Ototoxicity Screening and Audiologic Evaluation in Cancer Care

Ototoxicity is a broad term for exposure to an agent that damages the inner ear, leading to hearing loss or balance issues. It is an underrecognized side effect of cancer treatment because its manifestations can be subtle at first, but progression can lead to serious quality-of-life issues for patients. ONS member Jennessa Rooker, PhD, RN, OCN^®, director of nursing excellence at the Tampa General Hospital Cancer Institute in Florida, studied ototoxicity in patients with cancer as part of her PhD dissertation. She explained how oncology nurses can monitor for and address ototoxicity in the cancer setting.

Risk Factors and Mechanisms of Damage

Ototoxicity is associated with several risk factors: age, genetics and family history of hearing loss, preexisting hearing loss and previous severe noise exposure, cardiovascular factors, and certain cancer treatments. “Cisplatin is the most ototoxic chemotherapy out there,” Rooker said. Several other agents are associated with risk of ototoxicity: bortezomib, docetaxel, vincristine, carmustine, and other platins.

In the case of cisplatin, the drug enters the inner ear through the bloodstream and binds to DNA, creating reactive oxygen species, which damage inner ear sensory hair cells. “Those hairs send electrical signals to the brain that recognize sound. So that function is permanently gone once those hair cells are damaged,” Rooker said. 

Radiation therapy to the head and neck, specifically with the inner ear in the radiation field, is another major risk factor, she said.

Recognizing Ototoxicity

In general, ototoxicity manifests as hearing loss, which includes trouble hearing certain pitches or soft sounds, as well as tinnitus and balance issues.

Because ototoxicity is not commonly associated with cancer treatment, patients may not report it or attribute it to other causes, Rooker said. Education before treatment is essential so that patients understand the potential for treatment-related ototoxicity and when to report it.

Early intervention is vital because untreated ototoxicity can put patients at risk for more serious problems, including decreased spatial awareness, falls, social isolation and depression, and cognitive decline.

Screening

Rooker conducted a study on hearing loss screening as part of a pilot program to identify platinum-based chemotherapy–induced toxicities. “For my dissertation, I refined the study to focus exclusively on hearing loss and specifically on patients receiving cisplatin,” she said. The study involved screening adult patients with newly diagnosed solid tumors prior to chemotherapy infusion and throughout treatment, before their hearing could be affected by treatment.

During hydration before cisplatin administration, trained oncology nurses conducted the screening, which involved using a tablet computer, specialized hearing screening (audiometry) software called Shoebox, calibrated headphones, the Tinnitus Hearing Survey, and a semi-structured interview. 

With the tablet and headphones, patients could complete the simple screening in 10–20 minutes. “The program presented tones ranging from 1–20 kHz, with each ear tested individually. Patients pressed a green button when they heard a sound and a red button when they did not,” Rooker said.

Results of the screening were immediately available, so potential issues were quickly recognized. “The Shoebox software produced an audiogram for each ear and flagged any clinically relevant changes in hearing thresholds,” Rooker said. “If a hearing change or loss was identified, the principal investigator and audiologist reviewed the results and offered the participant a referral to the audiology clinic for diagnostic evaluation.”

Audiologic Evaluation

When patients are referred to audiology for further evaluation, they may be at various stages of treatment or survivorship. “The first step in evaluation is to understand where the patient is in their cancer treatment journey because the evaluation approach differs depending on whether it is a baseline assessment (before treatment and exposure to ototoxic agents), monitoring (during or after chemotherapy cycles), or a post-treatment rehabilitation referral,” Victoria Sanchez, AuD, PhD, CCC-A, an audiologist and associate professor in the Department of Otolaryngology at the University of South Florida Morsani College of Medicine, said. 

The audiologic evaluation comprises several tests. “The objective examination includes otoscopy, pure-tone audiometry through extended high frequencies, immittance test battery, otoacoustic emissions, speech audiometry in quiet and in noise, and potentially other assessments based on initial results of the core test battery,” Sanchez said. Evaluation of survivors posttreatment involves planning interventions and educating on preventing more hearing loss.

Based on guidelines from the American Speech-Language-Hearing Association, American Academy of Audiology, and International Ototoxicity Management Group, frequency of evaluation varies depending on where a patient is in the cancer continuum and other risk factors. Sanchez said that patients at high risk (receiving platinum agents and radiation) may be evaluated every one to two treatment cycles, or if regular monitoring is not possible, at least before and after treatment. 

“Once an auditory-vestibular insult is identified, management with at least annual assessments is required. These are permanent, chronic conditions likely to worsen with age, genetics, or other exposures,” Sanchez said.

Interventions to address ototoxicity-related hearing loss are highly individualized, depending on patient preference, communication style, and lifestyle. Hearing aids and assistive hearing devices are the most common interventions. 

“Hearing aids are now like mini super computers with advanced signal processing and connectivity features to connect to cellphones and TVs,” Sanchez said. Implantable devices, such as cochlear implants, may be options for more profound hearing loss. 

Although assistive devices are vital, Sanchez pointed to the importance of patient participation: “Most patients are only successful with assistive technology if they have self-efficacy and practice good communication strategies.” 

Collaborative Approach

As with other aspects of cancer care, monitoring for ototoxicity and managing hearing loss requires interprofessional collaboration. Medical and radiation oncology are responsible for dose adjustments, while nurses provide education and screening for hearing loss. When hearing loss or other ototoxic effects are detected, management may involve audiology, otolaryngology, speech-language pathology, physical therapy, and other specialties. 

“The overarching goal of audiological intervention is to minimize the communication, social, emotional, and functional impacts of hearing loss, thereby optimizing quality of life and enabling patients to maintain meaningful connections with others,” Sanchez said.