A food fair to promote dietary change in the Stockholm cancer prevention programme.

Involving organizations is crucial when developing community intervention strategies aimed at dietary change. This case study describes the use of a food fair as a change agent. The aim of the food fair was to obtain commitment and build up a network in the community comprised of professionals in the fields of food production, food distribution and information. The fair was organized in 1989 and intended to disseminate knowledge and information about healthy foods and encourage food industries, test kitchens and also publishing companies to develop and present products in accordance with the dietary objectives of the Stockholm Cancer Prevention Programme (ie a simultaneous reduction of fat and an increase in fibre intake). The food fair consisted of exhibitions and conferences/seminars. Policy makers, journalists, people in the educational and health professions and those working with food were invited to participate. Nearly 60 companies and organizations made presentations at the exhibition and 1,000 professionals attended the conferences and seminars. In all, 6,400 people visited the fair. Seventy-eight trade journals and newspapers and three radio stations reported on the fair. The food fair was so well received that a second fair was arranged in 1991.     

The approach of comprehensive tobacco control in cancer prevention: elements and evidence.

The aim of this overview is to present measures of comprehensive tobacco control (CTC) and recent evidence according to their efficacy. CTC includes eight measures: raising taxes, consumer regulations, information about tobacco products, advertisement and sponsoring, economic alternatives to the production of tobacco, programmes for the support of the motivation to stop smoking and maintain tobacco abstinence, including the change of attitudes and norms in the population to support non-smoking, financial and human resources of CTC, and quality assurance of CTC. These measures include single elements such as activities against smuggling, to be considered in conjunction with tax increases. Evidence, particularly from single US states, reveals the efficacy of CTC. As discussed, the literature shows that programmes have not yet included all single elements. This is due to individual, programme-related and external limiting factors. It is concluded that in spite of these, CTC programmes are effective in adults as well as minors. A dose-response relationship between CTC and reduction of smoker rates, the amount of tobacco consumption and tobacco-attributable mortality is probable.     

Community-based cancer prevention--the Stockholm Cancer Prevention Program.

The Stockholm Cancer Prevention Program (SCPP) is among the first comprehensive community intervention programs in the world aimed at reducing cancer incidence and mortality. The program began in 1987 in an urban area with more than 1.6 million inhabitants. In its work, SCPP utilizes a community-based approach focusing on (1) reduction in tobacco consumption, (2) reduction in dietary fat consumption and increase in dietary fiber consumption, and (3) changing sunbathing behavior in order to reduce the incidence of malignant melanoma. The overall philosophy of the program is to initiate activities capable of affecting the life style of the Stockholm population in these directions. SCPP intends to influence behavior through individual face-to-face contact. The tool for this contact is collaboration with independent organizations which are already active in the target communities. Food supply to the general public will be influenced through food producers, wholesalers, retailers, and caterers. Tobacco use, food habits, and sunbathing habits will be influenced via occupational health services; public health services including primary care, schools and municipal social services; voluntary organizations; and mass media. A model for possible ways of evaluating the program has been designed.     

A model for community participation in breast cancer prevention in Iran

Context: Genuine community participation does not denote taking part in an action planned by healthcare professionals in a medical or top-down approach. Further, community participation and health educationon breast cancer prevention are not similar to other activities incorporated in primary health care services inIran. Objective: To propose a model that provides a methodological tool to increase women’s participation inthe decision making process towards breast cancer prevention. To address this, an evaluation framework wasdeveloped that includes a typology of community participation approaches (models) in health, as well as fivelevels of participation in health programs proposed by Rifkin (1985&1991). Method: This model explains thecommunity participation approaches in breast cancer prevention in Iran. In a ‘medical approach’, participationoccurs in the form of women’s adherence to mammography recommendations. As a ‘health services approach’,women get the benefits of a health project or participate in the available program activities related to breastcancer prevention. The model provides the five levels of participation in health programs along with the ‘healthservices approach’ and explains how to implement those levels for women’s participation in available breast cancerprevention programs at the local level. Conclusion: It is hoped that a focus on the ‘medical approach’ (top-down)and the ‘health services approach’ (top-down) will bring sustainable changes in breast cancer prevention andwill consequently produce the ‘community development approach’ (bottom-up). This could be achieved usinga comprehensive approach to breast cancer prevention by combining the individual and community strategiesin designing an intervention program for breast cancer prevention.     

