Chondrosarcoma of the Mobile Spine: An Update on Patients Treated at a Single Institution.

Study design: Retrospective study.

Objective: The objective of this study was to report the clinical data for patients treated with mobile spine chondrosarcoma.

Summary of background data: Chondrosarcoma of the mobile spine is a rare and challenging entity. A handful of case series have been published that report the clinical results of treatment, largely influenced by chondrosarcoma of the appendicular skeleton and pelvis. The clinical results of patients treated for chondrosarcoma of the mobile spine from our institution were published over 10 years ago and this represents and update since that publication.

Methods: Inclusion criteria were adults patients treated for chondrosarcoma of the mobile spine at Massachusetts General Hospital between 2007 and 2020. Patients with large sacral tumors extending into the lumbar spine were excluded. Furthermore, we excluded patients with metastatic chondrosarcoma undergoing palliative decompressions for neurological instability or instrumented procedures for biomechanical instability. Therefore, only patients undergoing definitive surgery at the primary site of disease in the mobile spine were included.

Results: A total of 24 patients were included for review in this series. Seventeen of the 24 patients had their tumors excised with negative (R0) margins. Three of these 17 patients (18%) were dead of disease at final follow-up. There were two patients with R1 resections and five patients with R2 resections. Three of the seven patients (43%) with positive margins were dead of disease at final follow-up. A Cox proportional hazard analysis indicated total radiation dose was a significant covariate (HR=1.18, 95% CI: 1.01-1.39, P =0.03).

Conclusions: We found higher percentages of overall survival with R0 tumor resection and lower histologic grade, whereas development of metastatic disease was closely associated with local recurrence and poor survival. Despite the improvements in treatment paradigms, it is sobering that our findings largely mirror those of previous work considering patients treated between 1984 and 2006.