Pathologic Features of Initial Adenomas as Predictors for Metachronous Adenomas of the Rectum
04 Nov 1998-Journal of the National Cancer Institute (Oxford University Press)-Vol. 90, Iss: 21, pp 1661-1665
TL;DR: The risk of metachronous adenomas is closely related to the pathology of initial adenomatous polyps, thus allowing identification of a high-risk group of adenoma patients for close surveillance after their initial polypectomy.
Abstract: Background Colorectal cancer is the third most common cancer in the world, arising mostly from pre-existing adenomatous polyps (adenomas) of the large bowel. Patients with colorectal adenomas are at increased risk of colorectal cancer because of a high recurrence rate for adenomas. We followed a cohort of 1490 patients with rectal adenomas to determine whether recurrence might be related to pathologic characteristics of the initial adenomas. Methods The patients were identified in Haining County, China, from 1977 through 1978 by means of examination with a 15-cm rigid sigmoidoscope. They were followed by endoscopic examination at years 2, 4, 6, 11, and 16 after their initial polypectomy. New adenomas in the rectum were identified in 280 patients in these follow-up examinations. Results Statistically significant twofold to threefold elevated risks of metachronous (recurrent) adenomas were observed for patients who had more than two initial adenomas or whose most advanced initial adenoma was more than 1.0 cm in size, was of villous/tubulovillous type, or showed moderate to severe dysplasia. Much stronger associations were observed for advanced metachronous neoplasms, which are defined as cancers or adenomas with severe dysplasia, with multivariate adjusted relative risks (95% confidence interval) of 4.2 (1.8-9.9) for a large initial adenoma (>1.0 cm), 8.1 (4.2-15.6) for villous/tubulovillous architecture, and 14.4 (5.0-41.3) for severe dysplasia. In particular, patients who had a large (>1.0 cm) adenoma with severe dysplasia at baseline had a relative risk of 37 (7.8-174.7) of developing advanced metachronous neoplasms compared with patients who had small adenoma(s) with mild dysplasia. Conclusions The risk of metachronous adenomas is closely related to the pathology of initial adenomas, thus allowing identification of a high-risk group of adenoma patients for close surveillance after their initial polypectomy.
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01 Jan 2008
TL;DR: This document summarizes current capabilities, research and operational priorities, and plans for further studies that were established at the 2015 USGS workshop on quantitative hazard assessments of earthquake-triggered landsliding and liquefaction in the Central American region.
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TL;DR: Recommendable surveillance after colorectal cancer has greater consensus, but concerns remain and studies that predict the need and the needed timing of surveillance remain an important research priority.
Abstract: Surveillance examinations after detection of an adenoma are one of the largest contributors to the cost of colorectal cancer screening. Screening colonoscopy, beginning at the age of 50 years, is increasing in frequency and becoming part of the zeitgeist. Given the high rate of adenomatous polyp detection on colonoscopy, the amount of time spent and costs consumed by surveillance are likely to grow to significant levels in the coming years. Guidelines for surveillance examinations vary across specialty organizations. Individuals with advanced adenomas are at increased risk for recurrent advanced adenomas. The impact of multiple nonadvanced adenomas or a single nonadvanced adenoma on subsequent risk of an advanced adenoma or cancer is less clear. Recommended surveillance after colorectal cancer has greater consensus, but concerns remain. Studies that predict the need and the needed timing of surveillance remain an important research priority.
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TL;DR: It is considered that the significant parameters for dysplasia and malignant lesions are the size of lesions, multiplicity of polyps and villous architecture, and the main histological type was tubulo-villous adenomas.
Abstract: Although many papers had described the role of colo-rectal adenomas and the risk for colon cancer, there is a lack of data about epidemiological factors, the histological type, the pit-pattern and type of polyps in Romania. In polypoid adenomas the risk of malignant transformation is well known and is increasing over time, with size and villous architecture. In this paper we evaluate the predictive parameters that allowed us to establish a correlation between the macroscopical aspect and histological architecture of adenomas in our geographical area (South-West region of Romania). Two predictive parameters of cancer characterize early neoplastic lesions: their size and their surface elevation (elevated, flat or depressed). The morphology of adenomas and multiplicity of polyps also have a prognostic value. In our study the main localization of polyps was in the left colon, while the main histological type was tubulo-villous adenomas. We consider that the significant parameters for dysplasia and malignant lesions are the size of lesions, multiplicity of polyps and villous architecture.
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01 Jan 2012TL;DR: This chapter introduces the special situation and research work of colorectal tumors in China, which include the progress of epidemiological study on coloretectal cancer, the clue of microbe pathogens with coloreCTal cancer and the prevention strategy, and sequencing colorectoral cancer screening.
Abstract: Colorectal cancer is one of the most rapidly increasing cancers in China. It accounted for about 391,000 new cases and 186,800 deaths in 2007 from 38 registered area’s data, but the incidence rate of 29.4 lower than US rate of 46.4 is still not very high. There were some different high-risk factors of colorectal tumor compared with the Western countries. In this chapter, we will introduce the special situation and research work of colorectal tumors in China, which include the progress of epidemiological study on colorectal cancer, the clue of microbe pathogens (microcystin and H. pylori ) with colorectal cancer and the prevention strategy, and sequencing colorectal cancer screening.
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TL;DR: Chemoprevention has the potential to represent a cost-effective intervention, particularly when targeted at intermediate-risk populations, ages 61-70, following polypectomy, and may be combined with a cardiovascular and Alzheimer prophylaxis.
