Plasma retinoid levels in head and neck cancer patients: a comparison withhealthy controls and the effect of retinyl palmitate treatment

Vitamin A and related compounds, also known as retinoids are thought to pla y a role in the development of head and neck cancer. We measured levels of the major retinoids, retinol, all-trans retinoic acid, 13-cis retinoic acid and 13-cis-4-oxo retinoic acid in plasma of head and neck cancer patients in comparison with controls without cancer. No differences were found betwe en plasma levels of these retinoids between 25 head and neck cancer patient s and 21 controls. Mean baseline levels for the patients were 2458, 6.0, 6. 4 and 8.6 nM for retinol, all-trans retinoic acid, 13-cis retinoic acid and 13-cis-4-oxo retinoic acid, respectively. In addition, we selected 10 pati ents from the chemoprevention trial Euroscan and measured the effect on ret inoid levels of 300,000 I.U. daily retinyl palmitate intake during 1 month. Medication caused significant elevations in retinol levels (1.2 fold), all -tl ans retinoic acid (2.2 fold) and its metabolites 13-cis retinoic acid ( 5.8 fold) and 13-cis-4-oxo retinoic acid (8.9 fold). Because of its high in crease in levels, 13-cis-4-oxo retinoic acid seems a good candidate to serv e as a suitable marker to monitor patient compliance in future chemoprevent ion trials involving retinoids. No relations were found between the occurre nce of side-effects of retinyl palmitate and retinoid levels during treatme nt. However, the two patients who developed side-effects had the highest pr e-treatment levels of 13-cis retinoic acid and 13-cis-4-oxo retinoic acid, suggesting that retinoid toxicity is associated with relatively high basal retinoid metabolism. (C) 1998 Elsevier Science Ltd. All rights reserved.