Cochlea sparing optimized radiotherapy for nasopharyngeal carcinoma

Abstract Background Definitive chemoradiotherapy (CRT) is standard of care for nasopharyngeal carcinoma. Due to the tumor localization and concomitant platinum-based chemotherapy, hearing impairment a frequent complication, without defined dose-threshold. In this study, we aimed achieve maximum possible cochleae sparing. Materials methods Treatment plans 20 patients, treated with CRT (6 IMRT 14 VMAT) based on QUANTEC organs-at-risk constraints were investigated. The re-delineated independently by two radiation oncologists, whereas target volumes other organs at risk (OARs) not changed. initial plans, aiming mean cochlea dose < 45 Gy, re-optimized VMAT, using 2–2.5 arcs compromising coverage volume. Mean dose, PTV coverage, Homogeneity Index, Conformity Index OAR compared reference plans. Wilcoxon signed-rank test was used evaluate differences, p value 0.05 considered significant. Results achieved statistically significant lower both (median left right 14.97 Gy 18.47 vs. 24.09 26.05 respectively, 0.001) plan quality parameters. median NTCP tinnitus most exposed sites 11.3% (range 3.52–91.1%) original 4.60% 1.46–90.1%) ( 0.001). For loss, could be improved from 0.03% 0–99.0%) 0.00% 0–98.5%, Conclusions A significantly sparing beyond current feasible in carcinoma patients VMAT. As there appears no threshold toxicity after CRT, should future treatment planning.