions. This review illustrates the current state of screening techniques for CRC.

METHOD

Pubmed was searched for meta-analyses and prospective studies on screening for CRC, with an emphasis on colonography, computed tomographic colonography (CTC), magnetic resonance colonography (MRC), stool DNA testing, and colon capsule endoscopy, and critical appraisal of the research was done by the reviewers.

RESULTS

The imaging techniques (CTC and MRC) had similar detection rates for bigger lesions (≥10 mm) as colonoscopy. High-definition colonoscopy showed better efficiency with smaller lesions. The techniques developing around colonoscopy such as the retro-viewing colonoscope, the balloon colonoscope, or the 330-degree viewing colonoscope try to enhance efficacy by reducing the adenoma miss rate in right-sided, non-polypoid lesions. Colon capsule endoscopy and the stool detection systems are limited to identifying cancer but not necessarily adenomas.

CONCLUSION

Colonoscopy is the preferred CRC screening strategy and the undisputed gold standard in terms of efficacy.

Colonoscopy as a tool for evaluating colorectal tumor development in a mouse model

PURPOSE

A sporadic colon cancer mouse model with conditional mutations in adenomatous polyposis coli (Apc) is biologically relevant for human colorectal cancer (CRC). This study aimed to determine the utility and limitations of colonoscopy for evaluating colon tumors in this mouse model.

METHODS

We compared the estimates of location, size, and miss rate of tumors detected during colonoscopy with those determined by necropsy. Sixty-six CPC-Apc mice originating from Apc (F/wt) mice harbor a Cdx2-Cre transgene in which colorectal tumorigenesis was driven by Apc allelic loss. The sensitivity and specificity of colonoscopy for detecting tumors in a mouse CRC model were investigated.

RESULTS

A strong positive correlation was found between tumor location as measured by colonoscopy and the location determined by necropsy (p < 0.001). A total of 120 tumors were graded during colonoscopy (grades 1-5: 0, 8, 20, 27, and 65 lesions, respectively), and a strong positive correlation was found between the tumor grade determined by colonoscopy and size measured by necropsy (grades 2-5: 2.08, 2.98, 4.02, and 5.09 mm, respectively; p < 0.005). Although the miss rate was 47.1 %, most of the missed tumors (96 %) were in close proximity (within 5 mm) of another tumor.

CONCLUSIONS

A colonoscopic method for the reliable measurement of colorectal tumors in vivo has been established. The application of this technique to mouse models of colon carcinogenesis will provide a better understanding of the dynamics of tumor growth.

Ultrasound detection of colonic polyps: perspective

Colorectal cancer is often preventable if the precursor adenoma is detected and removed. Although ultrasound is clearly not one of the widely accepted screening techniques, this non-invasive and radiation-free modality is also capable of detecting colonic polyps, both benign and malignant. Such colon lesions may be encountered when not expected, usually during general abdominal sonography. The discovery of large colonic polyps is important and can potentially help reduce the incidence of a common cancer, whereas detection of a malignant polyp at an early stage may result in a curative intervention. This pictorial review highlights our experience of sonographic detection of colonic polyps in 43 adult patients encountered at our institutions over a 2-year period. 4 out of 50 discovered polyps were found to be malignant lesions, 3 polyps were hyperplastic, 1 polyp was a hamartomatous polyp and the rest were benign adenomas. The smallest of the detected polyps was 1.3 cm in diameter, the largest one was 4.0 cm (mean 1.7 cm; median 1.6 cm). In each case, polyps were discovered during a routine abdominal or pelvic examination, particularly when scanning was supplemented by a brief focused sonographic inspection of the colon with a 6-10 MHz linear transducer. In this paper, we illustrate the key sonographic features of different types of commonly encountered colonic polyps in the hope of encouraging more observers to detect these lesions, which may be subtle.

