Olfactory Neuroblastoma: A Multicenter Survival Analysis and Application of a Staging Modification Incorporating Hyam's Grade

Background: Olfactory neuroblastoma (ONB) is a rare sinonasal malignancy with favorable survival and frequent delayed recurrence. Current staging systems including the Kadish, modified Kadish (mKadish), and Dulguerov systems poorly delineate locally advanced tumors and do not incorporate histologic grade. The two primary aims of this multi-institutional study were to 1) examine the clinical covariates associated with survival and recurrence of ONB in the modern era and 2) incorporate Hyam's tumor grade into existing staging systems and to assess its ability to predict survival and recurrence.