Flat-type early colorectal cancer preferentially develops in right-sided colon in older patients

Potential Factors Predicting Histopathologically Upgrade Discrepancies between Endoscopic Forceps Biopsy of the Colorectal Low-Grade Intraepithelial Neoplasia and Endoscopic Resection Specimens

BACKGROUND

It was gradually accepted that endoscopic fragment biopsy (EFB) diagnosis cannot accurately guarantee the absence of higher-grade neoplasms within the lesion of the digestive tract. There are no well-established predictors for histopathologically upgrade discrepancies between EFB diagnosing colorectal low-grade intraepithelial neoplasia (LGIN) and endoscopic resection (ER) specimens.

METHODS

A total of 918 colorectal LGINs was histopathologically diagnosed by EFB, including 162 cases with upgrade discrepancy and 756 concordant cases. We compared clinicopathological data of EFB and ER specimens between these two groups. Multivariate analysis was performed to identify predictors for this upgrade histopathology.

RESULTS

The predominant upgrade discrepancy of LGINs diagnosed by EFB was upgrades to high-grade dysplasia (114/918, 12.4%), followed by upgrades to intramucosal carcinoma (33/918, 3.6%), submucosal adenocarcinoma (10/918, 1.1%), and advanced adenocarcinoma (5/918, 0.5%). NSAID history (OR 4.83; 95% CI, 2.27-10.27; p < 0.001), insufficient EFB number (OR 2.99; 95% CI, 1.91-4.68; p < 0.001), maximum diameter ≥ 1.0 cm (OR 6.18; 95% CI, 1.32-28.99; p = 0.021), lobulated shape (OR 2.68; 95% CI, 1.65-4.36; p < 0.001), erythema (OR 2.42; 95% CI, 1.50-3.91; p < 0.001), erosion (OR 7.12; 95% CI, 3.91-12.94; p < 0.001), surface unevenness (OR 2.31; 95% CI, 1.33-4.01; p = 0.003), and distal location of the target adenoma (OR 3.29; 95% CI, 1.68-6.41; p < 0.001) were associated with the histologically upgrade discrepancies.

CONCLUSION

NSAID history, insufficient EFB number, adenoma size and location, and abnormal macroscopic patterns are potential predictors for upgrade histopathology of LGINs diagnosed by EFBs. The standardization of EFB number and advanced imaging techniques could minimize the risk of neglecting the potential of this upgrade histopathology.

A twelve-year study of the prevalence, risk factors and characteristics of interval colorectal cancers after negative colonoscopy

INTRODUCTION

The objective of our study was to describe and analyse the Post-Colonoscopy Colorectal Cancers (PCCRCs) and endoscopist performance-related risk factors in the Isère regional screening programme.

METHOD

This was a population-based retrospective cohort study between 2002-2013, where Post-Colonoscopy Colorectal Cancers (PCCRCs) were defined as colorectal adenocarcinoma diagnosed between six and sixty months post-colonoscopy following a positive gFOBT. We analysed the endoscopist performance-related risk factors of the 62 gastroenterologists who had carried out at least 30 colonoscopies during this period.

RESULTS

During the period reviewed, there were 10,557 negative colonoscopies performed. Fifteen post-colonoscopy colorectal cancers were diagnosed from 2002-2013 with an average patient age of 67.1 years. Men comprised 73% of the cases and 53% of all the cases were found in the distal colon. These 15 cases comprised 1.1% of all Colorectal Cancers (CRCs) diagnosed in the screening programme, with an incidence rate of 0.42 (0.21-0.77) per 1,000 person-years. The aetiological breakdown was as follows: 47% related to missed cancers, 27% were new cancers, 20% were failed biopsy detection, and 6% related to incomplete removal. The Adenoma Detection Rate (ADR) among gastroenterologists was an average of 30%, but large heterogeneity was present within this number, ranging from 11% to 49%.

CONCLUSION

The post-colonoscopy colorectal cancer prevalence and incident rate were low relative to the literature. However, significant heterogeneity was present in the adenoma detection rate. Decreasing this heterogeneity by establishing a national benchmark, regular performance feedback and training modules should homogenise adenoma detection rates and decrease the number of interval cancers in the region.

Variations in clinical features and oncologic behaviors of T1 colorectal cancer according to tumor location

BACKGROUND

Different genetic characteristics according to tumor location result in variations in survival rates and treatment responses in advanced colorectal cancer (CRC). However, the effects of tumor location during early CRC are still unclear.

METHODS

Patients with T1 CRC treated between 2003 and 2019 were enrolled from a prospectively collected database. Patients were once divided into four groups, then combined into two groups (right- and left-sided CRC) according to the tumor location, and clinical features and oncologic behaviors were compared.

