A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial of Retinol Palmitate (Vitamin A) for Symptomatic Chronic Radiation Proctopathy

Abstract

This study was designed to determine whether oral retinol palmitate (vitamin A) can reduce the symptoms of radiation proctopathy. A randomized, double-blind trial comparing retinol palmitate (10,000 IU by mouth for 90 days) to placebo was conducted. Eligible patients were more than six months postpelvic radiotherapy and had significant symptoms as measured with the Radiation Proctopathy System Assessments Scale. Nineteen patients were randomized in total: ten to retinol palmitate and nine to placebo. The Radiation Proctopathy System Assessments Scale scores before and every 30 days for 90 days were measured. Five placebo nonresponders were crossed over to the retinol palmitate for another 90 days. Response was defined as a reduction in two or more symptoms by at least two Radiation Proctopathy System Assessments Scale points. Seven of ten retinol palmitate patients responded, whereas two of nine responded to placebo (P = 0.057). Mean pre-post-treatment change in Radiation Proctopathy System Assessments Scale (delta Radiation Proctopathy System Assessments Scale) in the retinol palmitate group was 11 +/- 5, whereas delta Radiation Proctopathy System Assessments Scale in the placebo group was 2.5 +/- 3.6 (P = 0.013, Mann-Whitney U test). Additionally, all five placebo nonresponders who were crossed over to treatment with retinal palmitate responded to treatment. In our trial, retinol palmitate significantly reduced rectal symptoms of radiation proctopathy, perhaps because of wound-healing effects. The current results can serve as the foundation for future trials examining retinol palmitate in the multi-institutional setting.