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PubMed1993

NSAID effect on sporadic colon polyps.

UNLABELLED: In this study, our objective was to determine whether 6 months of open-label therapy with sulindac 400 mg/daily or piroxicam 20 mg/daily promote regression of adenomatous colonic polyps left in situ. Left-sided colonic polyps (size 3-12 mm) detected at colonoscopy were measured and left without being biopsied. The bowel wall opposite to the polyps was marked with India ink submucosally. Patients were assigned to drug therapy, and compliance was determined by pill count. Polyps were measured during sigmoidoscopy after 3 and 6 months of treatment; polyps were removed at the 6-month examination. Examiners were not blinded to drug therapy or previous polyp measurements. Seven patients completed 6 months of therapy (five sulindac and two piroxicam). Two additional patients treated with piroxicam were withdrawn secondary to adverse events (bleeding gastric ulcer and rash). In one patient treated with sulindac, a 6-mm polyp disappeared, and two other polyps seemed to regress partially. One polyp regressed partially in a piroxicam-treated patient. All other polyps remained unchanged. CONCLUSIONS: We did not observe dramatic regression of sporadic colon adenomatous polyps to either sulindac or piroxicam after 6 months of therapy in this small uncontrolled pilot study.

Adenomatous Polyps↗
PubMed1982

A rationale for the endoscopic management of colonic polyps.

The incidence of invasive cancer in colonic polyps is related to the size of the lesion and the histologic type of the adenoma. It is greatest for villous adenomas and least for tubular adenomas. The malignant potential increases with the size of the polyp, and in lesions 3 cm and larger malignant disease is present in at least 12 per cent. In general, polyps with invasive malignant disease require colon resection, but for pedunculated adenomas, colonoscopic polypectomy is adequate treatment. Even when invasive cancer is close to the line of endoscopic resection but does not invade the stalk or does not display lymphatic or vascular invasion, a case may be made for conservative, endoscopic treatment alone because the occurrence of local or distal metastasis is very unusual.

Adenoma↗
PubMed2002

Endoscopic resection of large sessile colonic polyps by specialist and non-specialist endoscopists.

BACKGROUND: Patients with large sessile colonic polyps for which endoscopic resection might be feasible are often referred directly for operation. The aim of this study was to determine the outcome of patients with such polyps diagnosed by specialist and non-specialist colonoscopists. METHODS: Patients with large (greater than 2 cm) sessile polyps detected at colonoscopy from January 1995 to July 2000 were identified. Resection technique and clinical and endoscopic outcomes were recorded. Two of the colonoscopists (B.P.S., C.B.W.) are recognized as specialists. RESULTS: Some 130 polyps were identified, 100 detected by either of two specialist endoscopists (including 14 cancers) and 30 by 14 non-specialist endoscopists (including ten cancers). Endoscopic resection of benign polyps was attempted by experts in 80 (93 per cent) of 86 cases and by non-experts in 15 of 20 cases (P = 0.03), with successful management by endoscopy alone in 61 (76 per cent) of 80 and in six of 15 cases respectively (P = 0.01). Complications occurred following three polypectomies performed by an expert (bleeding, two; pain, one) and one by a non-expert (bleeding). The estimated end-cost of management by specialists was less than half of that by non-specialists. CONCLUSION: Endoscopic resection of large sessile colonic polyps is feasible in the majority of patients and should be considered as first-line therapy. Prompt referral to a specialist endoscopist may improve outcomes by avoiding operation or enabling complete excision at a single endoscopy session.

Adult↗
PubMed2005

Prevalence of advanced colonic polyps in asymptomatic Chinese.

