Nationwide Analysis of Olfactory Neuroblastoma in Japan: Evolving Treatment Approaches and Prognostic Outcomes

Background : Olfactory neuroblastoma (ONB) is a rare and malignant tumor of the nasal cavity. This study aimed to analyze cases of ONB from the Head and Neck Cancer Registry of Japan. Methods : We identified 346 patients with ONB from 90,885 head and neck cancer registrations between 2011 and 2019. Data on demographics, TNM stage, and treatment modalities (surgery, radiotherapy, and chemotherapy) were collected. Patients were divided into early (2011–2015) and late (2016–2019) groups to assess changes in treatment patterns. Survival was analyzed in 95 patients with available follow-up data. Results : T4 lesions were frequently observed, and 234 patients (67.6%) underwent surgery-based treatment, typically combined with radiotherapy. Over time, the use of endoscopic approaches increased significantly, replacing open cranial base surgery. Among the 95 patients with evaluable follow-up data, the 5-year overall survival (OS) rate was 85.1%, while the recurrence-free survival (RFS) rate was 62.7%. Patients younger than 60 years and female patients had improved OS. Postoperative radiotherapy improved RFS but did not impact OS. Chemotherapy was frequently used in cases requiring extensive cranial base resections. Conclusions : This large-scale, multicenter study provides insight into ONB treatment trends and outcomes in Japan. Although the 5-year prognosis is favorable, a significant risk of recurrence remains, emphasizing the need for optimized long-term treatment strategies. The widespread adoption of endoscopic surgery suggests shift toward less invasive approaches. Further prospective studies are needed to refine therapeutic options and improve long-term outcomes for patients with ONB.