Serum tissue polypeptide antigen (TPA): a marker of acute injury of salivary glands during radiation therapy.

The modifications of serum concentrations of TPA were monitored in patients undergoing curative radiation therapy. Patients with tumors localized in the head and neck were treated with one of four different schedules based on conventional fractionation or multiple daily fractionation where the dose per fraction and total daily dose varied. Serum TPA increased immediately on the first day of irradiation: the higher the dose, the greater the increase. These increases disappeared rapidly after the first few days of treatment. A more limited rise was observed in some cases when treatment was renewed after the first week-end split or after more prolonged interruptions. Results demonstrated that TPA is a valid biochemical marker of acute radiation injury to the salivary tissue.