Remission of oral leukoplakias and micronuclei in tobacco/betel quid chewers treated with beta‐carotene and with beta‐carotene plus vitamin A

Hf, Stich; Mp, Rosin; Ap, Hornby; Mathew, Babu; Sankaranarayanan, Rengaswamy; Mk, Nair

doi:10.1002/ijc.2910420209

Cited by 246 publications

(82 citation statements)

References 24 publications

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“…The approximately 30% reduction in micronuclei after P-carotene treatment is in accordance with the effect of Pcarotene reported in buccal mucosa of betel nut chewers (Stich et al, 1984a) and tobacco chewers (Stich et al, 1985(Stich et al, , 1988. Our findings extend these observations to cigarette smoke-induced tracheobronchial micronuclei, which may reflect lung cancer risk (Stich & Rosin, 1984b;Lippman et al, 1990a,b).…”

Section: Discussionsupporting

confidence: 91%

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Beta-carotene supplementation in smokers reduces the frequency of micronuclei in sputum

Poppel

Kok²,

Hermus³

1992

Br J Cancer

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Summary P-carotene has been hypothesised to reduce lung cancer risk. We studied the effect of 14 weeks of P-carotene supplementation (20 mg d-1) on the frequency of micronuclei in sputum in 114 heavy smokers in a double-blind trial. Micronuclei reflect DNA damage in exfoliated cells and may thus provide a marker of early-stage carcinogenesis.Pre-treatment blood levels of cotinine, P-carotene, retinol and vitamins C and E were similar in the placebo group (n = 61) and the treatment group (n = 53). Plasma 1-carotene levels increased 13-fold in the treatment group during intervention. Initial micronuclei counts (per 3,000 cells) were higher in the treatment group than in the placebo group (5.0 vs 4.0, P<0.05). During intervention, the treatment group showed a 47% decrease, whereas the placebo group showed a non-significant decrease (16%). After adjustment for the initial levels, the treatment group had 27% lower micronuclei counts than the placebo group at the end of the trial (95% CI: 9-41%).These results indicate that P-carotene may reduce lung cancer risk in man by preventing DNA damage in early-stage carcinogenesis.The scientific interest in the role of carotenoids and retinoids in the prevention of human cancer has culminated in recent years (Editorial, 1991;Meyskens, 1990 al., 1987;Fontham, 1990). Since these studies cannot prove causal associations, two large randomised trials are currently conducted to evaluate the beneficial effect of P-carotene on human cancer development (Hennekens & Eberlein, 1985;Albanes et al., 1986). These intervention studies, however, provide little information on biological mechanisms.Damage to DNA is considered a crucial mechanism in cancer development (Weinstein, 1988). Micronuclei, DNA fragments in exfoliated cells, may thus provide a marker of early-stage carcinogenesis in target tissues (Lippman et al., 1990a,b;Stich et al., 1984a). In cigarette smokers, elevated micronuclei counts in expectorated sputum (Fontham et al., 1986) or bronchial brushings (Lippman et al., 1990a) are thought to reflect increased lung cancer risk.So far, no studies have investigated the effect of P-carotene supplementation on sputum micronuclei, as a reflection of lung cancer risk. P-Carotene has been shown to reduce micronucleated buccal mucosal cells in tobacco chewers (Stich et al., 1984a(Stich et al., , 1985(Stich et al., , 1988 and may thus reduce risk for oral cancer. These trials, however, did not measure plasma levels of P-carotene and retinol. Moreover, other antioxidant vitamins may modify the effects of P-carotene (Meyskens, 1990 Blood and sputum samples were collected before and after the 14-week treatment. The participants were instructed to take capsules daily with the evening meal, two capsules per day during the first 2 weeks, followed by one capsule per day over the next 12 weeks. Every 4 weeks, the participants were sent their next strip of 28 capsules, and were asked to return the used strips with the capsules not taken to monitor compliance. In addition, P-carotene was determined...

