A Multicenter Study of Carbon Ion Radiotherapy for Head and Neck Adenocarcinoma
Menée au Japon à partir de données portant sur 47 patients atteints d'un adénocarcinome de la tête et du cou de stade T2-4 N0-1M0 et traités entre 2003 et 2014 (âge médian : 60 ans ; 30 hommes et 17 femmes ; durée médiane de suivi : 51 mois), cette étude évalue l'efficacité, du point de vue du contrôle local de la maladie et de la survie globale à 2 et 5 ans, et la sécurité d'une radiothérapie par ions carbone
Background : Head and neck (HN) adenocarcinoma is rare, and to date, there are no reports of prospective studies. We retrospectively evaluated the efficacy and safety of carbon ion radiotherapy (C-ion RT) for HN adenocarcinoma in institutions in Japan. Methods : HN adenocarcinoma patients with N0-1M0 disease who were treated with C-ion RT at institutions in Japan between November 2003 and December 2014 were analyzed retrospectively. Forty-seven patients (male, n = 30; female, n = 17; median age, 60) with HN adenocarcinoma were enrolled. Results : Primary sites included the nasal and paranasal sinus in 21 patients, orbit in 11, salivary grand in 7, oral cavity and pharynx in 6, and acoustic organ in 2. Thirty-two patients had T4, 6 had T3, and 6 had T2 tumors. Forty-five patients were diagnosed with N0, and two with N1. The median total dose of C-ion RT and the number of fractions were 64.0 Gy (relative biological effectiveness) and 16 fractions, respectively. The median follow-up was 51 months (range, 6–118 months). The 2- and 5-year overall survival rates were 87.9% and 60.4%, and the 2- and 5-year local control rates were 83.3% and 79.3%, respectively. Multivariate analysis showed that operability (operable patients) (p = 0.045), and fractionation (16 fractions) (p = 0.010) were significant independent prognostic factors for better overall survival. Grade 5 late morbidities were not at all observed. Grade 4 late morbidities were observed in four patients, and all of these grade 4 morbidities were visual impairments. All four patients with grade 4 visual impairment had T4 tumors in the nasopharynx or paranasal sinuses, which implied inoperable tumors with orbital or brain invasion. Conclusion : C-ion RT resulted in an excellent local control, and. C-ion RT could become a curative treatment option for HN adenocarcinoma with acceptable toxicities.