Hearing loss and cancer treatments.

Physicians are well aware of the many side effects of chemotherapy and radiation treatment. However, only in recent years has research addressed the risk of hearing loss and related conditions (e.g. tinnitus) as reported by numerous post-cancer treatment patients. These studies have revealed a strong link between hearing loss and cancer treatments, especially among certain chemotherapy medications. It is important for both physician and patient to understand the risk of ototoxicity when treating cancer, and its long-term implications, which may include permanent hearing loss.

Ototoxicity and its relationship to cancer treatments.

Certain chemotherapy medications or radiation therapy can cause ototoxicity, which may be manifested as temporary or permanent hearing loss. Ototoxicity resulting in sensorineural hearing loss (SNHL) refers to drug or chemical damage to the inner ear where cochlear hair cells vibrate in response to sound waves. This damage may affect vital hearing and balance information to the brain, resulting in hearing loss, tinnitus, and/or loss of balance. Platinum-based chemotherapy medications, particularly cisplatin and carboplatin, are considered the primary “culprits” when it comes to ototoxicity. Other potentially ototoxic chemotherapy drugs include Bleomycin, Vincristine, Vinblastin, Bromocriptine, and Methotrexate Nitrogen mustard.1Chemotherapy from the “platinum” group is frequently used to treat brain, head and neck cancers, as well as lung, bladder and ovarian cancers in adults. It is also commonly used to treat brain, bone and liver cancers in children.

Effects of ototoxicity in adults.

• Physical effects of hearing loss include balance issues and a greater likelihood of falls2 over time, especially in older adults. Hearing loss has also been linked to the development of certain forms of dementia3 and cognitive decline.
• Psychological fallout, including depression, isolation, anxiety, anger, and poor self-image.4
• Economic impact, which includes higher rate of unemployment, difficulty retaining a job or advancing career.5

Because of the long-term effects of hearing loss in adult survivors, and the debilitating effects associated with the condition, oncologists will likely do their utmost to mitigate ototoxic exposure during treatment. When aggressive treatment is necessitated, and the patient experiences hearing loss, it is important to consider treatment options such as hearing aids, which can help 95% of patients with hearing loss. As cancer treatments have more success, and cancer patients live longer, hearing loss treatment could improve the patient’s quality of life after cancer treatment.

Effects of ototoxicity in children.

Although limited statistical data is available, researchers believe the number of cancer-surviving children with hearing loss (as a result of ototoxic exposure) is significant. One landmark study of 67 patients age 8 to 23 undergoing chemotherapy found 61 percent developed hearing loss7 after treatment – most experiencing high-frequency hearing loss (HFHL). HFHL in children primarily affects comprehension, yet children may not realise they are not interpreting speech properly and so the condition goes underreported and undiagnosed. Left untreated, consequences include:

• Significant delay in speech and language development
• Negative impact on cognitive development and educational outcomes
• Interference with psychosocial development