Radiographic predictors of occult intracranial involvement in olfactory neuroblastoma patients

Abstract

BackgroundTraditional management of olfactory neuroblastoma (ONB) includes margin‐negative resection with removal of cribriform plate, dura, and olfactory bulb, regardless of intracranial disease. This approach may be overtreating certain patients. Our investigation examines risk factors associated with occult intracranial disease to optimize therapeutic outcomes.MethodsThis retrospective, multi‐institutional cohort study examined clinical covariates associated with occult intracranial involvement. Patient demographics, staging, Hyam's grade, and pathologic involvement of dura, olfactory bulb/tract, and brain were collected. Diagnostic imaging was reviewed. Positive and negative predictive value (NPV) were estimated along with effect size estimates. Cox hazard regression examined associations with overall survival (OS) and disease‐free survival (DFS).ResultsA total of 224 subjects with new diagnoses of ONB (2005–2021) were identified. Skull base bone involvement on computed tomography (CT) had the highest NPV for pathologic dura (88.0%), olfactory bulb (88%), and brain involvement (97.3%). Hyam's grade category was significantly associated with dural involvement (φC = 0.26; 95% confidence interval [CI]: 0.16, 0.42). Subjects without radiologic skull base involvement (n = 66) had pathologic positivity of 12.1%. Within this subgroup, Hyam's grade was clinically significant for dural positivity (φ = 0.34; 95% CI: −0.12, 0.71) with 28.6% involvement in high grade tumors. Neither clinical nor pathologic positivity of intracranial structures were associated with significantly different OS or DFS.ConclusionsBoth CT and magnetic resonance imaging (MRI) had reasonably good NPV for involvement of dura and olfactory bulb. Higher Hyam's grade was associated with dural involvement. Patients with low‐grade tumors not involving the skull base may be suitable for avoiding skull base resection; however, further investigation is warranted.

Treatment of unilateral olfactory neuroblastoma: Appropriate extent of surgical resection and potential for olfactory preservation

“…3 Among the subjects who did not have imaging evidence of intracranial disease, those patients with advanced Hyams grade (III/IV) tumors were more likely to have occult disease (29%) as compared to those with low-grade (I/II) disease (4%). 3 Several other studies evaluated the success of extracranial ONB resection in patients whose preoperative imaging did not show evidence of skull base or intracranial involvement. Cai et al reported their experience with extracranial ONB resection in which 11 patients (one Kadish A, seven Kadish B, one Kadish C, and two Kadish D) had 100% overall survival (OS) and 87% diseasefree survival (DFS) at 5 years.…”

“…For cases without obvious skull base involvement on imaging, a unilateral ONB resection including the dura and olfactory apparatus would capture any occult disease, estimated at 29% in grade III/IV and 4% in grade I/II tumors. 3 Small volume, low-grade tumors where midline dural margins can be easily cleared are best suited for this unilateral approach. The authors advocate against a completely extracranial ONB resection that preserves the cribriform plate, dura, and olfactory apparatus unless the tumor orig- inates from a region other than the olfactory cleft, leaving the skull base completely uninvolved (Figure 2).…”

“…Sole extracranial resection of ONB sparing the cribriform bone, dura, and olfactory apparatus risks leaving microscopic disease intracranially. In a recent multi‐institutional cohort study of 224 ONB patients, 12% of those without radiologic skull base involvement (8/66) had pathologically confirmed intracranial involvement ( n = 3 involving dura, n = 3 involving olfactory bulb, and n = 2 involving both) 3 . Among the subjects who did not have imaging evidence of intracranial disease, those patients with advanced Hyams grade (III/IV) tumors were more likely to have occult disease (29%) as compared to those with low‐grade (I/II) disease (4%) 3 .…”

“…In a recent multi‐institutional cohort study of 224 ONB patients, 12% of those without radiologic skull base involvement (8/66) had pathologically confirmed intracranial involvement ( n = 3 involving dura, n = 3 involving olfactory bulb, and n = 2 involving both) 3 . Among the subjects who did not have imaging evidence of intracranial disease, those patients with advanced Hyams grade (III/IV) tumors were more likely to have occult disease (29%) as compared to those with low‐grade (I/II) disease (4%) 3 . Several other studies evaluated the success of extracranial ONB resection in patients whose preoperative imaging did not show evidence of skull base or intracranial involvement.…”

“…Unilateral ONB resection including the cribriform plate, dura, and olfactory bulb and tract may be considered for cases under the following circumstances: (1) tumors not involving the contralateral septal mucosa or olfactory cleft and (2) adequate clearance of midline dural margins with intraoperative frozen pathology (Figure 1). For cases without obvious skull base involvement on imaging, a unilateral ONB resection including the dura and olfactory apparatus would capture any occult disease, estimated at 29% in grade III/IV and 4% in grade I/II tumors 3 . Small volume, low‐grade tumors where midline dural margins can be easily cleared are best suited for this unilateral approach.…”