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Query: UMLS:C0242379 (lung cancer)
 71,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemoprevention is a strategy used to block the development of cancers in human beings. This emerging field has broad potential for influencing cancer incidence rates in defined high-risk groups and the general population. In this review, we define some of the mechanisms of carcinogenesis, describe some of the genetic markers of carcinogenesis, and list possible biomarkers that may serve as surrogate end points in chemoprevention studies. A major component of this review is a description of the agents that are currently under investigation in animal systems or in human trials. They are grouped according to the agents that block or suppress mutation, such as oltipraz, selenium, vitamin C and the flavones, or according to agents that block promotion and proliferation, such as difluoromethylornithine, tamoxifen, nonsteroidal antiinflammatory drugs, and the vitamin A derivatives. We describe the issues that are considered in the design of chemoprevention trials and in the phase I, II, and III components of these trials. The following national trials are discussed: the Breast Cancer Prevention Trial, which uses tamoxifen; the Prostate Cancer Prevention Trial, which uses finasteride; and a Lung Cancer Prevention Trial, which uses 13-cis-retinoic acid. The review ends with some insights about future studies in chemoprevention.
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PMID:Chemoprevention of cancer. 800 1

The potential of a high intake of fresh fruits and vegetables in cancer prevention is well established. Epidemiological studies support carotene, vitamins A, C, E and selenium as the active compounds. Antioxidant properties and direct effects (e.g. inhibition of N-nitrosamine formation or cell-to-cell interactions) are invoked. The role of other trace elements is less clear. The modulation of immune function by vitamins and trace elements remains important and affects survival. In established cancers, the site-specific differences in the diet/cancer relation require appropriate dietary changes, e.g. low fat (20% by energy) in breast cancer, or high vegetable or fruit intake in lung cancer. Single high-dose supplements (e.g. vitamin C) have proved to have no curative or life-prolonging effect. Chemotherapy and radiation increase the requirements for antioxidant compounds. Supplementation can diminish the damage induced by peroxidation. Carefully planned and monitored trials that establish the optimal intake of micronutrients as adjuvants in cancer patients are required.
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PMID:Critical reappraisal of vitamins and trace minerals in nutritional support of cancer patients. 815 46

This paper reports the serum selenium concentration in 100 cases of lung cancer patients and 100 healthy controls. The results showed that the serum selenium level in patients with lung cancer was significantly lower than that of controls. Serum selenium level in lung cancer patients was inversely related to the stage of cancer, the amount of tobacco abuse and the serum Cu level. It was positively correlated with patient's nutritional status and the serum albumin level. Serum selenium level was decreased with cancer progression and increased with disease remission. These results suggest that the lower serum selenium level in lung cancer patients was the result rather than the cause of cancer.
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PMID:[Studies on the correlation of blood selenium and lung cancer. II. An analysis of serum selenium levels and influencing factors in patients with lung cancer]. 815 79

The concentrations of the elements antimony, arsenic, cadmium, chromium, cobalt, lanthanum, lead, selenium, and zinc were determined in lung tissue of 85 decreased smelter workers by neutron activation analysis and atomic absorption spectrophotometry. The concentrations of all these elements, except zinc, were significantly higher among the workers as compared with rural referents. Workers who died from lung cancer (N = 7) had the lowest lung selenium content relative to other metals, both compared with workers with other diseases and with rural (N = 15) and urban (N = 10) referents. The low lung tissue levels may have influenced the development of lung cancer. The highest lung cadmium concentrations were observed in the lung cancer group, in which, however, smokers and ex-smokers were over-represented. The observations make it likely that the excess lung cancer risk in this smelter environment is multifactorial in character, involving interactions between both carcinogenic and anticarcinogenic factors.
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PMID:Lung cancer in smelter workers--interactions of metals as indicated by tissue levels. 815 82

Epidemiological studies have not given sufficient evidence yet for the role of antioxidant nutrients in the prevention of cardiovascular disease. As regards cancer, an inverse association between beta-carotene intake and specific types of cancer, especially lung cancer, has been shown. For other cancer sites and other antioxidants, the association is less clear. The EURAMIC Study, an EC Concerted Action, is a case-control study conducted in 11 countries, in which the combined effect of vitamin E, beta-carotene and selenium, in relation to fatty acid intake, will be examined. The disease endpoints are acute myocardial infarction and early-stage breast cancer. The broad range of antioxidant intake, the use of biomarkers of exposure, and the analysis of pooled data will allow an estimate of the strength of the putative beneficial effect. In this paper the background and design of the study will be introduced.
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PMID:EURAMIC Study: antioxidants, myocardial infarction and breast cancer. Design and main hypotheses. 826 23

Selenium has been suggested to be anticarcinogenic and to play a role in the cellular defense against oxidative stress. The association between toenail selenium (a marker of long-term selenium status) and lung cancer was investigated in a cohort study of diet and cancer that started in 1986 among 120,852 Dutch men and women aged 55-69 years. After 3.3 years of follow-up, 550 incident cases of lung carcinoma were detected. Toenail selenium data were available for 370 lung cancer cases and 2459 members of a randomly selected subcohort. The rate ratio of lung cancer for subjects in the highest compared to the lowest quintile of toenail selenium, after controlling for age, gender, smoking, and education, was 0.50 (95% confidence interval, 0.30-0.81), with a significant inverse trend across quintiles (P = 0.006). The protective effect of selenium was concentrated in subjects with a relatively low dietary intake of beta-carotene or vitamin C. The rate ratio in the highest compared to the lowest quintile of selenium was 0.45 in the low beta-carotene group (95% confidence interval, 0.22-0.92; trend P = 0.028) and 0.36 in the low vitamin C group (95% confidence interval, 0.17-0.75; trend P < 0.001). The results of this study support an inverse association between selenium status and lung cancer and suggest a modification of the effect of selenium by the antioxidants beta-carotene and vitamin C.
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PMID:A prospective cohort study on selenium status and the risk of lung cancer. 840 74

