24P Sinonasal neuroendocrine tumors: Analysis of therapeutic strategies in an ultra-rare tumor

Sinonasal neuroendocrine tumors are a rare histological subtype of sinonasal carcinomas. Most of these tumors are diagnosed as an advanced disease and, due to their rarity, there is no optimal treatment sequence that has been established. The aim of the present work is to review our institutional experience with sinonasal undifferentiated carcinomas (SNUC) and esthesioneuroblastomas (ENB) as well as to analyze the different therapeutic strategies and their impact in terms of survival and disease control. This is a retrospective observational study, in which epidemiological data were collected and analyzed, as well as those related to the disease and its initial management in localized or locally advanced disease, in patients diagnosed with SNUC or ENB from 2009 until the present, at The Miguel Servet Hospital. The Kaplan Meier method was used to estimate disease-free survival (DFS) and overall survival (OS). We identified 15 patients with sinonasal neuroendocrine tumor; 73.3% were SNUC and 26.7% ENB. The median age at diagnosis was 61 years. Most cases were diagnosed as a locally advanced disease. Regarding initial management, 12 patients received induction chemotherapy (IC), and 3 underwent primary surgery. In all cases they received subsequent chemo-radiotherapy (CRT). With a median follow-up of 44 months, 26.7% of patients had relapsed, and only one patient had died. The 5-year DFS was 60.6%, while the 5-year OS was 83.3%. No significant differences were observed in DFS or OS according to the therapeutic strategy. We did observe a lower DFS in N+ patients in comparison to N0 patients (29 months vs 156 months, p=0.002), with a risk of relapse 10 times higher in N+ patients than in N0 patients (p=0.001). It seems to be no difference in terms of survival and disease control between IC and primary surgery, followed in both cases by CRT. Nodal involvement could be considered a risk factor for relapse. However, in order to compare therapeutic alternatives and analyze prognostic factors we would require a larger sample size and a prospective study design.