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PubMed1998

Volunteers as adjunct researchers in a cancer prevention trial: the American Cancer Society Colon Polyp Prevention Study.

BACKGROUND: In April 1991, the Virginia Division of the American Cancer Society (ACS) initiated the feasibility phase of the Colon Polyp Prevention Study (CPPS) to determine whether a high fiber supplement would decrease new adenomatous colorectal polyp occurrence. The feasibility phase had two specific objectives: 1) to evaluate accrual and compliance to the designed protocol and 2) to evaluate and demonstrate the effectiveness of volunteers as research assistants. The CPPS is an innovative project in which trained volunteers play a significant role in the research process. METHODS: In the CPPS, volunteer adjunct researchers (VARs) were trained to perform individual dietary data collection and intervention and other general study monitoring functions. VARs were trained, certified, and monitored in the performance of their assigned tasks by ACS staff and expert consultants. RESULTS: A total of 119 volunteers were trained as VARs, 74 of whom were certified and matched to a study participant. Between 1991-1995, only six VARs left the study. After active accrual of participants to the study ceased in 1995, 38 VARs (50% of the certified VARs) continued to monitor the active study participants. All VARs were consistently able to conduct the functions for which they were trained. CONCLUSIONS: In spite of expected volunteer attrition rates, a core of 38 dedicated VARs were matched to 72 participants and demonstrated the ability to perform selected data collecting activities on a consistent and efficient basis. The use of trained volunteers has allowed the CPPS to function in its feasibility phase at personnel cost considerably less than that of other similar cancer prevention trials.

American Cancer Society↗

PubMed1987

Mucin histochemistry in colonic polyps and cancer.

Mucins are the predominant glycoproteins found in gastrointestinal epithelia, and their structures differ according to the location in the GI tract and the state of cellular differentiation. Different forms of mucin are secreted in colonic polyps and cancers compared to those found in the normal colon. This paper reviews the methods available to probe mucin structure and the state of knowledge regarding the structures of neoplasia-associated mucins. Many of the assumptions made in the interpretation of classical histochemical stains on tissue sections have recently been questioned, and new insight into mucin structure has been gained from the development of newer methodologies such as lectin histochemistry and immunocytochemistry that use well-defined monoclonal antibodies.

Antibodies, Monoclonal↗

PubMed1994

Metastases from gastric adenocarcinoma presenting as multiple colonic polyps: report of a case.

A 53-year-old woman presented with symptoms of weight loss, diarrhea, and melena. A barium enema with endoscopy revealed multiple colonic polyps which were shown histologically to be metastatic deposits of poorly differentiated adenocarcinoma. The primary tumor, a poorly differentiated gastric adenocarcinoma, had been resected 11 years earlier. This appears to be only the second published report of polypoid colonic metastases from gastric adenocarcinoma.

Adenocarcinoma↗

PubMed2004

Registration of central paths and colonic polyps between supine and prone scans in computed tomography colonography: pilot study.

Computed tomography colonography (CTC) is a minimally invasive method that allows the evaluation of the colon wall from CT sections of the abdomen/pelvis. The primary goal of CTC is to detect colonic polyps, precursors to colorectal cancer. Because imperfect cleansing and distension can cause portions of the colon wall to be collapsed, covered with water, and/or covered with retained stool, patients are scanned in both prone and supine positions. We believe that both reading efficiency and computer aided detection (CAD) of CTC images can be improved by accurate registration of data from the supine and prone positions. We developed a two-stage approach that first registers the colonic central paths using a heuristic and automated algorithm and then matches polyps or polyp candidates (CAD hits) by a statistical approach. We evaluated the registration algorithm on 24 patient cases. After path registration, the mean misalignment distance between prone and supine identical anatomic landmarks was reduced from 47.08 to 12.66 mm, a 73% improvement. The polyp registration algorithm was specifically evaluated using eight patient cases for which radiologists identified polyps separately for both supine and prone data sets, and then manually registered corresponding pairs. The algorithm correctly matched 78% of these pairs without user input. The algorithm was also applied to the 30 highest-scoring CAD hits in the prone and supine scans and showed a success rate of 50% in automatically registering corresponding polyp pairs. Finally, we computed the average number of CAD hits that need to be manually compared in order to find the correct matches among the top 30 CAD hits. With polyp registration, the average number of comparisons was 1.78 per polyp, as opposed to 4.28 comparisons without polyp registration.

Algorithms↗

PubMed2006

Comparative study of conventional colonoscopy, chromoendoscopy, and narrow-band imaging systems in differential diagnosis of neoplastic and nonneoplastic colonic polyps.