Interval cancers in the Dutch breast cancer screening programme.

The nationwide breast cancer screening programme in The Netherlands for women aged 50-69 started in 1989. In our study we assessed the occurrence and stage distribution of interval cancers in women screened during 1990-1993. Records of 0.84 million screened women were linked to the regional cancer registries yielding a follow-up of at least 2.5 years. Age-adjusted incidence rates and relative (proportionate) incidences per tumour size including ductal carcinoma in-situ were calculated for screen-detected and interval cancers, and cancers in not (yet) screened women, comparing them with published data from the UK regions North West and East Anglia. In total 1527 interval cancers were identified: 0.95 and 0.99 per 1000 woman-years of follow-up in the 2-year interval after initial and subsequent screens respectively. In the first year after initial screening interval cancers amounted to 27% (26% after subsequent screens) of underlying incidence, and in the second year to 52% (55%). Generally, interval cancers had a more favourable tumour size distribution than breast cancer in not (yet) screened women. The Dutch programme detected relatively less (favourable) invasive cancers in initial screens than the UK programme, whereas the number of interval cancers confirms UK findings. Measures should be considered to improve the detection of small invasive cancers and to reduce false-negative rates, even if this will lead to increasing referral rates.     

Smokers can quit regardless of motivation stage in a worksite smoking cessation programme in Malaysia

Background: There is an unclear relationship between smoker’s early motivation and success rates. Here we aimed to explore the correlates of motivation and smoking abstinence and relapse in worksite smoking cessation programmes. Methods: This prospective cohort study involved employees from two major public universities in Malaysia. Participants were actively recruited into a smoking cessation programme. At the start of treatment, participants were administered a questionnaire on sociodemographic variables, smoking habits and ‘stage of change’. Behaviour therapy with free nicotine replacement therapy (NRT) was given as treatment for two months. A similar stage of change questionnaire was given at six months, and their smoking status was determined. Results: There were 185 smokers from both Universities, who joined the programme. At six months, 24 smokers reported sustained abstinence while the others had relapsed. Prior to the programme, the majority of smokers were seriously planning on quitting (59.5%- preparation stage), but over a third had no plans to quit (35.5%- contemplation stage). There was no significant difference noted in changes of motivation stage among the relapsers and the non quitters. In addition, logistic regression showed that sustained abstinence was not predicted by pre-session motivation stage, but this did predict higher relapse for the participants, compared to those in the preparation stage. Conclusion: It is possible to help smokers in the lower motivation groups to quit, provided extra caution is taken to prevent relapse. Healthcare providers’ recruitment strategies for cessation programmes should thus encompass smokers in all motivation stages.     

Nutrition in cancer prevention.

Although variation in diet may account for approximately one third of the variation in cancer incidence worldwide, epidemiologic studies have proven to be a blunt instrument for identifying causal relationships between intakes of specific food constituents and cancer risk at specific sites. Diets rich in fruits and vegetables seem to be protective, but the adverse effects of beta carotene supplementation trials on lung cancer incidence in smokers caution against the attribution of benefit to single substances. Important diet-gene interactions may exist, as illustrated by differential responses to variation in folate status in those with methylenetetrahydrofolate reductase polymorphisms. Targeting initial intervention studies in those with explicit genetic predisposition to cancer may have both greater cost-effectiveness and fewer ethical difficulties than do similar studies in the general public.     

Animal cancer tests and cancer prevention.

