ascorbic-acid and Intestinal-Polyps

One hundred and sixteen patients were included, during 18 months, in a double-blind placebo-controlled intervention study, with calcium, vitamins A, C, E and selenium (in a cocktail) or placebo against growth of colonic polyps. Patients were randomized within three arms, according to diameter of the largest polyp, < 5 mm, 5-9 mm or > 9 mm. Polyps > 9 mm were resected, the others were left to be measured annually before resection after 3 years. The protocol (performed in all of the patients) included registration of demographic data, family and personal history, measurement of polyps, collection of blood specimens, stools and biopsy samples. Registration of nutritional status, diet history and 5-day prospective food consumption, was performed in 108 patients. The patient compliance was registered every third month by the hospital pharmacist, with concomitant delivery of new boxes of capsules. Additionally, stool collections were performed from all of the patients for the measurement of faecal calcium, bile salts and fat. Inclusion rate of 37, 41 and 38 patients in each of the three 6-month periods was uniform. The group with the largest polyps measuring 5-9 mm comprised 44% of the material. The sex ratio corresponded to that in overall referrals for colonoscopy. The age relationship of size and multiplicity of polyps and the distribution of polyps in the large bowel corresponded to previous experience in polyp-bearing individuals of the same age.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Age Factors; Aged; Ascorbic Acid; beta Carotene; Calcium; Carotenoids; Colonic Polyps; Colonoscopy; Combined Modality Therapy; Double-Blind Method; Feces; Feeding Behavior; Female; Humans; Intestinal Polyps; Male; Middle Aged; Patient Compliance; Placebos; Prospective Studies; Rectal Neoplasms; Selenium; Vitamin E

Because supplements of vitamins C and E had been associated with reduction of fecal mutagen levels, a double-blind randomized trial was designed to examine the effects of these vitamins on the rate of recurrence of colorectal polyps, presumed precursors for colorectal cancer. Two hundred patients believed to be free of polyps after removal of at least one colorectal polyp were randomized to receive a supplement of 400 mg each of ascorbic acid and alpha-tocopherol, or a placebo. Fifteen patients had to be excluded because a review of pathology indicated that their polyps were not adenomatous. A second colonoscopic examination was planned after 2 yr of supplementation. One hundred thirty-seven people (75% of eligible subjects) completed the study; polyps were observed in the second colonoscopy in 41.4% of 70 subjects on vitamin supplements and in 50.7% of 67 subjects on placebos. After adjustment for differences between groups in demographic and dietary factors before study entry, the relative risk of polyp occurrence was 0.86, with 95% confidence limits from 0.51 to 1.45, in an analysis of 129 subjects with complete information on demographic and dietary factors who had completed the trial. Of the 48 patients who had not completed the study, 7 had died, 33 had not returned to their physician for an examination, and 8 had had a follow-up colonoscopy or sigmoidoscopy. Inclusion of the three polyps found in these eight examinations led to an estimate of relative risk of 0.86 (95% confidence limits, 0.51 to 1.43). The findings of this investigation suggest that any reduction in the rate of polyp recurrence associated with vitamin supplementation is small, and a larger study would be required to ensure that an effect of this size was not a chance finding.

Topics: Ascorbic Acid; Clinical Trials as Topic; Colonic Polyps; Diet; Female; Humans; Intestinal Polyps; Male; Neoplasm Recurrence, Local; Random Allocation; Rectal Neoplasms; Risk Factors; Vitamin E

This long-term study deals with the effect of ascorbic acid on chemically induced carcinogenesis of the small intestine in rats. Carcinoma was induced in 27 animals by application of N-Ethyl-N'-nitro-N-nitrosoguanidine (ENNG) alone in the drinking water (120 mg/1). The average survival time was 238 ( 40) days. The addition of large amounts of ascorbic acid to the food (3 g/100 g food) did not suppress the development of tumors. On the contrary, a significant reduction in the survival time was seen. All animals receiving ENNG and ascorbic acid only lived 207 ( 45) days on average. Neither histological type of tumor spread was influenced by the use of ascorbic acid. Giving ascorbic acid alone had no effect on the survival time and did not lead to changes in the tissue of the small intestine.