RESULTS

In total, 458 patients were analyzed. Right-sided CRC had a lower incidence of polypoid type tumor than left-sided CRC (36/126 (28.6%) vs 186/332 (56.0%), p < 0.001). There were no differences in tumor size, pathological grade, pT1 substage and lymphovascular invasion between right- and left-sided CRC. Overall, lymph nodal involvement was observed in 42/458 (9.1%) patients. Right-sided CRC had a lower rate of patients with lymph nodal involvement than left-sided CRC (6/126 (4.8%) vs 36/332 (10.8%), p = 0.04).

CONCLUSION

The present study revealed that there were significant differences in the macroscopic type and the incidence of lymph node involvement between right- and left-sided CRC. The clinical features and oncologic behaviors of T1 CRC are possible to vary according to tumor location.

Clinicopathological features of colorectal polyps in 2002 and 2012

BACKGROUND/AIMS

There are few comparative studies on the historical changes in the clinicopathologic characteristics of colorectal polyps in Korea. This retrospective study compared the clinicopathologic characteristics of colorectal polyps treated at our institution in 2002 and 2012.

METHODS

The medical records of 1,816 patients who underwent colonoscopy and were found to have colorectal polyps in 2002 (n = 597) or 2012 (n = 1,219) were reviewed retrospectively. Patient characteristics and polyp sizes, gross morphologies, locations, and pathologic results were analyzed and compared.

RESULTS

Mean age was older in the 2002 group than in the 2012 group (67.3 ± 11.1 years vs. 55.4 ± 10.8 years, p < 0.001). The 1,816 study subjects had a total of 3,723 colorectal polyps, with a mean of 2.05 polyps per patient. Mean polyp size was larger in the 2002 group than in the 2012 group (0.6 ± 0.4 cm vs. 0.4 ± 0.3 cm, p < 0.001). The most common histology was tubular adenoma and they were more common in the right colon in both study groups. Although the distribution of total adenoma was not significantly different between groups, the location of advanced adenoma differed significantly and was more common in the right colon in the 2012 group (30.4% vs. 63.2%, p = 0.01).

CONCLUSION

No significant change in total polyps and adenoma distribution was found between 2002 and 2012. However, advanced adenoma was more common in the right colon in 2012, which cautiously suggests a locational shift from the left to right colon. These findings indicate that right colon polyps require more attention.

A Clinical Wide-Field Fluorescence Endoscopic Device for Molecular Imaging Demonstrating Cathepsin Protease Activity in Colon Cancer

PURPOSE

Early and effective detection of cancers of the gastrointestinal tract will require novel molecular probes and advances in instrumentation that can reveal functional changes in dysplastic and malignant tissues. Here, we describe adaptation of a wide-field clinical fiberscope to perform wide-field fluorescence imaging while preserving its white-light capability for the purpose of providing wide-field fluorescence imaging capability to point-of-care microscopes.

PROCEDURES

We developed and used a fluorescent fiberscope to detect signals from a quenched probe, BMV109, that becomes fluorescent when cleaved by, and covalently bound to, active cathepsin proteases. Cathepsins are expressed in inflammation- and tumor-associated macrophages as well as directly from tumor cells and are a promising target for cancer imaging. The fiberscope has a 1-mm outer diameter enabling validation via endoscopic exams in mice, and therefore we evaluated topically applied BMV109 for the ability to detect colon polyps in an azoxymethane-induced colon tumor model in mice.

RESULTS

This wide-field endoscopic imaging device revealed consistent and clear fluorescence signals from BMV109 that specifically localized to the polypoid regions as opposed to the normal adjacent colon tissue (p < 0.004) in the murine colon carcinoma model.

CONCLUSIONS

The sensitivity of detection of BMV109 with the fluorescence fiberscope suggested utility of these tools for early detection at hard-to-reach sites. The fiberscope was designed to be used in conjunction with miniature, endoscope-compatible fluorescence microscopes for dual wide-field and microscopic cancer detection.

Yield of adenomas and colorectal cancers within 5 years of a negative colonoscopy: are the guidelines guiding?

BACKGROUND

Screening for colorectal cancers outside the recommended guidelines presents a considerable burden to resource management in many public hospitals. The aim of this study is to evaluate the frequency, indications and outcomes for repeat colonoscopy performed within 5 years of a negative colonoscopy.

METHODS

A retrospective review of all colonoscopies at Nambour Hospital in 2008 was performed to identify those with a negative colonoscopy. The charts of patients undergoing repeat colonoscopy at the same institution within 5 years of a negative colonoscopy were examined further, and data obtained regarding indications and outcomes of subsequent colonoscopies.

RESULTS

A total of 616 colonoscopies were identified, 427 (69.3%) were negative for adenoma and carcinoma. Of these patients, 74 (17.3%) underwent a repeat colonoscopy at Nambour Hospital within 5 years. Eighteen out of 74 (24.3%) were outside guideline recommendation. Overall, one patient (1.4%) had cancer and 11 patients (14.9%) had polyps detected at repeat colonoscopy. Most of the polyps detected had low-risk features and were detected in the fourth and fifth years of the study period.

