Proximal Polyps Research Articles

Diminutive colonic polyps

A prospective study investigated the significance of solitary diminutive colonic polyps discovered during screening flexible sigmoidoscopy. Eighty-two patients with a solitary diminutive polyp (less than or equal to 5 mm) underwent colonoscopy after cold biopsy of the index polyp. Of the patients with adenomatous index polyps, 42.5 percent had proximal neoplastic polyps. Of the patients with hyperplastic index polyps, proximal neoplastic polyps were found in 38.9 percent. These data suggest that diminutive polyps identified during flexible sigmoidoscopy, whether adenomatous or hyperplastic, place the patient in the intermediate risk group for colorectal neoplasia. We recommend that any patient with polyps seen during screening sigmoidoscopy, regardless of histopathology, should undergo colonoscopy.

Barium enema versus colonoscopy for patients with polyps found during flexible sigmoidoscopy

This prospective study compares the accuracy of barium enema examination performed by experienced radiologists to colonoscopy performed by experienced gastroenterologists blinded to the radiographic findings to detect proximal, synchronous lesions in patients with polyps detected during fiberoptic sigmoidoscopy. Three thousand six patients were examined, of whom 147 (5%) had polyps larger than 0.5 cm in diameter. Of 114 patients who completed the protocol, 46 patients (40%) had synchronous, proximal colonic lesions. There were no radiographic false positives, but the single-contrast barium enema missed polyps in 13 while detecting polyps in 2 patients (sensitivity = 13%). The double-contrast barium enema missed proximal polyps in 23 patients while detecting them in 8 (sensitivity = 26%). We conclude that patients with neoplastic polyps found during fiberoptic sigmoidoscopy should have colonoscopy without barium enema. If the entire colon cannot be examined at colonoscopy, we advise double-contrast barium enema.

Screening for colon malignancy with colonoscopy.

Screening of asymptomatic individuals for colon malignancy has been advocated for the past 20 yr in the hopes of reducing colon cancer mortality. Although sigmoidoscopy is an important element of current screening recommendations, the sensitivity of this test in asymptomatic subjects has never been studied. The purpose of this study was to determine the prevalence and location of polyps and cancers in an asymptomatic population by performing full colonoscopy. We wished to assess the sensitivity of screening flexible sigmoidoscopy to 60 cm by determining how many patients with adenomas or cancer had "index" adenomatous polyps in the distal 60 cm. One hundred five healthy male outpatients, over 50 yr old, with negative examinations for occult blood in stools and no prior history of colon pathology, had full colonoscopy. Careful examination of the distal 60 cm was performed, followed by a full colon examination to the cecum. Forty-three patients (41%) had adenomatous polyps, and only 19 of these patients had an index adenomatous polyp in the distal 60 cm. Therefore, the sensitivity of sigmoidoscopy was 44%. The prevalence of adenomas increased with age. Patients were assigned to one of three groups based on the findings in the distal 60 cm. Group 1 (n = 65) had no polyps in the distal 60 cm, but 18 of these patients (28%) had adenomatous polyps in the proximal colon. Among 21 patients with only hyperplastic polyps in the distal 60 cm (group 2), six patients (29%) had proximal adenomas. In group 3, eight of 19 patients (42%) with adenomas in the distal 60 cm also had proximal adenomatous polyps. We conclude that adenomatous polyps are common in asymptomatic men who have negative tests for fecal occult blood. Sigmoidoscopy to 60 cm had a sensitivity of only 44% in this patient population, suggesting that this is an insensitive test for the detection of patients with adenomatous polyps.

Differential activation of ornithine decarboxylase and tyrosine kinase in the rectal mucosa of patients with hyperplastic and adenomatous polyps

Hyperplastic polyps are considered to be benign colonic lesions with almost no potential for malignant transformation. Recent reports have shown an increased association of hyperplastic polyps with adenomatous polyps and have advocated a full colonoscopy in patients who harbor hyperplastic polyps. Hyperproliferative mucosa is known to be associated with adenomatous polyps, but its relationship to hyperplastic polyps is unknown. In the present pilot study, it is determined whether a change in mucosal proliferative patterns is observed in patients who harbor only hyperplastic polyps or a history of hyperplastic polyps relative to those who harbor both hyperplastic polyps and adenomatous polyps by measuring ornithine decarboxylase and tyrosine kinase activity in macroscopically normal rectal mucosa. Fifteen patients had either adenomatous polyps proximally or harbored adenomatous polyps and hyperplastic polyps. Seven patients had hyperplastic polyps and 15 patients had a prior history of hyperplastic polyps with no polyps found during the current examination. The ornithine decarboxylase activity of the rectal mucosa with proximal adenomatous polyps or both polyp types was significantly higher than that of hyperplastic polyps, the history of hyperplastic polyps, or controls, and values for hyperplastic polyps and the history of hyperplastic polyps were similar to controls. On the other hand, tyrosine kinase activity in the rectal mucosa of patients with both or either polyp type was elevated without any significant difference between hyperplastic and adenomatous polyps. Thus, it is concluded that although increased ornithine decarboxylase activity in rectal mucosa suggests the presence of adenomatous polyps or a combination of adenomatous with hyperplastic polyps, increased tyrosine kinase activity suggests the presence of any type of polyp.