Aspectos epidemiológicos dos pólipos e lesões plano-elevadas colorretais

INTRODUÇÃO: Os pólipos e as lesões plano-elevadas colorretais são importantes na prevenção do câncer colorretal pelo risco de malignização dos adenomas. OBJETIVO: traçar o perfil demográfico dos pacientes com diagnóstico endoscópico de pólipos e/ou lesões plano-elevadas colorretais no Hospital Universitário da Universidade Federal de Sergipe e Torres Centro Médico. MÉTODOS: Foram avaliados 6.919 prontuários de 2002 a 2007, enfatizando-se as variáveis: idade, gênero, procedência e indicação; número, tamanho, morfologia, histologia, grau de displasia, topografia, lesões sincrônicas e metacrônicas, e diagnósticos associados. RESULTADOS: Foram encontradas 1.031 (13,51%) lesões em 935 exames, correspondendo a 826 pacientes, 46% masculino e 54% feminino. A idade variou de 3 a 96 anos, com média de 53,64. A distribuição topográfica mais frequente das lesões polipoides foi em reto e sigmoide (58,40%). As lesões eram sésseis em 52,80%, pediculadas em 27,90% e plano-elevadas em 19,30% dos casos. Ocorreram lesões sincrônicas em 23,48% e metacrônicas em 30,10% dos pacientes. Histologicamente, 43,36% eram adenomas, sendo 85,70% tubulares, 9,60% tubulo-vilosos e 4,70% vilosos; 30,64% eram pólipos hiperplásicos, 15,80% inflamatórios e 10,20% possuíam outros tipos histológicos. Os adenomas apresentavam displasia de baixo grau em 83,40% dos casos e alto grau em 16,60%. Sete eram adenocarcinomas, um carcinoide e um tumor gastrointestinal estromal. CONCLUSÕES: A colonoscopia e a polipectomia são importantes no diagnóstico e prevenção do câncer colorretal.

Adenomatous colorectal polyps in patients referred for colonoscopy in a regional hospital in Kuwait

BACKGROUND/AIM

Adenomatous colorectal polyps (ACPs) are known to be the precursor lesions for colorectal cancer. The aim of the study was to determine the prevalence, endoscopic and pathological features of ACPs in patients referred for colonoscopy.

PATIENTS AND METHODS

The endoscopic and histological reports of adult patients who underwent complete colonoscopy in the gastroenterology unit of a regional Kuwaiti hospital between January 2008 and December 2008 were retrospectively studied. The specimens of polyps were reviewed by an experienced pathologist who was blinded to the clinical or endoscopic information. Non-neoplastic polyps were not included in the analysis.

RESULTS

Of 530 eligible patients (mean age, 45 years; male-female ratio, 2:1), 54 (10%) had 103 ACPs. Of the patients with ACPs (mean age, 57 years), 43 (80%) were males and 36 (67%) were Kuwaitis. Histopathological examination of the most significant polyp in each patient revealed that 40 (74%) polyps were tubular adenomas (TAs); 11 (20%), tubulovillous (TV) adenomas; and 3 (6%), villous adenomas. High-grade dysplasia was noticed in 4 (10%) adenomas. Fifteen (2.8%) of the 530 patients had advanced ACPs. Logistic regression analysis of some variables and their association with ACPs found that age (P < 0.001; OR, 1.9; CI, 1.5-2.3), history of adenoma (P=0.001; OR, 6.4; CI, .2.1-19.4) and being Kuwaitis (P=0.029; OR, 2.1; CI, 1.1-4.1) to be independently associated with ACPs.

CONCLUSION

The most common histological type of ACPs was tubular adenoma. Advancing age, being Kuwaiti nationals and prior removal of ACPs were significantly associated with the occurrence of ACPs.

