Proton radiation therapy for primary sphenoid sinus malignancies: treatment outcome and prognostic factors.

Background. The purpose of this study was to determine treatment outcome and prognostic factors in patients with locally advanced primary sphenoid sinus malignancy treated with proton radiation therapy. Methods. Between 1991 and 2005, 20 patients with primary sphenoid sinus malignancy received proton beam to a median dose of 76 Gray equivalent. Results. With a median follow-up of 27 months, the 2-year local, regional, and freedom from distant metastasis rates were 86%, 86%, and 50%, respectively. The disease-free and overall-survival rates at 2 years were 31% and 53%, respectively. In multivariate analysis, oropharyngeal involvement (p=.005) and anterior cranial fossa invasion (p=.02) were predictive for poor disease-free survival rate. Brain invasion was predictive for decreased overall-survival rate (p=.05). Conclusions. Proton radiation therapy results in excellent local control in patients with advanced primary sphenoid sinus malignancy. Brain invasion, involvement of the oropharynx and anterior cranial fossa are important prognostic factors. (C) 2009 Wiley Periodicals, Inc. Head Neck 31: 1297-1308, 2009