FACTORS AFFECTING PLASMA RETINOL DECLINE DURING LONG-TERM ADMINISTRATION OF THE SYNTHETIC RETINOID FENRETINIDE IN BREAST-CANCER PATIENTS

Administration of the synthetic retinoid Fenretinide lowers circulatin g retinol and may thus affect night vision. We have recently shown tha t plasma retinol levels below 100 ng/ml are associated with moderate a lterations of the dark adaptometry test. To identify which patients ar e more likely to experience a decrease of plasma retinol under this th reshold, we measured plasma levels of retinol, Fenretinide, and its me tabolite 4-MPR in a cohort of 28 women receiving Fenretinide at the da ily dose of 200 mg and studied their relationship with clinical charac teristics such as age, menstrual status, body mass index, and time on treatment. Our results show that patients aged over 55 years with a hi gher percentage of adipose tissue had higher plasma concentrations of 4-MPR, which turned out to be the major determinant of the retinol dec rease. This subgroup may thus deserve careful ophthalmological surveil lance.