APC and its modifiers in colon cancer

Colon cancer closely follows the paradigm of a single "gatekeeper gene." Mutations inactivating the APC (adenomatous polyposis coli) gene are found in approximately 80% of all human colon tumors and heterozygosity for such mutations produces an autosomal dominant colon cancer predisposition in humans and in murine models. However, this tight association between a single genotype and phenotype belies a complex association of genetic and epigenetic factors that together generate the broad phenotypic spectrum ofboth familial and sporadic colon cancers. In this Chapter, we give a general overview of the structure, function and outstanding issues concerning the role of Apc in human and experimental colon cancer. The availability of increasingly close models for human colon cancer in genetically tractable animal species enables the discovery and eventual molecular identification of genetic modifiers of the Apc-mutant phenotypes, connecting the central role of Apc in colon carcinogenesis to the myriad factors that ultimately determine the course of the disease.

Colorectal cancer screening

Colorectal cancer (CRC) constitutes the second leading cause of death from cancer in the United States. Increased screening for CRC have been associated with a decreased incidence in the past two decades. Continued efforts are necessary to maintain this trend. Appropriate risk stratification of individuals and compliance with recommended screening strategies are important. Colonoscopy continues to play an important role in screening; however, several different screening options are available for average-risk individuals. This article reviews the current options open to physicians to adequately screen patients for CRC based on inherit risks.

Endoluminal compression clip: full-thickness resection of the mesenteric bowel wall in a porcine model

BACKGROUND

Performing a full-thickness intestinal wall resection of a sessile polyp located on the mesenteric side with a compression clip may lead to compression of mesenteric vessels. The application of such a clip may therefore cause a compromised blood supply in the particular bowel segment, leading to perforation.

OBJECTIVE

To evaluate the performance of a newly developed, nitinol compression clip, called the NiTi clamp, for full-thickness resection of the bowel wall, while the clip is deliberately deployed endoluminally on the mesenteric side.

DESIGN

Prospective animal study. Multinational, multidisciplinary; gastroenterology and general surgery, research cooperation.

SETTING

Animal research laboratory.

INTERVENTION

Six pigs were operated upon and endoscopically evaluated and then killed after 3 weeks. Linear compression closure clips based on nitinol springs were used. Three longitudinal enterotomies were performed: in the cecum, spiral colon, and proximal rectum. Four clips were deployed in each animal.

MAIN OUTCOME MEASUREMENTS

A total of 23 clips were deployed. The average expulsion day was 9 days.

RESULTS

All but 3 clips were normally expelled. One pig developed bowel ischemia due to intussusception. In endoscopic procedures, no signs of significant segmental mucosal ischemia were found. The macroscopic appearance of the compression closure lines was thin and delicate, but epithelialization was significantly delayed at 5 sites.

LIMITATION

Differences between porcine and human colorectal anatomy.

CONCLUSION

Full-thickness clamping of the bowel with the NiTi clamp, including the local mesenteric vasculature, does not significantly impair local healing of the clamp site and gives hope to further development of novel full-thickness endoscopic resection technologies.

Intact and cleaved forms of the urokinase receptor enhance discrimination of cancer from non-malignant conditions in patients presenting with symptoms related to colorectal cancer

Background:

Colorectal cancer (CRC) is a leading cause of cancer-related morbidity and mortality in developed countries. It is known that early detection results in improved survival, and consequently there is a need for improved diagnostic tools in CRC. The plasma level of soluble urokinase plasminogen activator receptor (suPAR) was proposed as a marker in CRC patients. This study was undertaken to evaluate the individual molecular forms of suPAR as discriminators in a group of patients undergoing endoscopical examination following symptoms related to colorectal cancer.

Methods:

In a case–control study comprising 308 patients undergoing endoscopical examination following CRC-related symptoms, 77 CRC patients with adenocarcinoma were age and gender matched to: 77 patients with adenomas; 77 with other non-malignant findings, and 77 with no findings. The different uPAR forms were measured in citrate plasma collected before endoscopical examination, using three different Time Resolved – Fluorescence Immuno Assays (TR-FIA's).

