Feasibility of carbon ion radiotherapy for locally advanced sinonasal adenocarcinoma

BACKGROUND AND PURPOSE: \nTo evaluate the safety and efficacy of carbon ion radiotherapy (CIRT) for locally advanced sinonasal adenocarcinoma. \nMATERIAL AND METHODS: \nTwenty-two patients with sinonasal adenocarcinoma were treated with CIRT. CIRT was the primary treatment for 16 patients. Four patients received CIRT for local recurrence after surgery and two for residual tumour after surgery or chemotherapy. At the start of CIRT, 1 patient had T-classification (T) 2 disease, 2 had T3 disease, 5 had T4a disease, and 14 had T4b disease. Fourteen patients were treated with 57.6Gy equivalent (GyE)/16 fractions, and 8, with 64.0GyE/16 fractions. \nRESULTS: \nThe median follow-up period was 43months for all patients. The 3-year local control and loco-regional control rates for all patients were 76.9% (95% confidence interval [CI]=56.7-97.1%) and 61.3% (95% CI=38.5-84.1%), respectively. The 3-year overall survival and disease-specific survival rates were 59.1% (95% CI=38.6-79.6%) and 65.6% (95% CI=44.9-86.3%), respectively. Acute reactions of grade 3 of the skin and mucosa were observed in 2 and 4 patients, respectively. Late reactions included lateral visual loss (5 patients), mucosal ulceration (1 patient), and brain necrosis with clinical symptoms (1 patient). In the 5 patients who developed visual loss, the optic nerve was close to the tumour. \nCONCLUSIONS: \nCIRT was effective and generally safe for locally advanced sinonasal adenocarcinoma.