Osteosarcoma of the mobile spine: A single-institution experience of 32 patients.

Abstract

Background context: Osteosarcoma of the mobile spine is a rare and complex condition, with limited case series informing treatment decisions. Recent advancements in treatment paradigms, particularly in en bloc resection and novel radiation techniques, may incite new treatment guidelines and improve patient outcomes. The clinical outcomes of patients treated for osteosarcoma of the mobile spine at our institution were reported over a decade ago, and this study provides an updated assessment of management strategies and patient outcomes since the initial publication.

Purpose: To provide an updated analysis of clinical results for the treatment of mobile spine osteosarcoma.

Study design/setting: Retrospective cohort study.

Patient sample: Thirty-two patients treated at a single center for osteosarcoma of the spine over 22 years.

Outcome measures: Estimation of overall patient survival, local recurrence, and the presence of metastatic disease.

Methods: Inclusion criteria were adult patients treated for osteosarcoma originating in the vertebral column with the exclusion of the sacrum at Massachusetts General Hospital between 2001 and 2023. The overall survival was evaluated using the Kaplan-Meier method, grouped by type of resection (en bloc versus intralesional) and histological subtype (osteoblastic, chondroblastic, other/unknown). Prognostic factors were assessed using Cox proportional hazards modeling.

Results: Twenty-two of the 32 patients were given en bloc resection, while ten received piecemeal resection. We found higher overall survival with en bloc resection compared to intralesional resection (median survival 81.54 months versus 12.42 months, p=0.006) using Kaplan-Meier analysis techniques. However, in multivariable regression, neither en bloc resection nor histological subtype were predictive of better outcomes. Resection of greater than one level and younger age were associated with poor survival (p<0.05).

Conclusions: This study highlights the continued challenges for patients with spinal osteosarcoma despite advances in surgical techniques and radiation modalities. If feasible, en bloc resection yields improved overall survival compared to intralesional resection, but the five-year mortality rate remains high. Histological subtype did not significantly predict outcomes, while tumors involving multiple vertebral levels and younger age were associated with worse survival.