Results:

All soluble uPAR forms were found to be significantly higher in cancer patients than in patients presenting with other non-malignant findings; uPAR(I) P=0.0006, suPAR(I–III) P<0.0001 and suPAR(I–III)+(II–III) P<0.0001, whereas no significant difference was found when performing similar comparisons for patients presenting with adenomas. The odds ratio (OR) for the comparison of uPAR(I) in patients with CRC to subjects with other non-malignant findings was 3.44 (95% CI:1.86–6.37). CRC patients had a mean elevated level of 20.9% (95% CI:10.2–32.6) for suPAR(I–III) and 18.5% (95% CI:9.0–28.8) for suPAR(I–III)+(II–III) compared with subjects with non-malignant findings.

Conclusions:

The findings confirm reports on increased uPAR expression in cancer patients and in particular elevated levels of suPAR in blood from CRC patients and indicate that suPAR levels in blood are increasing during carcinogenesis. Although none of the measured uPAR forms were cancer specific, our findings suggest that uPAR expression could be useful in the early detection of CRC when combined with other markers and clinical variables.

Screening and surveillance for the early detection of colorectal cancer and adenomatous polyps, 2008: a joint guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology

In the United States, colorectal cancer (CRC) is the third most common cancer diagnosed among men and women and the second leading cause of death from cancer. CRC largely can be prevented by the detection and removal of adenomatous polyps, and survival is significantly better when CRC is diagnosed while still localized. In 2006 to 2007, the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology came together to develop consensus guidelines for the detection of adenomatous polyps and CRC in asymptomatic average-risk adults. In this update of each organization's guidelines, screening tests are grouped into those that primarily detect cancer early and those that can detect cancer early and also can detect adenomatous polyps, thus providing a greater potential for prevention through polypectomy. When possible, clinicians should make patients aware of the full range of screening options, but at a minimum they should be prepared to offer patients a choice between a screening test that primarily is effective at early cancer detection and a screening test that is effective at both early cancer detection and cancer prevention through the detection and removal of polyps. It is the strong opinion of these 3 organizations that colon cancer prevention should be the primary goal of screening.

Cancer stem cells: the lessons from pre-cancerous stem cells

How a cancer is initiated and established remains elusive despite all the advances in decades of cancer research. Recently the cancer stem cell (CSC) hypothesis has been revived, challenging the long-standing model of "clonal evolution" for cancer development and implicating the dawning of a potential cure for cancer [1]. The recent identification of precancerous stem cells (pCSCs) in cancer, an early stage of CSC development, however, implicates that the "clonal evolution" is not contradictory to the CSC hypothesis, but is rather an aspect of the process of CSC development [2]. The discovery of pCSC has revealed and will continue to reveal the volatile properties of CSC with respects to their phenotype, differentiation and tumorigenic capacity during initiation and progression. Both pCSC and CSC might also serve as precursors of tumor stromal components such as tumor vasculogenic stem/progenitor cells (TVPCs). Thus, the CSC hypothesis covers the developing process of tumor-initiating cells (TIC) --> pCSC --> CSC --> cancer, a cellular process that should parallel the histological process of hyperplasia/metaplasia (TIC) --> precancerous lesions (pCSC) --> malignant lesions (CSC --> cancer). The embryonic stem (ES) cell and germline stem (GS) cell genes are subverted in pCSCs. Especially the GS cell protein piwil2 may play an important role during the development of TIC --> pCSC --> CSC, and this protein may be used as a common biomarker for early detection, prevention, and treatment of cancer. As cancer stem cell research is yet in its infancy, definitive conclusions regarding the role of pCSC can not be made at this time. However this review will discuss what we have learned from pCSC and how this has led to innovative ideas that may eventually have major impacts on the understanding and treatment of cancer.

