Polyps and cancer of the large bowel

Morphologic Changes, Mucin Secretion, Carcinoembryonic Antigen (Cea) and Peanut Lectin Reactivity in Colonic Mucosa of Patients at High Risk for Colorectal Cancer

We studied 393 endoscopic colonic biopsies from 72 patients, classified in different groups after assessment of their risk factors, using: histologic, histochemical and immunohistochemical techniques (CEA-PAP and PNA-Px). In high risk patients (Groups A and B) the most relevant modifications were dysplasia with hyposecretion and hyperplasia with sialomucin secretion (TR-type change); in Group A 31 adenomas and 19 hyperplastic polyps also were found. A premalignant nature of dysplasia and predysplastic significance of TR change were suggested: 1) by finding the same alterations in mucosa of Group E (colectomized patients for carcinoma at after 1 year); 2) by increasing expression of CEA and PNA-Px ligands; 3) by their absence in Group D (normal controls). Hyperplastic polyps were confirmed not to be premalignant lesions, but since they had peculiar characteristics (increased CEA and PNA-Px positivity, association with adenomas) it does not seem justified to regard them as lesions unrelated to colorectal cancer, especially when associated with other risk factors. CEA and PNA-Px reactivity correlated well with the risk evaluation and with morphohistochemical changes in the mucosa; the reactivity significantly increased from normal mucosa to dysplasia.

Value of Multiple Forceps Biopsies in Assessing the Malignant Potential of Colonic Polyps

Fifty-nine colo-rectal polyps were detected at endoscopy and repeatedly biopsied before removal by endoscopic snare polypectomy. The aim of the present paper was to evaluate the reliability of multiple forceps biopsies in assessing both the malignant potential and the presence or absence of invasive cancers (IC) in colo-rectal adenomas (CRA). In order to achieve the first objective, the histologic types and the degree of dysplasia have been defined. The data obtained by means of multiple biopsies examination, compared with those of polyp in toto study, show that fractional biopsies were of value in the histologic classification of only the smallest 41 polyps (agreement 88.09 %), whilst no reliability of biopsies was demonstrated in the 18 largest polyps (agreement 27.68 %). In the field of dysplasia grading, the agreement was 55 % and 61 % for the smallest and the largest CRA respectively. These last figures are hardly acceptable. Biopsies examination gave also under- and overestimation of the histologic severity and of dysplasia as well as a significant incidence of false negative results in IC detection. It is concluded that polypectomy is the only method which provides adequate material for precise diagnosis, no matter how large a polyp. Therefore it should be performed whenever possible. Finally the authors discuss the management of small sessile adenomas.

Estimating and Comparing the Distribution of Onset of Disease from Prevalence Case-Control Data

Age at ascertainment from prevalence case-control data identifies the age-specific odds of disease. When age at onset is available from the cases, the conditional distribution of age at onset, given that disease occurs, is identifiable. Combining both kinds of information by introducing a multiplicative intercept allows identification of the marginal distribution of age at onset. Here, the approach is extended to the two-sample setting through a generalization of the multiplicative intercept model. The efficiency of the approach is explored and a test statistic based on the integrated difference between distribution function estimates is proposed. An approach to regularization of the likelihood is discussed. The methods are illustrated through an application to data on colorectal polyps obtained from a case-control study of individuals undergoing colonoscopy.

The emerging role of virtual colonoscopy

A review of the current status of virtual colonoscopy is germane and topical. Clinicians need to be knowledgeable about this rapidly evolving and clinically relevant technology to understand the test benefits and limitations and to refer patients for this test appropriately. A critical review of the exponentially expanding literature on this subject is important. This article describes the imaging meth-ods, adjunctive techniques, and radiologic interpretation of CT colonography, and comprehensively and critically reviews the clinical data to help the clinician evaluate the current and potential applications of this technology.