The toxicological significance of exposures to synthetic chemicals is examined in the context of exposures to naturally occurring chemicals. We calculate that 99.99% (by weight) of the pesticides in the US diet are chemicals that plants produce to defend themselves (nature's pesticides). Only 52 of these natural pesticides have been tested in high-dose animal cancer tests, and 27 are rodent carcinogens; these 27 are shown to be present in many common foods. The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food and that these defenses are effective against both natural and synthetic toxins. Synthetic toxins (eg, dioxin) are compared to natural chemicals (eg, indole carbinol [in broccoli] and ethanol). The finding that, in high-dose tests, a high proportion of both natural and synthetic chemicals are carcinogens, mutagens, teratogens, and clastogens (30%-50% for each group) calls into question current efforts to use these tests to protect public health by regulating low doses of synthetic chemicals. The administration of chemicals at the maximum tolerated dose in standard animal cancer tests is postulated to increase cell division (mitogenesis), which in turn increases rates of mutagenesis and, thus, carcinogenesis. The animal data are consistent with this mechanism, because a high proportion--about 50%--of all chemicals tested (whether natural or synthetic) are indeed rodent carcinogens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Behavior and cancer prevention.

This paper reviews research on the effects of behavioral risk factors on cancer incidence, as well as behavioral interventions for cancer prevention. Risk factors discussed here--tobacco use, diet, physical activity, and obesity/energy balance--are all linked with cancer etiology, and effective behavioral interventions have been developed in all of these areas. The most effective interventions appear to incorporate various components; for example, including individual as well as family activities, and involving multiple community organizations in behavior-changing activities. Behavioral theories have guided the design of these interventions, providing support that certain influences on behavior, such as self-efficacy, problem-solving skills, and social support, are important regardless of the specific behavioral target. As illustrated by the recent lowered lung cancer incidence and mortality rates for men and women, behavior change is possible and effective in cancer prevention. Clinical guidelines have been established for behavioral aspects of treatments for smoking cessation, dietary guideline compliance, physical activity, and obesity reduction, and new tools for dissemination of effective intervention materials will be helpful in increasing their use. Documenting the cost-effectiveness of behavioral interventions, using new technology interventions, and building on translational research to tailor interventions to individuals offer considerable promise for the future.     

Apoptosis in the genesis and prevention of cancer.

A strong rationale exists for developing cancer control strategies designed to suppress or reverse the development of precancerous lesions in order to reduce the occurrence and recurrence of this disease. Whereas numerous agents have been identified that inhibit tumor development, little is known about how they work. Recently the hypothesis has been raised that misregulation of apoptosis results in a failure of tissue size regulation that contributes to the development of cancer. If validated, this concept has important implications for the prevention of carcinogenesis and could lead to the development of new cancer control approaches that have as their basis the restoration of competence to regulate tissue size. Thus, it is essential to consider the role of cell loss in the tumorigenic process. In this regard investigation of the role of specific types of cell death in tumorigenesis, particularly the role of apoptotic cell death in maintenance of tissue homeostasis, has been neglected. The fact that apoptosis is a highly conserved, specific, and selective means of controlling tissue mass and shape also suggests that it can be exploited for the prevention or control of cancer.     

A model of interaction: Aflatoxins and hepatitis viruses in liver cancer aetiology and prevention

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and has an extremely poor prognosis. The majority of cases occur in south-east Asia and sub-Saharan Africa where the major risk factors are chronic infection with hepatitis B and C viruses (HBV and HCV) as well as dietary exposure to aflatoxins. Aflatoxin B1, the most commonly occurring and potent of the aflatoxins is associated with a specific AGG to AGT transversion mutation at codon 249 of the p53 gene in human HCC, providing mechanistic support to a causal link between exposure and disease. Prospective epidemiological studies have shown a more than multiplicative interaction between HBV and aflatoxins in terms of HCC risk. However, the biology underlying this statistical interaction is not fully understood. There are a number of potential mechanisms including, among others: the fixation of AFB1-induced mutations in the presence of liver regeneration and hyperplasia induced by chronic HBV infection; the predisposition of HBV-infected hepatocytes to aflatoxin-induced DNA damage; an increase in susceptibility to chronic HBV infection in aflatoxin-exposed individuals; and oxidative stress exacerbated by co-exposure to aflatoxins and chronic hepatitis infection. Priorities for prevention are global HBV vaccination, primary and secondary prevention strategies against aflatoxin and the avoidance of transmission of HCV through good hygiene practices.     

