SOME PLATINUM-BASED CHEMOTHERAPY DRUGS, including cisplatin, are ototoxic, meaning they can cause damage to the inner ear, which can result in hearing loss. New research shows this damage can be permanent, persisting more than a decade after treatment.

In a study published June 6, 2024, in JAMA Oncology, researchers looked at 100 people who had been treated with cisplatin for testicular cancer, with a median age of 48. None had profound hearing loss at the start of the trial. After a median of 14 years from finishing chemotherapy, 54% of participants reported hearing loss. However, audiology tests found 78% had hearing loss. The study also found participants who received high doses of cisplatin had worse hearing loss than those who received lower doses.

Among those who received these high cisplatin doses, hearing loss was more pronounced. “Not only was their hearing bad right after chemo; it continued to get worse in the years that followed,” says Victoria Sanchez, an audiologist at USF Health in Tampa, Florida, who led the research. Cisplatin remains in the ear long term, which may be the reason for this progressive hearing loss, but the exact cause remains unclear.

Treatment guidelines recommend people with cancer undergo a hearing test before receiving cisplatin chemotherapy so doctors can track any decline. However, a patient receiving cisplatin may not be referred for a hearing test until they or their oncologist notice a problem.

Rachel Raphael, an audiologist at Mercy Medical Center in Baltimore who was not involved in the study, says she hopes these results will convince health care providers to prioritize a hearing test before chemotherapy. “Many oncologists refer for hearing testing only when patients complain of hearing loss and not routinely, which is unfortunate,” Raphael says. Some patients may not be aware of their hearing loss, so they may not bring it up. Some common signs to look out for include asking people to repeat themselves, turning up the TV volume and being distracted by background noise.

Sanchez advises patients about to begin cisplatin treatment to talk with their doctor about having a baseline hearing test and to advocate for continued regular testing to monitor for hearing changes. A person who develops hearing loss can benefit from a hearing aid.

The study also showed people who had high cholesterol had a greater risk for hearing loss. Patients should discuss with their doctor the best ways to manage cholesterol levels and improve heart health. Additionally, a medication called Pedmark (sodium thiosulfate) was approved in 2022 to prevent hearing loss in children being treated for cancer with cisplatin. Researchers are working to develop similar medications for adults.

Sanchez says hearing loss forces people to work harder to process sounds, which can impact how the brain functions. In fact, some studies in adults have linked unaddressed hearing loss with accelerated brain atrophy, which is the natural shrinking of the brain that occurs with age. “Untreated hearing loss has been strongly linked to cognitive decline, social isolation and an increased risk of dementia,” Raphael says.

“That hearing aspect of someone’s life is so important for not only your social relationships, but also to keep your overall physical health and brain health,” Sanchez says.