Three-dimensional reconstruction and fractal geometric analysis of serrated adenoma

Serrated adenoma (SA) is a relatively newly defined entity of colorectal neoplasm first characterized by Longacre and Fenoglio-Preiser in 1990. This lesion is characterized by a complicated serrated edge of crypts. In this study, we performed three-dimensional (3-D) reconstruction, including 3-D distribution patterns of Ki-67-positive cells and fractal dimension of SA, in order to evaluate the nature of the complicated architecture, including its possible morphogenesis. We studied nine colonoscopic polypectomy specimens including three SAs, three tubular adenomas (TAs), and three hyperplastic polyps (HPs). Sixty serial tissue sections per case were stained alternately with hematoxylin and eosin (H&E) and Ki-67 immunostain. Each serial image was then digitized for 3-D computer analysis and the distribution pattern of Ki-67-positive cells was evaluated. Ki-67-immunostained sections were also subjected to 2-D quantitative morphometric study. In addition, the fractal dimensions of images from H&E-stained sections were examined using a box-counting method. Results of the 3-D reconstruction study demonstrated that glandular budding and branching were more frequent in SA than in TA or HP. These findings were confirmed quantitatively by the results of fractal geometric analysis of these polyps (fractal dimension:1.34 +/- 0.08 for SA, 1.23 +/- 0.07 for TA, and 1.28 +/- 0.12 for HP). Ki-67-positive cells in HP were localized mainly in the bottom of crypts and those in TA were diffusely distributed, while Ki-67-positive cells in SA were mainly aggregated in the depressed sites of serrated epithelia. These findings were also confirmed quantitatively using 2-D morphometry. These distribution patterns of the proliferative zone of SA are considered to contribute to the formation of the characteristic serrated epithelia and the complicated morphological appearance of SA.

The adenoma-carcinoma sequence in the colorectum--early appearance of a hierarchy of small intestinal mucin antigen (SIMA) epitopes and correlation with malignant potential

The colorectal adenoma-carcinoma sequence was examined in relation to the ectopic expression of the oncofoetal Small Intestinal Mucin Antigen (SIMA), to the development of morphologic changes in the adenoma and perineoplastic mucosa and to indices of malignant potential. Four anti-SIMA MAbs, which define a novel hierarchy of SIMA epitopes in the normal small intestine and adjacent to colorectal cancers, were used in a retrospective immunohistochemical study of Familial Adenomatous Polyposis (FAP, n = 183) and non-familial (n = 44) adenomas. Inappropriate expression of SIMA epitopes was first detected in mucosa adjacent to minute microadenomas larger than three glands, and with increase in size, in increasing amounts within adenomas themselves, but not with microadenomas smaller than three glands or regions of flat mucosa free of adenomas. SIMA epitope expressed in mucosa adjacent to adenomas preceded changes in perineoplastic morphology, which progressed with adenoma growth to resemble transitional mucosa (TM) adjacent to cancers. Thus, the onset of both SIMA expression and morphological changes in TM were consistent with reactive rather than pre-existing field change phenomena. The previously reported hierarchy of four SIMA epitopes (5C5, 3D4, 4D3, 6C5) was also consistently observed in the adenoma-carcinoma sequence, and applied to (i) the order of epitope detection, (ii) the number of positive adenomas and (iii) extent of staining; (iv) the height in the crypt and (v) distance from the adenoma to which epitopes were expressed in perineoplastic mucosa. These observations are consistent with a progression of changes in mucin composition with adenoma development. The percentage of positive adenomas and reactivity scores for each anti-SIMA MAb correlated with increasing adenoma size, degree of dysplasia and growth pattern. SIMA expression appears to predate the earliest reported oncogene and tumour suppressor gene changes, was persistent and increased throughout adenoma development. SIMA epitopes are thus markers of very early neoplastic change, whose expression correlates with malignant potential and may contribute to the accumulation of changes necessary for tumourigenesis.

Natural history of adenomas

One-third of individuals over the age of 55 years have single or multiple colorectal adenomas. During a subsequent period of 10 years, 3-5% of adenoma-bearing individuals will probably develop a carcinoma. The rather low conversion rate from benign to malignant disease indicates that most individuals with adenomas will never develop colorectal carcinoma. More knowledge is required to predict the outcome of the individual adenoma in a given patient. This will probably be obtained by increasing progress within gene technology and through large prospective follow-up studies of adenoma-bearing patients.

