Can Chemotherapy Affect Your Hearing?

Chemotherapy can damage your hearing, and the risk is substantial. Platinum-based drugs, especially cisplatin, are the primary culprits, with ototoxicity rates exceeding 50% among treated patients worldwide.¹ The hearing loss tends to start in high-pitched frequencies you may not immediately notice and can progress toward the range that matters for everyday conversation. It often comes alongside tinnitus, and in some cases the damage is permanent because the drug stays lodged in the inner ear long after treatment ends.

Which Chemotherapy Drugs Are the Problem

Out of more than 700 chemotherapy agents documented in drug databases, only about seven are reported to cause hearing loss.¹ The overwhelming majority of chemotherapy-related hearing damage comes from the platinum family, with cisplatin at the top of the list. Carboplatin, its chemical cousin, also poses a risk, though the evidence consistently shows it is less ototoxic. In a comparison of the two drugs in patients with nasopharyngeal carcinoma, hearing threshold shifts at high frequencies were significantly worse in the cisplatin group than in the carboplatin group three to six months after treatment, with median shifts of about 15 dB versus 10 dB.²

Beyond platinum drugs, there is laboratory evidence that paclitaxel, a widely used non-platinum agent, can damage cochlear hair cells and auditory nerve fibers in animal models at higher doses and longer exposure times.³ However, the clinical significance of this finding in human patients remains less well established compared to the platinum drugs, where the link to hearing loss is beyond debate.

What Happens Inside the Ear

Your ability to hear depends on tiny structures inside the cochlea, the snail-shaped organ in your inner ear. Outer hair cells amplify incoming sound, the stria vascularis maintains the chemical balance of the fluid surrounding those cells, and spiral ganglion neurons carry signals to the brain. Cisplatin attacks all three of these structures, but the stria vascularis appears to accumulate the drug at especially high concentrations. Mapping studies of human cochleae using laser ablation have shown that cisplatin accumulates heavily in the stria vascularis during treatment, and it barely clears out afterward. Sixty days after the last dose, blood levels of the platinum compound dropped by about 89%, but levels in the stria vascularis had only dropped by roughly half, and in the spiral ganglion they had decreased by just 25%.⁴

This retention matters because the stria vascularis generates an electrical potential that serves as the driving force for hearing. In mice, cisplatin treatment measurably reduced this potential both immediately after treatment and 60 days later, meaning the ears were still underperforming long after the drug had been cleared from the rest of the body.⁴ Researchers have debated whether the primary damage comes from cisplatin entering the hair cells directly or from degrading the stria vascularis first, with evidence supporting both pathways.¹ The practical takeaway is the same either way: once cisplatin lodges in the cochlea, the damage it causes is difficult to reverse.

How the Hearing Loss Shows Up

Cisplatin-related hearing loss typically strikes high frequencies first. In audiometric monitoring, early detection studies have found that about 84% of ears showed hearing loss during cisplatin treatment, and of those, roughly 71% were detected first in frequencies at or above 8 kHz, well above the range tested in a standard hearing check.⁵ Objective testing with otoacoustic emissions has shown that more than 60% of patients displayed signs of cochlear damage at high frequencies after just one cycle of cisplatin.⁶

Because the highest frequencies are affected first, you might not realize anything is wrong until the loss creeps into the speech range. Sounds like birdsong, children’s voices, or consonants like “s” and “f” tend to fade before you struggle with deeper-pitched sounds. By the time you notice difficulty following a conversation in a noisy restaurant, the damage may already be considerable.