AIM: To investigate the prevalence of advanced polyps in asymptomatic Chinese and to determine the risk of proximal advanced colonic polyps in subjects with and without polyps in the distal colon. METHODS: Data were collected prospectively during colonoscopic examinations performed in 5 973 subjects as part of health evaluation at our unit from December 1997 to December 2003. Polyps were considered advanced, if they were larger than 10 mm or were tubovillous, villous or malignant. Proximal colon was defined as the splenic flexure and more proximal portions of the colon. RESULTS: Colon polyps were detected in 971 (16.3%) subjects (613 males and 358 females) with their mean age being 56.6+/-10.7 years. Advanced polyps were noted in 199 (3.3%) individuals. Subjects were sub-classified according to the location of polyps into three groups: distal (569, 58.6%), proximal (284, 29.2%), and combined proximal and distal (118, 12.2%) groups. Subjects with advanced polyps in these three groups were 95 (9.8%), 56 (5.8%), and 48 (4.9%) respectively. In the 48 subjects with advanced combined polyps, 13 advanced polyps were distributed at the distal colon, 17 at the proximal colon, and 18 at both. Eighteen colon cancers including 12 at sigmoid and 6 at ascending colon were confirmed by final pathology. The relative risk for advanced proximal polyp according to distal findings was 3.1 (95%CI: 1.3-7.4) for hyperplastic polyp, 2.7 (95%CI: 1.4-5.3) for tubular polyp and 13.5 (95%CI: 5.1-35.4) for advanced polyp as compared to that for no polyp. However, 56 (28.2%) of 199 subjects with advanced polyps had no index polyps at the distal colon and might go undetected under sigmoidoscopic screening. CONCLUSION: Although distal lesions can predict the risk of advanced proximal polyps, a substantial portion of Chinese with advanced proximal polyps is not associated with any distal sentinel lesions. These data have implications for screening policy of colon cancers in Taiwanese Chinese.

Adult↗
PubMed2004

[Colonic polyps: dysplasia predictive factors].

OBJECTIVE: Analyze the presence of dysplasia in colonoscopy visualized colonic polyps, and the predictive factors for high grade dysplasia. MATERIAL AND METHODS: We studied the polyps observed in the colonoscopies carried out during the year 2001. Colonoscopies carried out in 2,144 patients were analyzed, with demonstration of polyps in 326 patients (average age: 67 12,6 years, 63,5% males). 732 polyps were analyzed, with average of 2.27 2 polyps by patient. RESULTS: 72% polyps were located distally to splenic flexure, and sigmoid colon was the most frequent location (34.7%). Most of the polyps (86%) were sessile. Only 3% were > 2 cm, and the majority (88%) was < 1 cm. The most prevalent histological type was tubular adenoma (36%). Dysplasia was observed in 42.2% (low grade in 40% and high grade in 2.2%) Size > 1 cm and location proximal to splenic flexure were the only variables with indendent significant association to high grade dysplasia. CONCLUSIONS: The presence of high grade dysplasia in the colonic polyps was related in our cohort both to the location of the polyps in the colon and to its size, so that greater risk was for proximal polyps and for polyps > 1 cm.

Aged↗
PubMed1987

Detection of colonic polyps on single-contrast barium enema study: emphasis on the elderly.

A systems approach was employed to improve results of the single-contrast barium enema examination for detection of colonic polyps. Improvements were made in each of the following areas: radiographic-fluoroscopic equipment, fluoroscopic-television images, screen-film combinations, barium suspensions, examination techniques, imaging sequences, and quality controls. Radiologic-endoscopic correlation was undertaken for 137 colonic polyps seen endoscopically in 91 patients. The average age of the patients was 69 years. The sensitivity of the single-contrast examination for detection of all polyps was 80%. Polyps 5-9 mm in size were detected with 66% sensitivity, while 94% of polyps 10 mm or larger were detected. The results indicate that the sensitivity of a suitably performed single-contrast barium enema examination may approach that of the double-contrast study for the detection of colonic polyps, even in an elderly and infirm patient population.

Adult↗
PubMed2003

Gene mutations in advanced colonic polyps: potential marker selection for stool-based mutated human DNA assays for colon cancer screening.