CONCLUSION

The yield of a second colonoscopy within 5 years of a good-quality negative colonoscopy is low but not zero. In the absence of new concerning symptoms or other risk factors, patients can be reassured and guidelines adhered to.

Meta-Analysis of the Effect of Bowel Preparation on Adenoma Detection: Early Adenomas Affected Stronger than Advanced Adenomas

Background and Aims

Low-quality bowel preparation reduces efficacy of colonoscopy. We aimed to summarize effects of bowel preparation on detection of adenomas, advanced adenomas and colorectal cancer.

Methods

A systematic literature search was performed regarding detection of colonic lesions after normal and low-quality bowel preparation. Reported bowel preparation quality was transformed to the Aronchick scale with its qualities “excellent”, “good”, “fair”, “poor”, and “insufficient” or “optimal” (good/excellent), “suboptimal” (fair/poor/insufficient), “adequate” (good/excellent/fair) and “inadequate” (poor/insufficient). We identified two types of studies: i) Comparative studies, directly comparing lesion detection according to bowel preparation quality, and ii) repeat colonoscopy studies, reporting results of a second colonoscopy after previous low-quality preparation.

Results

The detection of early adenomas was reduced with inadequate vs. adequate bowel preparation (Odds Ratio (OR) 0.53, CI: 0.46–0.62, p<0.001). The advanced adenomas were affected less in comparison (0.74, CI: 0.62–0.87, p<0.001). The large number of subjects considered in the present meta-analysis resulted in smaller confidence intervals compared to earlier studies. Classifying the bowel-preparation quality as suboptimal vs. optimal led to the same qualitative conclusion (OR: 0.81, CI: 0.74–0.89, p<0.001 for early adenomas, OR: 0.94, CI: 0.87–1.01, n.s. for advanced adenomas). Bowel preparation was equally important for right-sided/ flat/ serrated vs. other lesions in most observational studies but more relevant in some repeat colonoscopy studies; data regarding carcinoma detection were insufficient.

Conclusion

Inadequate bowel preparation affects detection of early colonic lesions stronger than advanced lesions.

Prevalence of advanced histological features and synchronous neoplasia in patients with flat adenomas

BACKGROUND AND AIMS

The prevalence of advanced histology in flat adenomas is uncertain. There are limited data on the prevalence of synchronous adenomas in patients with flat adenomas. The aims of this study were to determine whether the flat adenomas harbor advanced histology more than the polypoid adenomas and whether the presence of flat adenomas is an independent predictor of synchronous adenomas.

METHODS

A retrospective analysis of data from 3 prospective clinical trials conducted at 2 tertiary care referral centers that included patients undergoing screening or surveillance colonoscopy was performed. The location, size, and morphology of each polyp resected was documented and sent for histopathological examination in a unique specimen jar.

RESULTS

A total of 2931 polyps were removed in 1340 patients. Of the 1911 adenomas (65.2%), 293 (15.3%) were flat and 1618 (84.7%) were polypoid. The prevalence of advanced histology did not differ between flat and polypoid adenomas (1.4% vs 3.1%; P = .13). Multivariate analysis confirmed that the presence of at least 1 flat adenoma was a predictor of the presence of a large adenoma (P < .01; odds ratio [OR], 2.80; 95% CI, 1.86-4.22), advanced adenoma (P < .01; OR, 2.70; 95% CI, 1.80-4.06), and 3 or more adenomas (P < .01; OR, 2.44; 95% CI, 1.66-3.59).

CONCLUSION

Although the prevalence of advanced histology in flat adenomas is similar to that of polypoid adenomas, flat adenomas are associated with increased prevalence of synchronous large and advanced adenomas. Whether these results imply shorter surveillance intervals in patients with flat adenomas needs to be explored in future studies.

Prevalence of non-polypoid colorectal neoplasms in southern Brazil

BACKGROUND AND AIM

Several studies suggest that non-polypoid lesions (NPL) show higher aggressiveness than polypoid lesions, particularly depressed lesions. The present study aimed to assess the prevalence of NPL and the presence of advanced histology in a Brazilian population.

METHODS

Two thousand and sixty-seven superficial neoplastic lesions diagnosed in 1135 patients were analyzed. Lesions were classified as polypoid and non-polypoid (flat and depressed) types, and evaluated for site, size, and histology (adenoma with grade of dysplasia, or early cancer).

