Carboplatin and ototoxicity: hearing loss rates among survivors of childhood medulloblastoma.

PURPOSE

Patients with medulloblastoma are exposed to ototoxic treatments including radiation therapy and platinum chemotherapy. The favorable toxicity profile of carboplatin led us to substitute this chemotherapeutic agent for cisplatin in the HIT-1991, HIT-MED-1999, and HIT-2000 chemotherapy protocols. We retrospectively investigated its consequences in terms of overall survival and ototoxicity rates.

METHODS

Twenty-four medulloblastoma patients were treated according to HIT protocols with carboplatin substitution between April 1999 and June 2006. Nineteen (79%) patients had adequate baseline and post-treatment audiological data. Mean age at diagnosis was 9.3 (range 3.5-18.9) years with a mean follow-up time of 30.8 (8.1-111.3) months. Patients received a mean carboplatin cumulative dose of 2,131 (830-4312) mg/m(2).

RESULTS

Twenty-three patients were alive at the time of assessment. Hearing loss greater than 20 dB was observed in two (10.5%) of 19 patients. Both had grade 2 ototoxicity according to Brock's scale. There were no significant differences between the patients' baseline and post-treatment audiograms at any frequency. The observed hearing loss was significantly correlated to younger age at diagnosis and cumulative carboplatin dose (p<0.05).

CONCLUSIONS

The encouraging overall survival and low hearing loss rates in this medulloblastoma patient cohort suggest that protocols containing carboplatin may offer a viable alternative to standard cisplatin protocols and warrant further investigation.