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At least 991 records · Page 55Linked to original sources
PubMed1988

Large bowel adenomas containing carcinoma--a diagnostic and therapeutic approach.

Adenomas containing invasive carcinoma of the large bowel form the majority of early colorectal cancers. Conclusive histological diagnosis of early colorectal cancer depends on two conditions; first, the whole lesion must be examined and second the resection margin must border on healthy tissue. The presence of certain histopathological features makes it possible to distinguish between cases with high and low risk of having lymph node metastases. Sixty-six adenomas containing invasive carcinoma are reported. They comprised 3.15% of 2,095 adenomas removed by colonoscopic polypectomy during the same period. Five cases were lost to follow-up. Forty-nine patients considered to be at low risk of having lymph node metastases have been treated by endoscopic polypectomy only with a rigorous follow-up regime including CEA estimation, ultrasonography and total colonoscopy at regular intervals. In none have distant metastases been found on follow-up examinations at a mean duration of 3 years. Two of these cases have developed a metachronous colorectal carcinoma and 15 (30.5%) have metachronous adenomas. Two low risk patients with no tumour found in the operative specimen have undergone major surgical resection. Ten high risk cases have been referred for major surgery and lymph node metastases have been found in four (40%). The need for careful histological examination for lymphatic and veinous invasion is stressed by the presence of this finding in all four high risk patients with involved lymph nodes.

Aged↗
PubMed1986

Colorectal adenomas. Distribution, incidence of malignant transformation, and rate of recurrence.

In 282 patients, 731 colon polyps (643 adenomas and 88 hyperplastic polyps) were extirpated endoscopically or biopsied and investigated histologically. Localization of the adenomas with various degrees of atypia and the hyperplastic polyps, as well as their size distribution, were determined. In 66 patients with adenoma polypectomy on the first examination, one or more control colonoscopies were carried out (in all, 107). The median period of follow-up observation was 31 months. Thirty percent of the one-year control colonoscopies after polypectomy revealed new adenomas. The statistical analyses showed that patients with singular adenomas, on initial investigation, develop significantly fewer adenomas in the further course than patients with multiple initial findings, especially in negative results in the one-year control. The size of new adenomas found during the first 24 months after polypectomy does not exceed 10 mm. On the basis of these results and the literature data available so far, a follow-up program is presented for discussion.

Adenoma↗
PubMed1986

Colonoscopic excision of large and giant colorectal polyps. Technical implications and results over eight years.

Large polyps are sessile or pedunculated lesions that are larger than or equal to 3 cm in size. Sixty-six colonoscopic piecemeal excisions of large pedunculated and sessile polyps (75 percent of 88 recognized large polyps) were performed over eight years. The macroscopic feature of the lesions and the result of an extensive snare biopsy were the deciding factors for endoscopic as opposed to surgical removal. Only three complications (4.5 percent) were recorded (two hemorrhages and one colonic wall burn syndrome), none of which required surgery. Fifty patients with 52 adenomatous lesions had colonoscopic follow-up (range, 3 to 85 months). Of 36 sessile adenomas, two cases of residual (5.5 percent) and four of recurrent disease (11 percent) were observed. Colonoscopic removal is an alternative to local surgical excision of large benign colorectal polyps, and often can be an alternative method to elective colectomy in elderly and high-risk patients.

Adenocarcinoma↗
PubMed1988

Immunohistochemical study of epithelial cell proliferation in hyperplastic polyps, adenomas, and adenocarcinomas of the large bowel.

A monoclonal antibody to bromodeoxyuridine was used in tissue specimens previously incubated with bromodeoxyuridine to show S-phase cells by immunohistochemical technique. Biopsy specimens of normal mucosa (n = 10), hyperplastic polyps (n = 10), adenomas with low-grade dysplasia (n = 20), adenomas with high-grade dysplasia (n = 10), and invasive adenocarcinomas (n = 10) of the large bowel were studied. Labeling index and cell proliferative patterns were analyzed. No statistically significant difference was found in labeling index between normal mucosa and hyperplastic polyps or between adenomas with high-grade dysplasia and adenocarcinomas. The labeling index was significantly lower in normal mucosa and in hyperplastic polyps than in adenomas and adenocarcinomas (p less than 0.001). The difference in labeling index between adenomas with high-grade dysplasia and low-grade dysplasia was also statistically significant (0.01 less than p less than 0.05). In normal mucosa and in hyperplastic polyps the proliferative zone was confined to the lower two-thirds of the crypt; no kinetic activity was found in the upper portions of the crypt or in surface epithelium. In adenomas the labeled cells were either present in the upper third or scattered along the whole axis of the crypt and in the surface epithelium. Labeling patterns in invasive carcinomas were similar to those observed in adenomas with high-grade dysplasia. The difference in proliferative patterns between hyperplastic polyps and adenomas supports a different significance of the two polypoid lesions in the histogenesis of large bowel cancer; our results confirm the subsequent steps of the adenoma-carcinoma sequence. Immunohistochemical labeling patterns observed with monoclonal antibody to bromodeoxyuridine in polypoid and cancer lesions of the large bowel are similar to those described by autoradiographic studies.