RESULTS

Prevalence of NPL was 46.5%. NPL predominated in the right colon (62.9%), whereas polypoid lesions were detected mainly in the left colon (53.2%) (P < 0.001). NPL had a 34% higher probability of occurring in the right colon than polypoid lesions (P < 0.001). NPL were smaller than polypoid lesions (P = 0.03). There were 208 lesions >10 mm, of which 40 (19.2%) had advanced histology: 13% (18/138) of polypoid lesions; 27.3% (18/66) of flat lesions; and 100% (4/4) of depressed lesions (P < 0.001). Among 1859 neoplasms ≤10 mm, only 18 (1%) had advanced histology, and 15 of them were depressed lesions (P < 0.001). Advanced histology was more commonly detected in NPL than in polypoid lesions (P = 0.007), with significant difference in size (P < 0.001). NPL showed more advanced histology than polypoid lesions (OR 2.06; P = 0.01), especially depressed lesions (OR 36.35; P < 0.001). Among all neoplasms, the prevalence of depressed lesions was 2.2%.

CONCLUSION

NPL showed high prevalence and higher aggressiveness than polypoid lesions, especially the depressed type.

Advanced imaging in colonoscopy and its impact on quality

Detecting and resecting colonic polyps during endoscopy has been shown to reduce CRC. At the same time, endoscopy has faced substantial technical improvements and continues to undergo major changes. Detection of colorectal neoplasias is facilitated by using high-definition endoscopy, and characterization of lesions is more accurate by using virtual CE. High-definition endoscopy has found widespread use, whereas virtual CE is still more often used in tertiary centers and for high-risk patient groups. Endomicroscopy has opened the door for in vivo histology and functional as well as molecular imaging. Thorough training of the endoscopists is necessary, and redefined reimbursement codes may help make these techniques available in the clinical arena for high-risk patients who are most probable to benefit from the more advanced diagnostic endoscopy techniques. Over recent years, there has also been an increasing push by healthcare payors and providers to improve the quality of healthcare services. The ultimate goal of monitoring quality measures is to improve the overall health of the population and, for colon cancer screening, to reduce the incidence and mortality of colon cancer. However, the development of an appropriate quality measure and ensuring the accuracy of the data on which we base our efforts are among the first challenges that we must meet (Table 1). The continued technologic advancements in colonoscopy and endoscopic imaging may result in improvements in the quality of colonoscopy and should lead to a decrease in the incidence and mortality from colon cancer.

Advances in diagnostic and therapeutic colonoscopy

PURPOSE OF REVIEW

We review current studies on endoscopic and technologic advances for the detection and treatment of colorectal neoplasia.

RECENT FINDINGS

Improvements in adenoma detection have been shown to be possible with the use of high definition white light as well as water-related methods such as water exchange. Use of cap assist colonoscopy, when combined with water-related methods, has recently been shown to also improve the detection of adenomas. Narrow band imaging and confocal laser endomicroscopy may have an advantage of offering endoscopists the ability to make an 'optical diagnosis' with the possibility of discarding nonadenomatous tissue. Furthermore, educational interventions aimed at improving adenoma detection may have lasting effects on endoscopists' adenoma detection rates. Lastly, endoscopic mucosal resection and endoscopic submucosal dissection are being applied for the treatment of large colorectal polyps, obviating the need for surgery in most instances. However, further studies are needed to establish the optimal methods for polyp resection.

SUMMARY

Advances in endoscopic technology are being shown to enhance the detection of early cancers and precancerous lesions. However, these tools may be supplementary to a high-quality colonoscopy using excellent techniques, factors that are now being implemented in training programs.

Validation of the Harefield Cleansing Scale: a tool for the evaluation of bowel cleansing quality in both research and clinical practice

BACKGROUND

Variations in bowel cleansing quality before colonoscopy can cause confounding of results within clinical trials and inappropriate treatment decisions in clinical practice. A new tool-the Harefield Cleaning Scale-has been developed, which addresses the limitations of existing scales.

OBJECTIVE

Validation exercise for the new cleansing scale.

DESIGN

Retrospective validation study.

SETTING

Various colonoscopy units in France.

PATIENTS

Patients who had a total of 337 colonoscopies recorded.

INTERVENTION

Video-recorded colonoscopy.

MAIN OUTCOME MEASUREMENTS

Comparisons of 2 scoring systems to assess direct correlation, interrater reliability, internal consistency, and test-retest reliability, based on assessment of video recordings from 337 colonoscopies.

RESULTS

Correlation analysis for expert scores by using the 2 scales yielded a Spearman correlation coefficient of 0.833. Similarly, the comparison of the segmental sum score revealed a Spearman correlation coefficient of -0.778. Cross-tabulation for successful colon cleansing was 92.88% versus unsuccessful colon cleansing in 7.12%. Reliability assessment indicated an acceptable internal consistency with a Cronbach alpha coefficient of 0.81. Test-retest reliability demonstrated an overall agreement of 0.639 (kappa statistic). Receiver operating characteristic analysis versus Aronchick Scale scores yielded an area under the curve of 0.945, with sensitivity of 99% and specificity of 83% at the optimum score cut-off point.

