Cancer letters
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Randomized Controlled Trial Clinical Trial
Inhibition of oxidative DNA damage, 8-OHdG, and carbonyl contents in smokers treated with antioxidants (vitamin E, vitamin C, beta-carotene and red ginseng).
The chemopreventive effects of antioxidants (vitamin E, beta-carotene, vitamin C and red ginseng) on oxidative DNA and protein (globin) damages were comparatively investigated in the peripheral blood of smokers (> or = 20 cigarettes/day). Smokers showed a lower baseline level of plasma micronutrients (vitamin C and beta-carotene) (P < 0.01) and higher baseline level of oxidative DNA or protein damage than non-smokers (N = 5; P < 0.05). ⋯ Levels of urinary and plasma cotinine remained steady in smokers regardless of supplementation with antioxidants. 8-OHdG and carbonyl content decreased in a time-dependent manner (as the total intake dose increased) after supplementation with vitamin E (8-OHdG, 33.8%; carbonyl content, 43.6%) or red ginseng (8-OHdG, 31.7%; carbonyl content, 21.3%). These preliminary data suggest that supplementation with antioxidants might protect smokers from oxidative damages and could reduce cancer risk or other diseases caused by free radicals associated with smoking.
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Randomized Controlled Trial Clinical Trial
Retinoids in prevention of skin cancer.
Two chemoprevention randomized clinical trials were begun in 1984 to evaluate retinoids in the prevention of skin cancers. Moderate risk subjects with a history of at least 10 actinic keratoses and at most two prior skin cancers were enrolled in the SKICAP-AK trial and randomized to 25,000 IU retinol or placebo daily for 5 years. ⋯ The effect of retinoids had no significant benefit on squamous or basal cell skin cancers in the high risk subjects on the SKICAP-S/B trial, although intervention duration was less than planned. Daily retinol was effective in preventing squamous cell cancers in moderate risk subjects.