Positive Health Online

Abstract

SANKARANARAYANAN and colleagues, Unit of Descriptive Epidemiology, International Agency for Research on Cancer, Lyon France conducted a double-blind placebo-controlled trial to study the chemopreventive potential of vitamin A alone or beta carotene alone in people from Kerala India suffering from oral leukoplakia.

Background

Methodology

160 fishermen and women with oral precancerous lesions were randomised to receive either oral vitamin A (300,000 IU/week for 12 months, n = 50) or beta carotene (360 mg/week for 12 months, n = 55) or placebo. Samples of blood, saliva and urine were collected at baseline and the study conclusion for serum micronutrients and mutagenicity assays. Biopsies of mucosal lesions were performed at entry for the exclusion of malignancy. the participants were examined every 2 months to determine clinical response of lesions and toxicity, if any.

Results

There were 43 placebo, 42 vitamin A and 46 beta carotene participants. The complete regression rates were: 52% with vitamin A, 33% with beta carotene and 10% in the placebo group . Homogeneous leukoplakias and smaller lesions responded better than non-homogeneous and larger lesions. There were no major toxicities observed. Half the beta carotene and two thirds of the vitamin A responders relapsed following ceasing supplementation. Serum beta carotene concentration increased substantially following beta carotene administration however there was no change in serum retinol levels with vitamin A supplementation. In the vitamin A treated group there was a significant decrease in serum vitamin E.

Conclusion

Vitamin A administration resulted in a significant remission of oral leukoplakia without any side effects of prolonged vitamin A supplementation. These results, along with those of previous studies, provide strong supporting evidence to justify long term trials with vitamin A for people with high-risk leukoplakias using oral cancer as an endpoint .

References

Sankaranarayanan R et al. Chemoprevention of oral leukoplakia with vitamin A and beta carotene: an assessment. Oral Oncol 33(4): 231-6. July 1997 .