Effects of Radiotherapy on Human Parotid Saliva

Changes in parotid salivary function, as determined by flow rate and protein secretion, were measured in 31 cancer patients given radiotherapy to the head and neck. After the first week of treatment, a 50% decrease in salivary flow rate and a 60% decrease in protein secretion rate were observed. Salivary function remained at or below these levels during the next 3 weeks of treatment. Proteins in saliva were affected unequally, with the family of glycoproteins exhibiting greater sensitivity than amylase. Chromatography or irradiated (60 Gy) and unirradiated whole parotid saliva suggests that the observed alterations in salivary protein may be due to radiation effects on protein synthesis rather than on the proteins themselves.