Neutron Beam Radiation Therapy: An Overview of Treatment and Oral Complications When Treating Salivary Gland Malignancies

PurposeThere is limited information in the literature regarding the oral complications of neutron radiotherapy, with an associated lack of guidelines for their management. The purpose of this study was to review the indications, dosing, prognosis, and oral complications of neutron radiotherapy for salivary gland malignancies.Materials and MethodsThis is a retrospective case series of patients with salivary gland malignancies treated with neutron radiotherapy by the Radiation Oncology Department at the University of Washington from 1997 to 2006. Variables included patient demographics, tumor staging and characteristics, operative treatment, final diagnosis, operative and pathologic findings (ie, perineural invasion, lymph node involvement, and skull base invasion), dosing, complications, and locoregional control and survival rates. Data were extracted from patients' charts and by telephone for follow-up and quality-of-life information.ResultsThe sample was composed of 140 patients (49% men, 51% women) with a mean age of 53 years (standard deviation, 15 yr). Adenoid cystic carcinoma of the submandibular gland was the most common tumor type and location. Post-treatment trismus occurred in 56%. Acute mucositis and xerostomia occurred in approximately 88 and 89% of patients, respectively. Osteoradionecrosis was reported in 5.7% of patients. The 6-year survival rate was 58% and the 6-year locoregional control was 72%. The current standard neutron dose for head and neck tumors is 1.15 neutron Gray (nGy) 4 times per week for 4 weeks (total, 18.4 nGy), which is an equivalent amount of radiation as the standard 60 to 70 Gy given for 6 to 7 weeks with conventional photon radiation.ConclusionThe 6-year overall survival of 58% found in this study compares favorably to the survival rate reported in the literature for traditional photon radiation treatment of advanced salivary gland tumors. The dental profession should be educated regarding neutron radiotherapy and its indications, dosing methods, and oral complications.