Adenocarcinoma↗
PubMed2006

Flat elevated lesions of the colon and rectum: a spectrum of neoplastic and nonneoplastic entities.

The aim of this prospective study is to establish the frequency and the type (neoplastic and nonneoplastic) lesions defined endoscopically as flat elevated lesion (FEL) in the colon and rectum, as well as to compare flat adenomas (FAs) to polypoid lesions of the same size with morphometric and immunohistochemical analysis. One hundred nineteen patients were studied through fibrocolonoscopy with chromoscopy (indigo carmine spray). All detected lesions (total of 195) were removed, and FELs measuring 10 mm or smaller were also selected. Using histopathologic criteria, they were divided in neoplastic (adenomas and carcinomas) and nonneoplastic ones. In neoplastic lesions, the following parameters were evaluated to compare FAs with polypoid lesions: morphometric studies with Index of Structural Atypia (ISA) and Stratification Index (SI), evaluation of cellular proliferation with label index of Ki-67, and expression of p53 protein. Of 195 lesions resected, only 33 (17%) met the endoscopic requirements for FELs. Twelve (36.4%) were neoplastic and 21 (63.6%) considered nonneoplastic. Among the FAs, there were a percentage of high-grade (severe dysplasia) significantly more frequent than observed in polypoid lesions (16.7% vs 2.6%). In addition, the SI, Ki-67 label index and p53 positivity were significantly higher in FAs. The ISA also reached significant differences between both groups of adenomas. Non-neoplastic FELs included different entities such as hyperplasic polyps, focuses of colitis, normal mucosa, and scars. The endoscopic elements analyzed were shared between nonneoplastic FELs and FAs. A central depression, when air was properly insufflated, considered typical in neoplastic lesions, was frequently observed in nonneoplastic lesions. Following the endoscopic criteria of FELs, nonneoplastic lesions predominated over the adenomatous lesions, demonstrating that FELs and FAs are not homologous terms. The frequency of high-grade dysplasia was significantly more elevated in the adenomatous FELs than in polypoid adenomas. The ISA, SI, p53 expression, and Ki-67 label index were helpful in differentiating adenomatous FELs from polypoid lesions. Flat elevated lesions selected by endoscopic criteria are, in fact, a heterogeneous population of lesions.

Adenocarcinoma↗
PubMed2002

Isolation and sequencing of a novel tropomyosin isoform preferentially associated with colon cancer.

BACKGROUND & AIMS: Nonmuscle human tropomyosin (hTM) isoforms have distinct functions and may play important roles in various disease processes. METHODS: In an attempt to identify colon epithelial tropomyosin isoform, a complementary DNA library prepared from a human colon cancer cell line T84 was screened by an oligonucleotide probe complementary to messages of all known hTM isoforms. A novel clone called TC22 was obtained. The amino acid sequence of TC22 isoform is identical to isoform 5 (hTM5) apart from the C terminal domain, amino acids 222-247 coding the exon 9. RESULTS: Northern blot analysis showed that TC22 message is expressed in transformed epithelial cell lines and tumor tissues but not in normal epithelial cells. We developed a monoclonal antibody specific to TC22 isoform (TC22-4). By Western blot and immunoperoxidase assays, we analyzed 105 colonic specimens (fresh frozen and formalin fixed) from 96 patients with colon polyps (hyperplastic) or adenomas with or without dysplasia and cancer. Twenty-one of 22 (95%) of colon cancer specimens showed the presence of TC22, compared with only 1 of the 17 normal colon specimens and none of the 13 hyperplastic polyps (P < 0.0001). As assayed by immunoperoxidase staining, TC22 expression progressively increased in benign adenomatous polyps (35%) and polyps with mild and severe dysplasia (57% and 100%, respectively). CONCLUSIONS: We cloned and sequenced a novel hTM isoform, TC22, which is strongly associated with colonic neoplasia and carcinoma. TC22 may provide a useful biomarker for surveillance of colon cancer.

Adenoma↗
PubMed2003

A novel case with germline p53 gene mutation having concurrent multiple primary colon tumours.

