Effect of neutron and photon therapies on the activity of proteolytic salivary enzymes for head and neck cancer patients

Activity of salivary enzymes was studied for patients with oral cavity and salivary gland cancers who underwent radiation therapy. Out of the 18 patients included into the study, there were 5 patients who received 4,2-7,2 Gy neutron therapy (isoeffect dose 18-38 Gy) and 13 patients who received 40-44 Gy conventional external beam radiation therapy. The control group consisted of 10 healthy subjects. Activities of callicrein (CC) callicreinogen (CG), α-proteinase inhibitor and acid-stable inhibitor were determined in patients saliva. A significant increase in salivary enzymatic activity was observed in patients who underwent neutron therapy as compared to the control group. Neutron therapy produced more significant dosedependent decrease in callicrein and callicreinogen activities and increase in α-proteinase inhibitor activity as compared to external beam radiation therapy. Decrease in callicrein activity up to 50 mU/ml and less was associated with high risk for development of radiation-induced damages for oral cavity mucosa and salivary glands allowing radiation therapy correction.