LIMITATIONS

Test-retest reliability was assessed by using a different patient population to the other measures. There were insufficient patient numbers to assess performance by using adenoma detection rate.

CONCLUSION

This validation analysis has demonstrated that the Harefield Cleansing Scale is a robust, reliable, and consistent tool that has the potential to improve the effective standardization of bowel preparation assessment in both clinical and research practice.

Risk factors associated with colorectal flat adenoma detection

OBJECTIVES

Colorectal flat adenomas have been associated with a higher risk of colorectal malignancy. We describe demographic characteristics and endoscopic findings in patients with colorectal flat adenomas.

METHODS

In total, 1934 consecutive patients undergoing colonoscopy were prospectively included. Polyp shape was classified according to the Japanese classification. Chromoendoscopy was applied whenever a flat lesion was suspected. Indications for colonoscopy, demographic data, and characteristics of neoplastic lesions were recorded. Patients were classified as follows: group 1, no adenomas (n=1250); group 2, only protruding adenomas (n=427); group 3, protruding and flat adenomas (n=118); and group 4, only flat adenomas (n=139).

RESULTS

Approximately one in every 10 patients (13.2%) had flat adenomas. Among them, concomitant protruding adenomas were identified in approximately half of the cases. In multivariate analysis, age older than 50 years [odds ratio (OR)=1.62; 95% confidence interval (CI)=1.08-2.43, P=0.02], protruding adenomas (OR=2.17; 95% CI=1.65-2.87, P<0.001), follow-up colonoscopy for polyps or cancer (OR=2.22; 95% CI=1.59-3.10, P<0.001), screening colonoscopy (OR=1.60, 95% CI=1.15-2.22, P=0.005), and specifically trained endoscopist (OR=2.02, 95% CI=1.53-2.68, P<0.001) were associated independently with flat adenoma detection.

CONCLUSION

Flat adenomas have specific demographic factors that might help to improve detection. Particularly, age older than 50 years, colorectal neoplasia surveillance, and the presence of protruding adenomas should alert endoscopists to the possible presence of these lesions. Trained endoscopists may offer a greater chance of detecting these lesions.

The dimensions of the CRC problem

Colorectal cancer is a significant health problem, the importance of which will increase substantially in the coming years, both in more, as well as in less developed regions of the world. The present paper describes the dimensions of the problem from an epidemiologic viewpoint as well as from the perspective of policy makers and professionals seeking to control the disease. Currently, colorectal cancer is the third most common cancer and the fourth most common cause of cancer deaths worldwide, with 1.2 million estimated cases and 609,000 estimated deaths in 2008. Based on demographic trends, the annual incidence is expected to increase by nearly 80% to 2.2 million cases over the next two decades and most of this increase will occur in the less developed regions of the world (62%). These regions are ill equipped to deal with the rapidly increasing demand for cancer treatment resulting from population growth and higher life expectancy. Concerted efforts to control colorectal cancer are therefore of great importance worldwide. They will require allocation of additional resources and should be based on an appropriate balance between prevention, diagnosis and treatment.

Cholelithiasis is a risk factor for colorectal adenoma

OBJECTIVES

Postcholecystectomy patients show moderate risk of colorectal cancer. However, few studies have investigated the relationship between cholelithiasis and colorectal adenoma. We examined this possibility through a combination of colonoscopy and ultrasonography in asymptomatic Japanese.

METHODS

We reviewed a subgroup of subjects drawn from a prospective annual colonoscopy screening survey. Subjects who underwent both ultrasonography and colonoscopy, and completed a questionnaire regarding lifestyle habits were entered. We investigated whether subjects with cholelithiasis or a previous cholecystectomy showed an increased risk of colorectal adenoma, as compared with subjects with normal gallbladders.

RESULTS

Data of 4,458 subjects (men 3,053, women 1,405, mean age +/- SD 46.1 +/- 8.62 yr) were analyzed. Cholelithiasis was detected in 206 subjects, 4,189 subjects had normal gallbladders, and 63 subjects had cholecystectomies. The prevalence of colorectal adenoma was 29.6% (61/206) in subjects with cholelithiasis, which was significantly higher when compared with normal subjects, with a prevalence of 17.7% (741/4,189, P < 0.001). In cholecystectomy patients, only 15.9% (10/63) developed colorectal adenomas, which was not significantly different from the control group. In a multivariate analysis controlling for sex, age, family history of colorectal cancer, alcohol, smoking, and body mass index, cholelithiasis was shown to be an independent risk factor for colorectal adenoma (adjusted OR 1.57, 95% CI 1.14-2.18). Cholelithiasis was strongly associated with multiple (> or = 3 lesions, adjusted OR 2.39, 95% CI 1.21-4.72) and left-sided colorectal adenomas (adjusted OR 1.82, 95% CI 1.28-2.59).

