Postdoctoral scholar Stanford University, School of Medicine
Introduction: Esthesioneuroblastoma (ENB), also known as Olfactory Neuroblastoma, is a rare malignant tumor of neuroectodermal origin that arise from the olfactory neuroepithelium. We present a series of patients with ENB metastasizing to the brain, treated with CyberKnife(CK) stereotactic radiosurgery(SRS), and determine the safety and effectiveness of SRS for distant brain metastasis in these patients. To the best of our knowledge, there are no previous radiosurgical series on ENB brain metastases.
Methods: We performed a retrospective analysis of clinical and radiological outcomes of patients with ENB who underwent CK SRS at a single center. The clinical and radiological outcomes of patients including progression-free survival(PFS), overall survival(OS), distant tumor control(DTC), and local tumor control(LTC) were reported.
Results: From 2003 to 2022, 31 distant brain metastases in 8 patients were treated with CK SRS at Stanford University. The median patient age was 55years (range:47-73). Among 31 lesions, CK SRS was used as the primary treatment for most of the lesions (29 [94%]), whereas 2 lesions(6%) were previously treated with open surgery. The lesions were found in the frontal lobe(n=13), temporal lobe(n=9), parietal lobe(n=3), dura(n=3), parasagittal(n=2), and cavernous sinus(n=1). The median target volume was 1.5cc (range 0.09-21.54). CK SRS was delivered by a median marginal dose of 23Gy (range 15-30) and a median fraction of 3 (range:1-5) to a median isodose line of 77% ( range:70-88). The median follow-up period was 27 months (range:3-95) at which time the LTC was 70.6%. Median PFS and OS in months were 18 (range:4-104) and 29 (range:4-104) respectively. None of the patients reported adverse radiation effects. DTC was 88%, with only one patient (12%) with 2 new lesions.
Conclusion : Brain metastasis in ENB is rare and there is a paucity of scientific data on this topic. Treatment with SRS provides good clinical and radiological outcomes with no adverse events due to radiation.