During a search for causative genes in patients with concurrent multiple primary colon tumours, we found a novel case with a germline mutation of the p53 gene, from GCC (Ala) to GTC (Val) at codon 189. Of the six primary colon tumours that this patient had, one large advanced carcinoma exhibited a somatic p53 mutation and a somatic APC mutation, in addition to the germline p53 mutation. Two early carcinomas and three adenomas had somatic APC mutations but no somatic p53 mutation or loss of the p53 allele. K-ras-2 mutations were detected in an advanced carcinoma and an early carcinoma. The present results suggest that a patient with a certain type of germline p53 mutation is predisposed to concurrent multiple colon tumours. It is also suggested that in such a patient, a somatic APC mutation is involved in tumour formation and that an additional somatic p53 mutation contributes to tumour progression.

Aged↗
PubMed2002

Evaluation of telomerase mRNA (hTERT) in colon cancer.

Telomerase activation, a cardinal requirement for immortalization, is a crucial step in the development of malignancy and requires the induction of the catalytic component, human telomerase reverse transcriptase (hTERT), encoded by the hTERT gene. By reverse transcription-PCR, using primers within the reverse transcriptase domain of hTERT, we investigated telomerase messenger in 8 adenomatous and 9 dysplastic polyps, and in 32 paired cancer-normal mucosa specimens, one liver and one spleen metastasis from patients resected for sporadic colorectal cancer. Telomerase messenger was absent or very low in normal mucosa and in adenomatous polyps. Dysplastic polyps and adenocarcinoma samples showed hTERT mRNA, with higher levels in cancer tissues compared to dysplastic lesions. A high telomerase messenger level was shown to be associated with late-staged cancers and with metastasis; thus, detection of telomerase messenger may be useful in the early diagnosis of colon cancer, and telomerase may be a new target for therapeutic intervention.

Adenoma↗
PubMed1999

[New perspectives in 3D MR colonography].

Filling the colon lumen with contrast allows for 3D-MR-colonography. The 3D data set can be postprocessed to multiplanar reconstruction, surface shaded displays as well as virtual colonoscopy. The latter facilitates the differentiation between haustra and polyps and enables detection of polyps down to 6 mm in size. Multiplanar reconstructions provide the assessment of the inner wall contour. The morphology of the colonic wall itself can be assessed on T1- or T2-weighted images. T1-weighted sequences performed before and after i.v. contrast administration and T2-weighted sequences depict pathologies based on their contrast uptake respectively on their tissue water content. This concept of colonic imaging practicable in less than 15 minutes is useful for the assessment of inflammatory disease, for polyp detection as well as for tumour staging.

Colonic Diseases↗
PubMedDate not supplied

Adenomas and carcinomas may be histologically detected in apparently normal colonic mucosa. A study of carcinogen-treated rats.

Clinical reports indicate that colonic neoplasias may be overlooked at colonoscopy. We investigated, in an experimental model, whether both gross and high power microscopical examinations could detect all induced colonic neoplasias. Forty-nine Sprague-Dawley rats received 1,2-dimethylhydrazine for 27 weeks. The colons were scrutinized grossly and at high-power microscopy complemented with chromoscopy. Biopsies were obtained from all mucosal alterations seen at gross and at high power microscopy. The gross examination of the colonic specimens in the 49 animals revealed 196 polyps or suspected polyps. Histology showed that 85.2% (167 out of 196) were adenomas or adenocarcinomas. The remnant polyp-free colons were subsequently examined by high-power stereo microscopy (46 magnifications). Fifty-five new lesions were detected and removed. Histology showed 48.9% (n = 24) additional neoplastic lesions in the 49 colon specimens. The remnant polyp-free colons were subsequently processed for histology. The sections showed 57 additional neoplastic lesions in the 49 colon specimens: 93.0% (n = 53) were adenomas (n = 35) and crypt dysplasias (n = 18), while the remaining 7.0% (n = 4) were invasive carcinomas. Experimentally-induced colonic neoplasias may be overlooked even after a careful scrutiny of the colonic mucosa using high-power optical devices.

1,2-Dimethylhydrazine↗
PubMed2001

[Nested case-control study on the risk factors of colorectal cancer].

OBJECTIVE: To investigate the risk factors of colorectal cancer. METHODS: A nested case-control study was conducted based on a cohort of 64,693 subjects in Jiashan county, Zhejiang, China. One hundred and ninety-six cases of colorectal cancer were detected during a follow-up program for 10 years. Nine hundred and eighty non-colorectal cancer subjects were randomly selected from the cohort as controls. Univariate analysis and mutivariate non-conditional logistic regression were used to analyse associations between the exposure factors and colorectal cancer. RESULTS: The age of case group was significantly older than that of the control group. Moreover, the age at diagnose of colon cancer was significantly older than that of the rectal cancer. Other than age, the final regression model showed that mucous blood stool history and colon polyp history were significantly associated with colon cancer (OR = 2.961, 95% CI:1.202-7.298 and 8.941, 95% CI:1.820-43.926, respectively) while mixed sources of drinking water was found to be associated with rectal cancer with a OR value of 1.823 (95% CI:1.024-3.247). CONCLUSION: The risk factors of colon cancer were different from that of the rectal cancer. Age was an important factor influencing the incidence of both colon cancer and rectal cancer. Mucous blood stool history and colon polyp history were associated with colon cancer, while drinking mixed water was closely associated with rectal cancer.