Technology insight: endoscopic submucosal dissection of gastrointestinal neoplasms

Gastrointestinal neoplasms can be cured by local resection as long as the lesions are in the early stage and have not metastasized. Endoscopic resection is a minimally invasive treatment for early-stage gastrointestinal neoplasms, and endoscopic submucosal dissection (ESD) is one type of endoscopic resection that has been developed in the past 10 years. For ESD to be a reliable, curative treatment for gastrointestinal neoplasms, it is necessary for the endoscopist to detect the lesion early, make a precise pretreatment diagnosis, ensure that the patient has the correct indication for endoscopic resection, and have the skill to perform ESD. For early lesion detection, endoscopists should pay attention to subtle changes in the surface structure, the color of the mucosa and the visibility of underlying submucosal vessels. Chromoendoscopy and magnifying endoscopy are useful for determining the margin of the lesions for pretreatment diagnosis, and endoscopic ultrasonography and magnifying endoscopy are useful for determining the depth of invasion. For ESD to be successful, local injection of sodium hyaluronate helps maintain mucosal elevation during dissection. Selecting the appropriate knife, using transparent hoods wisely, employing a good strategy that uses gravity, and having good control of bleeding are all needed to make ESD reliable.

Cancer risk in endoscopically unresectable colon polyps

BACKGROUND

The purpose of the current study was to define the rate of underlying malignancy in endoscopically unresectable polyps.

METHODS

An institutional review board-approved review identified all patients undergoing colectomy for radiologically identified or endoscopically unresectable polyps between 1997 and 2006. Patients were included if the endoscopic impression and biopsy findings suggested an adenomatous polyp without invasive cancer. Patient information was abstracted.

RESULTS

Eighty procedures in 79 patients were identified. Median patient age was 66 (range 38 to 85) years, and patients were predominately male (98%) and Caucasian (73%). The median endoscopic size of polyps was 3.0 cm (range 0.8 to 10 cm). Polyps were most frequently proximal to the splenic flexure (72%). Biopsy histology included 36 (51%) tubulovillous and villous adenomas. Invasive cancer was identified in 13 of 80 (16%) subsequent surgical specimens, but only 3 of 71 (4%) were lymph node-positive. Surgical morbidity was 37% and in-hospital mortality 3%. Size of polyp (P = .81) and histologic type (P = .34) were not significantly associated with invasive cancer. Compared with polyps proximal to the splenic flexure, polyps located distally were more likely to harbor malignancy (rate; P < .02), by both univariate and multivariate analysis (odds ratio [OR] 1.38 [95% confidence interval 1.07 to 1.8]).

CONCLUSION

The cancer risk in polyps deemed inappropriate for endoscopic resection was lower than previously reported. Neither polyp size nor histologic type appeared to be significantly associated with invasive cancer. Location of an endoscopically unresectable polyp distal to the splenic flexure confers an increased risk for occult malignancy.

Endoscopic mucosal resection (EMR) in the management of large colo-rectal polyps

BACKGROUND

Colonoscopic polypectomy plays a major role in preventing colo-rectal cancer. However, resection of sessile, broad-based pedunculated and flat lesions carries a high risk of perforation. Endoscopic Mucosal Resection (EMR) may significantly reduce this risk. We aim to assess the safety and efficacy of EMR in our unit.

PATIENTS AND METHODS

A review of a prospective database over a 3-year period identified 87 patients who underwent endoscopic polypectomy for polyps in sizes from 10 to 50 mm, performed by two experienced endoscopists. A total of 33 EMRs were performed on 30 lesions in 24 of these patients.

RESULTS

Median size of lesions was 20 mm. Most were located in the rectum and sigmoid. 22 lesions were resected en-bloc while 8 were resected piecemeal. Histologically these lesions were predominantly adenomatous polyps. An incidental focus of adenocarcinoma was found in 7 lesions. Histologically complete excision was achieved in 10 lesions. Although histological completeness of excision was not confirmed in 19 lesions, repeat colonoscopy confirmed successful excision. Only one lesion was incompletely excised requiring surgical resection. Bleeding occurred during 2 EMRs, both times successfully controlled by further injection of adrenaline locally. There was no case of bowel perforation. Further surveillance colonoscopy was performed according to established guidelines. Median follow-up period was 21 months. None of the patients diagnosed with adenocarcinoma showed any evidence of recurrence.

