Abstract
e23510
Background: Ewing sarcoma is the one of the most common primary malignancies of bone, with an incidence of about 1 case per million in the United States. Ewing sarcoma typically affects the pelvis, axial skeleton, and femur. However, this cancer can affect other bony regions and, to the author’s knowledge, all possible primary sites have not been investigated in-depth in regards to tumor location and the effect it may have on outcomes. The aim of this study is to conduct such an investigation to see whether or not the primary site of the tumor in osteosarcoma patients may have an effect on survival. Methods: Using the NCDB, patients diagnosed with Ewing sarcoma between 2004-2018 were identified using ICD-O-3 histology code 9260. The cohort was analyzed to investigate survival outcomes in different primary sites. Univariate analysis was then performed assessing patient length of survival for each primary site subtype. Data was analyzed using SPSS and statistical significance was set at α = 0.05. Results: A total of 4284 patients with known primary site that had survival data were included. The sites with the best survival were the skull, face, and mandible and upper limb. Patients with primary tumor of the skull, face, and mandible survived significantly longer than all groups other than the upper limb (all p < .01). Upper limb patients survived significantly longer than all groups other than the skull, face, and mandible and lower limb (all p < .05). The labeled primary site with the lowest survival was the pelvis, sacrum, and coccyx and significantly lower than the lower limb, vertebral column, and ribs, sternum, and clavicle (all p < .01). Survival of patients with primary site of the upper limb versus lower limb, and vertebral column versus ribs, sternum, and clavicle did not differ (each p > .05). Conclusions: This study found numerous survival differences between patients diagnosed with Ewing sarcoma of different primary sites. Labeled primary sites of the skull, face, and mandible and upper limb were associated with best survival while the pelvis, sacrum, and coccyx were associated with worst survival. Future studies may benefit from investigations into variables that may impact the survival differences we have presented including staging, treatments, time from diagnosis to treatment, and insurance status.[Table: see text]