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

About 1% of the patients with oral cavity, larynx, and lung cancer get second primary malignant neoplasms every year. For laryngeal cancer the percentage exceeds 10. Second primary tumors in oral cavity, larynx, and lung cancer patients are also tobacco-related neoplasms. Smoking cessation by patients with oral cavity, larynx, and lung cancer may have significant influence on the prognosis. Vitamin A (retinol) and its analogues are promising for human cancer prevention.
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PMID:[Second primary malignant neoplasms in patients treated radically for carcinoma of oral cavity, larynx and lungs]. 809 Apr 86

Pilot studies are an essential component for major chemoprevention trials. Prior to initiating the multicenter Carotene and Retinol Efficacy Trial to assess the effectiveness of beta-carotene and retinol for preventing lung cancer, we conducted pilot studies in Seattle between 1985 and 1988 in two high risk populations: current and former heavy smokers and asbestos-exposed workers. The Asbestos Workers Pilot Study for the Carotene and Retinol Efficacy Trial demonstrated that recruitment of asbestos-exposed participants with relevant risk factors was feasible from identified sources. We documented negligible toxicity and high adherence with the protocol, schedule, and intervention. Results from the pilot led to extension of the placebo run-in period, changes in the eligibility criteria, improvements in recruitment strategies and scheduling, elimination of stratification by risk factors in randomization, modifications of study vitamin dosage and of side effects monitoring, and refinement of trial design parameters for Carotene and Retinol Efficacy Trial. The Smokers Pilot is reported in the accompanying article (G. E. Goodman et al., Cancer Epidemiol., Biomarkers & Prev., 2: 389-396, 1993).
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PMID:The Carotene and Retinol Efficacy Trial (CARET) to prevent lung cancer in high-risk populations: pilot study with asbestos-exposed workers. 834 62

As part of the multicenter Carotene and Retinol Efficacy Trial (CARET) lung cancer prevention study, we investigated the associations of baseline demographic, health history, and nutritional intake information and the prerandomization serum concentrations of beta-carotene, retinol, retinyl palmitate, and alpha-tocopherol in a random subset of 1182 smokers and asbestos-exposed workers. Dietary intake was estimated via a self-administered food frequency questionnaire using the recently updated United States Department of Agriculture/National Cancer Institute database. In multiple regression analyses, supplemental vitamin use was the strongest predictor of each of the four analytes. There was a statistically significant inverse relationship between smoking and beta-carotene concentrations. Lower serum beta-carotene was associated with current smoking, higher daily cigarettes smoked, and more pack-years. Serum beta-carotene concentrations were higher with increasing years since stopping cigarette use, which suggests a biological mechanism for the lower serum concentration of beta-carotene in smokers. We found weak inverse associations between alcohol intake and the serum concentrations of both beta-carotene and retinol. As in previous reports, dietary intakes as measured by a food frequency questionnaire can only moderately predict serum concentrations of beta-carotene, retinol, retinyl palmitate, and alpha-tocopherol.
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PMID:The association between participant characteristics and serum concentrations of beta-carotene, retinol, retinyl palmitate, and alpha-tocopherol among participants in the Carotene and Retinol Efficacy Trial (CARET) for prevention of lung cancer. 889 93

The association between serum beta-carotene or retinol concentration and level of ventilatory function was investigated in a population of asbestos-exposed men with a high rate of current and former cigarette smoking. The study population consisted of 816 subjects enrolled in the pilot component of the Carotene and Retinol Efficacy Trial (CARET), a placebo-controlled trial of supplemental beta-carotene and retinyl palmitate for the chemoprevention of lung cancer. Data available for analysis included baseline questionnaire, spirometry, chest X-ray, food frequency questionnaire, and serum beta-carotene and retinol concentrations. Serum beta-carotene concentration was associated with FEV1 (p < 0.05) and FVC (p < 0.05), with an approximately 100-ml increase over predicted values associated with raising the serum concentration from the 25th to the 75th percentile of the distribution in the study population (absolute difference = 155 ng/ml), even after adjustment for the confounding effects of asbestos exposure and cigarette smoking. Raising the serum retinol concentration from the 25th to the 75th percentile (absolute difference = 211 ng/ml) was associated with an approximately 70 ml increase in FVC (p < 0.05) over the predicted value. These results provide support for the hypothesis that beta-carotene and retinol have a protective effect on loss of ventilatory function.
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PMID:The protective effect of beta-carotene and retinol on ventilatory function in an asbestos-exposed cohort. 911 88