Colorectal adenomas containing invasive carcinoma. Pathologic assessment of lymph node metastatic potential

Adenomas that contain early invasive carcinoma (ACIC) represent the earliest form of clinically relevant cancer of the colorectum in most patients. In order to assess the incidence of nodal metastases of ACIC, we studied 31 patients in whom the colon was resected after endoscopic polypectomy (EP) done from 1975 to 1987. We also reviewed the pathologic features reported in individual cases and in literature series of ACIC with lymph node metastases published from 1958 to 1986. The lymph node metastatic potential of ACIC is relatively high, ranging from an average value of 8.5% in the literature of to 16.1% in our own study, and is equivalent to the range of 10%-17% that occurs in colorectal carcinomas that invade the submucosa. When an ACIC is seen in an EP specimen in which the polypectomy margin is normal, the decision as to whether the patient should enter a follow-up protocol or have radical surgical resection is determined by the assessment of the probability of the occurrence of nodal metastases. According to several authors, certain histopathologic features make it possible to distinguish between an ACIC with a high-risk of nodal metastases versus those with a low-risk. The most relevant pathologic parameters include the state of the resection margins, the grade of the invasive carcinoma, and the presence or absence of vascular invasion. Of 351 cases of ACIC that were operated on, derived from 16 literature series, 45.6% were high-risk cases and 8.5% had lymph node metastases. In our group of high-risk ACIC that had surgical resection subsequently, the lymph node metastatic rate was 35.7%. Our results help to estimate the nodal metastatic potential of early colorectal carcinomas and stress the importance of adequate pathologic evaluation in order to assess metastatic risk in these patients accurately.

Mucin profiles and potential for malignancy of human colorectal adenomatous polyps

The mucin histochemical and histologic features of 166 colorectal adenomatous polyps from 124 patients were studied. A majority of the polyps (62%) had a tubular growth pattern whereas 38% showed villous growth. Severe dysplasia was more frequently found in the latter group. A significant correlation (r = 0.27, P less than 0.001) was found between the severity of dysplasia and the size of the polyps. Moreover, the ratio between goblet and columnar cells was also found to decrease (P less than 0.0001) with the severity of dysplasia. Independent of the mucin stain used (periodic acid-Schiff, alcian blue, and high-iron diamine stains), mucin reactive cells were found to be negatively correlated (-0.17 less than r less than -0.44, P less than 0.01) with severity of dysplasia, especially in the tubular adenomas. These findings suggest that evaluation of mucin stain, related to dysplasia, may contribute to the assessment of premalignant and early malignant changes in adenomas of the colon.

Quantitative electron microscopic study on grades of atypia in adenomas of the human large bowel

Clarification of the ultrastructural features of the three different grades of histologic atypia of adenomas (i.e., mild, moderate, and severe atypia) with reference to carcinoma of the human colon and rectum was undertaken using electron microscopic quantitative analysis. Ten normal epithelia, 36 adenomas (14 with mild atypia, 13 with moderate atypia, and 9 with severe atypia) and 14 carcinomas (well-differentiated adenocarcinoma) were examined with light and electron microscopes. Although it has been generally accepted that malignant transformation of an adenoma gradually proceeds with increasing atypia, using light microscopy, ultrastructural quantitative analysis clearly revealed that fine features of individual atypia did not correspond with histologic grades of atypia. Ultrastructural changes occurred abruptly in moderate atypia and showed similar cellular characteristics to carcinoma cells. Mild atypia was almost similar in appearance to normal epithelial cells. Striking changes in the moderate atypic cells were plane apposition of the cell membrane, decrease of the desmosomes, and increase of the lysosomes. These atypical cells were assumed to play a significant role in the adenoma-carcinoma sequence. Therefore, radical surgical therapy would be required for moderate atypic adenoma of the large bowel that is difficult to remove endoscopically.

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.

