Estimation of long-term salivary gland damage induced by radiotherapy.

A classification is proposed for estimating salivary gland damage induced by radiotherapy to the head and neck. The volume of salivary glands irradiated was evaluated, and their relative proportions of whole saliva output were calculated. Stimulated salivary flow rate was measured in 61 patients treated with radiotherapy for head and neck malignancies. A highly significant negative correlation was found between the classification of salivary gland damage and stimulated salivary flow rate. The volume of the major salivary glands irradiated seems to be the most important factor affecting the postirradiation salivary flow after a curative dose of radiotherapy. If possible, partial sparing of the salivary glands may help to keep the patient's salivary secretion at an acceptable level and promote protection against dental caries. Most patients irradiated to the head and neck, however, need an effective prophylactic programme for the rest of their lives in order to preserve their teeth.