The detection and removal of advanced colonic polyps (ACPs) can help prevent the development of colorectal cancer. A set of DNA mutations known to be associated with colorectal carcinoma was tested against resected ACPs to determine the set s potential utility as a marker panel for ACPs. A sensitive mutation marker panel could be used by stool-based assays that look for mutated human DNA to detect the presence of ACPs. DNA from 32 ACPs = 1.0 cm in diameter was amplified and tested for 19 colorectal cancer associated DNA mutations and for deletions in BAT-26 (microsatellite instability). One or more mutations were identified by microsequencing in 28 of the 32 ACPs (88%). Mutations were identified in k-ras (59%), APC (33%), and p53 (22%). BAT-26 mutation, a marker for microsatellite instability, was not identified. Stool DNA based assays that can identify these mutations may significantly increase the identification of patients with potentially premalignant ACPs for evaluation and treatment by colonoscopy.

Adult↗
PubMed1986

When is endoscopic polypectomy adequate therapy for colonic polyps containing invasive carcinoma?

We correlated the histopathology with outcome for all patients with endoscopically removed colonic polyps containing invasive adenocarcinoma seen at our institution over a 10-yr period. Invasion was defined as infiltration of malignant cells into the submucosa. Of a total of 1523 adenomatous polyps, 41 polyps (2.7%) in 39 patients contained invasive adenocarcinoma. One patient was excluded from further analysis because of a synchronous colonic carcinoma. Fourteen patients (37%) had favorable histologic features (grade I or grade II carcinoma with free margin of resection and absence of lymphatic invasion), and none developed metastatic carcinoma during the follow-up period (mean 6.5 yr, range 4-10.6 yr). Twenty-four (63%) had unfavorable histologic features (grade III tumor with tumor at or near the margin of resection or lymphatic invasion), and 10 of these (42%) had either residual local or metastatic carcinoma in subsequent operations or during the follow-up period. This difference in outcome was statistically significant (p less than 0.05) when compared with the outcome of the group with favorable histology. We conclude that endoscopic polypectomy is adequate therapy for colonic polyps containing invasive carcinoma, provided that the favorable histologic features are present.

Adenocarcinoma↗
PubMed2006

Immunomodulation with low dose levamisole in patients with colonic polyps.

BACKGROUND: Levamisole (LMS) has immunomodulatory activity, stimulates the immune system of healthy, normal volunteers and has been proposed previously as a colon cancer preventive agent. METHODS: Patients with a history of colonic polyps who are at increased risk of colon cancer received LMS in a placebo-controlled, double-blinded clinical trail with crossover design. Primary endpoints were immunologic and included flow cytometry of peripheral blood mononuclear cells (PBMCs), measurement of interferon-gamma copy number (IGCN) in PBMCs, and an ex vivo serum immune assay. RESULTS: No differences were seen in the expression of multiple antigens by flow cytometry pre- and post-LMS. The IGCN partitioned subjects into two distinct groups defined by a gamma-distribution which had a differential response to LMS. Those with low basal IGCN had a lower percentage of CD25 expressing PBMCs and responded to low dose LMS by producing more PBMC-derived interferon-gamma and increasing the expression of CD25 and two NK cell markers, CD16 and CD56. In contrast, subjects with a high basal IGCN responded to low dose LMS with a reduction in PBMC-derived interferon-gamma and a decrease in the expression of CD25. CONCLUSIONS: In aggregate, these responses suggest that LMS may act as an immunostimulatory agent for one group, those with low basal IGCN, and as an immunosuppressive agent for the other. LMS may not be an optimal agent for most patients with colonic polyps and should be avoided in patients with normal immune function. IGCN may be useful as an immunologic surrogate endpoint biomarker in future cancer prevention trials with immunomodulatory agents.

Adjuvants, Immunologic↗
PubMed2004

Colonic polyp segmentation in CT colonography-based on fuzzy clustering and deformable models.