A morphometrical analysis of dysplasia in small adenomas of the large intestine

In a morphometrical study of 40 colorectal adenomas less than 10 mm in diameter and of 10 specimens of normal mucosa, it was found that nuclear size, perimeter and shape-factor of the epithelial cells were significantly different in neoplastic when compared with normal tissues. The same was found for the volume fraction of stroma, gland spaces, goblet and non-goblet epithelium, for the gland diameter, nuclear stratification height and stratification index, but not for the epithelial height nor the total volume fraction of the epithelium. In a multivariate analysis, stratification index and nuclear size of the epithelial cells contributed most significantly to determination of the histological grade of dysplasia in adenomas. By the combination of these two morphometric variables 75% of all adenomas could be correctly allocated to the grade of dysplasia.

The adenoma-carcinoma sequence of the colon and rectum

Morphological and epidemiological arguments in favour of an adenoma-carcinoma concept of evolution in the development of colorectal cancers are presented. It is highly probable that most colorectal cancers arise in adenomas. Therefore detection and endoscopic removal of adenomas is a means of reducing the incidence of colorectal carcinomas.

The significance of synchronous carcinoma and polyps in the colon and rectum

The relationship of colorectal carcinoma with polyps was studied retrospectively in 1202 patients. The incidence of synchronous carcinoma (SC) and metachronous carcinoma (MC), prognosis, and recurrence patterns were studied. Synchronous polyps (SP) were found in 36% of the patients. SC was found in 4.4% of the patients, and MC developed in 3.5% of patients. The incidence of SC and of MC increased with SP, and varied according to number, size, and histologic features of the polyps. The adjusted 5-year survival rate was improved in patients with SP compared with those without SP, both overall (79% versus 64%, respectively) and by Dukes' Stage B (87% versus 73%, respectively) and Dukes' Stage C (56% versus 39%, respectively). The pattern of relapse was the same for the SP and non-SP groups. Subtotal colectomy is recommended for colorectal carcinoma and SP in good-risk patients.

Coexisting juvenile polyps and tubulovillous adenoma of colon with carcinoma in situ: report of a case

The coexistence of juvenile and adenomatous polyps is confirmed by the present case of a 17-year-old girl who had two juvenile polyps and a tubulovillous adenoma of the colon with carcinoma in situ, a clinically benign lesion. The relation between the juvenile and adenomatous processes and the risk of the development of colonic carcinoma in such cases remain ill defined.

Colonic mucosa adjacent to adenomas and hyperplastic polyps--a morphological and histochemical study

The morphological and histochemical features of colonic mucosa adjacent to 142 adenomas and 31 hyperplastic polyps were studied. Three predominant patterns were identified: (1) normal mucosa, showing normal histological architecture and secretion of sulphomucins; (2) N+ type, histologically normal mucosa with predominance of sialomucins; (3) transitional mucosa; hyperplastic mucosa secreting sialomucins. Hyperplastic changes were observed in the immediate neighbourhood or at the base of adenomas and were more frequent and extensive near large adenomas than around smaller lesions. Sialomucins were often predominant in the mucosa adjacent to large adenomas, but N+ type mucosa was also seen near minute adenomas and hyperplastic polyps and remote from polypoid lesions. Moreover, both hyperplastic and secretory changes were more frequent in the left colon than in the right. These findings seem to suggest that mucosal hyperplasia more likely represents a local change, parallel with or secondary to tumour development rather than a pre-adenomatous lesion. Secretory modifications are widespread and may result from the action of various factors among which carcinogens cannot be excluded.

Late determinants of cancer

The paper reviews some findings on the frequency of latent carcinoma. Latent carcinomas are found much more frequently in the prostate, than would be expected from mortality or incidence data. The same applies to neuroblastomas in the adrenal cortex in infants. The problem has not been studied in detail in other organs. A satisfactory explanation of spontaneous regression of human cancers or the variable disease-free survival time of cancer patients has not been found. It is concluded that defence mechanisms of paramount importance exist, and need to be studied. Recent reports on serum retinol and serum cholesterol are reviewed since these are both lower in people who later develop cancer. Much more knowledge is needed but these phenomena could be linked.