AIM: To identify the feasibility of the narrow-band imaging (NBI) method compared with that of conventional colonoscopy and chromoendoscopy for distinguishing neoplastic and nonneoplastic colonic polyps. METHOD: This study enrolled consecutive patients who underwent colonoscopy using a conventional colonoscope between January and February 2006 at Chang-Gung Memorial Hospital, Linkou Medical Center, Taiwan. These 78 patients had 110 colorectal polyps. During the procedure, conventional colonoscopy first detected lesions, and then the NBI system was used to examine the capillary networks. Thereafter indigo carmine (0.2%) was sprayed directly on the mucosa surface prior to evaluating the crypts using a conventional colonoscope. The pit patterns were characterized using the classification system proposed by Kudo. Finally, a polypectomy or biopsy was performed for histological diagnosis. RESULTS: Of the 110 colorectal polyps, 65 were adenomas, 40 were hyperplastic polyps, and five were adenocarcinomas. The NBI system and pit patterns for all lesions were analyzed. For differential diagnosis of neoplastic (adenoma and adenocarcinoma) and nonneoplastic (hyperplastic) polyps, the sensitivity of the conventional colonoscope for detecting neoplastic polyps was 82.9%, specificity was 80.0% and diagnostic accuracy was 81.8%, significantly lower than those achieved with the NBI system (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%) and chromoendoscopy (sensitivity 95.7%, specificity 87.5%, accuracy 92.7%). Therefore, no significant difference existed between the NBI system and chromoendoscopy during differential diagnosis of neoplastic and nonneoplastic polyps. CONCLUSION: The NBI system identified morphological details that correlate well with polyp histology by chromoendoscopy.

Adult↗

PubMed1979

Intestinal lymphangiectasia and colonic polyps: surgical intervention.

A 36-mo-old boy with Milroy's Disease, intestinal lymphangiectasia, and an exudative enteropathy (EE), was shown to have four colonic polyps. A large adenomatous polyp was excised from the transverse colon in an effort to control his EE and hypoalbuminemia (1.95 g/dl). His clinical status then stabilized until age 50 mo when there was a marked exacerbation of his EE. Medical management resulted in a temporary stabilization of his condition. A partial resection (40 cm) of the visually worse affected jejunum was performed. There was no improvement in the EE as measured by 51Cr-tagged albumin study; however, his clinical response was dramatic. In the 10 mo since surgery, he has been well and has shown catchup in linear growth.

Child, Preschool↗

PubMed1979

Pathogenesis of colonic polyps in multiple juvenile polyposis: report of a case associated with gastric polyps and carcinoma of the rectum.

The pathogenesis of juvenile polyps of the colon was studied in a patient with multiple juvenile polyposis who underwent proctocolectomy for rectal carcinoma and antrectomy for associated polyps of the stomach. Numerous polyps up to 3 cm in diameter were present predominantly in the cecum and rectum, and in addition there was an adenocarcinoma in the rectum. Microscopically there were five categories of lesions: 1) Hyperplastic epithelial foci and small hyperplastic polyps; 2) Typical Juvenile polyps; 3) Juvenile polyps with focal adenomatous epithelium; 4) Adenomas; and 5) and adenocarcinoma. The five categories could represent a pathogenetic sequence, beginning with epithelial hyperplasia, leading to small hyperplastic polyps which become inflamed and enlarge, forming juvenile polyps. Focal adenomatous areas which develop in some juvenile polyps might give rise to adenomas and in turn lead to carcinoma. Although juvenile polyps are generally not considered to be premalignant lesions, this case demonstrates that neoplastic changes may occur in juvenile polyps in certain individuals, and raises the possibility that these may on occasion give rise to carcinoma.

Adenocarcinoma↗

PubMed1987

Peutz-Jeghers syndrome with adenomas and adenocarcinomas in colonic polyps.

A case of Peutz-Jeghers syndrome is reported in which 52 colonic polyps were resected endoscopically. Of these, 49 were hamartomatous and showed no adenomatous or carcinomatous changes. In the other three polyps, adenomatous change and foci of adenocarcinoma were present. The investigation of the sites of adenomas and carcinomas in this case and others previously reported indicates that such neoplastic changes are found on the luminal surfaces of the polyps of Peutz-Jeghers syndrome.

Adenocarcinoma↗

PubMed1996

Coexistence of multiple perifollicular fibromas and colonic polyp and cancer.

Perifollicular fibroma (PFF) is a rare cutaneous hamartoma that shows differentiation to the connective tissue sheath of the hair follicle. It may be solitary or multiple; the latter has been suggested to exhibit autosomal dominant inheritance and association with colonic polyposis. We report a 72-year-old Japanese female with multiple PFF on the face, possibly familial, who developed colon cancer in addition to colonic polyps.

