Radiation-Induced Parotitis

Epidemiology

Radiation therapy is frequently used for the treatment of head and neck cancers. Irradiating the parotid glands produces a spectrum of findings ranging from transient to permanent changes. Transient parotid swelling and pain may be seen in 5% of patients after the first few treatments. Acute radiation-induced parotitis is a rare clinical entity and appears during the course of radiation therapy. Almost all patients have subchronic or chronic changes after the delivery of 3500 cGy. In addition, there is a higher risk of ascending bacterial infection because of xerostomia.

Clinical Findings

Acute radiation-induced parotitis presents with gross facial swelling and pain. Xerostomia and increased risk of dental or salivary gland infection characterize chronic changes in the parotid glands.

Pathology

The pathogenesis and morphology of acute parotitis are poorly understood because biopsies are not obtained for obvious reasons. Radiation damages the glandular DNA and endothelial cells of the salivary glands. These damaged cells fail to replicate resulting in glandular fibrosis and subsequent atrophy.

Treatment