Ototoxicity and cochlear sparing in children with medulloblastoma: Proton vs. photon radiotherapy.

Abstract

To compare ototoxicity rates between medulloblastoma patients treated with protons vs. photons. The study included 84 children diagnosed with medulloblastoma treated with either passively scattered protons (n = 38) or photons (n = 46). Patients underwent maximal safe resection followed by craniospinal irradiation, posterior fossa and/or tumor bed boost and chemotherapy according to one of 3 multi-institutional trials. Median audiogram follow-up was 56 months for protons and 66 months for photons. Mean cochlear dose (D_mc) was lower in patients treated with protons for both standard (p < 0.0001) and high-risk disease (p < 0.001). Grade 3 and 4 ototoxicity was seen in 7 of 75 (9.3%) and 9 of 91 (9.9%) ears (Brock, p = 0.91), 13 of 75 (17.3%) and 19 of 91 (20.9%) ears (POG, p = 0.56), and 15 of 75 (20.0%) and 21 of 91 (23.1%) ears (SIOP Boston, p = 0.63) with protons and photons respectively. While cochlear doses were lower in the proton group, patients treated with either protons or photons had similar Grade 3 and 4 ototoxicity rates.