Based on a clinical trial, in which patients with unresectable bronchogenic cancer were treated with a combination of vitamin A plus chemotherapy, or vitamin A plus radiotherapy, a study was initiated in which vitamin A alone was given for tumor treatment. 9 male patients with metastatic unresectable squamous cell carcinoma of the lung were treated with vitamin A palmitate or 13-cis vitamin A acid. Up to seven treatment courses were given during a period of 60 weeks. Through weekly evaluation of the patients’ immune status, an immune potentiating effect of the vitamin A therapy could be demonstrated. An increase of lymphocyte blastogenesis response to PHA which is significant (p < 0.001) compared with the pretreatment values, was found in all patients at the end of one vitamin A treatment course. Increased delayed cutaneous hypersensitivity reactions were observed also in all patients. The immune potentiating effects of vitamin A therapy, as well as the demonstrated direct effect on the tumor, introduces a wide range of combination therapies.
Carcinogenesis and death caused by diethylnitrosamine(DENA)-induced hepatomas in Sprague Dawley rats can be significantly delayed by feeding only carrots for several days a week. As this result is not obtained by supplementing food with even higher concentrations of synthetic β-carotene, there must be several other factors which together with the carotenoid – contribute to the positive effect. Several other possibilities such as effects of fasting, direct interactions with the carcinogen, resorption, vitamin A storage in the liver, etc., are proposed and discussed.
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