Topics: Adenocarcinoma; Animals; Ascorbic Acid; Carcinogens; Digestive System; Gastrointestinal Neoplasms; Intestinal Polyps; Long-Term Care; Male; Methylnitronitrosoguanidine; Rats; Rats, Inbred Strains

Chemopreventive agents are natural or synthetic agents administered to prevent, inhibit or reverse one or more of the stages of carcinogenesis. Natural agents include vitamins, coumarin, indoles, flavones, plant sterols and selenium salts. Synthetic agents include retinoids, phenolic antioxidants, protease inhibitors and prostaglandin synthesis inhibitors. All have demonstrated inhibition of tumor models in vitro or in vivo. These agents may work in different ways; by stimulating the immune response, by inducing gene suppression, by detoxifying carcinogens, by blocking oxidative damage to DNA or by other mechanisms. Human trials are being carefully initiated. Retinoids have demonstrated effectiveness in controlling some proliferative skin tumors. In the gastrointestinal tract, ascorbic acid has demonstrated a modest suppressive effect on adenomas of the rectum in patients with polyposis. There is initial evidence that 13-cis-retinoic acid is effective in modifying leukoplakia of the oral cavity.

Topics: Ascorbic Acid; Coumarins; Gastrointestinal Neoplasms; Humans; Indoles; Intestinal Polyps; Protease Inhibitors; Selenium; Sterols; Vitamin A; Vitamins

Topics: Adult; Ascorbic Acid; Colonic Neoplasms; Dietary Fats; Female; Humans; Intestinal Polyps; Middle Aged; Rectal Neoplasms

Of one hundred and twenty-six patients with Gardner's syndrome, 60% showed soft tissue tumors, 32% showed osteomatosis, 67% polyposis, and 20% the complete triad. Bowel cancer developed in 32% of the patients. The frequency of other diseases in these patients showed fibrous tumors in 8%, and two patients with cancer of the ampulla of Vater; otherwise the diseases seen did not show any major variation from what might be expected for the group at risk. Laboratory evaluation has included the demonstration of increased fecal cholesterol and primary bile acids in these patients. The recommended surgical treatment is colectomy and ileorectal anastomosis at a measured 12 cm level. This level of ileorectal anastomosis may be vital in giving a regression of rectal polyps, which was seen in 15 to 17 patients so treated. The conversion of an ileosigmoid to an ileorectal anastomosis resulted in polyp regression in one patient. The oral administration of ascorbic acid gave polyp regression in seven of 10 patients. There may be a possible relationship of fecal coprostanol and cholesterol levels and polyp regression.

Topics: Adolescent; Adult; Ascorbic Acid; Bone Neoplasms; Child; Colectomy; Colon, Sigmoid; Female; Follow-Up Studies; Humans; Ileum; Intestinal Polyps; Male; Rectal Diseases; Rectum; Soft Tissue Neoplasms; Syndrome

Topics: Ascorbic Acid; Humans; Intestinal Polyps; Polyps; Rectal Neoplasms

Evidence for dehydrogenation by fecal bacteria in the genesis of colon cancer suggested that an antioxidant might modify these mechanisms. Ascorbic acid, 3 Gm. daily, was given to five patients who had active rectal adenomatous polyp formation long after ileorectal anastomosis for familial polyposis. During a 4 to 13 month study, rectal polyps disappeared in two, regressed partially in two, and increased in one. Among three additional treated patients with rectal polyps, one had a reduction in polyps and two were unaffected.

Topics: Adolescent; Adult; Antioxidants; Ascorbic Acid; Colectomy; Drug Evaluation; Female; Humans; Intestinal Polyps; Male; Rectal Neoplasms; Remission, Spontaneous