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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Polyp Prevention Trial (PPT) is a multicenter randomized controlled trial examining the effect of a low-fat (20% of total energy intake), high-fiber (18 g/1000 kcal), high-vegetable and -fruit (5-8 daily servings) dietary pattern on the recurrence of adenomatous polyps of the large bowel, precursors of most colorectal malignancies. Eligibility criteria include one or more adenomas removed within 6 months of randomization; complete nonsurgical polyp removal and complete colonic examination to the cecum at the qualifying colonoscopy: age 35 years of more; no history of colorectal cancer, inflammatory bowel disease, or large bowel resection; and satisfactory completion of a food frequency questionnaire and 4-day food record. Of approximately 38,277 potential participants with one or more polyps recently resected, investigators at eight clinical centers randomized 2,079 (5.4%; 1,037 in the intervention and 1,042 in the control arm) between June 1991 and January 1994, making the PPT the largest adenoma recurrence trial ever conducted. Of PPT participants, 35% are women and 10% are minorities. At study entry, participants averaged 61.4 years of age; 14% of them smoked, and 22% used aspirin. At the baseline colonoscopy, 35% of participants had two or more adenomas, and 29% had at least one large (> of = 1 cm) adenoma. Demographic, behavioral, dietary, and clinical characteristics are comparable across the two study arms. Participants have repeat colonoscopies after 1 (T(1)) and 4 (T(4)) years of follow-up. The primary end point is adenoma recurrence; secondary end points include number, size, location, and histology of adenomas. All resected lesions are reviewed centrally by gastrointestinal pathologists. The trial provides 90% power to detect a reduction of 24% in the annual adenoma recurrence rate. The primary analytic period, on which sample size calculations were based is 3 years (T(1) to T(4)), which permits a 1-year lag time for the intervention to work and allows a more definitive clearing of lesions at T(1), given that at least 10-15% of polyps may be missed at baseline. The final (T(4)) colonoscopies are expected to be completed in early 1998.
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PMID:The polyp prevention trial I: rationale, design, recruitment, and baseline participant characteristics. 916 4

In contrast to normal colorectal mucosa, peanut-agglutinin-(PNA)-reactive glycoconjugates are commonly expressed in most colorectal carcinomas and in some pre-malignant conditions such as adenomas and ulcerative colitis. Since enzymatically detectable galactose-beta1-3-N-acetyl-galactosamine residues are found in rectal mucus obtained from patients with carcinoma of the large bowel, it was investigated here whether PNA-reactive carbohydrate structures in rectal mucus can be exploited in the detection of colorectal neoplasia. Samples of rectal mucus obtained from 261 randomly selected patients with colorectal symptoms were applied on nitrocellulose filters. The presence of PNA-reactive glycoconjugates in mucus samples was determined by a peroxidase-conjugated PNA-overlay procedure. The results were correlated to findings from total colonoscopy/surgery and histopathology. PNA-reactive carbohydrate structures were detected in 76% of patients with carcinoma (p < 0.005), in 62% of patients with adenoma (p < 0.005), in 69% of patients with inflammatory bowel disease (p < 0.005), and in 38% of patients with hyperplastic polyps (NS), in contrast to 21% of the control subjects with macroscopically normal colorectal mucosa. These results show that PNA-reactive carbohydrate alterations in rectal mucus correlates with neoplastic and hyperproliferative conditions of the colorectal mucosa. The specificity of the PNA test for colorectal neoplasia was 76%. Therefore the use of more discriminate carbohydrate probes are needed for the pre-symptomatic detection of colorectal neoplasia.
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PMID:Detection of colorectal neoplasia with peanut-agglutinin (PNA)-reactive carbohydrate structures in rectal mucus. 942 64

