摘要:

The relation between oral contraceptives (OC) and cancer risk has been investigated extensively, mainly with reference to breast, female genital tract, liver cancer and cutaneous malignant melanoma, and will be summarized below. There is also some suggestion that OC use is related to other neoplasms, including a reduced risk of colorectal cancer among OC users, but the issue is still controversial and too preliminary to provide indications for informed contraception choice.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Breast cancer, although uncommon in western populations in the past, continues to rise in incidence, and now affects up to one woman in nine. In some countries, such as the US and Australia, the mortality rate is decreasing, albeit slightly. In developing populations, while of low occurrence, the disease is rising in incidence. Risk factors, which include certain reproductive practices, diet and physical activity, while apparent in some contexts, appear much less so in others; moreover, the avoiding measures do not lend themselves to primary prevention. For early detection, although regular mammography is advocated, it is a subject of controversy. Basically, avoiding measures fall within the usual recommendations for a 'prudent' lifestyle - avoid obesity, increase physical activity, stop smoking and restrict alcohol consumption.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

In industrial countries, women often have excess metabolic energy due to high food consumption and low physical activity. High lifetime energy availability results in high lifetime levels of ovarian steroid hormones. Oestrogens and progesterone are hypothesized to play a crucial role in the development and prognosis of breast cancer. Epidemiological studies document the importance of physical activity and caloric limitations in reducing breast cancer risk. The risk of breast cancer is much higher in industrial countries than in developing countries, where women are characterized by lower energy intake and higher energy expenditure. It is likely, that the beneficial effects of physical activity and of negative energy balance are mediated by the reduced levels of ovarian steroids. While both weight loss and physical activity may have similar efficacy in suppressing ovarian function and, therefore, in reducing the risk of breast cancer, we suggest that it may be more advantageous for premenstrual women to achieve lifetime reduction in steroid levels by increasing their physical activity, rather than by weight loss due to caloric restriction alone.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Epidemiological studies on the relation between coffee consumption and cancer risk have been mainly focused on cancers of the urinary bladder, pancreas and colorectum. The relation between coffee and bladder cancer is controversial, despite a large number of studies published over the last three decades. In most studies, the risk tends to be higher in coffee drinkers than in those who do not drink coffee, but the excess risk is generally moderate and is neither dose- nor duration-related. Thus, a strong association between coffee drinking and bladder cancer can be excluded, although it is still unclear whether the weak association is causal or nonspecific and due to some bias or confounding. For pancreatic cancer, a possible association with coffee consumption has been postulated in a large case-control study published in 1981; since then, however, most studies have shown no substantial association, and overall evidence suggests that coffee is not materially related to pancreatic cancer risk. Overall evidence on the coffee-colorectal cancer relation suggests an inverse association, since most case-control studies found odds ratios below unity, particularly for colon cancer. The pattern of risk is less clear for cohort studies. A plausible biological explanation has been given in terms of coffee-related reduction of bile acids and neutral sterol secretion in the colon. For other cancer sites, including oral cavity, oesophagus, stomach, liver, breast, ovary, kidney and lymphoid neoplasms, the relation of coffee drinking with cancer risk has been less extensively investigated, but the evidence is largely reassuring.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The influence of food groups on oesophageal cancer risk was analysed using data from a case-control study conducted between 1992 and 1999 in the Swiss Canton of Vaud on 101 incident, histologically confirmed cases (92 squamous cell, 9 adenocarcinomas) and 327 controls admitted to hospital for acute, non-neoplastic conditions. Multivariate odds ratios (OR) were computed after allowance for age, sex, tobacco, alcohol and non-alcohol energy. Significant increased risks emerged for red meat (OR =1.7 for an increase of one serving per day), pork and processed meat (OR = 1.6), and eggs (OR = 1.5), whereas inverse associations were observed for milk (OR = 0.7), raw and cooked vegetables (OR = 0.5), citrus and other fruits (OR = 0.5), as well as for a more varied diet (OR = 0.5). Most associations were apparently stronger in heavy alcohol drinkers, suggesting an interaction between poor diet and alcohol drinking in oesophageal carcinogenesis.