Outcome of T4 (International Union Against Cancer Staging System, 7th edition) or Recurrent Nasal Cavity and Paranasal Sinus Carcinoma Treated With Proton Beam

Abstract

To investigate the clinical features, prognostic factors, and toxicity of treatment for unresectable carcinomas of the nasal cavity and paranasal sinus (NCPS) treated with proton beam therapy (PBT). Seventeen patients (13 men, 4 women) with unresectable carcinomas of the NCPS who underwent PBT at the University of Tsukuba between 2001 and 2007 were analyzed. The patients' median age was 62 years (range, 30-83 years). The tumors were located in the nasal cavity in 3 patients, the frontal sinus in 1, the ethmoid sinus in 9, and the maxillary sinus in 4. The clinical stage was Stage IVA in 5 cases, IVB in 10, and recurrent in 2. The tumors were deemed unresectable for medical reasons in 16 patients and because of refusal at a previous hospital 4 months earlier in 1 patient. All the patients received PBT irradiation dose of 22-82.5 GyE and a total of 72.4-89.6 GyE over 30-64 fractions (median 78 GyE over 36 fractions) with X-ray, with attention not exceeding the delivery of 50 GyE to the optic chiasm and brainstem. The overall survival rate was 47.1% at 2 years and 15.7% at 5 years, and the local control rate was 35.0% at 2 years and 17.5% at 5 years. Invasion of the frontal or sphenoid sinus was a prognostic factor for overall survival or local control. Late toxicity of more than Grade 3 was found in 2 patients (brain necrosis in 1 and ipsilateral blindness in 1); however, no mortal adverse effects were observed. Proton beam therapy enabled a reduced irradiation dose to the optic chiasm and brainstem, enabling the safe treatment of unresectable carcinomas in the NCPS. Superior or posterior extension of the tumor influenced patient outcome.