Safety of High-Dose Vitamin A

The study from 1991 evaluated the safety and efficacy of high-dose vitamin A as an adjuvant treatment for stage I lung cancer in 283 patients, with 138 receiving retinol palmitate (300,000 IU daily for at least 12 months) and 145 under standard observation. After 28 months, the treatment was considered safe and well-tolerated, justifying the continuation of the study. The most common side effects were skin dryness and desquamation in 60% of treated patients, while less than 10% experienced dyspepsia, headache, nosebleeds, and mild hair loss, which were self-terminating. Treatment was discontinued in only 4 patients (3%) due to symptoms potentially related to vitamin A. Laboratory tests showed elevated gamma-GT levels in 69% of treated patients and higher serum triglyceride concentrations in 74% compared to controls, with no other signs of toxicity. The long-term effects on lipid metabolism were still undetermined.