Distal and Proximal Colon Adenomas

To the Editors: In the report of their prospective study of whether distal colonic hyperplastic polyps are a marker for proximal adenomatous polyps in symptomatic patients, Provenzale and colleague...

Colonoscopic screening of asymptomatic patients with a family history of colon cancer

The records of 201 asymptomatic patients who underwent colonoscopy based solely on a family history of colon cancer were reviewed. Eighty-five patients (42 percent) had a total of 166 lesions. Fifty-four (27 percent) patients of the screened population had neoplastic lesions, while 31 (15 percent) patients had nonneoplastic polyps. Four carcinomas were found. Twenty-five of the patients with polyps (29 percent) had no polyps distal to the splenic flexure; these proximal polyps (and two carcinomas) would have been missed on screening with fiberoptic sigmoidoscopy. Nineteen of these 25 patients had polyps smaller than 0.5 cm, which likely would have been missed with contrast enemas. Almost one half (47 percent) of all polyps discovered at screening colonoscopy were proximal to the descending colon. Only one patient younger than 40 years old had adenomas. The yield of polyps and cancer in patients with familial risk indicates screening colonoscopy should be considered after age 40.

Lectin histochemistry of adenomatous polyps. Not a predictor of metachronous lesions

The binding characteristics of fluorescein isothiocyanate conjugated lectins to normal colonic mucosa, and 43 adenomatous polyps were studied by fluorescence microscopy. The lectin, Dolichos biflorus agglutinin (DBA) stained intensely to upper crypt cells of the sigmoid colon and rectum but to a lesser degree to proximal colonic crypts or lower crypt cells distally. Peanut agglutinin (PNA) and Ulex europaeus agglutinin (UEA) did not bind to the theca of proximal or distal colonic crypts. The lectin Griffonia simplicafolia agglutinin (GSA1) bound intensely to upper and lower crypt cells of both regions. PNA binding was noted in 56% of adenomatous polyps, occurred more often in polyps of the distal colorectum, and increased with polyp size and villous histology. UEA bound to 26% of adenomatous polyps, 42% of proximal polyps, and 17% of distal polyps. DBA staining was noted in 72% of polyps without regional preference. GSA1 stained all polyp specimens. To determine if the lectin binding characteristics of an index (initial) polyp might serve as a predictor of metachronous lesions, 20 patients (29 polyps) without a history of polyps or cancer and who had at least one surveillance colonoscopy 1 to 3 years after the initial polypectomy were studied. The presence or absence of PNA, UEA, or DBA binding in an index polyp did not predict the occurrence of metachronous lesions. Five of the six patients with more than one index polyp had metachronous polyps at follow-up surveillance colonoscopy.

Histopathological assessment of bleeding from polyps of the colon and rectum.

One hundred and twenty seven colorectal polyps were examined to assess histopathological evidence of recent and old haemorrhage to test the usefulness of faecal occult blood tests in detecting colorectal neoplasia, in particular premalignant adenomas. Evidence of haemorrhage was consistently found in adenomas but was rare in non-neoplastic polyps. Haemorrhage within adenomas was predominantly stromal and associated with dilated, congested vessels. Factors associated with more severe haemorrhage were size, pedunculation, and villous growth; the degree of epithelial dysplasia and the age and sex of the patient were not associated factors. Proximal polyps showed more old haemorrhage than rectal polyps, but there was no such difference for recent haemorrhage.

Hyperplastic colonic polyps as a marker for adenomatous colonic polyps.

Hyperplastic colonic polyps are generally regarded as being of little or no clinical consequence. Recently, however, hyperplastic polyps have been found to share numerous functional similarities with colorectal carcinoma. To determine whether the presence of an isolated left-sided colonic hyperplastic (metaplastic) polyp could serve as a marker for more proximal synchronous adenomatous colonic polyps, we retrospectively analyzed all consecutive colonoscopic polypectomies performed over an 18-month period at two medical centers. It is the policy at both institutions to remove or biopsy all polyps, regardless of size. Indications for colonoscopy included known or previous colonic polyps or carcinoma, hemoccult positive stool, lower gastrointestinal bleeding, iron deficiency anemia, abnormal barium enema, inflammatory bowel disease, abdominal pain, and family history of colon cancer. The location of adenomatous polyps and hyperplastic polyps was recorded and compared. One hundred sixty-three of 845 consecutive patients (19.3%) had at least one colonic polyp. The prevalence of adenomatous polyps alone was 10.3%, hyperplastic polyps 9%, and both types 1.9%. The prevalence rate for an adenomatous polyp in patients without a hyperplastic polyp was 15%. In contrast, among patients with a hyperplastic polyp, 49% had a synchronous adenomatous polyp. Only 3.4% of patients had an adenomatous polyp proximal to the splenic flexure when no polyps were present in the left colon. Conversely, among the 29 patients in whom an isolated hyperplastic polyp was found in the left colon, there was a 32.5% prevalence of adenomatous polyps in the proximal colon (p less than 0.01). The results of this study suggest that left-sided hyperplastic colonic polyps (generally within the reach of a screening sigmoidoscopy) serve as a marker for neoplastic polyps.

