Carboplatin is a common chemotherapy agent with potential ototoxic side effects that is used to treat a variety

of pediatric cancers, including retinoblastoma. Retinoblastoma is a malignant tumor of the retina that is

usually diagnosed in young children. Since children with retinoblastoma have visual impairment in one or both eyes, it is important to know if carboplatin is causing an additional sensory loss. This pilot study was designed to examine if distortion-product otoacoustic emission (DPOAE) tests performed before and after several courses

of carboplatin could register a change in outer hair cell function in children due to the potential onset of carboplatin ototoxicity. Ten children (aged 3-72 months) diagnosed with unilateral or bilateral retinoblastoma were included in the sample. The children were tested before and after receiving 3-4 courses ( cumulative dosage: 515-1548 mg) of carboplatin chemotherapy. DPOAEs were acquired from both ears of the children with 65/55 dB SPL primary tones (f2= 793-7996 Hz) and a frequency resolution of 3 points/octave. Comparisons were made between pre- and post-therapy mean DPOAE levels with paired-sample t tests. Evidence of ototoxicity in individual children was

based on criterion reductions (≥6 dB) in DPOAE levels. Results indicated that significant differences (p = 0.001) in pre- and post-therapy mean DPOAE levels were only observed at f2=7996 Hz. On an individual basis, children

receiving higher doses of carboplatin exhibited criterion reductions in DPOAE level at several f2 frequencies.

These findings suggest that DPOAE tests can provide useful information when monitoring children at risk of

developing ototoxicity. This work as supported in part by grant CA 21765 from the U.S. Public Health Service and

by the American Lebanese Syrian Associated Charities (ALSAC).