(0697) Outcomes of Orbit-Sparing Treatment in Olfactory Neuroblastoma With Orbital Involvement: A Retrospective Cohort Study

Introduction: Olfactory neuroblastoma (ONB) is a rare, aggressive sinonasal cancer with a propensity to invade local structures, including the orbit. Treatment decisions in such cases require consideration of orbit-sparing vs non-orbit-sparing approaches. Here, we aim to evaluate outcomes in patients with ONB based on degree of orbital involvement.

Methods: A retrospective analysis of patients with orbital invasion of ONB at our institution between 1996 and 2019 was conducted. Patients were classified into groups based on the extent of orbital involvement: 1. Lamina abutted but intact; 2. Lamina thinned, but globe not displaced; 3. Lamina eroded, and globe displaced but periorbita not invaded; and 4. Orbit and periorbita grossly invaded. Descriptive statistics, Fischer exact tests for categorical, and Kruskal-Wallis analysis for numerical variables were employed for data analysis.

Results: Our cohort consisted of 40 patients with orbital invasion of ONB that underwent surgical interventions with orbital preservation. Median age was 53 years and was predominantly male (65%). The distribution among the four groups was: group 1 = 13 (33%); group 2 = 14 (35%); group 3 = 4 (8%); group 4 = 10 (25%). Gross total resection was achieved in 35 patients (88%), with group 4 patients more likely to undergo subtotal resection (p = 0.003). Margin-negative resection was achieved in 24 patients (60%). Additionally, 16 patients (40%) experienced postoperative functional deficits, with 5 exhibiting immediate deficits and 12 experiencing delayed deficits. Of patients with deficits, 5 regained full visual function. A sum of 23 patients (57.5%) experienced recurrence. No correlation was observed between the extent of orbital invasion and the likelihood of recurrence at any site (orbital, local, regional, or distant). At last follow-up (median 94.5 months), 27 patients (67.5%) were alive, and 13 (32.5%) were deceased. There were no discernible differences in survival based on the degree of orbital invasion.

Conclusions: Orbital preservation can be achieved with minimal functional deficits and reasonable oncologic outcomes in most cases of ONB with orbital involvement.