Long-term Outcomes after Proton Beam Therapy for Sinonasal Squamous Cell Carcinoma
Menée sur 54 patients atteints d'un carcinome épidermoïde de la cavité nasale ou des sinus paranasaux et traités entre 1991 et 2008 (durée médiane de suivi : 82 mois), cette étude évalue l'efficacité, du point de vue du taux actuariel de contrôle local et du taux de survie globale à 2 et 5 ans, et la toxicité d'une protonthérapie en fonction du statut tabagique et des performances physiques des patients
Purpose : Squamous cell carcinoma (SCC) is the most common sinonasal cancer and is associated with one of the worse outcomes. Proton therapy allows excellent target coverage with maximal sparing of adjacent normal tissues. We evaluated long-term outcomes of patients with sinonasal SCC treated with proton therapy. Methods and Materials : Between 1991 and 2008, 54 patients with SCC of the nasal cavity and paranasal sinus received proton beam therapy at our institution to a median dose of 72.8 Gy (RBE). Sixty-nine percent underwent prior surgical resection and 74% received elective nodal radiation. Locoregional control and survival probabilities were estimated with the Kaplan-Meier method. Tumor control and survival probabilities were compared in univariate analyses and multivariate analyses using the Cox proportional-hazards model. Treatment toxicity was scored using the Common Terminology Criteria for Adverse Events version 4.0 Results : With a median follow up of 82 months in surviving patients, there were 10 local, 7 regional, and 11 distant failures. The 2- and 5-year actuarial local control rate was 80%. The 2- and 5-year overall survival was 67% and 47%, respectively. Only smoking status was predictive for worse locoregional (LRC) with current smokers having a 5-year rate of 23% compared to 83% for non-current smokers in (p=0.004). Karnofsky performance status ≤ 80 was the most significant factor predictive for worse overall survival (OS) in multivariate analysis (adjusted hazard ratio 4.5, 95% CI 1.6 – 12.5, p=0.004). There were 9 grade 3, 6 grade 4, and no grade 5 toxicity. Wound complication was the most common grade 3-4 toxicity. Conclusions : Our long-term results show proton radiotherapy is well-tolerated and yields good locoregional for SCC of the nasal cavity and paranasal sinus. Current smokers and patients with poor performance status were associated with inferior outcomes. Prospective study is necessary to compare IMRT with proton in the treatment of sinonasal malignancy.