Survival outcomes of patients with de novo stage metastatic head and neck cancer: A single center experience.

e18024 Background: Metastatic head and neck cancer (HNC) at the time of diagnosis is rare and occurs in 10% of cases. It has a poor prognosis, however, immune therapy has improved the outcomes of patients with this aggressive disease. This study evaluates survival outcomes and prognostic factors in patients treated in a single center. Methods: We conducted a retrospective analysis and included all adult patients with de novo stage IVC HNC treated at Cleveland Clinic between 2010 and 2022. Cancers of the oral cavity, oropharynx (HPV-positive and -negative), hypopharynx, larynx, and sinuses were included. Treatments consisted of chemotherapy, immune therapy (IT) + platinum-based regimens, or pembrolizumab. Responses were assessed using RECIST v1.1 criteria. Kaplan-Meier analysis was performed for overall survival (OS) and progression-free survival (PFS), and multivariable Cox regression identified prognostic factors. Results: We identified 42 Stage IVC HNC patients who received treatment. 30 (71%) received chemotherapy, 5 (12%) received IT + platinum regimens, and 7 (17%) received pembrolizumab. Radiation therapy was given to 52% of patients and none of the patients had surgery. Table 1 describes the baseline characteristics of the patients. The median follow-up time for survivors was 34.6 months. The median OS was 14 months (95%CI: 10-18) with 1-year and 2-year OS rates of 52% (95%CI: 39-70%) and 23% (95%CI: 13-41%), respectively. Overall response to therapy was 41%. IT + platinum regimens showed the best 2-year OS (60%) compared to chemotherapy (20%) and pembrolizumab (14%), but not statistically significant (P=0.2). Median PFS was 11 months (95%CI: 7-18) with 1-year and 2-year PFS rates of 45% (95%CI: 32-63%) and 21% (95%CI: 11-38%). On multivariable Cox regression, when compared to chemotherapy alone, the use of IT + platinum regimens was associated with improved OS but this was not statistically significant (HR 0.41, 95% CI: 0.1-1.8, P=0.2). The use of single-agent pembrolizumab was associated with decreased OS but this was not statistically significant (HR 1.32, 95% CI: 0.54-3.23, P=0.4), when compared to chemotherapy alone. Conclusions: Stage IVC HNC remains challenging with poor survival despite novel treatment. In our study, IT + platinum regimens showed a non-significant higher survival rate compared to chemotherapy, likely because of sample size. Our findings are consistent with randomized trials’ results. Because this presentation is less frequent, multi-institutional collaborations are needed to understand its biological behavior and molecular characteristics compared to locoregional HNC. Characteristic (N=42) Age at diagnosis (IQR), years 67 (60-75) Gender, Male (%) 37 (88) Race, White (%) 36 (86) Current Smoker (%) 18 (43) ECOG 0/1/2 (%) 40 (98)