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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Memorial Sloan Kettering Cancer Center1, Harvard University2, Boston University3, University of Texas MD Anderson Cancer Center4, American Cancer Society5, Oregon Health & Science University6, University of Utah7, Kaiser Permanente8, University of Minnesota9, University of Colorado Denver10, University of Vermont11, University of Texas Southwestern Medical Center12, Creighton University13, Eastern Virginia Medical School14, Indiana University15
TL;DR: In this article, a careful analytic approach was designed to address all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be stratified more definitely at their baseline colonoscopy into those at lower risk or increased risk for a subsequent advanced neoplasia.
677 citations
Memorial Sloan Kettering Cancer Center1, Harvard University2, Boston University3, University of Texas MD Anderson Cancer Center4, American Cancer Society5, Oregon Health & Science University6, University of Utah7, Kaiser Permanente8, University of Minnesota9, University of Colorado Denver10, University of Vermont11, University of Texas Southwestern Medical Center12, Creighton University13, Eastern Virginia Medical School14, Indiana University15
TL;DR: A careful analytic approach was designed addressing all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be more definitely stratified at their baseline colonoscopy into those at lower or increased risk for a subsequent advanced neoplasia.
Abstract: Adenomatous polyps are the most common neoplastic findings uncovered in people who undergo colorectal screening or have a diagnostic workup for symptoms. It was common practice in the 1970s for these patients to have annual follow-up surveillance examinations to detect additional new adenomas as well as missed synchronous adenomas. As a result of the National Polyp Study report in 1993, which demonstrated clearly in a randomized design that the first postpolypectomy examination could be deferred for 3 years, guidelines published by a gastrointestinal consortium in 1997 recommended that the first follow-up surveillance be 3 years after polypectomy for most patients. In 2003, these guidelines were updated, colonoscopy was recommended as the only follow-up examination, and stratification at baseline into lower and higher risk for subsequent adenomas was suggested. The 1997 and 2003 guidelines dealt with both screening and surveillance. However, it has become increasingly clear that postpolypectomy surveillance is now a large part of endoscopic practice, draining resources from screening and diagnosis. In addition, surveys have demonstrated that a large proportion of endoscopists are conducting surveillance examinations at shorter intervals than recommended in the guidelines. In the present paper, a careful analytic approach was designed addressing all evidence available in the literature to delineate predictors of advanced pathology, both cancer and advanced adenomas, so that patients can be more definitely stratified at their baseline colonoscopy into those at lower or increased risk for a subsequent advanced neoplasia. People at increased risk have either three or more adenomas, or high-grade dysplasia, or villous features, or an adenoma ≥1 cm in size. It is recommended that they have a 3-year follow-up colonoscopy. People at lower risk who have one or two small (<1 cm) tubular adenomas with no high-grade dysplasia can have a follow up in 5 to 10 years, whereas people with hyperplastic polyps only should have a 10-year follow up as average-risk people. Recent papers have reported a significant number of missed cancers by colonoscopy. However, high-quality baseline colonoscopy with excellent patient preparation and adequate withdrawal time should minimize this and reduce clinicians' concerns. These guidelines were developed jointly by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society to provide a broader consensus and thereby increase utilization of the recommendations by endoscopists. Adoption of these guidelines nationally can have a dramatic impact on shifting available resources from intensive surveillance to screening. It has been shown that the first screening colonoscopy and polypectomy produces the greatest effects on reducing the incidence of colorectal cancer in patients with adenomatous polyps.
597 citations
Cites background from "Pathologic Features of Initial Aden..."
...Most of the studies that assessed risk factors for advanced adenomas at surveillance were either randomized controlled trials of surveillance,(25) chemoprevention trials, prospective surveillance studies,(24) or registry-based observational cohort studies of patients returning for surveillance with less structured follow up outside the context of a clinical trial.(7,12,21,30,31,33,35) The most consistent evidence for predicting subsequent advanced adenomas indicates that multiplicity, size, villous histology, and high-grade dysplasia are the important factors at baseline....
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...0 cm at baseline.(30) Noshirwani, et al....
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...4), respectively, for the development of subsequent advanced neoplasia (rectal cancer or severe dysplasia) in patients with moderate and severe dysplasia at baseline.(30) Lieberman, et al....
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...High-grade dysplasia is related to larger adenoma size and villous component at baseline and is an important predictor for subsequent advanced neoplasia in three of the observational cohort studies.(7,24,30) By definition, all adenomas have some level of dysplasia....
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...0) for the detection of advanced neoplasms (rectal cancer, or adenoma with severe dysplasia) at follow up.(30) Loeve reported a significant trend for increasing risk of colorectal cancer at surveillance in relationship to increasing villous component or carcinoma in situ compared with tubular histology....
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University of Arizona1, Dartmouth College2, Portland VA Medical Center3, National Institutes of Health4, Memorial Sloan Kettering Cancer Center5, Veterans Health Administration6, University of Minnesota7, United States Department of Veterans Affairs8, Harvard University9, Fred Hutchinson Cancer Research Center10
TL;DR: Factors that are associated most strongly with risk of advanced neoplasia are patient age and the number and size of prior adenomas.
507 citations
TL;DR: There is a strong association between results of baseline screening colonoscopy and rate of serious incident lesions during 5.5 years of surveillance and patients with 1 or 2 tubular adenomas less than 10 mm represent a low-risk group compared with other patients with colon neoplasia.
402 citations
TL;DR: Large or proximally located adenomas are important indicators of recurrence of advanced lesions and careful surveillance of this area is warranted.
255 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
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
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
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
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