Factors associated with success or failure of quit attempts: a clinical approach for lung cancer prevention

The objective of the study is to investigate the success rate of quit attempts and identify factors associated with success or failure of quit attempts in a quit smoking clinic. A cohort study was conducted with 495 smokers who enrolled in a quit smoking clinic from 2005 to 2008. The factors leading to quit smoking successfully were "being Malay", "having high blood pressure" "type of Nicotine Replacement Therapy" and "duration of follow up". In contrast, clerical staff had negative association to quit smoking. People who started smoking in their teenage years had a high risk of relapse. Integration of active follow up and tailor-made support programmes for quitters appear necessary in order to maintain their non-smoking status and encourage them to be permanent quitters. Integration of quit smoking clinics and primary care clinics could be another potential step for the success of quit smoking programmes.     

Retinoids in cancer prevention and therapy.

Retinoids are a class of compounds structurally related to vitamin A. In preclinical studies, all-trans retinoic acid (tretinoin), 13-cis retinoic acid (isotretinoin) and the aromatic retinoids etretinate and acitretin have preventive and therapeutic effects on carcinogen-induced premalignant and malignant lesions. Clinically, chemoprevention with isotretinoin and etretinate has been tested with some degree of success in such indications as basal cell carcinomas, squamous cell carcinomas, superficial bladder tumors and second primary tumors in patients with squamous cell carcinoma of the head and neck. Limited therapeutic success has also been achieved with retinoid treatment of precancerous and cancerous conditions of the skin, oral cavity, larynx, lung, bladder and vulva. Dramatic therapeutic effects have been observed in the treatment of acute promyelocytic leukemia with tretinoin, which leads to very high rate of complete remission. Excellent results were recently reported in the treatment of squamous cell carcinomas of the skin and cervix with a combination of isotretinoin and recombinant interferon alfa-2a (rIFN alfa-2a, Roferon-A). The mechanism of action of retinoids is through modulation of cell proliferation and differentiation. Retinoids vary in their capacity to induce differentiation and to inhibit proliferation in a series of human transformed hematopoietic and epithelial cell lines. Some cytokines potentiate the retinoid-induced cell differentiation and act synergistically with retinoids to inhibit cell proliferation. The pattern of synergism is dependent upon the combination and tumor cell line tested. The discovery of nuclear retinoid receptors has contributed substantially to the understanding of the mechanism of action of retinoids at the molecular level. Further understanding of the molecular biology of retinoids is expected to contribute to a rational design of new retinoids in the future, which in turn may result in improvements in the prevention and therapy of cancer.     

A collaborative case-control study of nutrient intake and pancreatic cancer within the search programme.

Case-control studies of pancreatic cancer were conducted in 5 populations with moderate to high rates and differing dietary practices, using a common protocol and questionnaire. Comprehensive diet histories were completed for a total of 802 cases and 1669 controls identified in Adelaide (Australia), Montreal and Toronto (Canada), Utrecht (The Netherlands) and Opole (Poland). Positive associations were observed with intake of carbohydrates and cholesterol, and inverse associations with dietary fiber and vitamin C. These relationships were generally consistent among the 5 studies, and showed statistically significant and generally monotonic dose-response relationships. The relative risks for highest vs. lowest quintile of intake were estimated for carbohydrates to be 2.57 (95% confidence interval 1.64-4.03), cholesterol 2.68 (1.72-4.17), dietary fiber 0.45 (0.30-0.63), and vitamin C 0.53 (0.38-0.76). The consistency, strength, and specificity of these associations provides evidence for the hypothesis that some or all of these dietary factors may alter the risk of pancreatic cancer.