The prognostic implications of Hyam's subtype for patients with Kadish stage C esthesioneuroblastoma

Esthesioneuroblastoma (EN) is a rare sinonasal tumor with varied aggressiveness and potential for intracranial invasion. EN is staged anatomically with radiographic evaluation using the Kadish staging system (stages A, B, and C) and histologically by using Hyam's criteria (grades 1-4). Here we show that despite radiographic evidence of aggressive features, the prognosis of patients with Kadish stage C EN is best predicted by tumor histology using Hyam's criteria. We retrospectively analyzed patients with EN with Kadish stage C who were evaluated and treated at our institution between 1995 and 2009. Clinical information was collected using patient medical records, imaging, and review of pathological specimens. Twenty patients with Kadish stage C EN were identified with mean age of 51 years (31-70 years) with a median follow-up of 41.4 months (1.3-175 months). Upon pathological review, 44.4% of patients had low-grade (1/2) and 55.6% had high-grade (3/4) histology. About 37.5% of patients with low-grade EN had undergone gross total resection (GTR) and the remaining 62.5% had GTR and adjuvant radiation, whereas 50% of patients with high-grade ER had undergone GTR, 20% had undergone GTR and adjuvant radiation, and 30% had been treated with a subtotal resection (STR) and adjuvant radiation. The 5-year and 10-year survival in patients with low-grade EN was 86% in comparison to 56% and 28% with high-grade EN, respectively. In patients with low-grade EN, the 2-year progression free survival (PFS) was 86% and the 5-year PFS was 65% in comparison to 73% and 49% in patients with high-grade EN, respectively. The patient's tumor histology (Hyam's criteria) appeared to be the best way of predicting the prognosis and for selecting patients for adjuvant radiotherapy.