Detailed evaluation of hearing loss (HL) associated with high-dose (HD) carboplatin for salvage treatment of germ cell tumors (GCT).

Abstract

401 Background: HD carboplatin is an essential part of curative salvage high-dose chemotherapy (HDCT) for GCT. Although ototoxicity is a known side effect of HD carboplatin, data on severity and characteristics of HL in this population are limited. Methods: Eligible patients (pts) received salvage HD carboplatin for GCT at our center from 1993-2017 and had audiograms pre- and post-HDCT. All pts were planned for 3 sequential cycles of HD carboplatin; some had audiograms after each cycle. HL severity was classified by ASHA criteria (slight: 15-24dB; mild: 25-40dB; moderate: 41-55dB; moderately severe: 56-70dB; severe: 71-90dB; profound: >90dB). Change in hearing threshold at each frequency (0.25 – 8 kHz) was analyzed by clinical and treatment variables using the Wilcoxon rank-sum test. The proportion of pts recommended for hearing aids was also recorded. Results: Of 115 pts (median age 31, 77% nonseminoma), 96 received TI-CE and 19 received TI-TIC on a clinical trial (Feldman CGUC 2015). Pts varied by prior cisplatin exposure (77% with ≤4 vs 23% with 5-9 cycles) and number of HD carboplatin cycles (89% had 3, 10% had 2, and 2% had 1). Carboplatin AUC was 21 in 23%, 24 in 75%, and 28 in 3%. Moderate to profound HL was present in 23% pre-HD carboplatin vs 82% post, preferentially at high frequencies (Table). Of 89 pts with normal to mild HL at baseline, 78% developed moderate or worse HL post-HD carboplatin, including 61% with moderately severe or severe HL. Higher AUC (24 vs 21) and number of HD carboplatin cycles were associated with greater HL with HD carboplatin whereas prior cisplatin exposure was not. Due to moderate or severe HL in the vital speech frequency range (2 – 4kHz), 20 (17%) pts were recommended for hearing aids post-HD carboplatin. Conclusions: In the largest series to detail ototoxicity in pts receiving salvage HD carboplatin for GCT, we show HL, particularly at high frequencies, is a major dose-dependent toxicity. Most pts will have at least moderate high frequency HL after HD carboplatin with approximately 1 in 6 recommended for hearing aids. [Table: see text]