Dysplasia in inflammatory bowel disease (IBD) is categorized as either flat or associated with a raised lesion or mass (dysplasia-associated lesion or mass [DALM]). One specific subtype of a dysplasia-associated lesion or mass consists of isolated discrete nodules or polyps that are difficult to distinguish from sporadic adenomas. Because the clinical management of these two lesions is different, we performed this study to (1) evaluate the clinical presentation, pathologic features, and natural history of polypoid dysplastic lesions and sporadic adenomas in patients with IBD and (2) determine whether there are clinical, endoscopic, or pathologic findings useful in differentiating between these two lesions. The morphologic features of 89 benign polypoid epithelial neoplasms from 59 patients with IBD (51 with ulcerative colitis, 8 with Crohn's colitis) were evaluated and correlated with the clinical, endoscopic, and follow-up data. In a separate analysis, patients were categorized arbitrarily as having (1) a probable sporadic adenoma if the polypoid epithelial neoplasm was not located within areas of histologically proven colitis, (2) a probable IBD-associated polypoid dysplasia if the lesion developed within an area of colitis, and associated flat dysplasia or an adenocarcinoma was detected during follow-up evaluation or (3) an indeterminate polyp, which was seen in the remainder of the cases. The clinical, endoscopic, and histologic data were compared among these three patient and polyp subgroups. There were 35 males and 24 females (median age, 57 years; range, 27-85 years). Median duration of disease was 10 years. Forty-nine percent of the patients had pancolitis; 66% had histologically active disease at the time of presentation. Nearly 70% of patients had only one polyp; the majority occurred in either the left colon or the rectum (66%). Most polyps were described as a sessile nodule, whereas only 7 (7.8%) were pedunculated. Polyps ranged from 2 mm to 50 mm (median, 5 mm); most had a tubular architecture (84.3%) and contained low-grade dysplasia (64%). In addition, most polyps had mildly increased lamina propria and intraepithelial neutrophilic and mononuclear inflammation. At follow-up evaluation (40 patients; median follow-up time, 13 months; range, 1-78 months), a further neoplastic lesion developed in 20%; low-grade flat dysplasia was seen in 5 (12.5%), and adenocarcinoma developed in 3 (7.5%). However, dysplasia or adenocarcinoma did not develop in the patients who had polyps located outside of areas of histologically proven colitis. In addition, at least one more benign polypoid epithelial neoplasm developed in 15 of 40 patients (37.5%). Patients with probable IBD-associated polypoid dysplasia had a statistically significant (p < 0.05), longer disease duration than patients with probable sporadic adenoma. A statistically significant, higher proportion of polyps with tubullovillous or villous architecture, an admixture of normal and dysplastic epithelium at the surface of the polyps, and increased lamina propria mononuclear inflammation was noted in probable IBD-associated polypoid dysplastic lesions compared with those considered to be sporadic adenomas. Several clinical and pathologic features may be useful to help categorize a polypoid dysplastic lesion as a sporadic adenoma or an IBD-related neoplasm in a patient with IBD. This distinction is important because the natural history of these two lesions (as shown by the results of this study) and their subsequent management are quite different.
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PMID:Polypoid dysplasia and adenomas in inflammatory bowel disease: a clinical, pathologic, and follow-up study of 89 polyps from 59 patients. 950 Jul 69

Light-induced fluorescence endoscopy (LIFE) has been shown to differentiate between normal mucosa and dysplastic lesions, and dysplastic lesions of the colon occult to routine white-light colonoscopy may thus be visualized by LIFE. We compared the sensitivity and specificity of LIFE to routine white-light colonoscopy in patients with colonic dysplasia. In a pilot study 20 patients with colonic adenoma, inflammatory bowel disease, or with a history of colon cancer were screened for colonic dysplasia during routine colonoscopy. Forty-two sites of mucosal abnormalities regarded as suspicious for dysplasia during white-light colonoscopy were additionally examined with a prototype LIFE system. Biopsies were taken from all 42 colonic sites. The LIFE images were classified as positive or negative for dysplasia. Sensitivity and specificity were calculated by correlating positive and negative findings to the histopathological results. Histopathology detected 21 adenomas with low-grade dysplasia and one with high-grade dysplasia. All dysplastic lesions were found by routine white-light endoscopy. The specificity of conventional white-light endoscopy was 80%. Of the 22 dysplastic lesions 20 were detected by LIFE (sensitivity 91%). The specificity of LIFE was 90% (two false-positive results). LIFE combined with conventional endoscopy may thus improve the detection of colonic dysplasia.
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PMID:Detection of colonic dysplasia by light-induced fluorescence endoscopy: a pilot study. 1020 34

