Impact Of Local Therapy On Survival In Hpv Plus And Hpv- Metastatic Oropharyngeal Cancer

Recent evidence suggests a benefit to local treatment in select patients with metastatic cancer. We queried the National Cancer Database (NCDB) to assess whether local radiation therapy (RT) improves survival in patients presenting with metastatic oropharyngeal cancer. Patients with M1 oropharyngeal squamous cell carcinoma diagnosed between 2004-2016 were identified in the NCDB. Management of these patients included RT to the head and neck, local surgery, chemotherapy, immunotherapy, and no cancer directed therapy. We used multivariable Cox regression to determine hazard ratios (HR) for each treatment modality while adjusting for age, sex, insurance type, oropharynx subsite, Charlson/Deyo score, diagnosis year, T category, and N category. Each treatment was included in the Cox model as a time-varying covariate. The association between HPV status and overall survival (OS) was assessed using Kaplan-Meier survival curves. HPV status information was not collected until 2010, and 66% of patients with known status were identified from 2013-2015. We identified 2597 patients with a mean age of 61 years. A majority of patients were male (81%) and a majority had a Charlson/Deyo score of 0 (76%). The most common AJCC 7th edition clinical T category was T4 (34%) and over half of patients (55%) had clinical N2 disease. A majority of patients received chemotherapy (68%), almost half (47%) received RT to the primary site, a small percentage received local surgery (12%) and a sizable group received neither systemic therapy nor radiation (22%). The median time from diagnosis to start of therapy was 39 days for chemotherapy and 54 days for RT. On multivariable analysis, receiving systemic therapy, radiation therapy, or surgery independently improved the HR for death (Table 1, all patients). Limiting the dataset to only those patients receiving chemotherapy, the HR for death was similarly improved in patients who received RT or local surgery in addition to chemotherapy (Table 1, chemotherapy subgroup). Increasing RT dose was associated with higher median survival in unadjusted analysis. Median survival was 7.5 months, 13.7 months and 20.3 months for total doses of 8-30 Gy, 31-59 Gy and 60+ Gy, respectively. HPV status was known in 27% of patients and HPV-positive patients had a higher overall survival (HR = 0.718, p = 0.0011) when compared to HPV-negative patients. For HPV-negative disease, Kaplan-Meier curves showed a 2-year OS of 25% for patients not receiving RT and 34% for patients receiving RT. Similarly, in HPV+ patients, 2-year OS increased from 35% without RT to 50% with RT. Radiation to the primary site improves overall survival in patients with metastatic oropharyngeal cancer at diagnosis. This benefit is maintained if a patient is receiving systemic chemotherapy.Abstract 3916; TableAll patients (n = 2597)Chemotherapy subgroup (n = 1737)HRp valueHRp valueChemotherapy0.609<0.0001refrefRadiation0.8870.02460.8550.0116Surgery0.7670.00060.8210.0463 Open table in a new tab