Hearing loss related outcomes post-lateral temporal bone resection and other oncologic treatment

e18069 Background: Lateral temporal bone resection (LTBR) is used to treat malignancies originating from the auricle, periauricular skin, external auditory canal, parotid gland, or temporal bone. LTBR is the workhorse of otologic cancer surgery; however, few studies have described audiologic outcomes in a large sample of patients. The current literature focuses on overall survival rates post-surgery; however, hearing loss-related outcomes after surgery and adjuvant therapy are lacking in the literature. Following surgery, patients are expected to have maximal conductive hearing loss in the affected ear which can be augmented by ototoxic effects of adjuvant treatment such as radiation and systemic therapy. This type of hearing loss significantly impacts quality of life, making it difficult to understand speech directed to the surgically closed ear, localize sounds, and understand conversational speech in noisy environments. Less is known about the rate and severity of sensorineural hearing loss (SNHL) following LTBR. Methods: A retrospective chart review was conducted among 252 patients who underwent LTBR at single tertiary care center from 2010 to 2020. We evaluated changes in ipsilateral bone conduction (BC) hearing thresholds after LTBR ± adjuvant therapy, including head and neck radiation, chemotherapy, and immunotherapy. Patients who completed at least 1 preoperative and 1 postoperative audiogram within 2 years of surgery were included. Patients who had preoperative chemotherapy, immunotherapy, or temporal bone radiation were excluded. Of 252 patients reviewed, 94 met the eligibility criteria. Audiometric data included pure tone average (PTA) for BC thresholds. A significant decline in hearing was defined as an increase in PTA ≥ 10 decibels (American Academy of Otolaryngology-Head and Neck Surgery). Three treatment subgroups were analyzed, including LTBR only, LTBR and radiation therapy, and LTBR with radiation and systemic therapy. Results: Among all patients, BC PTA increased on average by 7dB after treatment (p<0.001); 30% of patients had ≥ 10dB shift. Patients undergoing LTBR with adjuvant therapy had a higher rate of hearing loss compared to patients undergoing LTBR alone (22/69, 32% vs. 5/25, 20%, respectively). Conclusions: LTBR can cause significant long-term decline in BC hearing that is worsened with the addition of adjuvant therapy. Therefore, it is critical to systematically obtain preoperative and post-treatment audiologic testing to monitor and rehabilitate hearing loss over time. The findings of this study may help patients understand realistic expectations of long-term treatment outcomes related to hearing loss, as an initial step to help improve quality of life with hearing rehabilitation such as osseointegrated bone conduction devices.