An automatic method to segment colonic polyps in computed tomography (CT) colonography is presented in this paper. The method is based on a combination of knowledge-guided intensity adjustment, fuzzy c-mean clustering, and deformable models. The computer segmentations were compared with manual segmentations to validate the accuracy of our method. An average 76.3% volume overlap percentage among 105 polyp detections was reported in the validation, which was very good considering the small polyp size. Several experiments were performed to investigate the intraoperator and interoperator repeatability of manual colonic polyp segmentation. The investigation demonstrated that the computer-human repeatability was as good as the interoperator repeatability. The polyp segmentation was also applied in computer-aided detection (CAD) to reduce the number of false positive (FP) detections and provide volumetric features for polyp classification. Our segmentation method was able to eliminate 30% of FP detections. The volumetric features computed from the segmentation can further reduce FP detections by 50% at 80% sensitivity.

Algorithms↗
PubMed1989

Positive predictive value and posttest probability of diagnosis of colonic polyp on single- and double-contrast barium enema.

The positive predictive value for a radiographic diagnosis of colonic polyp, the prevalence of polypoid disease, and posttest probability relative to patient age were studied. The positive predictive value for colonic polyp on single- and double-contrast barium enema was determined for 191 polyps found radiographically in 136 patients who also underwent colonoscopy for confirmation. Of 72 polyps seen in 54 patients on single-contrast examination, 59 were confirmed endoscopically; 110 of 119 polyps seen in 82 patients on double-contrast examination were confirmed similarly, giving positive predictive values of 82% and 92%, respectively. Positive predictive values per patient, disregarding the number of polyps present, were 87% (47/54) and 90% (74/82) for the single- and double-contrast examinations, respectively. False-positive errors were due to stool, air bubbles, haustration, and misinterpretation of an appendiceal stump. By using specificities derived from our prevalence of polypoid disease and previously reported sensitivities, we drew posttest probability curves showing that predictive values depend both on the chance of disease before the test is done and on the efficacy of the test used.

Aged↗
PubMed2005

Differential labeling by monoclonal antibodies Adnab-9 and anti-alpha-defensin 5 based on the distribution and adenomatous tissue content of colonic polyps.

We sought a correlation between site and morphology of colonic polyps by labeling with neoplastic and general Paneth cell markers, monoclonal antibodies Adnab-9 and anti-alpha-defensin 5, respectively. Proportions labeled by Adnab-9 and anti-alpha-defensin 5 were, respectively, 42 and 85% for adenomas, 39 and 63% for early tubular adenomas, 41 and 44% for serrated, 34 and 20% for mixed, and 11 versus 2.7% for hyperplastic polyps. Compared with hyperplastic polyps, the proportion of other polyps labeled by Adnab-9 or anti-alpha-defensin 5 was higher but this difference was more significant for distal (P = 0.008 for Adnab-9 and P = 0.0001 for anti-alpha-defensin 5) than proximal (P = 0.645 and P = 0.154, respectively) polyps. While increased labeling of all proximal polyps compared to distal ones mirrored the colonic distribution of Paneth cells, distal adenomas tended to have a higher proportion labeled by Adnab-9, suggesting that Adnab-9 labels Paneth cells associated with increased neoplastic potential.

Adenomatous Polyps↗
PubMed1990

Contents of tissue CEA and CA19-9 in colonic polyp and colorectal cancer, and their clinical significance.

In precancerous states or early cancer, the serum levels of tumor markers are almost not detectable. Therefore, the tissue contents of CEA and CA19-9 were measured in 48 colonic polyps, 8 colorectal cancers and 5 normal colonic mucosa. These tissue specimens were obtained by endoscopic polypectomy, surgery or autopsy, and homogenated in normal saline (10 ml/wet g of tissue). After centrifugation, the supernatant was assayed by enzyme or radioimmunoassay. There was no correlation between serum levels and tissue contents of CEA or CA19-9 in colonic adenomas and colorectal cancers. The mean contents of tissue CEA and CA19-9 in colonic polyp and colorectal cancer were significantly higher than normal colonic mucosa, and the highest contents of CEA and CA19-9 were found in colorectal cancer. The contents of tissue CEA and CA19-9 in cancerous regions were markedly increased as compared with noncancerous regions. In adenomas, there was a relationship between the degree of histological dysplasia and the tissue content of CEA. Relationships were also found between macroscopic findings and tissue tumor markers in adenomas. These results suggest the possibility that the measurement of tissue tumor markers may be useful for borderline colonic lesions.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1988

Phenotypic markers for a spectrum of colonic polyps and cancers. The malignancy potential ratio.

