Role of induction chemotherapy in advanced‐stage olfactory neuroblastoma

Abstract Objectives To evaluate the treatment outcomes in patients with advanced‐stage olfactory neuroblastoma (ONB) who received induction chemotherapy (IC). Materials and methods The clinical data of 38 patients with advanced‐stage ONB who received initial IC were retrospectively analyzed. The response was defined using the Response Evaluation Criteria in Solid Tumors version 1.1. Patients with complete remission or partial remission were defined as responders. Results Seventeen (44.7%) patients responded to IC. The response rate was higher in patients with high Hyams grade tumor (III/IV) compared to those with low‐grade tumors (I/II) (60% vs. 22.2%, p = 0.038). Overall, the 5‐year cancer‐specific survival (CSS) rate was 76.0%. Among nonresponders to IC, a significant difference in 5‐year CSS rates was observed between surgery with adjuvant radiotherapy (RT) (100%) versus definitive RT or chemoradiotherapy (CRT) (68.6%) (log‐rank p = 0.006). However, for responders, there was no significant difference in 5‐year CSS rates between surgery with adjuvant therapy (75%) and definitive RT or CRT (51.1%) (log‐rank p = 0.536). When only high‐grade tumors were considered among responders, the 5‐year CSS rate was significantly higher in patients who received RT or CRT (51.4%) compared to those who underwent surgery with adjuvant therapy (0%) (log‐rank p = 0.008). Conclusion In advanced‐stage ONB, RT or CRT may be preferable for high‐grade tumor responding to IC. Higher response rate and a potential role for induction IC in determining the optimal definitive treatment modality suggest a positive role for advanced‐stage high‐grade ONB.