Changes in the protein composition of whole saliva during radiotherapy in patients with oral or pharyngeal cancer.

We analyzed the radiation-induced changes in the flow rate and protein composition of stimulated whole saliva in eleven patients treated for malignant conditions of the head and neck. In all patients the radiation field covered all major salivary glands and a large area of the oral mucosa. Paraffin-stimulated whole saliva samples were collected once 2 to 21 days before therapy and then after 20, 40, and 60 gray (Gy) cumulative dose of irradiation. Five patients also provided samples 6 months after the therapy. Hyposalivation or xerostomia occurred in all patients, although the pretreatment secretion rates were already relatively low. Salivary amylase activities decreased with increasing dose of radiation, especially when expressed as the amount of enzyme secreted per minute. Unusually high salivary concentrations of albumin, lactoferrin, lysozyme, salivary peroxidase, myeloperoxidase, and total protein were observed during the therapy, but most values slowly returned to pretreatment levels after cessation of radiation. It is concluded that the observed qualitative changes in whole saliva components are net effects caused by the cancer itself, radiation therapy given, systemic diseases, or medications, as well as mucosal inflammations.