Adenocarcinoma↗

PubMed1983

[The results of a dispensary follow-up after endoscopic electroexcision of colonic polyps].

With the help of fibrocolonoscopy 200 electroexcisions of epithelial polyps of the colon were performed in 116 patients. Control endoscopic examinations revealed 24 cases (12,0%) of recurrent polyps in the zone of their excision. A rational method of the dispensary follow-up of the patients after electrosurgical polypectomy during fibrocolonoscopy was elaborated on the bases of studying some factors influencing substantially the prognosis of the disease.

Aged↗

PubMed1986

Detection of the c-myc oncogene product in colonic polyps and carcinomas.

The c-myc oncogene has been implicated in the processes of normal cell proliferation and differentiation. Elevated levels of c-myc mRNA and its gene product (p62c-myc), have been detected in a variety of solid tumours and cultured cel lines. Its precise role in normal cell function and in neoplastic transformation and progression has yet to be elucidated. We have used a monoclonal antibody, raised by peptide immunisation, to determine the distribution by immunoperoxidase staining of the c-myc oncogene product in archival specimens of colonic polyps and carcinomas. Samples from 42 patients with colon carcinoma, 24 with benign polyps and 15 normal colon biopsies were examined. Normal colon revealed maximum staining in the mid-zone of the crypts, corresponding to the zone of differentiation and maturation. The staining was predominantly cytoplasmic. Adenomatous polyps revealed the most intense pattern of staining in areas of dysplastic change. Colonic tumours showed a wide range of staining. Well differentiated tumours contained more cytoplasmic p62c-myc than poorly differentiated tumours. These findings suggest that the c-myc oncogene product may play an important role in the evolution of colonic neoplasia.

Adenoma↗

PubMed2002

High-resolution chromoendoscopy for classifying colonic polyps: a multicenter study.

BACKGROUND: Chromoendoscopy may reliably separate adenomatous from nonadenomatous polyps. The aim of this multicenter trial was to determine the accuracy of high-resolution chromoendoscopy for the determination of colonic polyp histology. METHODS: This multicenter trial included 4 academic centers and a primary care practice. In 299 patients referred for routine colonoscopy or sigmoidoscopy, 520 polyps 10 mm in size were sprayed with indigo carmine dye. Using a high-resolution endoscope, the endoscopist predicted the histology of each polyp based on its surface characteristics. Hyperplastic polyps had a "pitted" surface pattern of orderly arranged "dots" that resembled surrounding normal mucosa. Adenomatous polyps had at least one surface "groove" or "sulcus." Each polyp was subsequently resected for histopathologic evaluation. RESULTS: The resected polyps were comprised by 193 adenomas (37%), 225 hyperplastic polyps (43%), and 102 "other" types (20%). Forty polyps (7.7%) could not be classified by high resolution chromoendoscopy with indigo carmine dye. For the remaining polyps, the sensitivity, specificity, and negative predictive value of indigo carmine dye staining for adenomatous polyps were, respectively, 82%, 82%, and 88%. The results were consistent among the academic centers and the primary care practice. CONCLUSIONS: High-resolution chromoendoscopy with indigo carmine dye demonstrates morphologic detail of diminutive colorectal polyps that can reliably be used to separate adenomatous from nonadenomatous polyps.

Adenoma↗

PubMed1975

[Endoscopic resection of colonic polyps. A propos of 45 polypectomies].

Endoscopic resection of polyps of the colon is, no doubt, a considerable therapeutic advance. It avoids surgical operation permits histological examination and makes simple biopsy unnecessary. It is indicated in the presence of pediculated polyps of a diameter or less than 3 cm, whatever the site of the polyp. Thus we were able to remove 45 polyps without complications. The method is not indicated in a large size polyp, sessile polyps or diffuse polyposis. The follow-up is still insufficient to assess : 1) the true risk of resection which can only be undertaken after long experience of colonoscopy ; 2) the frequency or recurrent adenomas. Endoscopic resection is at present the simplest method of detection and treatment of carcinoma in situ of the colon of which we observed four cases in our series. The problem of surgical reoperation is discussed.

Colonic Neoplasms↗

PubMed1978

[Pathology of colonic polyps].