Dysplasia in Barrett's esophagus (BE) is a precursor to adenocarcinoma and most commonly occurs as a flat, grossly undetectable lesion. Rarely, dysplasia in BE may grow as a polypoid lesion. Most BE-associated polypoid dysplastic lesions have been referred to as "adenomas" because of their histological similarity to a colonic adenoma. BE-associated polypoid dysplastic lesions have been less well characterized than the flat type. Therefore, our aim was to characterize the clinicopathologic and molecular features of five cases of BE-associated polypoid dysplasia and to review the literature on this entity. The cases were evaluated clinically, histologically, immunostained for MIB-1 and p53, and genotyped for loss of heterozygosity (LOH) at the adenomatous polyposis coli (APC) locus. Mucosal biopsy specimens of five BE patients without dysplasia, and five BE cases with high-grade flat dysplasia, were used as controls. The study patients were all male (average age, 71 years) who presented with symptoms of gastroesophageal reflux disease. Endoscopically, all five cases had a well-defined sessile or pedunculated polypoid lesion ranging from 0.4 to 1.5 cm in size in the mid (n = 1) or distal (n = 4) esophagus and were associated with specialized-type BE (four long segment, one short segment). Histologically, the polyps consisted of intestinalized epithelium with low- and high-grade dysplasia. All five cases contained adenocarcinoma (four within the polyp, one in adjacent BE). All polyps showed increased cell proliferation in the form of surface MiB-1 staining and showed positive p53 staining. Three of three (100%) informative cases showed LOH at the APC locus in the dysplastic epithelium and in areas of adenocarcinoma. All five flat dysplasia controls also showed surface MIB-1 staining and p53 positivity, and three of three informative controls showed LOH for APC. None of the nondysplastic BE controls showed any of these findings. Three patients were treated with esophagectomy and two with polypectomy. All were alive, without metastasis, from 2 months to 6 years later. A literature review of esophageal "adenomas" uncovered 12 cases. Four of these had no clinical or pathological information, two were, in fact, gastric heterotopic lesions, one was composed entirely of intestinal-type epithelium, and five were polypoid dysplastic lesions similar to the cases described here (three male, two female; mean age, 59 years). Four of these five cases were associated with adenocarcinoma in the polyp (two intramucosal, two submucosal). In summary, BE-associated polypoid dysplasia share similar clinical, pathological, and molecular features as flat dysplasia and are often associated with adenocarcinoma. Thus, we agree with other authors who recommend that the term adenoma, which usually carries a benign connotation, be abandoned in favor of a descriptive diagnostic term, such as "BE-associated polypoid dysplasia." BE patients with this lesion should be considered strong candidates for esophageal resection similar to lesions of this kind that occur in inflammatory bowel disease.
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PMID:Polypoid dysplasia in Barrett's esophagus: a clinicopathologic, immunohistochemical, and molecular study of five cases. 1041 92

Dysplasia is a morphological term that ethymologically means 'malformation'. For the definition of inflammatory bowel disease-related dysplasia, the nature and origin of the malformation are stressed and the lesion is defined as an epithelial malformation that is unequivocally neoplastic but noninvasive. The use of a precise definition is necessary because of the clinical consequences related to the finding of dysplasia in IBD. The microscopic diagnosis of dysplasia, however, remains difficult. Clinically, it is important to make a proper differential diagnosis between polypoid IBD-related dysplasia and sporadic adenoma occurring in IBD, and between therapy-related 'pseudodysplasia' and genuine dysplasia. When dysplasia is diagnosed, a second opinion may be indicated because of the clinical consequences. Additional techniques to search for genetic defects associated with carcinogenesis can help to support the diagnosis. They can identify changes in DNA content and molecular changes resulting from defects of genes controlling cell proliferation and death or tissue structure. These changes can, however, be absent, appear early or late in the transition from normality toward dysplasia and cancer, or appear during repair. Positive findings indicate an increased cancer risk, but the magnitude of the risk remains to be defined. A positive diagnosis of genuine dysplasia necessitates clinical action - either follow-up of the patient or treatment. In practice, treatment means surgery because dysplasia can be a precursor and/or a marker of malignancy, except for sporadic adenomas, which can be removed locally.
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PMID:Dysplasia in inflammatory bowel diseases: definition and clinical impact. 1054 55

Ulcerative colitis(UC) is an ulcero inflammatory disorder of unknown etiology affecting only the mucosa and submucosa of colon and, with Crohn's disease, is included in the term idiopathic inflammatory bowel disease. The macroscopic and microscopic features vary according to the stage of the disease process, and an acute phase and a chronic or resolving phase can be recognized. The main differential diagnosis of UC is with colorectal Crohn's disease. The most feared long-term complication of UC is cancer. The progression of UC to carcinoma is closely associated with dysplasia arising in multiple sites. The dysplastic changes should be distinguished from the epithelial changes resulting from regenerative atypia, and the evaluation of these changes is difficult. P53 immunohistochemical staining is helpful in confirming the presence of dysplasia. Molecular events in colorectal carcinogenesis of UC may be somewhat different from those of so-called adenoma-carcinoma sequence.
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PMID:[Morphologic features of ulcerative colitis]. 1057 5