Vitamin A analogs (retinoids) suppress oral and lung carcinogenesis in animal models and prevent the development of second primary tumors in head, neck, and lung cancer patients. These effects result from changes in the expression of genes that regulate cell growth and differentiation. Retinoic acid receptors (RARs; -alpha, -beta, and -gamma) and retinoid X receptors (RXRs; -alpha, -beta, and, -gamma) are retinoid-activated transcription factors, which mediate effects of retinoids on gene expression. Therefore, alterations in receptor expression or function could interfere with the retinoid signaling pathway and thereby enhance cancer development. We found that the expression of RAR beta was suppressed in more than 50% of oral and lung premalignant lesions in individuals without cancer and in dysplastic lesions adjacent to cancer and in malignant oral and lung carcinomas. The expression of the other receptors was not different among normal, dysplastic, and malignant oral tissues. However, the expression of RAR gamma and RXR beta was somewhat decreased in lung cancers. These results show that RAR beta expression is lost at early stages of carcinogenesis in the aerodigestive tract and support the hypothesis that the loss of RAR beta expression may facilitate the development of some of these cancers.
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PMID:Roles of retinoids and their nuclear receptors in the development and prevention of upper aerodigestive tract cancers. 925 92

The Carotene and Retinol Efficacy Trial (CARET) was a double-blind, placebo-controlled trial of the daily administration of 25,000 IU vitamin A and 30 mg beta-carotene for the prevention of lung cancer. Of close to 18,500 participants, more than 4,000 were asbestos-exposed men recruited from shipyard and construction trades at five study centers in the United States. While the primary endpoint of the trial was the incidence of lung cancer, a number of questions about the natural history of asbestos-related disease will also be addressed. The mean age at entry into the trial was 57 years and the mean duration of follow-up on active intervention was 4 years. With the exception of 133 never-smoker pilot participants (3%), all subjects recruited were by intention current (38%) or ex-smokers (58%), with a mean cumulative smoking exposure at entry of 43 pack-years. Mean years from first asbestos exposure were 35, and mean duration of asbestos exposure in a high-risk trade was 19 years. The distribution of radiographic abnormalities was as follows: normal, 34%; parenchymal opacities (ILO profusion score > 1/0) alone, 18%; pleural thickening alone, 27%; both parenchymal opacities and pleural thickening, 21%. The CARET cohort, when compared to previously reported asbestos-exposed cohorts, is characterized by substantial asbestos exposure and high proportion of asbestos-related radiographic findings. The active intervention was halted in 1996, after a mean duration of 40 years. Passive follow-up of the cohort will continue until the year 2000.
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PMID:The CARET asbestos-exposed cohort: baseline characteristics and comparison to other asbestos-exposed cohorts. 935 12

Lower lobe origin and histologic diagnosis of adenocarcinoma have been described as useful parameters for attributing lung cancer to prior asbestos exposure. To assess whether these characteristics differed between asbestos-exposed individuals and smokers, we evaluated lobe of origin and histologic type of tumors in 78 asbestos-exposed and 214 nonexposed heavy smokers developing lung cancer during the Carotene and Retinol Efficacy Trial (CARET), a prospective cancer chemoprevention trial. Most tumors in both cohorts, regardless of radiographic fibrosis at baseline, originated in upper lobes, representing 67% in asbestos-exposed and 80% in smokers, respectively (adjusted OR for lower lobe = 1.41; 95% CI = 0.69-2.91). Adenocarcinoma represented 32% of lung tumors in the asbestos cohort, and 30% in the smoking cohort (adjusted OR = 0.78; 95% CI = 0.40-1.55), and was inversely associated with radiographic fibrosis (adjusted OR = 0.19; 95% CI = 0.06-0.62). We conclude that neither anatomic site nor histologic cell type of tumors distinguishes effectively between smoking and asbestos as causal factors in development of lung cancer.
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PMID:Lobe of origin and histologic type of lung cancer associated with asbestos exposure in the Carotene and Retinol Efficacy Trial (CARET). 935 13

