INFLUENCE OF PLASMA GSH LEVEL ON ACUTE RADIATION MUCOSITIS OF THE ORAL CAVITY

Purpose: To see how pretreatment plasma GSH level influences the sever ity of acute radiation mucositis of the oral cavity during therapeutic irradiation in patients with oral cancer. Methods and Materials: Thir teen patients with squamous cell carcinoma of the oral cavity form the subject material. Radical radiotherapy (60 Gy in 25 fractions over 5 weeks) was given using telecobalt. Pretreatment plasma GSH level was m easured by Beutler's method. The normal tissue reaction during radioth erapy was monitored and graded. Results: The GSH levels ranged from 10 .6-90.5 mu M/L (mean 30.6 mu M/L). Those who had higher GSH levels dev eloped less severe mucositis. The mean GSH levels in the groups with d ifferent severity fo reactions were: Grade 2 (four patients) = 50.7 mu M/L; Grade 3 (five patients) = 26.1 mu M/L; Grade 4 (two patients) = 20.4 mu M/L and Grade 5 (two patients) = 26.1 mu M/L; Grade 4 (two pat ients) = 20.4 mu M/L and Grade 5 (two patients) = 13.6 mu M/L. Conclus ion: Plasma GSH estimation has the potential to predict individual sen sitivity to acute radiation mucositis and may particularly be useful i n hyperfractionated regimes. The study also affirms the radioprotectiv e role of GSH and suggest that this effect is either due to protection against membrane lipid peroxidation (since GSH does not enter the cel l freely) or DNA damage (fractionated radiotherapy may permit freer en try of GSH into cell).