What Is Ototoxic Chemotherapy?
Some forms of chemotherapy can damage structures within the inner ear, leading to hearing loss, balance problems, and persistent noises in the ear. This side effect, known as ototoxicity, is most commonly associated with platinum-based chemotherapy agents. While these drugs are effective at treating cancer, their impact on the ear can be permanent and may affect a person's quality of life long after treatment ends.
The inner ear contains two critical sensory systems: the cochlea, which is responsible for hearing, and the vestibular system, which helps maintain balance and spatial orientation. Chemotherapy can damage the sensory hair cells in both of these areas, and once these cells are destroyed, they do not regenerate in humans.
Effects on Hearing
Chemotherapy-related hearing loss typically affects both ears symmetrically and is most noticeable at high frequencies first. Many people first notice difficulty understanding speech in noisy environments or trouble hearing the voices of women and children, which are higher-pitched. As the damage progresses, lower frequencies may also become affected, leading to a more generalised hearing impairment.
The severity of hearing loss depends on several factors, including the total dose of chemotherapy, the specific drug used, the age of the person receiving treatment, and whether they have also received radiation therapy to the head or neck. Routine audiological monitoring during chemotherapy is important because early detection of hearing changes may prompt your care team to adjust the treatment plan when possible.
Vestibular Effects and Oscillopsia
Beyond hearing, chemotherapy can also damage the vestibular organs, leading to dizziness, unsteadiness, and difficulty with spatial orientation. One particularly distressing symptom is oscillopsia, which is a visual disturbance in which the world appears to bounce, shift, or sway with every step taken. This occurs because the vestibular system is no longer able to stabilise the eyes during head movement, so the brain receives conflicting signals about the position of the body in space.
People with chemotherapy-related vestibular damage may find it difficult to walk in the dark, navigate uneven surfaces, or move their head quickly without becoming dizzy. Vestibular rehabilitation therapy, guided by a trained professional, can help the brain compensate for reduced balance function, although oscillopsia may persist in some cases.
Tinnitus and Ear Symptoms
Another common consequence of ototoxic chemotherapy is tinnitus, a perception of sound that has no external source. Tinnitus is often described as ringing, buzzing, hissing, or roaring in the ear, and it can be intermittent or constant. For some individuals, tinnitus is mildly annoying, while for others it can severely disrupt sleep, concentration, and emotional wellbeing.
Because tinnitus can be accompanied by a feeling of fullness or pressure in the ear, people sometimes mistake it for an infection or blockage. Any new or worsening ear symptoms during chemotherapy should be reported to a healthcare provider promptly. Although there is currently no cure for tinnitus related to chemotherapy, sound therapy, cognitive behavioural support, and hearing aids can help reduce its impact on daily life.
Monitoring and Coping Strategies
Given the potential for permanent damage, many cancer treatment centres recommend a baseline hearing test before chemotherapy begins, followed by regular tests during and after treatment. Vestibular evaluations may also be offered to people who report balance difficulties. These assessments help document the effects of chemotherapy on the ear and guide decisions about hearing rehabilitation.
Several strategies can help people cope with chemotherapy-related hearing and balance problems:
- Hearing aids or assistive listening devices to improve communication in difficult listening situations.
- Vestibular rehabilitation exercises to improve stability and reduce dizziness.
- Protecting the ears from additional noise exposure by using earplugs in loud environments.
- Discussing any tinnitus with a healthcare professional who can recommend management techniques.
- Allowing time for rest and avoiding sudden head movements to reduce oscillopsia symptoms.
Researchers continue to explore ways to prevent or reduce the ototoxic effects of chemotherapy, including investigational protective agents and alternative dosing schedules. However, at present, early monitoring and proactive symptom management remain the most effective approaches for preserving the ear's function whenever possible.