Postoperative intensity-modulated radiotherapy in sinonasal carcinoma: clinical results in 39 patients

Abstract

Background: Carcinoma of the paranasal sinuses is rare. Standard therapeutic modalities consist of surgery and radiotherapy (RT). Because of the often advanced stage and the vicinity of optic structures, RT-induced ocular toxicity is a feared side effect of conventional RT. Intensity-modulated radiotherapy (IMRT) is a relatively new technique, which is implemented with the hypothesis that, compared with conventional RT, it would result in a lower rate of ocular toxicity for an equal local control (LC).

Methods: Between 1998 and 2003, 39 consecutive patients received postoperative irradiation by means of IMRT for an adenocarcinoma (n = 31) or squamous cell carcinoma (n = 8) of the paranasal sinuses (n = 36) or nasal cavity (n = 3). T-classification was T2 in 41%, T3 in 15%, T4a in 23%, and T4b in 21% of patients. Invasion through the cribriform plate was seen in 11 patients. Orbital invasion was present in 36% of patients. The median delivered dose was 70 gray (Gy) (range, 60-70 Gy). The authors compared the overall survival (OS) and LC of the patients with a historic cohort (HC) (n = 30), treated with conventional or 3-dimensional conformal RT.

Results: The median follow-up was 31 months. The actuarial OS rates were 68% at 2 years and 59% at 4 years. The actuarial LC rates were 73% at 2 years and 68% at 4 years. Invasion through the cribriform plate was a significant prognostic factor for LC and OS, with a median time to local disease recurrence of 7 months if present, and a 2-year LC rate of 90% if not present. In the comparison between the IMRT and HC groups, no significant differences were found for LC and OS. Acute toxicity was mild. Two patients developed decreased vision after RT. No RT-induced blindness was observed.

Conclusions: Postoperative IMRT for sinonasal carcinoma resulted in good LC, with a low acute toxicity and no RT-induced blindness.