ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Overnutrition, as a factor in carcinogenesis, has been a matter of concern for over 80 years. Overnutrition relates to excess intake of calories, and fat is the major contributor to caloric burden. Thus, fat has been the focus of many epidemiological studies, but as long ago as 1975 some investigators were suggesting that excess energy intake might be the major factor relating to cancer incidence. Ecological studies support the idea that a high fat (high energy?) diet may represent a risk for cancer but case-control or follow-up studies generally do not. The effects of undernutrition have been studied experimentally. Mostly conducted in rats or mice, they show virtually uniformly that caloric (energy) restriction inhibits the growth of spontaneous, transplanted or induced tumours. The effect is observed even when the calorie-restricted animals ingest more fat than do the controls. Energy utilization via exercise reduces tumour growth in rats and a life history of physical labour reduces risk in man. The mechanism(s) by which caloric restriction exerts its effects are moot, but it has been shown to reduce insulin levels and to reduce oncogene expression. Energy restriction also increases activity of antioxidant enzymes and leads to enhanced DNA repair. Increased energy flux (by means of decreased intake or increased output) may provide a simple and inexpensive approach to reducing the risk of cancer in man.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Comparisons of cancer mortality in Catalonia and Spain have shown an intermediate position of these areas in relation to the rest of Europe. This study compares the overall cancer mortality in Catalonia and Spain in the periods 1975–77 and 1987–89 in relation to other European countries selected on the basis of geographical proximity and availability of information. Adjusted and truncated cancer mortality rates and relative changes in these rates have been assessed for both sexes. The mortality rate for males in Catalonia, Spain, Italy, Portugal and France has increased from 1975–77 to 1987–89 with relative increments of 13.5%, 13.7%, 10.1%, 9.6% and 4.3% respectively, whereas in Switzerland and England and Wales this rate has decreased. The mortality rate for females showed a slight drop between the two periods in all the studied countries except England and Wales and Portugal. By age groups, in males, the 0–44 year interval in Catalonia, Spain, France and Portugal, in descending order, showed the highest rates. The marked contrast of the evolution of the cancer mortality rate in Catalonia, Spain, Italy, France and Portugal, compared with Switzerland and England and Wales, and especially the considerable increase of the mortality in young people in Catalonia, indicates the extremely urgent need for all countries to adopt the measures to control cancer that have already shown themselves to be effective elsewhere.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Little is known about the aetiology of Barrett's oesophagus, a condition in which columnar epithelium replaces normal squamous epithelium above the juncture of the oesophagus with the stomach. An exploratory retrospective study of males from the Tucson Veteran's Affairs Medical Center (Tucson, AZ, USA), looking at 22 Barrett's cases and 22 controls, was undertaken to: (1) determine whether risk factors previously reported for squamous oesophageal cancer were also potential risk factors for Barrett's oesophagus; and (2) explore which of several retrospectively determined dietary factors would permit maximum discrimination of Barrett's cases from controls. Because of the recognized difficulty with retrospective dietary assessment, an intensive interview-based life history approach was developed to assess behavioural factors throughout adulthood. We examined the dose-response relationship involving questions (1) and (2) separately for subjects with lesions less than or greater than 7 cm in length. A literature-based oesophageal cancer risk factor score (including use of tobacco and intakes of alcohol, fat, vitamin A, linoleic acid and protein) discriminated cases from controls. Alcohol consumption alone discriminated patients with lesions < 7 cm in length from controls, and a more complex risk factor score (including tobacco use, alcohol, fat, fruits and vegetables) discriminated patients with lesions > 7 cm in length from controls.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

