PP-30 Cumulative Incidence Rate of Radiation-Induced Hearing Loss after Radiotherapy in Pediatric Brain Tumor

Abstract

Objectives

This retrospective cohort study aims to report the cumulative incidence of RIHL, associated risk factors, and develope normal tissue complication probability (NTCP) models for predicting hearing loss (HL) in Thai children with brain tumors receiving radiotherapy.

Methods

Data of pediatric brain tumor patients who received radiotherapy session at King Chulalongkorn Memorial Hospital were collected. Audiometric assessments were performed at and/or after 6 months post-radiotherapy. Cumulative incidences of any grade of HL and deleterious hearing loss (≥ grade 2 HL, DHL) were calculated based on demographics and treatments, including patients have received not only radiotherapy, but also chemotherapy and/or surgery. Logistic regression, NTCP models, and statistical analyses were employed to evaluate factors influencing ototoxicity.

Results

Data from 56 eligible participants who underwent radiotherapy between January 2017 and June 2023 were included in our study. With a median follow-up time of 3.4 years, the cumulative incidence of ≥ grade 1 and ≥ grade 2 of hearing loss were 41.1%, and 37.4%, respectively. Predictive factors of RIHL included infratentorial location, mean dose (Dmean) of cochlea, and/or internal acoustic canal (IAC). We provided two NTCP models, incorporating Dmean of auditory organs and location of tumor in the formula. The first model predicted the probability of HL and DHL by calculation from Dmean of cochlea. Whereas the second model used the cut-off level of Dmean to cochlea and IAC, 32 and 37 Gy, respectively to prevent HL. Both models demonstrated good performance.

Conclusion

Over a third of pediatric brain tumor patients who underwent radiotherapy developed DHL. Dmean of cochlea and IAC, and location of tumor were associated with both HL and DHL. Our findings recommends limiting Dmean of cochlea and IAC below 32 and 37 Gy, respectively, to reduce HL and DHL.