Adult↗
PubMed1989

[Precancerous lesions of the colon and rectum].

Adenomatous polyp, adenomatosis coli and dysplasia in the inflammatory bowel disease are noted as precancerous lesions. 1) Adenomatous polyps are easily found by colonoscopy as protruded lesions and diagnosed by histopathological study. 2) Adenomatosis coli is easily diagnosed by barium enema and colonoscopy. Adenomatosis coli is accompanied with cancer frequently. As soon as adenomatosis coli is detected, we recommend surgery. IRA (total colectomy and ileorectal anastomosis) is mainly undertaken for adenomatosis coli. But when there are many adenomas in the rectum, we recommend IAA (total colectomy, rectal mucosectomy and ileo-anal anastomosis). 3) Diagnosis and therapy of dysplasia accompanied with the inflammatory bowel disease (ulcerative colitis, tuberculosis, Crohn's disease) remain unclear. There is a deep relationship between cancer and dysplasia and inflammation.

Adenoma↗
PubMed1988

Follow-up colonoscopy in patients with colorectal adenomatous polyps.

Multiple follow-up colonoscopies were performed in 44 asymptomatic patients after polypectomy of colorectal adenomatous polyps. Twenty-six patients (59%) developed new adenomatous polyps. In 81% the new polyps were located in the same segment of the colon where a previous polyp had been totally removed. Polyps removed during follow-up, compared with the initial polyps, revealed significantly more benign and smaller polyps. The number of initial polyps together with occurrence of atypia were factors determining a short time interval for developing new adenomatous polyps. The mean time for developing a 5-mm or larger polyp was significantly longer than polyps less than 5 mm in diameter.

Adenoma↗
PubMed1986

[Clinical significance of the adenoma-carcinoma sequence. Results of a retrospective study].

Follow-up checks were applied to 81 of 140 patients with 249 adenomas of the large intestine. The results obtained from that study are reported in this paper. The generally known dependence of adenoma carcinoma sequence on histology, size, and basis of adenomas was confirmed. Since patients with adenoma are exposed to higher risk of carcinoma, colonic polyps, basically, should be removed as a form of cancer prophylaxis, and patients concerned should be regularly monitored. A follow-up programme is proposed in this paper, with reference being made to the authors' own rates of recurrence and to those reported in the literature.

Adenocarcinoma↗
PubMed1986

Antigen expression in normal and neoplastic colonic mucosa: three tissue-specific antigens using monoclonal antibodies to isolated colonic glands.

Monoclonal antibodies to normal colonic glands were used to localize three tissue-specific antigens in sections of 40 hyperplastic polyps, 29 adenomas, 43 colorectal adenocarcinomas, and blocks or rolls of histologically normal large bowel mucosa. Two antibodies identified antigens (designated 3NM and 17NM) associated with the mucin vacuole of goblet cells and the third antibody identified a cell membrane antigen (designated 6NM). Antigen 3NM was absent from virtually all carcinoma cells and from all, or most, cells of hyperplastic polyps. Antigen 17NM was absent from 21 carcinomas, with some antigen-positive cells present in the others. Antigen 6NM content was unchanged compared to normal mucosa in 12 carcinomas, decreased somewhat in another 20, and either absent or markedly depleted in 11. Antigen 6NM increased in 22 hyperplastic polyps. Three cancer patients synthesized 6NM in their normal mucosa but the cellular distribution was abnormal. Antigens decreased in most adenomas, with heterogeneity of expression seen in glands and cells of some adenomas. Low concentrations of one or more antigens in normal mucosa were significantly more frequent (P less than 0.05) in patients with metastases than in those with stage A or B tumors.

Adenoma↗
PubMed1985

[Carcinoembryonic antigen (CEA) in the diagnosis of benign and malignant tumors of the large intestine].

Carcinoembryonic antigen was studied in 241 controls--patients with different diseases, 121 cases of intestinal polyp, 69 cases of large bowel carcinoma, 28 cases of stomach cancer and 65 patients with malignancies at other sites (total-524). Significantly high levels were found in large bowel and stomach cancer as well as cases of extensive tumor growth, relapse or metastases.

Adenocarcinoma↗