CONCLUSION

Within our unit endoscopic mucosal resection appeared to be safe and effective procedure for resecting large colorectal polyps not suitable for conventional polypectomy. This data would support prompt referral of lesions fulfilling these criteria to specialist units offering this service to avoid unnecessary surgery.

Local recurrence after transanal endoscopic microsurgery for rectal polyps and early cancers

BACKGROUND

Transanal endoscopic microsurgery (TEM) allows for local excision of rectal neoplasms with greater exposure than transanal excision and less morbidity than transabdominal approaches. This study examines the implications of the procedure with respect to predictors of recurrence.

METHODS

We performed a retrospective analysis of 144 consecutive TEMs from 1993 to 2004.

RESULTS

The study comprises 107 patients presenting for TEM with benign disease and 32 patients with cancer. Patients had a mean age of 64+/-14 (SD) years. TEM was performed for recurrent lesions in 17% of cases. Pathologic classification of the lesions after TEM was benign adenoma in 45%, adenoma with high-grade dysplasia (HGD) in 17%, cancer in 33%, and other in 4%. Complications occurred in 10%, and local recurrence occurred in 15% of patients. Median follow-up was 44 months, with a median time to recurrence of 14 months. Positive margins did not influence lesion recurrence. Recurrence of cancers correlated with the depth of tumor invasion (P<.05). On multivariate analysis, independent predictors of recurrence were lesion size and the presence of HGD within adenomas (P<.05). Five-year neoplastic recurrence probabilities were 11% for benign adenomas, 35% for adenomas with HGD, and 20% for cancers (P=.31); invasive recurrence probabilities were 0% for benign adenomas, 15% for adenomas with HGD, and 13% for cancers (P<.05).

CONCLUSIONS

Close endoscopic follow-up is warranted after TEM for both benign and malignant disease, with special attention to lesions with HGD. TEM can be performed safely for early rectal cancer with careful patient selection.

Polypoid pleomorphic sarcoma of the colon

In contrast to common colonic epithelial neoplasms, polypoid mesenchymal tumors of the colon are extremely rare. The majority of uncommon gastrointestinal mesenchymal tumors are associated with the so-called gastrointestinal stromal tumors (GIST). We present a case of a rare colonic pleomorphic sarcoma, macroscopically mimicking a common epithelial colonic polyp, which did not match the criteria of GIST. In this case report we discuss the clinical and pathological characteristics of a rare polypoid-shaped, pleomorphic colonic sarcoma and refer a mark-off to other rare mesenchymal neoplasms of the gut.

Family history assessment to detect increased risk for colorectal cancer: conceptual considerations and a preliminary economic analysis

BACKGROUND

Although the rationale for earlier screening of persons with a family history of colorectal cancer is plausible, there is no direct evidence that earlier assessment is either effective or cost-effective.

OBJECTIVE

To estimate the clinical and economic effect of using family history assessment to identify persons for colorectal cancer screening before age 50.

METHODS

We developed a decision model to compare costs and outcomes for two scenarios: (a) standard population screening starting at age 50; (b) family history assessment at age 40, followed by screening colonoscopy at age 40 for those with a suggestive family history of colorectal cancer. The analysis was conducted using the health insurer perspective.

RESULTS

Using U.S. population estimates, 22 million would be eligible for family history assessment, and one million would be eligible for early colonoscopy; 2,834 invasive cancers would be detected, and 29,331 life years would be gained. The initial program cost would be USD $900 million. The discounted cost per life year gained of family history assessment versus no assessment equals USD $58,228. The results were most sensitive to the life expectancy benefit from earlier screening, the cost of colonoscopy, and the relative risk of colon cancer in those with a family history.

CONCLUSIONS

The cost-effectiveness of family history assessment for colorectal cancer approaches that of other widely accepted technologies; yet, the results are sensitive to several assumptions where better data are needed. Because of the relatively high prevalence of family history in the population, careful analysis and empirical data are needed.

