Stereotactic radiosurgical salvage treatment for locally recurrent esthesioneuroblastoma

Background: Esthesioneuroblastoma (ENB) is a rare malignant neuroendocrine tumor considered to be radiation sensitive. Local recurrence may be treated in a variety of ways, including stereotactic radiosurgery (SRS); however, little information on its effectiveness is available. Objective: To determine whether SRS is effective in providing local control for recurrent ENB. Methods: This was a retrospective single-institution experience including 109 patients with ENB treated at the Mayo Clinic (1962-2009). Sixty-three patients presented with Kadish stage C disease, and 21 patients developed local recurrence. Of these 21 patients, 7 patients underwent SRS at our institution and an additional patient underwent SRS after transnasal biopsy. Therefore, a total of 8 patients are reported. Results: The median age at time of local recurrence was 50 years. All patients had Kadish C disease at initial diagnosis. Six of 8 patients were found to have Hyams grade 3 disease; the remaining 2 patients had grade 2 disease. The median treatment volume was 8.4 cm (mean, 18.9 cm; range, 1.4-76.3 cm), and the median dose to the tumor margin was 15 Gy (mean, 14.4 ± 2.2 Gy; range, 10-18 Gy). Of the 16 treatments, 13 had adequate follow-up to assess treatment response, with 92% achieving local control over a median follow-up of 42 months from the time of SRS. Five lesions decreased in size, 7 lesions stabilized, and only 1 lesion had in-field progression. There were no documented complications secondary to SRS. Conclusion: SRS appears to be a reasonable and safe option for treatment of intracranial recurrence of ENB. Abbreviations: EBRT, external beam radiotherapyENB, esthesioneuroblastomaSRS, stereotactic radiosurgery.