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Section: Discussionsupporting

confidence: 91%

“…P-Carotene has been shown to reduce micronucleated buccal mucosal cells in tobacco chewers (Stich et al, 1984a(Stich et al, , 1985(Stich et al, , 1988 and may thus reduce risk for oral cancer. These trials, however, did not measure plasma levels of P-carotene and retinol.…”

mentioning

confidence: 99%

Beta-carotene supplementation in smokers reduces the frequency of micronuclei in sputum

Poppel

Kok²,

Hermus³

1992

Br J Cancer

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“…This modest experience is thus consistent with and corroborates reports from other groups that cite advantages of ''Antioxidant Therapy'' in treatment of leukoplakia [1,[27][28][29][30][31].…”

Section: Does Antioxidant Therapy Influence Lipid Peroxidase?supporting

confidence: 90%

Role of Measurement of Antioxidant Enzymes in Evaluation of Antioxidant Therapy in Tobacco Abusers with Oral Leukoplakia

Jain

Singh

et al. 2011

Indian J Otolaryngol Head Neck Surg

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Antioxidants are widely used in chemoprevention of malignancy. Numerous studies in medical literature have reported the evaluation of this treatment protocol by indirect methodology-epidemiology, invitro studies, pharmacology and animal models etc. However, there is a paucity of literature on the measurement of antioxidant enzymes as a parameter for assessing the outcome of antioxidant therapy. This study explores the efficacy and outcome of antioxidant enzyme assay in relation to antioxidant therapy in tobacco abusers, hitherto unreported in medical literature. A prospective cohort study with control in 50 patients carried out at a tertiary care teaching Institution (Institute of Medical Sciences, Banaras Hindu University, Varanasi, India). Out of these patients, 10 patients acted as control, rest 40 patients-all tobacco users in some form, were divided into three groups on the basis of histopathological grading of dysplasia-no dysplasia, mild or moderate dysplasia. The levels of Lipid peroxidase (LPO), Superoxide dismutase (SOD) and Catalase (CAT) in mucosa and serum were assayed in each group, and re-evaluated at the end of 3 months after intervention with antioxidant treatment. To detect any alteration in degree of dysplasia a repeat biopsy was also done at the end of 3 months. The results were statistically analysed using paired t test. A statistically significant decrease in level of LPO and SOD, and an increase in CAT levels were recorded both in mucosa and serum. However, no change in dysplasia and no new case of dysplasia were observed. Further, antioxidant treatment was continued for a year and the final out come of the lesion was assessed by ''Carter's criteria''. A final success rate of 74.19% was recorded in terms of partial or complete regression of the lesion. This study confirms the therapeutic efficacy of antioxidants in oral leukoplakia, and cites the importance of LPO, SOD and CAT in evaluating the efficacy of antioxidant treatment. However, the study failed to elucidate any relationship between enzyme measurement and the final outcome of the lesion.

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“…A number of trials of β-carotene for oral leukoplakia have been published, but only 2 were randomized. 36 …”

Section: Carotenoidsmentioning

confidence: 99%

Chemoprevention of Head and Neck Cancer

Armstrong

Meyskens

2000

Otolaryngol.--head neck surg.

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728Increasing emphasis has been placed on chemoprevention as understanding of the genetic and molecular events of carcinogenesis has evolved. More than 1000 compounds that inhibit cancer development in vitro or in animal models have been identified, and active research is under way to determine which of these agents will be both effective and nontoxic in human beings. Currently, 13-cis-retinoic acid is the most studied chemopreventive agent against head and neck cancers. Unfortunately, this vitamin A derivative has significant clinical toxicity, which limits its utility in a practice setting. The efficacy of the retinoids, however, has stimulated efforts to find other chemopreventive compounds that are both effective and nontoxic. This review discusses head and neck premalignancy, chemoprevention strategies, retinoids, and several other classes of chemopreventive agents with potential efficacy against head and neck premalignancy.

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Remission of oral leukoplakias and micronuclei in tobacco/betel quid chewers treated with beta‐carotene and with beta‐carotene plus vitamin A

Cited by 246 publications

References 24 publications

Beta-carotene supplementation in smokers reduces the frequency of micronuclei in sputum

Beta-carotene supplementation in smokers reduces the frequency of micronuclei in sputum

Role of Measurement of Antioxidant Enzymes in Evaluation of Antioxidant Therapy in Tobacco Abusers with Oral Leukoplakia

Chemoprevention of Head and Neck Cancer

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