Do forceps biopsies truthfully reflect the nature of endoscopically uncovered polypoid lesions of the colon?

BACKGROUND

Total excision of colonic polyps is not always attainable and in some patients it is clinically contraindicated. Also, a resected polyp may be lost at any step between its endoscopic removal and its embedding in paraffin. The aim of this study was to compare the histological features of colonic polyps as analysed by the study of biopsy-forceps obtained samples with those assessed on scrutinizing the totally resected growths.

PATIENTS AND METHODS

This prospective study included a cohort of 59 patients in whom, in the course of an elective colonoscopy, a total excision of a 6 mm-sized or larger polyp was called for. Sizeable biopsies were obtained by means of an Olympus Multibyte forceps prior to the total polypectomy. Subsequent to the study of the polypectomy specimens, the forceps biopsy samples were submitted for histological examination. The pathologists were blinded as to the source of the tissue they were studying. The diagnoses rendered by evaluating the biopsy samples and polypectomy specimens of each patient were contrasted with each other.

RESULTS

Major discrepancies between the histological features of the fragments captured by the biopsy-forceps and the factual nature of the totally removed polyps were uncovered in 11 (18.6%) of 59 cases. Intriguingly, the grade of the tumours was underrated in all the 11 cases, as judged by contrasting the tentative diagnoses of the forceps-biopsies with the decisive diagnoses of the polypectomies. Importantly, 2 adenocarcinomas would have been missed by just looking at the forceps-retrieved sample.

CONCLUSIONS

In our experience, a discordance of 18.6% is to be expected between the diagnoses rendered after examining forceps-biopsies of and totally excised colonic polyps. Nevertheless, it is advisable to procure biopsies prior to the excision of the growths, because on those occasions in which patients' growths cannot be removed or have not been retrieved for one reason or another, a small forceps-captured tissue sample correctly reflects the characteristics of the polyp in 81.4% of the cases. Finally, the biopsies may be discarded in the event that total removal was successful.

[Oncologic screening with whole-body MRI: possibilities and limitations]

In the last decade the interest in radiological screening examination increased among informed laymen enormously. Independent from the evidence of whole-body examinations for cancer prevention the discussion about screening must again be considered again due to the newest technical developments, since MRI of the whole-body with high spatial resolution is feasible now within one single examination. The newest system permits simultaneous connection of up to 76 coil elements and signal reception from 32 independent receiving channels. Whole-body MRI including magnetic resonance colonography (MRC) is feasible within 60 min. In this review potential investigation protocols will be presented. Potentials, challenges and limitations of whole-body MRI in the prevention of the malignancies most frequently leading to death are discussed on the basis own experiences examples and the literature.

CT colonography: feasibility of substantial dose reduction--comparison of medium to very low doses in identical patients

In a feasibility study, the authors compared polyp detection and interobserver variability at computed tomographic (CT) colonography in 15 patients with doses ranging from medium to very low (12.00-0.05 mSv). At levels down to 2% of the medium dose, the mean detection of polyps 5 mm or larger remained at least 74%, while the number of false-positive results decreased and the interobserver agreement remained constant. Initial observations indicate that it is feasible to reduce the radiation dose required for CT colonography. Further studies are needed, however, to investigate the clinical value of very low-dose CT colonography.

Nephroangiography in Wegener's granulumatosis. A comparison with panarteritis nodosa

Three cases of Wegener's granulomatosis with a classical course are described, 2 of which with fatal outcome in spite of immuno-suppressive therapy. Nephroangiography was performed during the oliguric or anuric phase. The appearances were similar to those encountered in glomerulonephritis and were compared with those in three cases of panarteritis nodosa. Two of these represented the classical form with intrarenal arterial aneurysms; the third was a case of the microscopic type presenting blurred intrarenal arteries with lumen variations and occlusions. These observations support the opinion that Wegener's granulomatosis nodosa are different diseases. Nephroangiography seems to be of value in their differentiation.