Frequency of isolated proximal colonic polyps among patients referred for colonoscopy

• The American Cancer Society now advocates screening asymptomatic populations over the age of 40 to 50 years for colonic malignancy. It is possible, however, that fecal occult blood testing and sigmoidoscopy to 60 cm would fail to identify patients with adenomatous polyps located only in the proximal colon. The purpose of this study was to determine how many patients without polyps in the distal 60 cm of the colon would have more proximal lesions. Ninety-eight consecutive patients with positive fecal blood test results or suspicious barium enema results were studied, using the assumption that if they had been seen six months earlier, when asymptomatic, they would have been candidates for screening examination. Forty-one (42%) of 98 patients had adenomatous polyps or cancer, and 15 (37%) of these patients had isolated proximal lesions. The polyp detection rate from 0 to 60 cm was significantly less than the detection rate for a full colonoscopy (27% vs 42%). We conclude that isolated proximal colonic polyps may be common. (<i>Arch Intern Med</i>1988;148:473-475)

Frequency of Isolated Proximal Colonic Polyps Among Patients Referred for Colonoscopy

The American Cancer Society now advocates screening asymptomatic populations over the age of 40 to 50 years for colonic malignancy. It is possible, however, that fecal occult blood testing and sigmoidoscopy to 60 cm would fail to identify patients with adenomatous polyps located only in the proximal colon. The purpose of this study was to determine how many patients without polyps in the distal 60 cm of the colon would have more proximal lesions. Ninety-eight consecutive patients with positive fecal blood test results or suspicious barium enema results were studied, using the assumption that if they had been seen six months earlier, when asymptomatic, they would have been candidates for screening examination. Forty-one (42%) of 98 patients had adenomatous polyps or cancer, and 15 (37%) of these patients had isolated proximal lesions. The polyp detection rate from 0 to 60 cm was significantly less than the detection rate for a full colonoscopy (27% vs 42%). We conclude that isolated proximal colonic polyps may be common.

The efficacy of barium-enema examinations in patients with anorectal disease.

This retrospective study examines the value of an air contrast barium enema examination in detecting proximal neoplasia in the patient presenting with benign anorectal disease as determined by history, physical examination, rigid, and flexible sigmoidoscopy. In 428 of these patients, the roentgenographic studies showed proximal colonic cancer or polyps in less than 1 percent of patients reviewed. In addition, a review of 402 patients with known colon and rectal cancer were surveyed using the same criteria for diagnosis, and less than 1 percent were misinterpreted as having benign anorectal disease.

Asymptomatic Polyps of the Colon and Rectum

Four hundred and fifty-six distal polyps were detected in 160 (53%) of 300 patients over 45 years of age examined by routine proctosigmoidoscopy after July 1, 1965. Sixty-five percent of these lesions were multiple, 97% were 5 mm or less in size, and 75% were located in the middle third segment of the rectocolon visualized. Sixteen proximal polyps were revealed in 8 (3.8%) of 211 patients examined by roentgenogram of the colon. Half of these lesions were less than 1 cm in size. Higher up polyps were roentgenologically demonstrated in patients with distal polyps almost twice as frequently as in those with normal results of endoscopy. A significantly higher incidence of both distal and proximal polyps was found in cigarette smokers and ex-smokers as compared with nonsmokers. Selecting smokers rather than those with distal polyps for subsequent proctologic procedures should efficiently increase the yield of benign adenomatous polyps, at half the cost of similar studies in an unselected population.

Asymptomatic polyps of the colon and rectum. 3. Proximal and distal polyp relationships

Asymptomatic polyps of the colon and rectum. 3. Proximal and distal polyp relationships

Gastric Carcinoma as a Small, Polyp-Like Lesion with Associated Benign Polyp

By means of radiology and endoscopy, two small antral polyps were found in a 58-year-old male. Whereas the macroscopic aspect was unsuspicous of malignancy, directed biopsy of the proximal polyp revealed carcinomatous structures. In the resected stomach lymphangiosis carcinomatosa of the submucous layers could also be demonstrated. Therefore, this type of carcinomatous lesion could not be classified as early carcinoma.