Gardner, Paul

Importance Adjuvant radiotherapy can improve locoregional control and survival in patients with olfactory neuroblastoma (ONB), particularly with advanced-stage and histologic-grade disease. Standard radiotherapy treatment is with intensity-modulated radiotherapy (IMRT). Proton beam radiotherapy (PBRT) provides theoretical advantages in greater sparing of dose to uninvolved organs at risk. Objective To investigate if there are differences in the effectiveness and radiation treatment–related adverse events (RTAEs) between adjuvant IMRT and PBRT for patients with ONB. Design, Setting, and Participants This propensity score–matched cohort study included patients with ONB treated between February 2005 and April 2021 with either IMRT or PBRT at 9 academic tertiary care centers in North America. Patients were matched 1:2 based on age, modified Kadish stage, and Hyams grade. Data were analyzed from July 2024 to January 2025. Exposure Adjuvant IMRT or adjuvant PBRT. Main Outcomes and Measures Local recurrence-free survival (RFS), any RFS, and overall survival (OS). RTAEs, ie, grade 2 events or higher based on Common Terminology Criteria for Adverse Events, were recorded for both modalities. Results Of 54 included patients, 27 (50%) were female, and the mean (SD) age was 46.2 (15.4) years. A total of 18 were treated with PBRT and 36 were treated with IMRT. Most patients had modified Kadish stage C disease (33 of 54 [61%]), and 24 patients (44%) had Hyams grade III or IV disease. The RTAE rate was 20% (8 of 40); IMRT had a rate of 21% (6 of 29), and PBRT had a rate of 18% (2 of 11). The difference in the point estimates for 10-year RFS showed a potential clinical benefit favoring IMRT, although the wide confidence interval indicates uncertainty (10-year RFS: IMRT, 63.3%; 95% CI, 44.6-89.8; PBRT, 37.8%; 95% CI, 14.2-100; difference, 25.5 percentage points; 95% CI, −17.6 to 68.6). There were no clinically meaningful differences in 10-year local RFS (IMRT, 75.6%; 95% CI, 59.8-95.4; PBRT, 72.7%; 95% CI, 45.2-100; difference, 2.9 percentage points; 95% CI, −35.9 to 41.7) or 10-year OS (IMRT, 61.8%; 95% CI, 42.8-89.1; PBRT, 57.1%; 95% CI, 24.3-100; difference, 4.7 percentage points; 95% CI, −49.2 to 58.6), although wide confidence intervals indicate considerable uncertainty. Conclusions and Relevance Due to the imprecision of estimates, no definitive conclusions can be made regarding the comparative effectiveness of IMRT vs PBRT for patients with ONB. These preliminary data may inform the design of appropriately powered prospective studies evaluating the efficacy of PBRT vs IMRT in this population.

AbstractObjectiveNeck metastases are a poor prognostic factor in olfactory neuroblastoma (ONB). Pathologic dural invasion (pathDI) may increase the risk of neck metastases due to invasion of dural lymphatics. We aim to evaluate the prognostic value of pathDI in predicting rates of neck metastases and recurrence using a large, multicenter database of ONB patients.Data sourcesRetrospective review of a prospective, multicenter database of electronic health records of all patients who presented with ONB between 2005 and 2021 at nine tertiary academic care centers within North America.Review methodsClinicopathologic features including modified Kadish staging systems, margin status, treatment modalities, Hyams grading, follow‐up time, and survival.ResultsOf 258 ONB patients, 189 patients met the inclusion criteria. The 10‐year neck recurrence‐free survival (neck‐RFS) rates were 85.7% (75.6‒97.3) and 61.8% (47.9‒79.8) for patients without and with pathDI, respectively (p = 0.018). Time‐to‐event multivariable regression analysis found pathDI to have an odds ratios of 9.7 (95% confidence interval [CI] 1.2–80.4, p = 0.04) for neck‐RFS and 9.5 for RFS at any site (95% CI 1.1–83.3, p = 0.04).ConclusionIn multivariable analysis, the presence of pathDI appears to be the strongest predictor of neck recurrence and recurrence at any site. Future studies exploring the benefit of elective neck dissection or radiation for patients with pathDI may impact disease management.