Published August 30, 2025 | Version v1

A Study to Assess the Preservation of Hearing Function in Cochlear Sparing Radiation Therapy in Patients of Head and Neck Carcinoma Treated with Definitive Concomitant Chemo-Radiation

  • 1. Senior Resident, MD (Radiation Oncology), Department of Radiation Oncology, Acharya Harihar Post Graduate Institute of Cancer, Cuttack, Odisha 753007
  • 2. Assistant Professor, MD (Radiation Oncology), Department of Radiation Oncology, Murshidabad Medical College and Hospital, Berhampore, West Bengal 742101
  • 3. Associate Professor, MD (General Medicine), DM (Cardiology), Department of General Medicine, Deben Mahata Government Medical College & Hospital, Purulia, West Bengal 700064
  • 4. Professor, MD (Radiation Oncology), Department of Radiation Oncology, Medical College & Hospital, Kolkata, West Bengal 700073
  • 5. Associate Professor, MS (ENT), Department of ENT, Medical College & Hospital, Kolkata, West Bengal 700073
  • 6. Assistant Professor, MD (Radiation Oncology), Department of Radiation Oncology, Medical College & Hospital, Kolkata, West Bengal 700073

Description

Abstract 
Introduction: Head and neck carcinoma (HNC) is commonly treated with definitive concomitant chemo
radiation (CCRT), which, while effective, can result in significant treatment-related toxicities, including 
sensorineural hearing loss due to radiation exposure of the cochlea.  
Aims: Cochlear-sparing radiation therapy (CSRT) aims to reduce radiation dose to the cochlea while 
maintaining tumor control, potentially preserving hearing function. 
Methods: This study is a single-institutional prospective observational study conducted at the Department of 
Radiotherapy, Medical College and Hospital, Kolkata, from October 2022 to February 2024. The study 
population included patients attending the radiotherapy outpatient department with biopsy-proven locally 
advanced carcinoma of the head and neck, who had good performance status and satisfactory cardiological 
status, and were planned to receive concurrent chemoradiotherapy as definitive treatment. 
Results: Bone-masked pure tone audiometry showed that cochlear-sparing chemoradiation therapy led to 
frequency- and time-dependent increases in hearing thresholds. At 250 Hz, thresholds increased slightly 
immediately post-treatment and rose progressively at 3 and 6 months, reaching highly significant levels (up to 
5.86 dB, p < 0.001). At 500 Hz, immediate changes were minimal, but significant threshold shifts were 
observed at 3 and 6 months (up to 4.11 dB, p < 0.001). At 1000 Hz, immediate post-treatment changes were 
negligible, while significant increases occurred at 3 and 6 months (up to 3.61 dB, p < 0.001). Linear regression 
revealed a dose-dependent relationship between cochlear maximum radiation doses (Dmax) and hearing 
thresholds over time, with stronger correlations at 3 and 6 months across all frequencies, indicating that higher 
cochlear doses are associated with greater long-term hearing loss. 
Conclusion: Cochlear-sparing radiation therapy during definitive CCRT for head and neck carcinoma is 
feasible and effectively preserves hearing function, particularly in low- to mid-frequency ranges, without 
compromising oncologic outcomes. Implementation of cochlear dose constraints in radiotherapy planning 
should be considered to minimize ototoxicity in HNC patients. 

Abstract (English)

Abstract 
Introduction: Head and neck carcinoma (HNC) is commonly treated with definitive concomitant chemo
radiation (CCRT), which, while effective, can result in significant treatment-related toxicities, including 
sensorineural hearing loss due to radiation exposure of the cochlea.  
Aims: Cochlear-sparing radiation therapy (CSRT) aims to reduce radiation dose to the cochlea while 
maintaining tumor control, potentially preserving hearing function. 
Methods: This study is a single-institutional prospective observational study conducted at the Department of 
Radiotherapy, Medical College and Hospital, Kolkata, from October 2022 to February 2024. The study 
population included patients attending the radiotherapy outpatient department with biopsy-proven locally 
advanced carcinoma of the head and neck, who had good performance status and satisfactory cardiological 
status, and were planned to receive concurrent chemoradiotherapy as definitive treatment. 
Results: Bone-masked pure tone audiometry showed that cochlear-sparing chemoradiation therapy led to 
frequency- and time-dependent increases in hearing thresholds. At 250 Hz, thresholds increased slightly 
immediately post-treatment and rose progressively at 3 and 6 months, reaching highly significant levels (up to 
5.86 dB, p < 0.001). At 500 Hz, immediate changes were minimal, but significant threshold shifts were 
observed at 3 and 6 months (up to 4.11 dB, p < 0.001). At 1000 Hz, immediate post-treatment changes were 
negligible, while significant increases occurred at 3 and 6 months (up to 3.61 dB, p < 0.001). Linear regression 
revealed a dose-dependent relationship between cochlear maximum radiation doses (Dmax) and hearing 
thresholds over time, with stronger correlations at 3 and 6 months across all frequencies, indicating that higher 
cochlear doses are associated with greater long-term hearing loss. 
Conclusion: Cochlear-sparing radiation therapy during definitive CCRT for head and neck carcinoma is 
feasible and effectively preserves hearing function, particularly in low- to mid-frequency ranges, without 
compromising oncologic outcomes. Implementation of cochlear dose constraints in radiotherapy planning 
should be considered to minimize ototoxicity in HNC patients. 

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Additional details

Dates

Accepted
2025-08-26