Ototoxicity of cisplatin plus standard radiation therapy vs. accelerated radiation therapy in glioblastoma patients

Purpose : To assess the effect of cisplatin (CDDP) plus concurrent radiation therapy on hearing loss. Methods : 451 patients with glioblastoma multiforme (GBM) were randomly assigned after surgery to: Arm A: Carmustine (BCNU) + standard radiation therapy (SRT); Arm B: BCNU + accelerated radiation therapy (ART: 160 cGy twice daily for 15 days); Arm C: CDDP + BCNU + SRT; or Arm D: CDDP + BCNU + ART. Patients on arms C and D received audiograms at baseline, and prior to the start of RT, and prior to cycles 3 and 6. Otologic toxicities were recorded at each visit. Results : 56% of patients had hearing loss at baseline. 13% and 50% of patients experienced worsening ototoxicity after 1 year of treatment in arms A and B vs. C and D, respectively, with 13% of those on arms C and D experiencing significant ototoxicity (≥ grade 3) at 6 months. Increasing age was associated with an increased risk of ototoxicity. Conclusions : Increased exposure to CDDP increases the risk of ototoxicity over time. Older patients are more susceptible to hearing loss with CDDP. The low proportion of patients with clinically significant ototoxicity suggests that baseline screening is unnecessary in GBM patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43476/1/11060_2005_Article_9049.pd

Ototoxic Effects of Irradiation

In this study ototoxic effect of ionizing radiation was studied in 70 ears with minimum follow up of 6 months post radiotherapy. Patients of nasopharyngeal carcinoma and with conductive deafness pre radiotherapy were excluded from the study to eliminate mechanical obstruction that may play role in Eustachian tube dysfunction. We found that Eustachian tube dysfunction and conductive deafness were reversible where as Sensorineural hearing loss was an irreversible effect of radiotherapy. Dose of radiation was directly proportional to ototoxicity, minimum 60 Gys of total radiation dose was required to produce significant ototoxicity