Impact of nodal involvement on survival outcomes in chondrosarcoma: retrospective cohort analysis of Surveillance, Epidemiology, and End Results (SEER) database (2004-2015)

Objectives: Factors associated with nodal involvement in chondrosarcoma and outcomes based on treatment modality were analyzed using the Surveillance, Epidemiology, and End Results (SEER) database. Methods: Chondrosarcomas involving axial and appendicular parts of the body diagnosed from 2004 to 2015 were identified in SEER. Clinical, pathologic, and treatment parameters were compared with respect to nodal status at initial diagnosis by Fisher's exact or Student's t-test. Disease-specific survival (DSS) and overall survival (OS) were evaluated by Kaplan-Meier analyses, and by Cox regression models. Results: Synchronous regional nodal metastases were present in 1.3% of chondrosarcoma patients. Lymph node involvement was associated with primary tumor location in extraskeletal tissue and the pelvis, and with distant metastasis and larger primary tumor size at diagnosis. Patients with nodal involvement had 5-year DSS of 48% [95% confidence interval (CI): 28%-65%], versus 82% (95% CI: 80%-84%) for those without (log-rank P0.001). 5-year OS with and without nodal involvement were 38% (95% CI: 21%-55%) and 73% (95% CI: 71%-75%), respectively (log-rank P0.001). Surgical excision of nodes was associated with improved DSS and OS. Radiation and chemotherapy were not associated with improved DSS/OS. Conclusions: The nodal disease is uncommon at presentation in chondrosarcoma. Greater clinical vigilance for regional nodal metastases may be warranted for those with specific risk factors, including extraskeletal or pelvic primary sites, myxoid, mesenchymal, or dedifferentiated histologies, and large size. Surgical excision of regional nodes is associated with improved DSS/OS. This analysis suggests a therapeutic effect of surgical treatment, rather than selection for favorable underlying biological factors.