Association of Extent of Local Tumor Invasion and Survival in Patients with Malignant Primary Osseous Spinal Neoplasms from the Surveillance, Epidemiology, and End Results (SEER) Database

BACKGROUND: Malignant osseous spinal neoplasms are aggressive tumors associated with poor outcomes despite aggressive multidisciplinary measures. It remains unknown whether increased local tumor invasion at time of treatment predicts worse survival. The surveillance, epidemiology, and end results (SEER) registry was reviewed to determine whether extent of local tumor invasion at presentation was independently associated with overall survival. METHODS: The SEER registry (1973-2003) was queried to identify cases of histologically confirmed primary spinal chordoma, chondrosarcoma, osteosarcoma, or Ewing sarcoma. Extent of local invasion was defined at time of care by histology, radiology, or intraoperative assessment and classified as confined (tumor within periosteum), local invasion (extension to surrounding tissues), or distal metastasis. The association of extent of local tumor invasion with overall survival was assessed by Cox analysis. RESULTS: One thousand eight hundred ninety-two patients were identified (414 chordoma, 579 chondrosarcoma, 430 osteosarcoma, 469 Ewing sarcoma). Overall median survival was histology specific (osteosarcoma, 11 months; Ewing sarcoma, 26 months; chondrosarcoma, 37 months; chordoma, 50 months) and correlated with extent of local tissue invasion or metastasis at presentation. Presence of metastasis was associated with marked decrease in survival (P < 0.001) for all tumor types. For patients with isolated spine tumors, neoplasms confined within the periosteum were associated with improved overall survival independent of age, radiotherapy, or surgical resection for chordoma (hazard ratio [HR], 0.50; P = 0.08), chondrosarcoma (HR, 0.62; P = 0.03), and osteosarcoma (HR, 0.68; P = 0.05), but not Ewing sarcoma (HR, 0.62; P = 0.27). CONCLUSIONS: The preoperative radiographic recognition of local tissue invasion may identify patients with a more aggressive tumor and help guide the level of aggressiveness in subsequent treatment strategies.