Stich H F, Hornby A P, Mathew B, Sankaranarayanan R, Nair M K
Environmental Carcinogenesis Unit, British Columbia Cancer Research Centre, Vancouver, Canada.
Cancer Lett. 1988 May;40(1):93-101. doi: 10.1016/0304-3835(88)90266-2.
Tobacco/betel nut chewers (Kerala, India) with well-developed oral leukoplakias were chosen for a short-term intervention trial of vitamin A therapy. Participants were randomly distributed into two groups, one receiving 200,000 IU vitamin A per week (0.14 mg/kg body wt/per day) for 6 months, and the other receiving placebo capsules. Their cancer-causing habit, which can be quantitated (an average of 13.1 betel quids/day, 26.1 min/quid), did not change during the trial period. The 6-month oral administration of vitamin A caused complete remission in 57.1% of participants, and a total suppression of the development of new leukoplakias in all chewers receiving vitamin A (n = 21), as compared to 3% and 21%, respectively, in the placebo group (n = 33). The results were substantiated by examining the histological and cytological changes on small biopsies which were taken at the onset and at the completion of the trial period. Over the 6-month period of vitamin A administration, the number of layers of spinous cells decreased in 85% of the participants, the loss of polarity of basal cells was reduced from 72.2% to 22.2% of chewers, subepidermal lymphocytic infiltration was greatly diminished from 66.7% to 5.5% of chewers, and nuclei with condensed chromatin disappeared from the epidermal layer (72.2% before to 0% at the end of the trial).
来自印度喀拉拉邦、患有严重口腔白斑的烟草/槟榔咀嚼者被选入一项维生素A治疗的短期干预试验。参与者被随机分为两组，一组每周接受200,000国际单位维生素A（0.14毫克/千克体重/天），持续6个月，另一组接受安慰剂胶囊。他们致癌的习惯（平均每天咀嚼13.1个槟榔块，每次咀嚼26.1分钟）在试验期间没有改变。6个月的维生素A口服治疗使57.1%的参与者完全缓解，并且在所有接受维生素A的咀嚼者（n = 21）中完全抑制了新白斑的发展，相比之下，安慰剂组（n = 33）的这一比例分别为3%和21%。通过检查在试验开始和结束时采集的小活检组织的组织学和细胞学变化，证实了该结果。在维生素A给药的6个月期间，85%的参与者棘细胞层数减少，基底细胞极性丧失从72.2%的咀嚼者减少到22.2%，表皮下淋巴细胞浸润从66.7%的咀嚼者大幅减少到5.5%，并且表皮层中具有浓缩染色质的细胞核消失（试验开始前为72.2%，试验结束时为0%）。
