Analysis of ototoxicity in young children receiving carboplatin in the context of conservative management of unilateral or bilateral retinoblastoma.

Background: Carboplatin plays an important role in the conservative management of retinoblastoma, but is associated with risk of ototoxicity in these young children whose sensory prognosis may be also compromised by their loss of vision. This retrospective study analyzed the impact of carboplatin on hearing in the context of conservative management of children with retinoblastoma.

Methods: Data for 175 children treated at the Institut Curie between 1994 and 2002 were analyzed.

Results: Median age at diagnosis was 8 months (0-60). Carboplatin was administered on 3 days (200 mg/m(2)/day) or 5 days (160 mg/m(2)/day) with etoposide and with diode-laser therapy at the dose of 560 mg/m(2) (chemothermotherapy). Median cumulative dose of carboplatin was 2,880 mg/m(2) (560-6,160). Ototoxicity was investigated by pure-tone audiometry and scored by Brock's grading scale before and after treatment. The median follow-up of hearing assessment was 5 years (1.8-11). Ototoxicity was detected in 8 children: 3 grade 1, 1 grade 2, and 2 grade 4. The two patients with grade 4 hearing-loss required a hearing aid. Two children developed bilateral high frequency hearing-loss, considered to be secondary to carboplatin but with less than Brock grade 1. Ototoxicity was observed for a median cumulative dose of carboplatin of 3,120 mg/m(2) (1,200-5,830). Only one child developed ototoxicity during treatment. All other cases were discovered after the last dose of carboplatin with a median interval of 3.7 years (0-7.6). No other risk factor for ototoxicity was able to account for these lesions.

Conclusion: Children receiving carboplatin require long-term audiometric follow-up.