Functional Sparing of Salivary Glands Using MRI Sialography for Patients Undergoing Definitive Radiation Therapy for Head and Neck Cancers of the Oropharynx

The proposed study is an attempt to improve patient xerostomia (dry mouth) after definitive radiation therapy treatment for head and neck cancer. Xerostomia is a frequently experienced symptom for those receiving radiation therapies to the head and neck that persists after treatment, potentially indefinitely. It has been shown that stem/progenitor cells preferentially reside in large ducts of salivary glands and that these cells have the ability to repair radiation induced salivary damage. Current practice does not specifically attempt to spare these regions and considers the entire salivary gland to have equal importance and function. This study will involve the acquisition of pre-treatment MRI sialogram images which enable visualization of salivary ducts (using saliva itself as a contrast agent) that can then be avoided during radiation treatment planning. Saliva samples will also be collected at this time to quantify baseline saliva secretion and saliva characteristics. The primary objective will be to obtain patient reported outcomes (PRO) measure of xerostomia related symptoms for comparison with a historical cohort. Xerostomia symptom information will be obtained by use of a patient reported quality of life survey administered prior to treatment and at 6, 12, 18, and 24 months after treatment. The secondary objectives will be to quantitatively assess post-treatment changes in saliva secretion, salivary gland volume, and ductal visibility using MRI sialograms. The target sample size for this study is 40 patients. The investigator hypothesizes that reducing the dose to these stem cell containing salivary ducts will facilitate improvements in patient reported symptoms as well as improved recovery of salivary secretion, salivary gland volume, and intra-glandular ductal visibility using MRI sialograms.