[Boost in proton for locally advanced nasopharyngeal carcinoma: A Curie Institute experience].

Purpose: The aim of this study was to assess the treatment outcome and toxicity for patients with locally advanced nasopharyngeal carcinoma treated with a complementary dose with proton.

Patients And Methods: Between November 1999 and September 2016, 17 patients have been treated for a stage III-IVa nasopharyngeal carcinoma in the proton therapy centre of Curie Institute. Bilateral lymph node in the neck (I-V levels) received from 40 to 54Gy with photon beam. The primary tumor volume including microscopically extensions received a complementary dose with proton in order to reach the dose of 70 to 78Gy. All the patients received a concomitant chemotherapy. The end-points of the study were loco-regional control, survival, and treatment-related toxicity.

Results: Patients characteristics were: median age 49, 71 % male, 88% stage IVa, with a majority (82%) of T4N0M0. The median follow-up was 99 months. The 2-, 5- and 10-year actuarial locoregional free survival and overall survival were 94% and 88%, 86% and 74%, and 86% and 66%, respectively. The grade≥3 late adverse events were sphenoid bone radionecrosis (5.9%) and hearing loss (23.5%).

Conclusion: This study showed that a complementary dose with proton seems to be a good option for the treatment of locally advanced nasopharyngeal carcinoma, particularly for T4N0M0.