Tinnitus and Balance Problems

Hearing loss is the most common auditory side effect, but it rarely comes alone. In a large study of adult cancer survivors who had received cisplatin, roughly 40% reported tinnitus, and the presence of tinnitus was significantly correlated with reduced hearing at every tested frequency.⁷ A prospective study of tinnitus onset rates found that cisplatin increased the risk of developing tinnitus by about 5.5 times, while carboplatin increased it by roughly 3.75 times compared to non-ototoxic medications.⁸

Tinnitus risk scales with cumulative dose, but the relationship is not perfectly linear. In testicular cancer survivors, the risk of cisplatin-induced tinnitus jumped by about 2.6-fold once cumulative doses exceeded 400 mg/m², while doses in the 300–400 range showed a less dramatic increase. Those who developed tinnitus also reported significantly more difficulty hearing in crowds and a higher rate of vertigo.⁹

The vestibular system, which governs balance, uses some of the same hair cell structures as the hearing system, and platinum drugs can damage these too. A scoping review found histological evidence of severe hair cell loss in the vestibular sensory organs of treated patients, including crystalline deposits consistent with benign paroxysmal positional vertigo.¹⁰ Balance problems after chemotherapy are probably underreported, partly because dizziness gets attributed to other side effects and partly because vestibular testing is not routinely performed the way hearing tests are.

What Drives the Risk Up or Down

Cumulative dose is the single biggest modifiable factor. In audiometric follow-up of cancer survivors, hearing loss progression was significantly worse in patients who received more than 300 mg/m² of cisplatin compared to those who stayed at or below that threshold.¹¹ But total dose is not the only thing that matters. How the dose is divided up also plays a role. In a study of over 560 patients with head and neck cancer, those who received lower weekly cisplatin doses had significantly less hearing loss than those who received higher doses every three weeks, even though overall cancer survival was the same between the two schedules. Clinically significant hearing loss (grade 2 or higher) hit about 18% of the weekly group versus 50% of the three-week group.¹²

In younger patients, a large cohort study found that higher fractionated doses per day and per cycle were independently associated with hearing loss risk, even after accounting for total cumulative dose. That study also identified vincristine, a non-platinum chemotherapy drug often given alongside cisplatin, as an independent risk factor for hearing loss.¹³

Age at treatment, pre-existing hearing conditions, and kidney function all modulate risk as well. Younger children tend to be more susceptible than adults, partly because the developing cochlea may be more vulnerable to toxic insult. On the other end of the age spectrum, older adults whose hearing has already declined naturally start from a lower baseline, so even modest additional damage can push them into functionally significant hearing loss more quickly.

Genetics and Who Is Most Vulnerable

Not everyone receiving the same dose of cisplatin experiences the same degree of hearing loss, and genetic variation helps explain why. Researchers have identified several gene variants, particularly in TPMT, ABCC3, and COMT, that are associated with higher risk. In one replication study in children, a TPMT variant carried an odds ratio of about 6 for developing cisplatin-induced hearing loss, meaning children carrying that variant were roughly six times more likely to lose hearing than those without it. A predictive model combining these genetic variants with clinical variables like age and tumor type significantly improved the ability to forecast who would develop hearing loss compared to using clinical risk factors alone.¹⁴

Growing evidence suggests that many of these risk-associated gene variants are expressed in the stria vascularis, the same structure where cisplatin accumulates most heavily.¹⁵ This convergence is pushing researchers toward the idea that the stria vascularis is the key vulnerability point, and that pharmacogenomic testing before treatment could eventually help clinicians personalize cisplatin dosing or choose alternative regimens for patients at the highest genetic risk. That kind of routine pre-treatment genetic screening is not standard practice yet, but the groundwork is being laid.

When Radiation Is Added to the Mix

Many patients with head and neck cancers or brain tumors receive radiation therapy alongside cisplatin. The combination makes things worse for the ear, though the interaction appears to be additive rather than synergistic. In pediatric patients treated with cranial irradiation and cisplatin-based chemotherapy, the cochlear radiation dose added to the risk of hearing loss on top of what cisplatin alone would cause, but the two did not multiply each other’s effects.¹⁶ A separate study in children confirmed no synergistic effect between radiation and either cisplatin or carboplatin.¹⁷

Still, “additive” is bad enough. Modeling studies in adults with head and neck cancer have estimated that a patient receiving 100 mg/m² of cisplatin along with high-dose radiation to the cochlea could experience hearing shifts approaching 38 dB at 8,000 Hz, whereas radiation alone at doses below 40 Gy caused no significant loss.¹⁸ This means that treatment planning for tumors near the ear should account for cumulative cochlear exposure from both modalities, keeping radiation dose to the cochlea as low as technically feasible when cisplatin is part of the protocol.

