Increased Incidence of Mastoiditis in Nasopharyngeal Carcinoma following Anti-PD-1 Therapy: A Propensity-Matched Analysis

Abstract

Background Mastoiditis can be triggered by radiotherapy and is closely associated with hearing loss. We aimed to explore the incidence rate of mastoiditis in locally advanced nasopharyngeal carcinoma (LANPC) patients following anti-programmed death 1 (PD-1) therapy. Methods Patients with primary locoregionally advanced nasopharyngeal carcinoma who were treated with intensity-modulated radiotherapy (IMRT) and concurrent cisplatin-based chemotherapy with or without anti-PD-1 therapy between from January 2020 to January 2022 in one medical facility were retrospectively reviewed. Group A received neoadjuvant chemotherapy (NACT) + concurrent chemoradiotherapy (CCRT) + anti-PD-1 therapy, while Group B did not receive anti-PD-1 therapy. A propensity score matching (PSM) method was used to match patients from each group in a 1:1 ratio. Severity of mastoiditis was evaluated by magnetic resonance imaging (MRI), specifically, mastoid opacification was graded from mild to severe on a scale of 0–3. Results In total, 146 out of 259 eligible patients were propensity matched, with 73 patients in Group A and 73 patients in Group B. No significant differences were observed in the patient and tumor characteristics between Group A and Group B. There were no significant differences between the two groups for the incidence rates of severe mastoiditis before NACT, before CCRT and 0 month following CCRT; while the incidence rates of severe mastoiditis 3, 6 months following CCRT in the Group A versus Group B were 34.2% versus 20.5% (p = 0.044), 37.7% versus 21.9% (p ＜ 0.001), were significance different respectively. The analysis of variance (ANOVA) with repeated measures showed that anti-PD-1 therapy (p = 0.031) significantly increased the incidence rate of severe mastoiditis in LANPC patients compared to that of immunotherapy-free patients following CCRT (p < 0.001). Conclusions LANPC patients following anti-PD-1 therapy experienced severe mastoiditis with an increased probability.