CONCLUSIONS

Cholelithiasis is a risk factor for colorectal adenoma.

Differences between right- and left-sided colon cancer in patient characteristics, cancer morphology and histology

BACKGROUND AND AIM

Recently, the clinical and biological differences between right- and left-sided colon cancers have been widely debated. However, close analyses of these clinical differences, based on large-scale studies, have been scarcely reported.

METHODS

A total of 3552 consecutive Japanese colorectal cancer cases were examined and the clinical differences between right- and left-sided colon cancer cases were investigated.

RESULTS

The proportion of right-sided colon cancer was relatively high in patients aged less than 40 years (33%) and more than 80 years (43%). The proportion of right-sided colon cancer in patients aged 40-59 years was relatively low (male 22% and female 29%). In male patients the proportion increased in the 70-79 years age group (30%), while in female patients the proportion increased in the 60-69 years age group (39%). Right-sided colon cancer was more likely to be detected at an advanced stage (T1 stage; left 22%, right 15%) (P < 0.01) with severe symptoms. Polypoid-type early cancer was dominant in the left colon (left 59%; right 40%) (P < 0.01), while the proportion of flat-type early cancer in the right colon was significantly higher than that in the left colon (left 25%; right 44%) (P < 0.01).

CONCLUSIONS

Specific age distribution of right-sided colon cancer was observed and the difference between male and female patients was highlighted. Other clinical features also differed between right- and left-sided colon cancer, suggesting that different mechanisms may be at work during right and left colon carcinogenesis.

Clinicopathologic characteristics and malignant potential of colorectal flat neoplasia compared with that of polypoid neoplasia

PURPOSE

Because of their potential for malignancy, flat colorectal neoplasias are a current topic of debate. This study was designed to investigate the clinicopathologic features of flat neoplasia and to compare them with those of polypoid neoplasia, as well as to identify the determinants of malignant transformation of both flat and polypoid colorectal neoplasia.

METHODS

A prospective, cross-sectional study of 3,360 patients diagnosed with adenomas via total colonoscopy and polypectomy was performed at 11 tertiary medical centers between July 2003 and July 2004. In this study, potential risk factors for malignant transformation were analyzed. If multiple adenomas were identified, then only the adenoma with the most advanced degree of histology was recorded for the patient.

RESULTS

Of a total of 3,360 neoplasias identified, we found that the incidence of flat and polypoid neoplasias were 207 (6.2 percent) and 3,153 (93.8 percent), respectively. Patients with flat neoplasias tended to be older (59.6 vs. 57.1, P < 0.01), with the neoplasia located more frequently in the right colon than polypoid neoplasias (49.3 percent vs. 32 percent, P < 0.01). The incidence of high-grade dysplasia or cancer in flat neoplasias was similar to that of polypoid neoplasias (5.4 percent vs. 4.6 percent, P = 0.36). Multivariate analysis revealed that a size of > or =11 mm (odds ratio, 6.8; 95 percent confidence interval, 4.8-9.7) and location in the left colon (odds ratio, 1.6; 95 percent confidence interval, 1.1-2.4) were significant determinants for the malignancy potential of colonic neoplasias.

CONCLUSIONS

The clinicopathologic indices for the propensity of malignant transformation in colorectal neoplasias were a size > or =11 mm and location in the left colon rather than flat gross morphology.

Genetic and epigenetic alterations of Ras signalling pathway in colorectal neoplasia: analysis based on tumour clinicopathological features

Activation of RAS signalling induced by K-ras/BRAF mutations is a hallmark of colorectal tumours. In addition, Ras association domain families 1 and 2 (RASSF1 and RASSF2), the negative regulators of K-ras, are often inactivated by methylation of the promoter region in those tumours. However, reports showing differences in the occurrence of these alterations on the basis of tumour characteristics have been scarce. We analysed K-ras/BRAF mutations and the methylation status of RASSF1 and RASSF2 promoter regions in 120 colorectal adenomas with respect to their clinicopathological features. K-ras/BRAF mutations and RASSF2 methylation were observed in 49 (41%) and 30 (25%) of the samples, respectively, while RASSF1 methylation was observed in only 3 (2.5%). Adenomas with RASSF2 methylation often carried K-ras/BRAF mutations simultaneously (22 out of 30, P<0.01). Multivariate analysis revealed that the concomitance of these alterations was frequently observed in serrated adenomas (odds ratio (OR) 11.11; 95% confidence interval (CI) 1.96–63.00), but rarely in adenomas located in the sigmoid or descending colon (OR 0.13; 95% CI 0.03–0.58). A comparison between adenomas and cancers showed a significantly higher prevalence of these alterations in cancers than in adenomas in the proximal colon (58 vs 27%, P=0.02). Frequency and the time point of the occurrence of Ras signalling disorders differ according to colorectal neoplasia’s characteristics, particularly the location.