Patients with inflammatory bowel disease (IBD) have long been known to be at increased risk of development of colorectal cancer; however, there are many nuances to cancer prevention strategies in IBD that remain unresolved. During the past year, two publications reported on the resection of otherwise typical adenoma-like masses by means of polypectomy, after which these patients were followed with continued endoscopic surveillance, rather than pursuing colectomy. Another concern in IBD is whether there is an increase in the number of other cancers, in particular lymphomas. One issue regarding lymphoma risk is whether immunomodulatory drug use predisposes to this cancer. One study of a large group of 6-mercaptopurine users did not suggest an increased risk for patients with IBD using this drug. There are a variety of nonintestinal problems that patients with IBD may confront. Osteopenia has received considerable attention in the past decade. This year, data have been published that quantify for the first time the risk of fractures in patients with IBD based on population, and these data were compared with a matched control group from the same population. Data on the further exploration of the issue of osteopenia in pediatric IBD have also been reported, as have some of the only studies of therapy for osteopenia in IBD. These and data on other extraintestinal manifestations of IBD have all emerged in the past year.
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PMID:Neoplastic and other complications of inflammatory bowel disease. 1107 46

As an animal model for human inflammatory bowel disease and colorectal cancer, the cotton-top tamarin remains controversial. Demonstration of antigenic similarity to the human would enhance its validity. Using colonic extracts and washings, we compared binding of seven monoclonal antibodies reactive with bowel and cancer antigens in both tamarins and humans with inflammatory bowel disease. Additionally, telomerase activity was tested for. Expression of a mucin antigen specific to human cancer was increased in tamarin colonic washings as well as aminoproteoglycans and EGFR in tamarin extracts, as compared to those of humans with inflammatory bowel disease (P < 0.005). An adenoma-associated antigen and k-ras p21 protein were negative in the tamarin. A trend to greater telomerase activity exists in tamarins. The antigenic similarity validates this model for human inflammatory bowel disease and colorectal cancer. A trend to increased telomerase activity in tamarins is consistent with the greater predisposition to cancer in these animals.
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PMID:Gastrointestinal tract antigenic profile of cotton-top tamarin, Saguinus oedipus, is similar to that of humans with inflammatory bowel disease. 1125 47

Pathobiology of dysplasia in chronic inflammatory bowel disease: Current recommendations for surveillance of dysplasia. Patients with ulcerative colitis and Crohn's disease bear an about 10- and 4-fold increased risk, respectively, for developing colorectal carcinoma. Apart from typical locations of colorectal carcinoma in the sigmoid colon and rectum other locations were also often observed, e. g. right hemicolon or multifocal distribution. Histologically colorectal neoplasms frequently present as mucinous adenocarcinoma (signet-ring cell carcinoma). The risk for neoplasm depends on extension, severity, duration and therapeutic responsiveness of chronic colonic inflammation, and it seems pathogenetically to be similar in ulcerative colitis and Crohn's disease. Colorectal carcinoma in inflammatory bowel disease arises from epithelial dysplasia. Since there are no reliable biological markers available to date, surveillance-programs continue to rely on the discovery of dysplasia (unequivocal intraepithelial neoplasia). Detection of dysplasia by colonoscopy achieves 70-85 % sensitivity.Endoscopic surveillance should start after 8 years of disease's duration in pancolitis, after 10-12 years in left- sided colitis and after 12 years in Crohn's disease of the colon, with regular intervals every 1-2 years. 3-5 biopsies should be done every 10 cm from mucosa free of inflammation. Additionally, every fine or discrete alteration of the mucosal surface should be recorded. Multiple biosies should also be taken from such minimal lesions as well as from more macroscopically suspicious areas like plaques, nodular lesions or stenosis. The clinical consequence of a positive screening for dysplasia is colectomy because of an assumed risk of cancer of about 40-70 %. Dysplasia in macroscopically suspect areas bear the highest risk of cancer (non-adenoma like dysplasia), followed by multiple high-grade lesions without a macroscopic lesion, and multiple low-grade dysplasias. Detection of single dysplastic lesions in flat mucosa should be followed by a control endoscopy after 2-6 months, and if dysplasia is seen again, colectomy is recommended.
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PMID:[Pathobiology of dysplasia in chronic inflammatory bowel disease: Current recommendations for surveillance of dysplasia]. 1160 56


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