Isolated leptomeningeal progression from sinonasal carcinomas: Implications for staging workup and treatment

Purpose To evaluate the rate and risk factors of isolated leptomeningeal progression in sinonasal carcinomas. Methods We retrospectively reviewed imaging and clinical records to determine progression patterns, and estimated rates using the Kaplan‐Meier method. We evaluated risk factors using proportional hazard regression. Results We analyzed 120 patients who received adjuvant or primary radiotherapy for sinonasal carcinomas. Most patients had T4 disease (68%) and underwent surgery (84%) and chemotherapy (72%). Twenty‐seven (23%) patients developed distant metastases (DM), including 20 (17%) with isolated DMs. Leptomeningeal progression was the most common site of isolated DMs (n = 9; 45%) with an average disease‐free interval of 1.2 years (0.1‐4.3 years). High‐grade histology (P = 0.0003), intracranial invasion (P