Juvenile polyposis of the colon with atypical adenomatous changes and carcinoma in situ. Report of a case and review of the literature

Juvenile polyps are thought to have no malignant potential; however, we report a case of diffuse juvenile polyposis coli in a 19-year-old man where mucosal dysplastic changes ranging from mild dysplasia to carcinoma in situ are present. The pathogenetic development of these polyps and their malignant potential are discussed.

Reliability of routine double-contrast examination (DCE) of the large bowel in polyp detection: a prospective clinical study

A total of 2,118 consecutive patients, examined with double-contrast examination of the large bowel (DCE), were evaluated radiographically, clinically, and endoscopically for up to 48 months. A total of 402 polyps were diagnosed during the follow-up period. Of these, 307 were revealed at the first DCE and 95 at subsequent endoscopy or autopsy. The accuracy of the DCE for demonstrating or excluding patients with polypoid lesions of the colon was 97%, whereas the predictive value of a positive DCE report was 96% and a negative one, 97%. However, the ability to demonstrate every known polyp at DCE was only 63%, although the probability of a polypoid lesion demonstrated at DCE being a true polyp was 92%.

A solitary juvenile polyp with hyperplastic and adenomatous glands

This report describes a 21-year-old man with chronic rectal bleeding, who was found to have a solitary juvenile polyp containing hyperplastic and adenomatous glands. This admixture of glandular elements has not been clearly recognized previously. The significance of this finding is uncertain at this time. Since adenomatous polyps are considered premalignant lesions, and juvenile polyps have been associated with colon cancer, we recommend that juvenile polyps with adenomatous glands also be regarded as premalignant lesions.

A comparison of tube leukocyte adherence inhibition assay and standard physical methods for diagnosing colorectal cancer

In vitro antitumor immunity, measured by means of a tube leukocyte adherence inhibition (LAI) assay, was able to demonstrate early colorectal cancer in cases yet undiagnosed. Testing 106 patients attending a colonoscopy clinic, we found that nine of 15 (60%) patients with colorectal cancer were LAI-positive. The nine included: five of six with Dukes' A and B; one of two with Dukes' C; and three of seven with Dukes' D lesions. Of 58 patients without colon neoplasia, one had a positive test. By contrast, barium enema results were diagnostic for 13 of 15 (87%) cases and colonoscopy for 11 of 15 (73%). There were 32 colon polyps discovered by means of barium enema and colonoscopy. Of 13 adenomas removed, four had stimulated positive LAI responses. Of another 19 polyps not removed two incited positive LAI responses. Two patients with histories of recurrent adenomas were LAI-positive, though only one had a new polyp that could be detected by means of barium enema. For a procedure to be of diagnostic value for a given disease, sensitivity and specificity must be at least 1.0. If this sum is 2.0, the test is ideal. The sum of sensitivity and specificity for the tube LAI assay, barium enema, and colonoscopy were 1.58, 1.87, and 1.73, respectively, for colorectal cancer; 1.81, 2.0, and 2.0, respectively, for early colorectal cancer; and 1.42, 1.77, and 1.55 respectively, for advanced colorectal cancer. In this limited series of patients, the barium enema seems to be superior to the tube LAI assay for diagnosing colorectal cancer, but the difference in sensitivity and specificity is not statistically valid by the paired chi square test. The results of this study shows conclusively, that the tube LAI is of diagnostic value and suggest its use for evaluating suspected cases, especially early ones, of colorectal cancer.

Limitations of biopsy in preoperative assessment of villous papilloma

Between January 1975 and December 1979, 58 patients were diagnosed as having villous papilloma of the large bowel. A retrospective review was performed and all histologic specimens were re-examined by one gastrointestinal histopathologist (H.T.). On review, 19 (23 per cent) lesions were reclassified as not being villous papilloma. Results of preoperative biopsy examinations were misleading in 13 of the 29 patients who had biopsy procedures reported by any member of the histopathology department. When the assessment of malignancy in the initial biopsy specimens was compared with that of the final histologic diagnosis, there were ten (34 per cent) false-negative and three (10 per cent) false-positive reports. Even when the excised specimens were reviewed for malignancy by a specialist gastrointestinal histopathologist, there were seven (24 per cent) false-negative results.

