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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies in our laboratory on the co-carcinogenic effect of the ingestion of an industrial carbon black (CB) on chemically induced colon cancer in rats and mice demonstrated no differences in tumor incidences attributable to CB feeding. The present study examined the effect of CB ingestion within the context of a high fat diet, formulated to simulate the typical diet of western industrialized nations. Corn oil was added to ground commercial chow at 20% by weight and CB added at 2.05 g/kg diet and fed for 52 weeks to female Sprague-Dawley rats. Colon tumors were induced with 16 weekly injections of 1,2-dimethylhydrazine (DMH, 10 mg/kg body weight). Tumor incidences in DMH-treated rats ingesting CB were significantly (P less than 0.05) higher than in those with no CB added to the diet (76% vs. 60%). The survival of CB + DMH treated animals (64%) was also lower than that of animals treated with DMH and not ingesting CB (80%). These findings may implicate CB ingestion as a co-carcinogen for industrial workers when acting in synergism with high fat diets and other unknown colon carcinogens.
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PMID:Co-carcinogenic effect of carbon black ingestion with dietary fat on the development of colon tumors in rats. 278 1

The histopathology of 304 patients registered in the Canadian Familial Polyposis Registry (CFPR) with a diagnosis of supposed adenomatous polyposis (AP) was reviewed. The diagnosis was changed in 17 (5.6 percent) of these patients. Group 1 consisted of nine patients who had adenocarcinomas plus multiple tubular adenomas (seven) or metaplastic polyps (two). Eight patients who had no colon cancer comprised Group 2. In these patients, the diagnosis was changed to lymphoid polyposis (2), metaplastic polyps (3), isolated adenomas (2), or juvenile polyposis (1). All 17 patients had had previous colonic resections. Following the change in diagnosis, this treatment was considered inappropriate in 11 patients. Treatment, prognosis, and follow-up of patients and affected family members depend on the type of polyposis syndrome diagnosed. Correct histologic assessment of polyps prior to initial surgery is essential.
Dis Colon Rectum 1987 Aug
PMID:Surgery based on misdiagnosis of adenomatous polyposis. The Canadian Polyposis Registry experience. 362 61

The characteristics of 702 colorectal cancer patients are described in relation to the presence of absence of a family history of colorectal cancer in near relatives. No statistically significant associations were found between those with a family history of colorectal cancer and age at detection, sex, country of birth, religion, number of cancers (single, synchronous, or metachronous), previously removed benign colorectal polyps, and adenomatous polyps found in the resection specimen. The family history rate of colorectal cancer for colon cancer cases was statistically significantly higher than for rectal cancer cases (chi 2(1) = 3.8, P = .05) and there was a gradient of decreasing risk from colon to rectum. The family history rate of colorectal cancer in parents of those who were less than 50 years old was twice that of those 50 or older (P = .07), consistent with the view that earlier age of onset is a characteristic of those with a family history of colorectal cancer. There was a statistically significantly higher family history rate of colorectal cancer in respondents who knew of the disease compared with those who did not (chi 2(1) = 5.5, P less than .05). It is unclear if this effect represents recall bias or self-selection bias. In contrast, the rates for a family history of heart disease and stroke were similar, irrespective of the respondent's knowledge of their colorectal cancer status. Thus in the Melbourne study, the family history rate of colorectal cancer was higher in colon cancer than in rectal cancer, there was a decreasing gradient of risk from colon to rectum, and a tendency for earlier age of onset of colorectal cancer in those with a history of this cancer in a parent.
Dis Colon Rectum 1987 Aug
PMID:The Melbourne Colorectal Cancer Study. Characterization of patients with a family history of colorectal cancer. 362 63

Anticarcinoembryonic antigen (CEA) antisera which showed no reactions with normal adult feces were prepared in guinea pigs. Using these, levels of CEA in feces from patients with colorectal carcinoma were measured by gel diffusion and rocket immunoelectrophoresis. Sixteen of 22 (73 percent) patients with carcinoma of the colon or rectum (Dukes' A4/6, B6/8, C6/7, D0/1) had detectable CEA in their feces, while none was detected in the feces of four patients with gastric ulcers or in those of 22 normal volunteers. Five of the 16 fecal CEA-positive patients showed no elevation of plasma CEA levels. Measurements using a commercial CEA kit (Abbott Laboratories) could not detect the differences between fecal CEA values of patients with colorectal carcinoma and benign diseases, or those of normal volunteers. These results suggest that measurement of fecal CEA by specific anti-CEA antisera will be valuable in screening and diagnosis of colorectal carcinoma.
Dis Colon Rectum 1987 Aug
PMID:Usefulness of carcinoembryonic antigen measurement in feces of patients with colorectal cancer. 362 64

Members of colon cancer-prone nonpolyposis families who had multiple primary malignant tumors were analyzed to determine the frequencies, locations, and stages of their cancers, and the duration of their survival. Colon cancers tended to be more proximal, were in a less advanced stage than in the general population, and in a majority of instances were associated with colonic adenomas. The multiple primary malignant tumors were more common in women, and occurred at a younger age than in the general population. Six or more multiple primary malignant tumors occurred in each of 4 patients. All patients survived for more than 10 yr after the diagnosis of the first cancer. Extracolonic cancers were most frequent in the breast and endometrium.
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PMID:Multiple primary malignant tumors. 362 21

