Ototoxicity in children with malignant brain tumors treated with the "8 in 1" chemotherapy protocol

Adjuvant chemotherapy has improved the outcome of childhood malignant brain tumors in large randomized trials. With increasing survival rates, treatment toxicity has become a matter of concern. Radiation therapy and cisplatinum are known to be ototoxic.

We evaluated the incidence and factors predisposing to ototoxicity in children treated with the "8 in 1" chemotherapy protocol in Finland during 1986--1993. Thirty-five of the 82 children survived for at least 1 year after diagnosis. Thirty of these children were old enough to have an audiogram.

Seventeen of the 30 children had normal hearing, seven had hearing loss at high frequencies, and six (20%) had severe hearing loss in the speech range. The risk factors for severe hearing loss were young age, a high cumulative dose of cisplatinum, and deteriorating renal function. In the presence of these factors, the risk of severe hearing loss was over 50%. Hearing loss at high frequencies could occur after low cumulative doses of cisplatinum, but severe hearing loss correlated with high cumulative doses.

Cisplatinum-induced hearing loss at high frequencies is common, but hearing loss in the speech range also occurs, particularly in children with predisposing factors, and may progress insidiously and rapidly. Therefore a hearing test before each "8 in 1" course is important.