Influence of plasma GSH level on acute radiation mucositis of the oral cavity.

Abstract

To see how pretreatment plasma GSH level influences the severity of acute radiation mucositis of the oral cavity during therapeutic irradiation in patients with oral cancer. Thirteen 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 measured by Beutler's method. The normal tissue reaction during radiotherapy was monitored and graded. The GSH levels ranged from 10.6-90.5 microM/L (mean 30.6 microM/L). Those who had higher GSH levels developed less severe mucositis. The mean GSH levels in the groups with different severity of reactions were: Grade 2 (four patients) = 50.7 microM/L; Grade 3 (five patients) = 26.1 microM/L; Grade 4 (two patients) = 20.4 microM/L and Grade 5 (two patients) = 26.1 microM/L; Grade 4 (two patients) = 20.4 microM/L and Grade 5 (two patients) = 13.6 microM/L. Plasma GSH estimation has the potential to predict individual sensitivity to acute radiation mucositis and may particularly be useful in hyperfractionated regimes. The study also affirms the radioprotective role of GSH and suggests that this effect is either due to protection against membrane lipid peroxidation (since GSH does not enter the cell freely) or DNA damage (fractionated radiotherapy may permit freer entry of GSH into cell).