Recent developments in the field of polyps of the colon are discussed. The WHO classification represents a definite improvement. Apart from standardization, non-neoplastic polypoid changes of varying etiology and hamartomatous polyps are clearly distinguished from neoplastic, non-malignant adenomas. The various changes are outlined briefly in their essential characteristics. Clear-cut differentiation from early invasive cancer is of considerable importance for practical therapeutic purposes. Focal carcinoma within an adenoma is referred to only if invasion through the muscularis mucosae is established, while all other changes confined to the mucosa are termed adenomas with focal epithelial atypia. With regard to the relation between adenoma and cancer of the colon, recent results on topographical distribution of adenomas through the colon are of considerable significance. From serial studies of biopsy and autopsy specimens on the one hand, and from assessment of colon carcinoma incidence compared with mortality rates in carcinomas of different localizations on the other, it is evident that special attention should be given henceforward to adenomas, possible precursors, and carcinomas in the upper segments of the colon.

Adenoma↗

PubMed1999

N-acetylcysteine suppression of the proliferative index in the colon of patients with previous adenomatous colonic polyps.

This investigation is part of an effort to develop chemoprevention for carcinogenesis of the large bowel. The agent investigated is N-acetylcysteine (NAC). We used as a predictive biomarker, the proliferative index (PI), in a short-term human study. Patients with previous adenomatous colonic polyps are a cohort with increased risk for colon cancer and an increased PI of colonic crypts. They were randomly assigned to an experimental group given 800 mg/day of NAC for 12 weeks or a placebo group. Using proliferative cell nuclear antigen immunostaining, the PI of colonic crypts was measured prior to and after the treatments. The PI of the NAC group was decreased significantly (P < 0.02) while the placebo group showed no difference (P > 0.45). Since this decrease in PI may be an indicator of decreased risk of colon cancer, more extensive studies of the potential of NAC as a chemopreventive agent for colon cancer appear warranted.

Acetylcysteine↗

PubMed1996

The difference in colon polyp size before and after removal.

BACKGROUND: Accurate knowledge of polyp size is important in assessing cancer risk in both clinical studies and individual patients. We sought to determine if a difference exists between the endoscopic estimation of colon polyp size and the actual measurement after removal. METHODS: We measured polyps in a systematic fashion. Using open biopsy forceps as a guide, the largest diameter of 31 pedunculated polyps was estimated endoscopically. The polyp was then removed by snare polypectomy and directly measured by a technician who was blinded to the endoscopic estimate. Each polyp was also measured after formalin fixation by a pathologist who was blinded to previous measurements. RESULTS: There was a significant difference between the endoscopic estimates and the postpolypectomy measurements. Endoscopic estimates on average were 1.6 mm greater than the postpolypectomy measurements (p< 0.05), representing an 18% difference. Twenty-three of the 31 (74%) endoscopic estimates were larger than the postpolypectomy measurements. There was not a significant difference between the postpolypectomy and postfixation measurements. CONCLUSIONS: The size of polyps measured endoscopically is significantly larger on average than postpolypectomy measurements. This is most likely due to factors involved in the removal of the in vivo polyp.

Adult↗

PubMed1987

Colonoscopic polypectomy as a tool for management of colonic polyps and detection of new lesions.

Over the past 14 years 1,000 polyps were removed via colonscope and histologically examined. There were 869 neoplastic polyps including 125 carcinomas. Non-neoplastic polyps included 32 inflammatory polyps, 32 metaplastic polyps, 27 juvenile polyps and 17 Peutz-Jeghers type polyps. Ninety-eight focal carcinomas were adequately treated by polypectomy only, whereas 9 out of 26 invasive carcinoma required further operations with one residual carcinoma in the pararectal tissue and colonic wall respectively. The criteria requiring additional surgery in invasive carcinoma are 1) lymphatic permeation of the submucosa, 2) poorly differentiated carcinoma or 3) massive invasion close to the cut end. Not only polypoid adenomas but also flat adenomas were found to exist and seem to play an important role in the adenoma-carcinoma sequence. It became clear that colonscopic polypectomy was a useful tool for the management of colonic polyps.

Adenoma↗

PubMed2005

Colon polyps and cancer.

The role of endoscopy, in particular colonoscopy, clearly is paramount in the screening, diagnosis, and prevention of colorectal cancer. In preparation for writing this "state-of-the-art" review on colon polyps and cancer, a PubMed literature search linking the topic with endoscopy yielded an enormous number of papers published in peer-reviewed journals just in the past 12 months. I have selected a few of these to highlight that I believe are most germane to current issues of risk stratification, screening and surveillance, prevention, and the premalignant potential of different types of adenomas detected by endoscopy. Several of these papers address the advantages and limitations of direct colonoscopy screening for colorectal neoplasia, and discuss the emerging role of virtual colonoscopy screening.

Colonic Neoplasms↗