Sensitivity of immunochemical fecal occult blood test to small colorectal adenomas

BACKGROUND

Although the immunochemical fecal occult blood test (FOBT) is reportedly more sensitive to large adenomas or colorectal cancer (CRC) than the guaiac-based FOBT, the sensitivity of the immunochemical FOBT to small adenomas has scarcely been reported. Previous reports have indicated that the guaiac-based FOBT can detect small adenomas only by serendipity.

OBJECTIVES

To investigate the sensitivity of immunochemical FOBT to small adenomas using a large-scale cohort.

METHODS

We analyzed 21,805 consecutively enrolled asymptomatic persons who underwent colonoscopy and immunochemical FOBT.

RESULTS

The sensitivity to adenomas </=9 mm was significantly higher than the false-positive rate as revealed by analysis of all eligible subjects (7.0%vs 4.5%, P < 0.001). In men, the sensitivity was superior to the false-positive rate and increased with age (<50 yr 6.1% and >60 yr 11.3%). On the other hand, the sensitivity in women was not significantly different from the false-positive rate in any generation (5.1%vs 4.7% for all eligible women, P= 0.72).

CONCLUSIONS

Immunochemical FOBT detected a small percentage of small adenomas in men at a rate that is significantly higher than the false-positive rate. Studies comparing the guaiac and immunochemical FOBTs using the end point of CRC-related death are expected.

The clinical and endoscopic characteristics, treatment, and long-term prognosis of early colorectal cancer in Taiwan

PURPOSE

This study was designed to realize the incidence, clinical and endoscopic characteristics, treatment, and prognosis of early colorectal cancer in Taiwan.

METHODS

A retrospective study was conducted to review the data from January 1, 1991 to December 31, 2005 at the National Taiwan University Hospital. Patients' clinical information, demographic data, endoscopic pictures, treatment regimens, pathologic, and outcome details for these cases were reviewed, recorded, and analyzed. Mann-Whitney U test and log-rank test were used for the statistical analysis.

RESULTS

A total of 61 patients from this 15-year period were included (39 males; mean age of disease onset, 63.5 years). The follow-up period ranged from 0.05 to 15 (mean, 6.8) years. Five-year survival rate in our early colorectal cancer patients was 98.4 percent. The size of the early colorectal cancer ranged from 0.3 to 5 cm with the mean of 1.4 cm. The most common site of early colorectal cancer was the sigmoid colon (56.1 percent). Protruded (Type I) lesions accounted for the majority (73.6 percent) of the cases. Endoscopic polypectomy/mucosectomy was the most common type of treatment (72.3 percent). There was no statistical difference in the survival status between the endoscopic treatment group and the operation group (log-rank test, P = 0.368).

CONCLUSIONS

Most of the early colorectal cancer lesions could be removed successfully by endoscopic method without mortality and major morbidity. However, regular follow-up after treatment is recommended even after five years to reduce early colorectal cancer mortality and morbidity.

Systematic review: oral bowel preparation for colonoscopy

BACKGROUND

There are many published trials of colon cleansing regimens for colonoscopy but no clear consensus regarding relative performance.

AIM

To identify high quality controlled trials comparing two or more bowel preparation regimens and to compare efficacy and tolerability.

METHODS

A comprehensive systematic review was carried out to identify candidate studies. Quality appraisal was carried out on all identified studies. Results were meta-analysed where possible and qualitatively compared if not.

RESULTS

Eighty-two studies qualified for analysis. Polyethylene glycol and sodium phosphate were the most frequently investigated preparations. There was no significant efficacy difference between the two, but sodium phosphate was better tolerated. Sodium picosulphate/magnesium citrate, a commonly prescribed preparation, was investigated in four studies, with no clear benefit over other regimens demonstrated. Safety was not recognized as a problem in the randomized controlled trials. Published case series demonstrate that sodium phosphate is associated with the highest risk of clinically significant electrolyte disturbances.

CONCLUSION

Shortcomings in study design limit the value of many of the studies. Based on these results, no single bowel preparation emerges as consistently superior. New preparations are required that combine better efficacy and tolerability, in addition to rigorous new validated study designs, allowing unequivocal comparisons to be made.

