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

Abstract\ud \ud Background\ud 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.\ud \ud \ud Methods\ud 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.\ud \ud \ud Results\ud 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.\ud 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/m2 (p < 0.01).\ud \ud \ud Conclusions\ud 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/m2.This study was supported by Instituto Israelita de Responsabilidade Social\ud (IIRS) of Hospital Israelita Albert Einstein (HIAE)

Validating the SIR: a better prognostic score index for patients with brain metastases treated with stereotactic radiosurgery

Objective: The aim of this paper is to validate the score index forsurvival in patients treated with stereotactic radiosurgery, using aclassification prepared to better evaluate the prognosis of patientswith brain metastasis submitted to stereotactic surgery, re-evaluatingsurvival of patients and reviewing the medical literature. Methods:Data from 100 patients with brain metastases treated with stereotacticradiosurgery at a single institution, between July 1993 and February2000, were retrospectively analyzed. The prognostic factors andscores studied were age, Karnofsky performance status, extracranialdisease status, number of brain lesions, volume of the largest lesion,primary tumor type, treated or not with whole brain radiation therapy,SIR, and RPA. Kaplan-Meier actuarial survival curves for subsets werecalculated and compared by log-rank test. Complete and backwardelimination Cox models were utilized to identify the prognostic factorsand scores independently associated with survival. Results: Karnofskyperformance status, extracranial disease status, volume of the largestbrain lesion, RPA, and SIR were significantly correlated with prognosisin Kaplan-Meier survival analysis. Applying Cox models, significancewas observed for KPS and volume of the largest lesion (p < 0.0001and p = 0.0182, respectively), as well as for SIR and RPA when testedindividually (p < 0.0001 and p = 0.0002, respectively). However, whentesting SIR and RPA together, only SIR reached independent statisticalsignificance (p < 0.0001). Conclusion: SIR classification demonstrateda better accuracy in predicting survival time than RPA. SIR was testedin other centers, showing superior accuracy and applicability than theRPA, thus validating this score