Ototoxicity evaluation in medulloblastoma patients treated with involved field boost using intensity-modulated radiation therapy (IMRT): a retrospective review

Background: Ototoxicity is a known side effect of combined radiation therapy and cisplatin chemotherapy for the treatment of medulloblastoma. the delivery of an involved field boost by intensity modulated radiation therapy (IMRT) may reduce the dose to the inner ear when compared with conventional radiotherapy. the dose of cisplatin may also affect the risk of ototoxicity. A retrospective study was performed to evaluate the impact of involved field boost using IMRT and cisplatin dose on the rate of ototoxicity.Methods: Data from 41 medulloblastoma patients treated with IMRT were collected. Overall and disease-free survival rates were calculated by Kaplan-Meier method Hearing function was graded according to toxicity criteria of Pediatric Oncology Group (POG). Doses to inner ear and total cisplatin dose were correlated with hearing function by univariate and multivariate data analysis.Results: After a mean follow-up of 44 months (range: 14 to 72 months), 37 patients remained alive, with two recurrences, both in spine with CSF involvement, resulting in a disease free-survival and overall survival of 85.2% and 90.2%, respectively. Seven patients (17%) experienced POG Grade 3 or 4 toxicity. Cisplatin dose was a significant factor for hearing loss in univariate analysis (p < 0.03). in multivariate analysis, median dose to inner ear was significantly associated with hearing loss (p < 0.01). POG grade 3 and 4 toxicity were uncommon with median doses to the inner ear bellow 42 Gy (p < 0.05) and total cisplatin dose of less than 375 mg/m(2) (p < 0.01).Conclusions: IMRT leads to a low rate of severe ototoxicity. Median radiation dose to auditory apparatus should be kept below 42 Gy. Cisplatin doses should not exceed 375 mg/m(2).

Instituto Israelita de Responsabilidade Social (IIRS) of Hospital Israelita Albert Einstein (HIAE)

Hosp Israelita Albert Einstein HIAE, Dept Radiat Oncol, São Paulo, Brazil

Univ São Paulo HCFMUSP, Fac Med, Hosp Clin, Dept Radiat Oncol, São Paulo, Brazil

Universidade Federal de São Paulo IOP GRAACC UNIFESP, Dept Pediat Oncol, Inst Oncol Pediat, Grp Apoio Ao Adolescente & Crianca Com Canc, São Paulo, Brazil

Universidade Federal de São Paulo IOP GRAACC UNIFESP, Dept Speech Therapy, Inst Oncol Pediat, Grp Apoio Ao Adolescente & Crianca Com Canc, São Paulo, Brazil

Univ São Paulo HCFMUSP, Dept Pediat Oncol, Inst Tratamento Canc Infantil ITACI, Hosp Clin,Fac Med, São Paulo, Brazil

Universidade Federal de São Paulo IOP GRAACC UNIFESP, Dept Pediat Oncol, Inst Oncol Pediat, Grp Apoio Ao Adolescente & Crianca Com Canc, São Paulo, Brazil

Universidade Federal de São Paulo IOP GRAACC UNIFESP, Dept Speech Therapy, Inst Oncol Pediat, Grp Apoio Ao Adolescente & Crianca Com Canc, São Paulo, Brazil

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