Can Anything Protect the Ear During Treatment

Sodium thiosulfate is the most studied otoprotective agent for cisplatin-induced hearing loss. It works by binding to platinum and neutralizing it, while also scavenging the free radicals that cisplatin generates.¹⁹ In a clinical trial of children receiving cisplatin, those who also received sodium thiosulfate had a 48% lower incidence of hearing loss compared to cisplatin alone: about 33% developed some degree of hearing loss versus 63% in the control group.²⁰

The catch is timing and route. Sodium thiosulfate given intravenously must be delayed after cisplatin infusion to avoid neutralizing the drug before it has done its job against the tumor, and there has been concern that it could still weaken the chemotherapy’s anticancer effect. To get around this, researchers are developing a formulation designed for injection directly through the eardrum before cisplatin administration, delivering high concentrations of the protectant straight to the cochlea while minimizing systemic interference with the cancer treatment.²¹ This approach is still in early clinical trials, but it represents a shift toward localized protection that could sidestep the efficacy concern entirely.

The Monitoring Gap

Given how common this side effect is, you might expect that hearing tests are a routine part of chemotherapy care. They often are not. In a review of cisplatin-treated patients at one institution, only about 39% received a baseline hearing test before starting treatment, a mere 4% had any audiologic evaluation during chemotherapy, and roughly 36% had at least one hearing test after treatment ended. Follow-up testing dropped to less than 10% beyond the first three months post-treatment.²² This matters because early detection of high-frequency shifts can influence decisions about dose adjustments, otoprotectant use, or even switching to a less ototoxic drug while there is still hearing to preserve.

The monitoring shortfall is not just a patient-awareness problem. A survey of audiologists in the VA system found disagreement among clinicians about appropriate testing schedules and unclear lines of responsibility between oncology and audiology departments. Barriers included care coordination challenges, heavy audiology workloads, and a lack of standardized protocols.²³ If you are starting or have recently completed platinum-based chemotherapy and nobody has mentioned hearing testing, it is worth bringing up with your oncology team yourself.

Children Face Higher Stakes

Hearing loss in adults is disruptive, but in children it can derail language development, academic performance, and social skills at critical windows of growth. Childhood cancer survivors with cisplatin-induced hearing loss face risks that extend well beyond the audiogram: early detection and management can mitigate academic, speech, language, social, and psychological harm.²⁴ Parents of children with treatment-related hearing loss have reported concerns about their child feeling frustrated, anxious, and isolated, and the children themselves describe withdrawing from group conversations because of the effort involved in trying to keep up.²⁵

Adults are not immune to these quality-of-life effects. Cancer survivors with tinnitus report more psychotropic medication use than those without it, and those with cisplatin-induced tinnitus rate their overall health as poorer.⁹ Surviving cancer only to be left struggling to hear your grandchildren or participate in social life is the kind of trade-off that patients deserve to understand before treatment begins, not discover afterward.

Why Regeneration Remains a Hard Problem

In some animals, lost hair cells in the ear can regenerate. Humans lack this ability, which is why cisplatin-induced hearing loss is so often permanent. But the problem goes deeper than that. Research on mouse inner ears has shown that cisplatin does not just kill hair cells — it also damages the supporting cells and resident stem cells that would theoretically be needed for any regeneration strategy to work. If the cells that serve as precursors for new hair cells are themselves destroyed by the drug, coaxing the ear into growing replacements becomes far more difficult.²⁶

Researchers are working around this obstacle using inner ear organoids grown from human stem cells. These miniature lab-grown structures mimic some of the architecture of the real inner ear and can be exposed to drugs like cisplatin to study the damage and test potential protective agents in a human-relevant system.²⁷ These organoids will not restore hearing for current patients, but they represent one of the more promising platforms for screening new otoprotective drugs without relying entirely on animal models. For now, prevention and early detection remain the only realistic tools for preserving hearing through platinum-based chemotherapy.

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