The hypotheses that the antioxidant vitamin E provides protection against lung cancer and that this hypothetical protection is modified by smoking status were investigated using two different study designs--a cohort study and a nested case-control study--among Finnish men aged 15 years and over. In the cohort study the association between vitamin E intake and lung cancer risk was studied among 5,254 individuals with 121 lung cancer cases that occurred during a 19-year follow-up, and in the nested case-control study the association between serum vitamin E level and lung cancer risk was studied using 144 lung cancer cases and 270 matched controls as a basis. There was a significant inverse association between vitamin E status and lung cancer occurrence among nonsmokers but not among smokers in both designs. The relative risk of lung cancer between the lowest and highest tertiles of vitamin E intake was 3.3 among nonsmokers and 0.8 among smokers. The corresponding results for serum vitamin E were 6.6 and 0.8, respectively. Nonsmokers with simultaneously low serum levels of vitamin E and other micronutrients (i.e., beta-carotene, retinol and selenium) had a 12-fold greater risk of lung cancer in comparison with men having more satisfactory levels. The corresponding number among smokers was three. The results suggest that vitamin E status is primarily associated with lung cancer risk among nonsmokers. Firm conclusions can, however, be drawn only on the basis of intervention trials.
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PMID:Vitamin E and smoking and the risk of lung cancer. 851 53

Evidence supports the potential role of beta-carotene in cancer prevention. Basic research has demonstrated that beta-carotene can trap organic free radicals and/or deactivate excited oxygen molecules which may have an anticancer effect by preventing tissue damage. Although observational epidemiologic studies are not entirely consistent, many show an inverse association between dietary intake or blood levels of beta-carotene and subsequent cancer risk. Two large-scale randomized trials of beta-carotene have been completed. A Finnish trial demonstrated no benefit of beta-carotene among middle-aged male smokers, with those assigned to this supplement in fact experiencing an increased risk of lung cancer. However, because of the long latency period for cancer, which may be a decade or more, the six-year duration of treatment in this trial may have been inadequate to detect an anticancer effect. A Chinese trial demonstrated a modest reduction in cancer mortality from a combined regimen of beta-carotene, vitamin E, and selenium. The effect of the individual agents could not be assessed, and because the trial was carried out among a nutritionally deficient population, its results may not have direct relevance to well-nourished individuals. Several additional large-scale trials of beta-carotene are ongoing. The Physicians' Health Study, which is testing beta-carotene among 22,071 US male physicians, will have an average duration of treatment of 12.5 years at its scheduled termination in late 1995. Data in women will be available from the Women's Health Study, which began in 1992, and will randomize approximately 40,000 US female health professionals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:beta-carotene and cancer chemoprevention. 853 2

Epidemiologic evidence on the relationship between nutrition and lung cancer is reviewed. Observational studies of diet and lung cancer, both prospective and retrospective, continue to suggest strongly that increased vegetable and fruit intake is associated with reduced risk in men and women; in various countries; in smokers, ex-smokers, and never-smokers; and for all histologic types of lung cancer. Prospective studies of blood beta-carotene levels, arguably the best available biomarker of vegetable and fruit intake, indicate that low levels are predictive of increased lung cancer incidence. However, in a randomized, placebo-controlled clinical trial in male smokers, lung cancer incidence and total mortality were increased significantly among the men receiving beta-carotene supplements. If beta-carotene can prevent lung carcinogenesis, which the trial cannot rule out, then the dosage, duration of use, method of administration, and/or subpopulation are critical. Ongoing clinical trials, some of which include women, will provide much-needed information. Other carotenoids, other phytochemicals, and associated dietary patterns may explain the beneficial effects of vegetables and fruits and have not been explored adequately in epidemiologic work. Several observational epidemiologic studies, both prospective and retrospective, have indicated that diets high in fat, saturated fat, and cholesterol may increase the risk of lung cancer and that the effect is not mediated through vegetable and fruit intake. The relationship, although not yet established, merits further investigation. Since beta-carotene can function as an antioxidant, other micronutrients with this potential, specifically vitamins E and C and selenium, also have been proposed to reduce lung cancer risk. However, the totality of the epidemiologic evidence is not, at present, persuasive for any one of these micronutrients.
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PMID:Nutrition and lung cancer. 885 Apr 43

A critical review of epidemiological studies on diet and lung cancer over the last 20+ years has not provided overwhelming evidence that higher consumption of vegetables, fruit, low-fat/low-cholesterol foods or such micronutrients as carotenoids, selenium and vitamins A, C or E is associated with reduced lung cancer risk. Results from case-control studies have been more positive, with about one half showing fruit and vegetables or their associated micronutrients to be associated with reduced risk. However, most results from cohort and serum micronutrient studies, which avoid the problems of inaccurate accounting of diet and recall bias, were statistically insignificant. Moreover, although most studies were conducted on white male smokers in North America and Europe, the few studies which found significant contrary trends were among subjects of different backgrounds, i.e., black American males and Chinese women in China. Since male smokers vs. nonsmokers in Europe, North America and Japan have been shown in other studies to be lower consumers of fruit/vegetables, and less likely to pursue "perceived healthier lifestyles," the possibility that some of the epidemiological findings on diet and lung cancer are artifactually due to inadequate adjustment for behavioral correlates of smoking and health seekers in a particular society must be considered. This is especially true with recent chemoprevention trials showing higher lung cancer incidence and deaths among consumers of beta-carotene supplements vs. placebo.
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PMID:Diet and lung cancer 20+ years later: more questions than answers? 920 16


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