Hearing loss protection recommendations made for paediatric CNS, head and neck cancer patients

By CH News On Oct 21, 2021

medwireNews: The risk of high-frequency hearing loss (HL) in children undergoing cancer treatment for the central nervous system (CNS) or head and neck region may be reduced by minimizing radiation doses to the cochlea and limiting cumulative doses of cisplatin or carboplatin, say Canadian researchers.

“Our findings may identify children for whom early intervention with tools and neurocognitive evaluation should be sought,” Derek Tsang, of the Princess Margaret Cancer Center in Toronto, Ontario, and colleagues write in the Journal of Clinical Oncology.

“Efforts should be made to conserve the cochlea during [radiotherapy] planning, if possible, without compromising tumor coverage,” they advise.

The team examined HL in 340 ears from 171 children treated for CNS or head and neck tumors between 2005 and 2017.

Multivariable weighted regression analysis showed that increasing levels of HL, based on the International Society of Pediatric Oncology-Boston grade, were significantly predicted by an increase in mean radiation dose to the cochlea (odds ratio [OR]=1.04 per Gy), and with increasing doses of cisplatin (OR=1.48 per 100 mg/m2) and carboplatin (OR=1.41 per 1000 mg/m2).

The researchers report “a rapid onset of high-frequency HL after early treatment exposure, followed by a delayed onset of intermediate and low-frequency HL over time.”

They also report the “striking finding” that 5 years after completion of radiotherapy, there was a 50% or greater incidence of high-frequency HL, above 4 kHz, when patients had received a mean cochlea dose of more than 30 Gy of radiation, and the risk of HL on all frequencies continued to increase for more than 5 years.

And the researchers emphasize that “[p]patients receiving platinum-based chemotherapy had a markedly increased risk of high-frequency HL, especially if the mean cochlear doses were > 20 Gy”, as well as children who were less than 3 years old at the time of radiotherapy, “even at modest doses”.

However, Tsang et al note that the effect of combination treatment with radiotherapy and chemotherapy had an additive but not synergistic effect on HL.

“We propose a mean cochlea dose of 30 Gy as a target threshold to minimize the risk of HL. In patients receiving chemotherapy, a lower threshold (20-25 Gy) may be considered to minimize the cumulative ototoxic burden,” they write.

This independent news story was supported by an educational grant from L’Institut Servier, Suresnes, France.

J Clin Oncol 2021; doi: 10.1200/JCO.21.00899