The association between intake ofN-nitrosodimethylamine (NDMA), the most commonly occurring of the volatile nitrosamines derived from foods, and gastric cancer risk has been investigated using data from a case-control study conducted in Northern Italy between 1985 and 1993, including 746 incident cases of gastric cancer and 2,053 controls admitted to hospital for acute, non-neoplastic and non-digestive tract diseases, not related to long-term modifications of diet. Information was collected on frequency of consumption of 29 food items, including selected sources of NDMA. Compared with subjects in the lowest tertile of NDMA intake, the odds ratios (ORs) were 1.1 in the intermediate and 1.6 in the highest tertile of intake. These estimates were not appreciably modified after allowance for total energy intake, other major dietary and non-dietary correlates of gastric cancer, and estimated intake of nitrite and nitrate: the multivariate OR for the highest NDMA intake tertile was 1.4 (95% CI 1.1–1.7). The association was consistent across strata of sex and age, but somewhat stronger in males and in subjects below age 60 (OR in the highest tertile, 1.8). Limitations of exposure assessment and absence of information on otherN- nitrosamines preclude, however, any definite assessment of the possible role of exogenousN-nitrosamines in gastric carcinogenesis.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Guaiac tests for faecal occult blood are used for colorectal neoplasia screening. Specificity may be improved by using an immunochemical test for human blood. We evaluated and compared, within an endoscopic study, an immunochemical test for human stool albumin, BM-Test Colon Albumin™, with the guaiac test, Hemoccult® SENSA™. Both tests were given to 527 screenees who had had a low-peroxidase diet before and during the tests. All had a colonoscopic (59%) or flexible sigmoidoscopic (41%) examination. Both tests were easy to perform and develop. They were of similar sensitivity (35–30%) for adenomas ≥ 1.0 cm in diameter or cancers, but Colon Albumin™ had a higher specificity (90%) than Hemoccult® (85%P< 0.05). The latter, however, had a higher sensitivity for neoplasia of all sizes (25%vs20% NS) but lower specificity (85%vs90%P< 0.05). Colon Albumin™ was positive in 11.2%, while Hemoccult® SENSA™ was positive in 16.7% and appears very sensitive to dietary peroxidases. Positivity was reduced to 7% by changing the methodology protocol. Overall, the guaiac test is more sensitive but less specific than the immunochemical test for colorectal neoplasia. However, the technical and diagnostic limitations of these tests must be appreciated, and because of their high positivity rate neither is suitable for mass screening. A more specific test for neoplasia is needed.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Histological changes of lichen sclerosus (LS)—a chronic inflammatory disease—are frequently found in association with squamous cell carcinoma (SCC) of the vulva, suggesting that women with this disorder are at increased risk. However, follow-up studies have been less convincing, showing that the vast majority of these patients do not go on to develop cancer. In this study, a series of 211 women affected by histologically demonstrated vulval LS were treated with topical therapy (testosterone, clobetasol) and followed prospectively by repetitive vulval examination. Three patients developed SCC of the vulva (two invasive, onein situ) at the sites affected by LS during an average follow-up period of 1 year and 8 months. Compared with the reference population, the number of cases of invasive SCC detected significantly exceeded the number estimated to occur in a comparable age-matched group. The standardized incidence rate of vulval SCC in the LS cohort was 317 (95% CI 35.7–1146.2). Cumulative risk was 14.8% (0.06% in the general female population), with a relative risk of 246.6. In conclusion, these data support the view that LS is a precursor of SCC, although characterized by slight tendency to evolve to carcinoma. Medical treatment of LS, although useful in the control of severity of disease, did not seem to be able to prevent the evolution to malignancy.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

摘要:

Melatonin, an indole of pineal origin, is known to have an oncostatic effect on carcinogen-induced rat mammary tumours. We have assessed for the first time, the efficacy of melatonin alone and in combination with a sub-optimal dose of tamoxifen, a partial oestrogen antagonist, on N-nitroso-N-methylurea-induced rat mammary tumours. Both these agents were administered to Sprague-Dawley rats following excision of the primary tumours. Melatonin (200 μg/day/rat) at the given dose level could significantly suppress the appearance of second generation mammary tumours and the latency period of tumour appearance was also significantly increased (P< 0.001) as compared to vehicle-treated animals. Tamoxifen (60 μ/week/rat) does not suppress the development of second generation mammary tumours. Co-administration of melatonin and low dose of tamoxifen had no additive or synergistic effect on the prevention of second generation of mammary tumours. The results warrant the clinical evaluation of melatonin for chemoprevention and adjuvant therapy.

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID

ISSN:0959-8278    

出版商:OVID    

年代:1995

数据来源: OVID