Abstract: Colorectal cancer (CRC) is a major health concern worldwide. In 2011 1,200,000 new cases are predicted and half of them are going to die from the disease. CRC carcinogenesis is a multi-step process that spans over 10–20 years, providing a window of opportunity for effective intervention. CRC can be prevented by life style modification and screening program. However, although these strategies are standard clinical practice, their impact is limited due to low adherence. The number of deaths due to CRC remains alarming high, and makes CRC prevention a paramount. Chemoprevention interferes with the carcinogenesis process by targeting key molecular pathways. It involves the use of a variety of natural or chemical compounds that can delay, prevent or even reverse the adenoma to carcinoma sequence. Numerous chemopreventive agents have been studied but the most efficient are the NSAID group of agents. Much of their efficacy and toxicity has been attributed to their potent inhibition of the cyclooxygenase (COX) enzymes. Chemoprevention has the potential to represent a cost-effective intervention, particularly when targeted at intermediate-risk populations, ages 61–70, following polypectomy. Chemoprevention in this setting is as very important as polyp recurrence in this population can be as high as 50%, even with surveillance colonoscopy every 1–3 years. The most challenging task is to find the proper place for these interventions in the entire effort of general wellbeing. Subjects are likely to be more adherent to prescribed regimens if cancer prevention may be combined with a cardiovascular and Alzheimer prophylaxis. Subjects with a normal colon or non advanced adenomas can be safely monitored with surveillance colonoscopy every 5–10 years. The ideal chemopreventive agent remains to be discovered with great emphasis on the need not to harm. Possibly, combinations of agents will maximize effectiveness while limiting drug toxicity. Finally, personalized approaches would include the ability to predict risk, as well as benefit for a specific individual based on specific SNP's or other genetic profiles.
3 citations
References
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TL;DR: A model for the genetic basis of colorectal neoplasia that includes the following salient features is presented, which may be applicable to other common epithelial neoplasms, in which tumors of varying stage are more difficult to study.
11,576 citations
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TL;DR: The results of the National Polyp Study support the view that colorectal adenomas progress to adenocarcinomas, as well as the current practice of searching for and removing adenomatous polyps to prevent coloreCTal cancer.
Abstract: Background The current practice of removing adenomatous polyps of the colon and rectum is based on the belief that this will prevent colorectal cancer. To address the hypothesis that colonoscopic polypectomy reduces the incidence of colorectal cancer, we analyzed the results of the National Polyp Study with reference to other published results. Methods The study cohort consisted of 1418 patients who had a complete colonoscopy during which one or more adenomas of the colon or rectum were removed. The patients subsequently underwent periodic colonoscopy during an average follow-up of 5.9 years, and the incidence of colorectal cancer was ascertained. The incidence rate of colorectal cancer was compared with that in three reference groups, including two cohorts in which colonic polyps were not removed and one general-population registry, after adjustment for sex, age, and polyp size. Results Ninety-seven percent of the patients were followed clinically for a total of 8401 person-years, and 80 percent returned...
4,310 citations
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TL;DR: Evidence is presented which suggests that most cancers of the colon and rectum have evolved through the polyp‐cancer sequence although the majority of adenomas do not become cancerous during a normal adult life span.
Abstract: The malignant potential of adenomas of the colon and rectum varies with size, histological type and grade of epithelial atypia. The adenomatous polyp is usually small and has a low malignant potential, whereas tumors with a villous structure are usually larger and have a much higher cancer rate. Severe atypia is more common in villous adenomas than in adenomatous polyps. Evidence is presented which suggests that most cancers of the colon and rectum have evolved through the polyp-cancer sequence although the majority of adenomas do not becoma cancerous during a normal adult life span. The slow evolution of the polyp-cancer sequence is stressed. The implications of the polyp-cancer sequence for the design of cancer prevention programmes and the study of the aetiology of large bowel cancer are discussed.
1,944 citations
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TL;DR: The long-term risk of colorectal cancer after rigid-instrument sigmoidoscopy and polypectomy in 1618 patients with rectosigmoid adenomas who did not undergo surveillance was assessed, finding that surveillance may not be of value because the risk of cancer is so low.
Abstract: Background and Methods Surveillance by repeated colonoscopy is currently recommended for patients with colorectal adenomas. We assessed the long-term risk of colorectal cancer after rigid-instrument sigmoidoscopy and polypectomy in 1618 patients with rectosigmoid adenomas (tumors of the rectum or distal sigmoid colon) who did not undergo surveillance. A total of 22,462 person-years of observation were accrued (mean, 14 years per patient). Results The incidence of subsequent rectal cancer in these patients was similar to that in the general population (standardized incidence ratio, 1.2; 95 percent confidence interval, 0.7 to 2.1). Most rectal cancers developed in patients whose adenomas had been inadequately removed; the risk was very low after complete removal. The risk of subsequent colon cancer depended on the histologic type, size, and number of adenomas in the rectosigmoid. Among 842 patients with a rectosigmoid adenoma that was tubulovillous, villous, or large (≥1 cm), colon cancer developed...
1,018 citations
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TL;DR: Colonoscopy performed three years after colonoscopic removal of adenomatous polyps detects important colonic lesions as effectively as follow-up colonoscopy after both one and three years.
Abstract: Background The identification and removal of adenomatous polyps and post-polypectomy surveillance are considered to be important for the control of colorectal cancer. In current practice, the intervals between colonoscopies after polypectomy are variable, often a year long, and not based on data from randomized clinical trials. We sought to determine whether follow-up colonoscopy at three years would detect important colonic lesions as well as follow-up colonoscopy at both one and three years. Methods Patients were eligible if they had one or more adenomas, no previous polypectomy, and a complete colonoscopy and if all their polyps had been removed. They were randomly assigned to have follow-up colonoscopy at one and three years or at three years only. The two study end points were the detection of any adenoma, and the detection of adenomas with advanced pathological features (defined as those >1 cm in diameter and those with high-grade dysplasia or invasive cancer). Results Of 2632 eligible patients, 141...
933 citations