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The expression of cytoplasmic c-erb B2, epidermal growth factor receptor (EGFR), proliferating cell nuclear antigen (PCNA) and dipeptidylpeptidase IV (DPP IV) was significantly higher in sporadic cancer of the right than of the left colon. In addition, cytoplasmic c-erb B2 displayed the same difference in the adjacent (less than 2 cm) and distant (more than 5 cm from the tumour margin) mucosa. The findings cannot be related to Dukes staging. It is suggested that different ontogenic development of the right (from the midgut) and the left (from the hindgut) colon may be a possible explanation. Therefore, data on the expression of different molecular markers in colorectal cancer and surrounding mucosa should always be supplemented by data on tumour location.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The integration of routine Pap smear practice based on self-referral into an organized programme based on personal invitation is the recommended approach to cervical cancer screening. In this study, the cytology archive of the integrated cervical screening programme implemented in the Faenza district (northern Italy) was used to compare the population of women responding to invitation with that of self-referred women for the cumulative probability of early (< 36 months) repeat Pap smear after a negative result. Between 1995 and 1998. women aged 25–64 living in five municipalities of the district were targeted by the first round of the programme. Eligible for the study were 2356 women responding to invitation for screening and 2221 women not invited because of self-referral for Pap smear at any other setting. The probability of early repeat Pap smear was estimated by the life table method. Differences were evaluated by the Gehan test. Multivariate determinants were assessed by the Cox regression analysis. At 36 months' follow-up, the cumulative probability of early repeat Pap smear was 44% among self-referred women and 6% among women responding to invitation (relative hazard = 4.8). For self-referred women, the probability was related to age (with a peak at 35–44 years), previous Pap smear history and municipality of residence. Among women responding to invitation, only an inverse association with age was demonstrated. In conclusion, the observed differences in overall probability and determinants of early repeat Pap smear between the two screening populations provided important information on Pap smear usage in the total target population.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Carcinogenic N-nitroso compounds (NOCs) are not only ingested from the environment but are also formed endogenously from precursors. It has been reported that nitrate, an NOC precursor, has an enterosalivary cycle and that the cycle increases the chance of exposure to NOCs. However, there is no information on the salivary excretion of NOCs. In the present study, the toxicokinetics of N-nitrosodimethylamine (NDMA) in dogs was evaluated, focusing on the salivary excretion. Following intravenous injection of 2 mg/kg NDMA, the plasma concentration showed a monoexponential decline, and the total body clearance and apparent distribution volume were greatly in excess of the hepatic plasma flow and total body water, respectively. A high concentration of NDMA was immediately detected in the plasma after oral administration of the same dose, and the oral bioavailability was almost 100%. NDMA was rapidly excreted into the saliva after both treatments, and the concentration in saliva was higher than that in the plasma. These results suggest that NDMA also has an enterosalivary cycle: NDMA is partially excreted from blood into saliva, delivered into the gastrointestinal tract by swallowing the saliva, and then completely reabsorbed into the systemic circulation. This concept was also supported by kinetic analysis based on a compartment model. The enterosalivary cycle of NDMA cannot be ignored in the risk assessment of carcinogenesis.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The anticarcinogenic effect of aqueous extract of fruit of Momordica charantia (bitter gourd), which is widely used as a vegetable in India, was studied in a two-step skin carcinogenesis model in mice. The possible mode of action was also investigated. Oral administration of the fruit extract was found to have an adverse effect on the general health and lifespan of the animals when used at a high concentration. But when this dose was reduced by half, the test extract afforded protection from the development of skin tumour and increased life expectancy. Carcinogen-induced lipid peroxidation in liver and DNA damage in lymphocytes were found to be reduced following treatment with Momordica. The fruit extract was found to significantly activate the liver enzymes glutathione-S-transferase, glutathione peroxidase and catalase (P < 0.001), which showed a depression following exposure to the carcinogen. The results suggest a preventive role of water-soluble constituents of M. charantia fruit during carcinogenesis, which is mediated possibly by their modulatory effect on enzymes of the biotransformation and detoxification system of the host.

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0959-8278    

出版商:OVID    

年代:2000

数据来源: OVID