Immune checkpoint inhibitors-associated periodontitis: A propensity score-matched retrospective cohort study

e14618 Background: Immune checkpoint inhibitors (ICIs) have been associated with a wide spectrum of immune-related adverse events (irAE) including oral mucositis and xerostomia. Periodontitis is another form of common oral pathology characterized by severe gingival inflammation but has not been investigated in patients receiving ICIs. We aimed to evaluate the risk of periodontitis associated with the use of ICI and to determine the clinical outcome of ICI-associated periodontitis. Methods: We conducted a 1:1 propensity score-matched retrospective cohort study involving patients receiving ICIs between January 2010 and November 2021. The primary outcome was periodontitis and the secondary outcomes were overall survival (OS), progression-free survival (PFS), and objective response rates. The propensity score matching was performed using basic demographics, underlying comorbidities, cancer type, and cancer therapy. The risk of periodontitis and associations between periodontitis and survival were evaluated using Cox proportional hazard analysis and Kaplan-Meier survival analysis. Results: We matched 868 patients receiving ICIs to patients who did not receive ICIs. Among ICI users, 41 (4.7%) patients developed periodontitis. The incidence rate of periodontitis was about 2-fold higher in ICI users than non-users (55.3 vs 25.8 per 100 patient-years; incidence rate ratio: 2.1 [95% CI: 1.4-3.3], p < 0.001). In Cox regression analyses, the use of ICI was associated with an 80-90% increased risk of periodontitis. The presence of immune-related periodontitis was associated with improved OS (median not reached vs. 17.8 months, p < 0.001), PFS (median 14.9 vs. 5.6 months, p = 0.009), and objective response rates (complete or partial response, 55% vs. 27%, p < 0.001). In Cox regression analyses, ICI use was associated with a 30-60% lower risk of all-cause mortality or disease progression. Conclusions: ICIs were associated with an increased risk of periodontitis. ICI-related periodontitis was associated with better survival outcomes and treatment responses.[Table: see text]