The Carotene and Retinol Efficacy Trial (CARET), a randomized, placebo-controlled lung cancer chemoprevention trial of 30 mg of beta-carotene and 25,000 IU of retinyl palmitate, was prematurely terminated when a 46% excess lung cancer mortality was found in subjects on the active arm. Before the CARET intervention ended, 21 men were recruited to participate in a 6-month biomarker study using the same intervention as CARET that determined the effect of this supplementation on lung nutrient levels. Plasma and bronchoalveolar lavage (BAL) cell nutrient levels were measured before and after the intervention. The group in the active arm (n = 10) had plasma carotene level increases of over 10-fold, with a small increase in plasma retinol levels BAL cell levels of beta-carotene in the active group also increased 10-fold, from 4.5 to 46.3 pmol/10(6) cells (P = 0.0008), with no change in BAL cell retinol levels. Surgically obtained lung tissue from three CARET subjects in the active arm showed elevated carotene lung tissue levels but no increase in lung retinol levels compared to a group of surgical controls. Combined with our previous work showing a strong correlation between BAL and lung tissue nutrient levels, these findings suggest that supplementation with beta-carotene and vitamin A results in increased lung tissue as well as BAL cell levels of beta-carotene, with little change in lung retinol.
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PMID:Effect of supplementation with beta-carotene and vitamin A on lung nutrient levels. 952 35

Lung cancer chemoprevention continued to make progress in 1997. The incidence of tobacco abuse continues to slowly fall in the United States, and paralleling it, lung cancer incidence. Biomarkers of carcinogenesis and susceptibility continue to be an important area in identifying high-risk patients. The analyses of two major lung cancer prevention trials, beta-Carotene and Retinol Efficacy Trial (CARET) and Alpha-Tocopherol Beta-Carotene (ATBC), were also published this past year. Both found an increased incidence of lung cancer in individuals receiving beta-carotene. In both trials, heavy smokers seem to be the most adversely affected group. The mechanism of this increased incidence of cancer and total deaths still eludes investigators.
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PMID:Prevention of lung cancer. 955 34

The Beta-Carotene and Retinol Efficacy Trial tested the effect of the combination of beta-carotene (30 mg) and retinyl palmitate (25,000 units) daily on the incidence of lung cancer in high-risk individuals. In study centers located in Seattle, WA; Portland, OR; and Irvine, CA, we recruited current and recent ex-cigarette smokers, aged 50-69 years. Our primary method of recruitment was by mailing study information and eligibility questionnaires to age-selected health insurance subscribers. A total of 1,216,549 subscriber households were contacted, which resulted in 16,449 enrollments and 12,184 randomizations. Other methods of recruitment yielded 1421 enrollments and 1002 randomizations. Seventy-four % of those participants who enrolled in the 3-month placebo run-in were randomized. The major reasons for nonrandomization once subjects were enrolled were: becoming ineligible (13%), concern about or development of side effects attributed to the study vitamins (18%), loss of interest or being too busy (23%), and not showing up at the appointed time or not willing to come to the study center (23%). Here, we discuss the reasons for nonparticipation and for subjects leaving the trial prior to randomization and possible modifications of trial design and procedures to address these problems. This recruitment approach provided a constant flow of potentially eligible participants, screened out many ineligible and uninterested persons prior to the scheduling of a study center visit, and ensured randomization of committed participants. A major limitation of this study was that the pool of minorities that was reached was small.
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PMID:Strategies for recruitment to a population-based lung cancer prevention trial: the CARET experience with heavy smokers. Beta-Carotene and Retinol Efficacy Trial. 961 Jul 90


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