Survival impact of postoperative radiotherapy in patients with olfactory neuroblastoma: 513 cases from the SEER database.

PUPOSE To evaluate the impact of postoperative radiotherapy (PORT) on survival in olfactory neuroblastoma (ONB) patients with different tumor staging. MATERIAL AND METHODS Patients with ONB were selected in the Surveillance, Epidemiology and End Results (SEER) database from 2004-2016. Survival analyses were performed using Kaplan-Meier (K-M) method, Cox regression analysis, and competing risk model. RESULTS A total of 513 patients were included in the study. Univariate and multivariate analysis results demonstrated that PORT was not an independent prognostic factor for overall survival (OS) of modified Kadish stage A and B patients (P=0.699 and P=0.248, respectively). Kadish stage C and D patients who underwent PORT had significantly better OS than those who did not undergo PORT (P=0.03 and P<0.0001). K-M curves revealed that the 5- and 10-year OS rates of patients who underwent PORT vs. non-PORT were 85.3% vs. 70.4% and 68.2% vs. 56.8% in stage C patients, respectively. For stage D patients, the 5-year OS rates were 70.7% and 42.6%, and 10-year OS rates were 53.4% and 29.5% in the PORT and non-PORT groups, respectively. The competitive risk model revealed that the 5-year cancer-specific cumulative mortality incidence decreased by 26.6% while the 10-year mortality incidence decreased by 41.4% in Kadish stage C patients who were treated using PORT; meanwhile, for Kadish stage D patients who were treated with PORT, the 5- and 10-year mortality incidences were reduced by 35.3% and 42.6%, respectively. Furthermore, we found that chemotherapy was not related to the prognosis of ONB patients (all P>0.05). CONCLUSION Our results indicate that PORT improved survival outcomes of modified Kadish stage C and D ONB patients. However, PORT may not affect survival for modified Kadish stage A and B individuals. Chemotherapy was not recommended for ONB; therefore, further studies are warranted to determine its therapeutic significance.