Selective partial salivary glands sparing during intensity-modulated radiation therapy for nasopharyngeal carcinoma*

Radiotherapy is one of the main treatments for head and neck cancers, especially nasopharyngeal cancer. During radiotherapy, the salivary glands, parts of which are commonly included in or very close to the target volume, receive a high radiation dose on both sides, which can lead to xerostomia (dry mouth). Xerostomia can produce a number of negative effects on the patient’s quality of life, affecting dietary habits, speech, taste, and increasing the risk of oral infections [1]. Intensitymodulated radiotherapy (IMRT) has now become the standard modality of radiotherapy for nasopharyngeal cancer, which may reduce xerostomia by delivering tumoricidal doses to the target volume while sparing normal structures at the same time; however, severe xerostomia is still experienced by many patients (39.3%) after IMRT [2]. Currently, the management of irradiation-induced xerostomia remains largely limited to palliative therapy. Sparing damage to the salivary glands during radiotherapy may be the key to preventing radiationinduced xerostomia. The salivary glands include three pairs of major salivary glands: the parotid, Selective partial salivary glands sparing during intensity-modulated radiation therapy for nasopharyngeal carcinoma*