The purpose of this study was to determine if a panel of monoclonal antibodies could define phenotypic markers that could be used in risk assessment of a spectrum of colonic polyps and colon cancers. Using the ABC immunoperoxidase technique on formalin-fixed sections of surgical specimens, the following results were obtained: 1) Mab B72.3 demonstrated increased reactivity in villous lesions and cancers compared with hyperplastic polyps and tubular adenomas; 2) Mab anti-CAA demonstrated increased reactivity in polyps compared with colon cancers; and 3) using the two antibodies (Mab B72.3 and Mab anti-CAA), a malignancy ratio was obtained that determined malignancy risk for individual polyps. No hyperplastic polyp gave a positive ratio, but about 30 percent of villous lesions were positive. Over 50 percent of villous lesions greater than 2 cm in size had a positive ratio. The malignancy potential ratio may be a valuable marker in assessing risk of malignancy in an individual case.

Adenomatous Polyposis Coli↗
PubMed1977

Localization by immunoperoxidase and estimation by radioimmunoassay of carcinoembryonic antigen in colonic polyps.

A 3-layer immunoperoxidase technique was used to demonstrate carcinoembryonic antigen (CEA) in colonic polyps from patients with or without previous or concurrent malignancy. CEA was demonstrated in a higher percentage of the polyps received as fresh specimens that were rapidly frozen and fixed in ethanol, than in formalin-fixed, paraffin-embedded sections. Tissue CEA content of both colonic carcinomas and polyps was determined by radioimmunoassay, and it was found that benign colonic tumours had levels of tissue CEA comparable to colonic cancer, indicating that CEA concentration in a tumour does not reflect its grade of malignancy. In fact, in one case in which both colonic cancer and polyps were removed, the polyps had the higher quantities of tissue CEA. Further, tissue CEA concentration of a polyp was not dependent on its size or location. Studying the titres of circulating CEA in these patients revealed an elevation of plasma CEA in one-third of the patients with only colonic polyps, whilst the patients with cancer all had increased titres.

Carcinoembryonic Antigen↗
PubMed2006

Determinants of compliance with colonoscopy in patients with adenomatous colon polyps in a veteran population.

AIM: To determine factors affecting compliance of a follow-up colonoscopy in patients with previously diagnosed adenomatous colon polyps. METHODS: A retrospective review was performed on patients with adenomatous polyps excised between January and December 1998. Twenty-nine clinical factors were assessed in patients grouped into whether they were compliant (n = 81) or noncompliant (n = 38) with follow-up colonoscopy. Significant variables by univariate analysis were included in multivariate regression. RESULTS: One hundred and nineteen patients with adenomatous colon polyps were identified. Of 119 patients, 114 had a documented recommendation for follow-up of 5 years or less, with 69% having been compliant. In a univariate analysis, greater number of polyps (P = 0.04), NSAID use (P = 0.02), statin use (P = 0.005), first-degree relatives with colon cancer (P = 0.05) and compliance with out-patient clinic follow-up (P < 0.001) were significantly associated with patient compliance. Multivariate analysis revealed statin use (P = 0.05), first-degree relatives with colon cancer (P = 0.06) and compliance with out-patient clinic follow-up (P < 0.001) were independent predictors of compliance. CONCLUSIONS: History of statin use and family history of colon cancer are good predictors of compliance. The strongest predictor can be anticipated with compliance assessed with encounters for other visits. Strong efforts should be directed at improving patient education about colon cancer by the physician and facilitating patient compliance.

Adenomatous Polyps↗