Colorectal polyps and carcinoma in Southern Iran

A study was made of the prevalence of colorectal polyps (excluding juvenile polyps, familial polyposis coli and villous adenomas) and the minimum frequency of colorectal carcinoma in Southern Iran. A total of 801 large intestines from necropsies performed on individuals 20 years or older was examined with or without magnifying lens for presence of polyps. Our prevalence rate was then compared with those reported on postmortem material from the USA, Australia, South Africa (Bantus), Colombia, and Hawaii (Japanese immigrants). Our surgical pathology files were reviewed for colorectal polyps over a 22-year period (1952-1973). Colorectal carcinomas diagnosed in the Department of Pathology were reviewed over 11 years (1963-1973) and the minimum frequency rates compared with corresponding age- and sex-specific incidence rates from Connecticut, USA. The data indicate 1) a very low prevalence rate for colorectal polyps as well as carcinoma in our region and 2) a rather striking predominance of right-sided colonic carcinoma.

Analysis of 6,293 routine proctosigmoidoscopies

7,679 proctosigmoidoscopies were performed on 6,293 patients during a period from 1962 to 1974 at the Third Department of Internal Medicine, Tohoku University Hospital. Results were summarized as follows: Polyps were observed in 470 patients (7.5%) and cancer was found in 178 patients (2.8%). 129 patients (2.0%) were observed to have ulcerative colitis. There were 57 patients with melanosis coli, 12 radiation proctitis, 7 amebic colitis, 5 granulomatous colitis, 2 endometriosis coli, 2 carcinoid and 2 intestinal tuberculosis. Thus, 879 out of 6,293 patients examined had some forms of disease, an over-all incidence being 14.0%. Biopsies were performed under the proctosigmoidoscopic observation in 82.4% out of 273 patients with polyps during the 6-year period from 1969 to 1974 and 105 patients (46.7%) were observed to have adenomatous polyps. The age-specific distribution pattern and incidences of these patients with adenomatous polyps were mostly consistent with those of 178 patients with cancer of the large bowel, which were observed by proctosigmoidoscopy during the 13-year period from 1962 to 1974. Thus, it is suggested that etiological correlation exists between polyps of adenomatous type and cancer of the large bowel.

The incidence and clinical significance of rectal polyps

Adenomata of the large bowel were discovered at proctosigmoidoscopy in 28 out of 1000 patients examined; this is a much lower frequency than those reported from American sources. The distribution and histological features of these tumours are considered and lack of correlation between the microscopic and macroscopic characters noted.

Polyps and diverticulosis of large bowel in autopsy population of Akita prefecture, compared with Miyagi. High risk for colorectal cancer in Japan

A necropsy study of polypoid lesions and diverticula of the large bowel in the Japanese prefectures of Akita and Miyagi indicated that adenomatous polyps were more numerous in Akita (30%) than Miyagi (18.3%). They also were larger and showed more severe atypia in Akita. The sigmoid colon and rectum showed the most severe atypia in both prefectures. Hyperplastic polyps and diverticula were very uncommon in both prefectures. These results are discussed in relation to the different levels of risk to colorectal carcinoma in these prefectures and in Japanese migrants to Hawaii.

Diseases of the colon and rectum in Bolivia

A review of the surgical and autopsy records from two general hospitals in La Paz, Bolivia, discloses an incidence of colon and rectal disease, excluding hemorrhoids, of 0.6 per cent (138 of 22,361 surgical cases) and 2.5 per cent (16 of 640 consecutive autopsies). Acquired megacolon complicated by volvulus represented more than half of all cases in the surgical series. Ulcerative colitis, diverticular disease, and neoplastic polyps represented less than 10 per cent of the cases of colonic disease. Only ten cases of carcinoma of the colon were seen, whereas five cases of granulomatous colitis or ileocolitis were detected in the same surgical material. Among sixty-four lesions of the rectum, so-called retention polyps accounted for 54.5 per cent of the cases, with carcinoma next in frequency (25 per cent), and the remainder being different varieties of inflammatory conditions. In the autopsy material almost half of the cases were infectious conditions, followed by congenital malformations and complicated acquired megacolon. No case of diverticular disease of the colon or neoplastic polyps was seen, and there was only one case of cancer of the large bowel. Because of the high incidence of acquired megacolon and the low incidence of cancer, ulcerative colitis, adenomatous polyps, and diverticular disease of the colon, possible etiopathogenic factors of these conditions are discussed in comparison with their incidence in other developed and developing countries of the world.

Intestinal polyps in the Nigerian African

Intestinal polyps appear to be relatively rare in the African including Nigerians, South African Bantus, and Ugandans. Only 40 histologically confirmed cases were encountered over a period of ten years. Analysis of these cases reveals a preponderance (60%) of the non-neoplastic juvenile type of polyp. Neoplastic polyps were not encountered in any female patient. The mean ages of the patients are much lower than what has been observed in Caucasians inhabiting developed and industrialized countries. It is felt that there is probably a common or related aetiological agent for neoplastic intestinal polyps and carcinoma because the frequency of intestinal carcinoma appears to be relatively low in areas with a low frequency of neoplastic polyps.

Intestinal polyps in American negroes and Nigerian africans

Forty Africans from Nigeria and 89 American negroes with colorectal polyps were analysed by age, sex and type of polyp. The Nigerians were much the younger group (mostly under 20 years of age, whereas most of the American negroes were over 50) and far fewer of their polyps were truly neoplastic (7.5% compared with 87% of the Americans). These differences may be partly due to the American negro population being older than the Nigerian, and partly to environmental factors like those previously postulated to account for the difference in colon cancer incidence between these populations.

Carcinoma of the large bowel in the Sudan

Large bowel cancer is not common but is showing increased frequency in the northern part of the Sudan. It is relatively uncommon among southerners, which may be due to the socio-economic factors prevailing in the Sudan. The disease affected our population at a younger age than has been generally reported in the literature, and the lesions in nearly 30 per cent were of the mucoid and undifferentiated types. The incidence in young adults is difficult to explain in the absence of precancerous lesions, and there is not enough evidence to incriminate parasitic infestation.

A cost accounting of routine sigmoidoscopic examinations

Proctosigmoidoscopic examinations were performed on 363 patients who had gastrointestinal but no colonic symptoms. Thirty-four, all over the age of 40, were found to have polypoid lesions, 24 of which were adenomatous. Air-contrast barium enemas were utilized to rule out higher lesions in the patients with one or more adenomatous polyps. One early carcinoma of the ascending colon was so discovered. The cost of finding an adenomatous polyp in a patient without colonic symptoms was calculated to be $523.75 and of a carcinoma $12,570.

Polyps of the rectum and colon

Four hundred and thirty-three patients with adenomatous polyps were examined and followed up. It was found that well differentiated adenomas are stable but dedifferentiated polyps can lead to invasive cancer, usually over a long period of time. Thus the concept of malignant transformation becomes meaningless, and should be replaced by an initial histological evaluation of polyps of the rectum and colon so that their development can be predicted.