Study design: A retrospective cohort study.
Objective: We performed a retrospective study of patients treated at our institution over the last 3 years to assess predictive value of immunotherapy exposure on overall survival (OS) of patients with metastatic melanoma to the spine in an effort to better inform surgical decision making.
Summary of background data: Modern management of metastatic melanoma includes adjuvant targeted therapies and immunomodulators that have shown to significantly improve OS.
Methods: Baseline characteristics were recorded for patients, including performance scores, use of adjuvant therapies, progression-free survival (PFS), and OS. Pre-procedural imaging was reviewed to assign Spinal Instability Neoplastic Score (SINS) and epidural spinal cord compression (ESCC) classification. Kaplan-Meier survival analysis was performed.
Results: We identified 18 patients with metastatic melanoma to the spine treated between 2012 and 2015. Instrumented fixation was performed for median SINS 12. Eleven patients undergoing surgery were noted to have ESCC classification of at least 2. Median OS for the entire group was 117 days. Univariate analysis revealed that prior immunotherapy treatment was associated with significantly shorter survival following surgery (median survival 98 vs. 315 days for patients previously on immunotherapies compared to those who were not). Meanwhile, neither BRAF mutation status nor treatments targeting these pathways were associated with this prognostic effect.
Conclusion: Progressive metastatic spine disease following immunotherapy may herald a particularly aggressive time point and recognizing this natural history is critical for appropriate multimodal planning.
Level of evidence: 4.