Outcomes of Nasal Cavity and Paranasal Sinus Cancers Treated With Proton Therapy

Abstract

Sixty-eight patients with cancers of the nasal cavity and paranasal sinuses have completed treatment with proton therapy since January of 2007. The disease characteristics, treatment planning and delivery techniques, and follow-up results of 49 patients who have completed treatment more than 1 year ago are presented. Of 49 patients, 43 had prior surgery, 23 with close/positive margins. Six patients had biopsy only. Skull-base invasion was noted in 34 of 49 patients, (69%). Ages ranged from 16 to 82 years with a median of 58 years. Histology included sino-nasal undifferentiated carcinoma, adenoid cystic carcinoma, esthesioneuroblastoma, mucosal melanoma, spindle-cell carcinoma and osteogenic sarcoma. Prescribed doses ranged from 64.8 GyE to 69.6 GyE for post-op negative margins, to 74.4 GyE for presence of positive margins or presence of gross unresectable tumor at 1.2 GyE twice-a-day. Proton treatments were delivered with orthogonal kV x-ray imaging guidance to achieve 1 mm setup accuracy for each fraction. All patients completed their prescribed treatment. Follow-ups ranged from 0.4 to 4.1 years (median 2 years). Brisk skin reactions developed in all patients, and resolved within 4 weeks after completion. Medial retinopathy occurred within the treated volume in 1 patient at 11 months after completion without negative impact on vision. Complete local disease control was noted in 43 of 49 patients (88%). In-field recurrence was noted in 2 post-operative patients at 9 and 12 months; one of them is free of disease after surgical salvage. Progressive meningeal seeding was identified in 1 patient within 2 months after radiation and was salvaged by additional therapy. Six patients who at initial diagnosis were inoperable and received 74.4 GyE had varying local response, succumbed to disease progression in 6 months to 20 months. Five patients who received post-operative proton radiation died of distant metastasis between 12 and 15 months without any evidence of local recurrence. The overall survival at 1- and 2-years was 94% and 73% respectively. Patients with cancers involving the nasal cavity and paranasal sinuses with skull base invasion will benefit from high-dose conformal proton therapy.