Carboplatin and Hearing Loss: How Its Ear Risk Differs From Cisplatin

Carboplatin is a platinum-based chemotherapy drug that can damage hearing, but at standard doses its ear risk is generally lower than that of cisplatin. Risk rises sharply at high or myeloablative doses, such as those used before stem-cell transplant. Tinnitus (ringing) often appears before you notice any change in hearing, so baseline and monitoring audiograms matter.

How does carboplatin affect hearing?

Carboplatin is a platinum compound. Platinum drugs can accumulate in the cochlea, the hearing organ of the inner ear, and damage the delicate hair cells that convert sound into nerve signals. Because these hair cells do not regrow, the resulting hearing loss is usually permanent (ASHA: Ototoxic Medications).

Researchers studying cisplatin, carboplatin's close relative, have shown that platinum can stay in the inner ear far longer than in most other body tissues, which helps explain why platinum-related hearing loss can be lasting (NIDCD, NIH). Hearing damage from platinum drugs tends to be dose-related and to begin in the higher pitches before affecting the speech range (Merck Manuals: Drug-induced ototoxicity).

This is an association between the drug and hearing change, managed as a known side effect, not a certainty that every patient will be affected.

Is carboplatin less risky for hearing than cisplatin?

Generally, yes at standard doses. Cisplatin is considered one of the more strongly ototoxic chemotherapy drugs, while carboplatin at conventional doses is usually gentler on the ears (Harvard Health: Ototoxic drugs).

The important caveat is dose. At high-dose or myeloablative levels, for example the intensive regimens used before a bone-marrow or stem-cell transplant, carboplatin's risk to hearing increases substantially. Risk can also rise when carboplatin is combined with other ototoxic agents or radiation to the head, or in people with existing hearing loss. Your oncology team weighs these factors when planning treatment.

To understand where carboplatin sits among other cancer drugs, see our pillar guide, Chemotherapy and Hearing Loss: Which Cancer Drugs Affect Your Ears and How to Protect Them.

Why does tinnitus often come before hearing loss?

Many people notice tinnitus, a ringing, buzzing, or hissing in the ears, before they detect any drop in hearing. High-frequency hair cells are usually affected first, and damage there can produce tinnitus while everyday conversation still sounds normal (MedlinePlus: Ototoxicity).

Treat new or worsening tinnitus during carboplatin treatment as an early warning sign. Report it to your oncology team promptly, even if your hearing feels unchanged. Catching it early gives everyone more room to adjust monitoring and plan.

How is hearing monitored during carboplatin treatment?

The standard approach is a baseline hearing test before chemotherapy starts, followed by repeat audiograms during and after treatment. This lets audiologists compare results over time and detect small shifts before they affect daily life (ASHA: Ototoxic Medications).

If you or a family member is starting carboplatin, ask your oncologist whether ototoxicity monitoring is part of your plan. You can book a baseline hearing test with our audiologists, and if travel is difficult during treatment, ask about a home visit. If symptoms appear between scheduled tests, contact us rather than waiting.

Can carboplatin hearing loss be prevented or treated?

There is no guaranteed way to prevent platinum-related hearing loss. One protective medicine, sodium thiosulfate, has been approved to reduce the risk of hearing loss from cisplatin in certain children with localised solid tumours, but that approval is specific and does not automatically apply to carboplatin or to all patients (National Cancer Institute). Research in this area is still emerging.

Whether any protective option fits your situation is a decision only your oncology team can make, because it must be balanced against treating the cancer effectively. If hearing loss does develop, hearing aids and other rehabilitation can help you communicate and stay connected.