Hearing Monitoring Guidelines for Platinum-Based Chemotherapy
All patients receiving platinum-based chemotherapy (cisplatin, carboplatin) require baseline audiometric assessment before treatment initiation, with serial monitoring during therapy and long-term surveillance afterward, using pure-tone audiometry including extended high frequencies (9-16 kHz), with immediate referral to audiology/otolaryngology for any detected hearing loss. 1
Who Requires Monitoring
High-Risk Populations:
- All patients receiving cisplatin - Level A evidence shows dose-dependent increased risk of hearing loss 1
- All patients receiving carboplatin - Expert opinion supports increased ototoxicity risk 1
- Younger patients - Children and adolescents face higher risk than older patients (Level B evidence) 1
- Patients receiving concurrent ototoxic medications - Furosemide (Level C) and aminoglycosides (Level C) increase risk 1
- Patients receiving cranial radiotherapy - Especially ≥30 Gy, which compounds platinum ototoxicity (Level B-C) 1
The FDA label for cisplatin explicitly states that audiometric testing should be performed prior to initiating therapy and prior to each subsequent dose, and that cisplatin commonly causes cumulative ototoxicity that may be severe 2.
Testing Modalities
Essential Components:
- Pure-tone audiometry (0.5-8 kHz) - Standard conventional frequency testing 1
- Extended high-frequency audiometry (9-16 kHz) - Critical for early detection, as 94.1% of children showed bilateral ototoxicity in EHF range before conventional frequency changes 3
- Speech audiometry - Provides information on real-world hearing function and phoneme detection 1, 4
- Distortion product otoacoustic emissions (DPOAEs) - Evaluates outer hair cell function; 81.3% showed changes before conventional audiometry detected loss 3
- Tympanometry - Assesses middle ear function 1
Research demonstrates that extended high-frequency audiometry and DPOAEs reveal ototoxic changes before conventional audiometry detects hearing loss, making them superior early detection tools 3, 5.
Monitoring Schedule
During Active Treatment:
- Baseline assessment - Complete audiometric battery before first platinum dose 1, 2
- Serial monitoring - Prior to each subsequent chemotherapy cycle 2
- Pediatric patients - Audiometric testing at baseline, prior to each dose, and continuing for several years post-therapy 2
Post-Treatment Surveillance:
The Children's Oncology Group recommends 1:
- Once at beginning of long-term follow-up for cisplatin or myeloablative carboplatin-treated patients
- At least yearly if hearing loss is detected during treatment
- Yearly for 5 years, then every 5 years for patients ≥10 years old who received ≥30 Gy cranial radiotherapy
- Yearly until age 10, then every 5 years for patients <10 years old who received ≥30 Gy cranial radiotherapy
The Dutch guidelines suggest every 5 years for cisplatin-treated patients, though this represents a less intensive approach 1.
Critical caveat: Hearing function may deteriorate over time after platinum-based chemotherapy (Level C evidence), even years after treatment completion, necessitating long-term surveillance 1.
Action Thresholds
When Hearing Loss is Detected:
- Immediate referral to audiology/otolaryngology specialists - All three major guideline groups (COG, Dutch, UK) concordantly recommend specialist referral 1
- Increase monitoring frequency - At least yearly audiometry if hearing loss detected 1
- Consider hearing aids - Level C evidence shows effectiveness for improving speech comprehension and spatial location 1
- Cochlear implants - Level C evidence supports effectiveness for severe hearing loss 1
The NCCN specifically emphasizes that institutional audiology/otolaryngology teams should determine the appropriate schedule for subsequent evaluations in children with impaired hearing, as screening is particularly important to minimize delays in speech and language development that impact academic performance and social development 1.
Risk Factors Requiring Enhanced Surveillance
Dose-Related Factors:
- High cumulative cisplatin dose - Most important risk factor (Level A evidence) 1, 6
- Individual dose intensity - Higher per-cycle doses increase risk 6
Patient Factors:
- Younger age at treatment - Consistently associated with increased risk (Level B) 1
- CSF shunts - Increases risk (Level B) 1
- Baseline hearing status - Patients with better baseline hearing show larger declines 5
Combination Exposures:
- Concurrent furosemide - Level C evidence for increased risk 1
- Concurrent aminoglycosides - Level C evidence for increased risk 1
- Cranial radiotherapy - Synergistic effect with platinum agents 1
Additional Monitoring Considerations
Beyond Pure-Tone Audiometry:
- Tinnitus assessment - 60% of pediatric survivors report tinnitus, which can be debilitating 7
- Speech-in-noise testing - Standard audiometry inadequately captures real-life hearing difficulties 4
- Self-reported hearing handicap scales - Provides valuable information about functional impact not captured by audiometry alone 4, 7
- Envelope-following response (EFR) - Emerging evidence suggests this may detect cochlear synaptopathy before subjective complaints or audiometric changes 5
Common Pitfall: The most significant threshold shifts occur at 8 kHz and higher frequencies, with the 8 kHz frequency showing up to 35 dB shifts 6. Monitoring protocols that omit extended high frequencies will miss early ototoxicity.
Protective Strategies
Evidence-Based Interventions:
- Sodium thiosulfate - Level B evidence shows decreased ototoxicity risk when co-administered 1
- Amifostine - Level C evidence suggests protective effect 1
Contraindications: The FDA label explicitly states cisplatin is contraindicated in patients with pre-existing hearing impairment 2.