Grades of atypia in tubular and villous adenomas of the human colon. An electron microscopic study

Of a total of 544 tubular, villous and tubulo-villous adenomas of the human colon which were investigated by light microscopy, six tubular and six villous adenomas were examined under the electron microscope. It was shown that the two types of adenoma differ in their tissue architecture, but not in their cytological appearance. Different grades of epithelial atypia occur in both types of adenoma. These are designated as grades I to III, correspond to mild, moderate and severe atypia respectively. Whereas adenoma cells with atypia grade I clearly show a cytological relationship with crypt epithelia of the normal colonic mucosa under the electron microscope, adenoma cells with atypia grade III have largely lost the differentiation characteristics of the parent cells and there is no longer intracytoplasmic organization. In the cytoplasm of adenoma cells with atypia grade II, glycogen storage is found as a special feature which does not occur in normal colonic epithelium. A similar finding has been described in the course of malignant transformation of the liver and kidney and thus can be regarded as a further indication of the precancerous nature of the adenomas.

Colonoscopic polypectomy in diagnosis and treatment of early carcinoma of the large intestine

Histologic investigation and analysis of 370 polyps, removed via colonoscope, demonstrated a malignancy rate of adenomas of about 20 per cent. Even small adenomas under 1 cm in diameter were found to have a higher malignant potential than previously appreciated. The malignancy rate was higher with increasing size, and adenomas in females had a much higher malignant potential than in males. It is obvious that colonoscopic polypectomy is valuable in detecting and treating early carcinomas of the colon.

Colorectal polyposis with mixed juvenile and adenomatous patterns

An unusual form of colorectal polyposis is described displaying juvenile, adenomatous and mixed patterns in a 17-year-old girl. Although juvenile polyposis is generally considered to be non-neoplastic in nature, in both the present and in other case reports histological findings support a neoplastic nature. Since an increase in the incidence of large bowel carcinomas has been found in subjects with a previous diagnosis of juvenile polyposis, these patients should be considered to be at risk, and submitted to follow up.

Colonic adenomas--a colonoscopy survey

A colonoscopy survey of 620 patients with 1049 colon adenomas showed a predominantly left-sided distribution (77%). Of these lesions 97% were amenable to endoscopic removal or ablation. Sixty per cent of patients presented with rectal bleeding as their major symptom. There was agreement between radiology and colonoscopy in only 62% of patients, as many of the studies were single contrast barium enemas, performed before referral. Forty-eight per cent of adenomas in our series were less than 1.0 cm in diameter. Of the larger adenomas (greater than 2.0 cm in diameter) 66% were situated in the sigmoid colon, and of those containing invasive carcinoma (4.8% of the total) an even higher percentage (94%) were in the sigmoid and low descending colon. With increasing polyp size, there was a greater predominance of villous elements and this was associated with a higher risk of malignant change than the more frequent and generally smaller tubular adenoma. Local colonoscopic excision alone is sufficient treatment for adenomas with malignant change unless they are poorly differentiated histologically and providing adequate resection is demonstrated. Twenty-eight patients treated in this way are alive without recurrence at periods from six to 62 months. Although 65% of patients had only one adenoma, and 90% three or less, there is a risk of developing other benign and malignant colon neoplasms and careful follow-up is required.

Polyps of the large intestine in Northern Norway

In unselected autopsies on 171 males and 109 females over 20 years of age in Tromsø, Northern Norway, adenomas of the colon and rectum were present in 40% of the males and 33% of the females. The frequency of adenomas increased with age in both sexes. Hyperplastic polyps were found in 20% of all cases with no variation in frequency with sex or age. Before the age of 65 most adenomas were located in the distal half of the large intestine in both sexes. After 65 years in males and 75 years in females the predilection site was shifted to the proximal half of the large intestine. The average size and grade of atypia of adenomas increased with age, but no significant difference in grade of atypia was found between the proximal and distal halves of the large intestine. The occurrence of adenomas was not associated with any of the common chronic diseases thought to be related to a western-style diet or to malignant or benign neoplasms elsewhere in the body. A significant association was found between the occurrence of adenoma and high body weight. The findings support the role of adenomas as precursors of colorectal carcinoma.