Changing sites of colorectal cancer in the Israeli Jewish ethnic populations and its clinical implications

Countries at risk for colorectal cancer noted an increase in right-sided colorectal cancer. We examined this in the Israeli Jewish populations. Israel Cancer Registry data, 1982-2001, were computed by sex, age, ethnic group and colorectal cancer site: 'rectal cancer' included the recto-sigmoid junction, 'right-sided' colorectal cancer included proximal colon up to and including the splenic flexure. In both sexes, colorectal cancer trends increased significantly owing to colonic cancer (P<0.01) whereas rectal cancer decreased (P<0.01). Left and right colorectal cancer trends decreased in Israel born people (P<0.01), but in Asia-Africa born people increases were seen at both sites in the male (P=0.02 and 0.06, respectively) and female (P=0.03 and 0.01, respectively) population. In those > or =65 years old, right colorectal cancer trends increased in all men (P=0.05) and women (P=0.01). On comparing data from 1982-1986 with that from 1997-2001 right colorectal cancer showed an increase in both sexes (P<0.01): to 32.7% of male colorectal cancer and 57.6% of female colorectal cancer. In the period 1997-2001, the total male population > or =65 years had increased relatively by 7.5% (P<0.01), and women by 22.6% (P<0.01) and the proportion of right colorectal cancer in > or =65 years olds increased relatively by 10.9% in the male population, and 18.2% in the female population, with one-third of this increase occurring in Russian immigrants arriving after 1990. In conclusion, there is a trend for right colorectal cancer in Jews aged > or =65 years. The proportion and amount of colorectal cancer increased most significantly in older women, which was partially explained by their increasing numbers and by colorectal cancer occurring in recent immigrants from Russia, who were at high-risk for colorectal cancer. These results should influence colorectal cancer screening and diagnostic methodologies used.

Differential gene expression between flat adenoma and normal mucosa in the colon in a microarray analysis

BACKGROUND

Flat adenomas in the colon are associated with a relatively higher potential for malignancy. Distinct genes may be involved in the development of flat adenoma. The aim of this study was to profile gene expression changes in flat adenomas in the colon.

METHODS

A genomewide expression analysis was carried out by using flat adenoma and adjacent normal mucosa in the colon to detect differences in gene expression. Because the right and left colon have different embryonic origins, each sample was classified according to its location, and the gene expression levels between flat adenoma and adjacent normal mucosa were also compared among samples derived from the right or left colon.

RESULTS

A total of 180 genes were differentially expressed between flat adenoma and normal mucosa in the colon, including matrix metalloproteinase 7 (MMP7), cadherin 3 (CDH3), S100P, and dual oxidase 2 (DUOX2). In addition, a total of 89 and 49 genes were differentially expressed between flat adenoma and normal mucosa among the samples from the right and left colon, respectively. Subsequent quantitative real-time reverse transcriptase-polymerase chain reaction supported the reliability of the expression analysis. Immunohistochemical analysis confirmed differential CDH3 and MMP7 protein expression.

CONCLUSIONS

This is the first report characterizing the genes differentially expressed in flat adenomas using a microarray analysis. Considerable differences in the gene expression profiles of flat adenomas also exist between the right and left colon. These data should lead to new insights into the pathogenesis of flat adenomas in the colon as well as to new therapeutic strategies.

Risk assessment for delayed hemorrhagic complication of colonic polypectomy: polyp-related factors and patient-related factors

BACKGROUND

Hemorrhage is among the most serious complications of colorectal polypectomy and may occur after a longer postprocedure interval.

OBJECTIVE

We aimed to elucidate the risk factors for delayed postpolypectomy hemorrhage, including both polyp characteristics and the general condition of the patients.

DESIGN

Retrospective cohort study.

PATIENTS

A total of 6617 cases of colorectal polypectomy was performed in 3138 consecutive patients in Japan.

MAIN OUTCOME MEASUREMENTS

The risk factors for delayed postpolypectomy hemorrhage were assessed among polyp characteristics (form, size, histologic features) and the method of resection by unconditional logistic regression. Patient conditions (smoking, alcohol, hypertension, diabetes mellitus, hyperlipidemia) were compared between case-control pairs matched on polyp-related characteristics by conditional logistic regression.

RESULTS

Hemorrhage occurred in 38 lesions (0.57%) of 37 patients (1.2%): 22 required endoscopic hemostasis and 1 required blood transfusion. Although polyp size was associated with the occurrence of delayed hemorrhage (10.0 +/- 6.9 mm in hemorrhage cases vs 5.6 +/- 3.8 mm in others, P < .0001), other polyp-related factors were not significant. Hypertension was a complication in 25 of 37 (68%) cases and in 21 of 74 (28%) matched controls, showing an adjusted odds ratio of 5.6 (95% CI 1.8-17.2, P = .001). Other patient characteristics were not significant. The interval between polypectomy and hemorrhage was significantly longer in patients with hypertension (median 6 days, range 2-14 days) than in those without hypertension (2.5 days, 1-9 days; P = .019).

LIMITATIONS

This study does not provide information regarding prevention of hemorrhage.

CONCLUSIONS

Hypertension is a significant risk factor for delayed colorectal postpolypectomy hemorrhage. The interval between polypectomy and hemorrhage can be as long as 14 days in the presence of hypertension.