Recent epidemiologic findings indicate that relative risk of colon cancer is augmented with increasing proportion of time spent on sedentary occupations, and reduced with occupations requiring high levels of work-related physical activity. Therefore, the influence of exercise on experimental colon carcinogenesis was investigated. Spontaneous running wheel activity was related to incidence of 1,2 dimethylhydrazine (DMH) colon tumor induction. Colon tumor incidence was significantly reduced in animals that were allowed spontaneous wheel activity throughout the period of DMH tumor induction vs standard housed controls (p less than 0.05), indicating that, in the rat, physical activity protects against colon tumorigenesis. Further comparisons reveal a mild positive association (p = 0.07) between activity and incidence of tumors in the left colon. These results are in accord with epidemiologic findings indicating reduced colon cancer risk with increased physical activity. Possible mechanisms for the protective influence of physical activity on tumorigenesis include reduction in fecal pH, body weight and increased antioxidant enzyme activity. To the extent that epidemiologic associations between colon cancer and activity are inclusive of the multidimensional nature of physical activity, animal models such as that utilized in this experiment can be utilized for investigating the etiologic potential, or strength of association in variables that have been epidemiologically associated with colon cancer risk.
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PMID:The influence of physical activity in 1,2 dimethylhydrazine induced colon carcinogenesis in the rat. 367 72

This investigation was based on an epidemiologic association of milk consumption and decreased intestinal cancer risk. Furthermore, there is also some indirect evidence that calcium supplementation in humans and animals may decrease colon cancer risk and that calcium, by inference, may be the protective factor in milk. In order to investigate these associations in a controlled laboratory setting, dietary supplementation of low fat dried milk (37 g/kg diet; N = 18) and calcium carbonate (40 mg/kg rat/day; N = 17) were compared separately to regular diet controls in the rat-dimethylhydrazine colon carcinogenesis model. The results of this investigation showed that neither milk-supplemented rats nor calcium carbonate-supplemented rats had fewer DMH-induced colorectal (P = .374) or total gastrointestinal tumors (P = .291) than did regular diet controls (N = 10; by analysis of variance [ANOVA]). Milk supplementation did result in a significant decrease in tumor burden when measured by incidence of metastases (P = .035) and of intestinal obstruction (P = .011; by chi-square test), when compared with calcium-supplemented and control rats. Though this implies that milk supplementation provides protection against some aspects of carcinogenesis of the colon, in rats fed low fat diets, this does not appear to be mediated through the calcium content of milk.
Dis Colon Rectum 1987 Dec
PMID:The effect of dietary milk and calcium on experimental colorectal carcinogenesis. 369 Dec 67

Since the medical management of persons with adenomatous colorectal polyps differs from that of those with hyperplastic polyps, accuracy of diagnosis is essential. Although many physicians have grown confident that their skills of visual diagnosis are adequate, few data exist to support this confidence. In order to examine the accuracy of physicians' judgments regarding colorectal polyp histology, the visual diagnosis of physicians experienced in endoscopy was compared with the histologic report. Eighty-one polyps were discovered by flexible sigmoidoscopy among 718 participants in a colon cancer screening program. Eighty percent of all polyps were detected accurately. The diagnostic sensitivity of detecting adenomas was 69 percent, while specificity (accurate diagnosis of hyperplastic polyps) was 86 percent, and there were an additional eight false negative and eight false positive diagnoses. Further analyses revealed that there are individual patterns of diagnostic mistakes made by physicians and that mistakes frequently are related to polyp size. These findings are particularly important in light of the expanding numbers of relatively inexperienced primary care providers performing flexible sigmoidoscopy whose diagnoses may be strongly dependent on polyp size.
Dis Colon Rectum 1987 Apr
PMID:Physician accuracy in diagnosing colorectal polyps. 382 72

In a prospective study of 402 colorectal cancer patients, 133 patients (46 men and 87 women) presented with right colon cancer. There was no significant difference between men and women in right colon cancer incidence. Common presenting features were abdominal pain, weight loss, and anemia. Ninety-one patients underwent resection with curative intent. There were significantly fewer Dukes' A tumors in the right colon cancer series (P less than 0.05). Significantly more women in the right colon cancer group were over 70 years old (P less than 0.05). The findings of peritoneal metastases and poorly differentiated lesions at initial surgery also were associated significantly with women who had right colon cancer (P less than 0.05). This study confirms previous reports of more advanced tumors in the right colon. The need for age, sex, and subsite differences to be taken into account when assessing treatment outcomes or survival is emphasized.
Dis Colon Rectum 1986 Apr
PMID:Age and sex differences in right colon cancer. 394 13

A study was done to determine if continuous administration of exogenous secretin would inhibit the trophic effect of elevated endogenous gastrin on colon neoplasms in rats. Colon tumors were induced in 37 Fisher rats by subcutaneous injection of 1,2-symdimethylhydrazine, 20 mg/kg, weekly for 18 weeks. Elevation of endogenous gastrin was achieved by antral exclusion surgery. Control rats received a sham operation. Subcutaneous osmotic minipumps delivered 35.5 U/kg/day of secretin for 7 days before the rats were killed. Rats receiving antral exclusion had significantly elevated serum gastrin levels and increased 3H-thymidine incorporation into tumor DNA compared with sham rats (P less than 0.05). There was a significant decrease in tumor DNA uptake in antral exclusion rats that received secretin as compared with antral exclusion rats without secretin (P less than 0.05). Therefore it appears that gastrin does have a trophic effect on rat colon neoplasms and that secretin does inhibit this effect, in a dose-related manner. The results of this study imply that hormonal manipulation of colon cancer may eventually become a viable therapeutic modality.
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PMID:Inhibitory effects of secretin on gastrin-stimulated rat colon neoplasms. 397 Dec 92


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