Carbon Ion Radiotherapy For Adenoid Cystic Carcinoma of The Head-and-Neck

Purpose/Objective(s): To estimate the toxicity and efficacy of carbon ion radiotherapy for adenoid cystic carcinoma of the head-and-neck.Material/Methods: Between April 1997 and February 2010, a total of 134 patients with adenoid cystic carcinoma of the head-and-neck were treated with carbon ion radiotherapy with a phase II clinical trial. All of these patients had neither regional lymph node nor distant metastasis before radiotherapy. The prescribed tumor doses were 57.6 or 64.0 GyE in 16 fractions over four weeks. All patients provided written informed consent before enrollment in this study. The National Institute of Radiological Sciences Ethical Committee on Human Clinical Research has approved this study.Results: The patients consisted of 55 males and 79 females aged from 21 to 80 years with an average age of 53 years. The most frequent primary site was the nasal and parenasal sinus. One hundred eight of 134 patients with unresectable tumors or with recurrence and residual tumors after other treatment were permitted to partake in the carbon ion radiotherapy. The clinical target volume ranged from 18.8 to 529.9 ml, with an average of 179.5 ml. Median follow-up time was 42.5 months (range, 8.1-123 months). Although acute grade 3 mucosal reaction appeared in 32 patients (24%), almost all of the late skin and mucosal reactions were grade 1 or less. A late grade 2 brain reaction was detected in 9 patients (9%), which necessitated steroid administration. At the time of analysis, there was no evidence of any unexpected severe toxicity to the critical organs. The 5-year local control and overall survival rates of all patients were 80% and 70%, respectively. As for the T stage studied, the 5-year local control rates were 96% for stage from T1 to T3 and 78% for T4 or recurrence and residual tumors after other treatment. The 5-year overall survival rates were 91% and 67%, respectively. There was no significant difference in outcome between the two groups.Conclusion: Our results showed acceptable toxicities and excellent therapeutic effectiveness for adenoid cystic carcinomas.ASTRO 53rd Annual Meetin