SADA-22 CHARACTERIZING MOLECULAR AND CLINICAL FEATURES OF SYSTEMIC CANCERS THAT SPREAD TO THE INTRADURAL SPINE

Abstract

Metastatic cancers to the central nervous system (CNS) usually affect the brain, but a small and clinically significant portion also affect the intradural spinal space. Here, we characterize the molecular features of metastatic intradural spinal disease and describe the metastatic chronology such lesions go through to reach this space. All patients with MRI spine findings of intramedullary or leptomeningeal lesions from 2020–2025 at a tertiary academic center were screened. Patients with primary CNS cancer or non-cancer diagnoses were excluded. Demographic information, imaging findings, dates of primary cancer and metastasis detection, and molecular data across disease sites were collected. The primary outcome of interest was overall survival (OS) after primary diagnosis. 69 patients met inclusion criteria out of 1401 patients screened. The most common primary pathologies were lung (33.3%) and breast (31.9%). 11.6% of patients underwent surgery for intradural disease. The distribution of intradural spine disease on initial detection was 55.1% cervical, 65.2% thoracic, and 76.8% lumbar. The mortality rate was 87.0% within a median follow-up of 20.6 (IQR 42.0-72.9) months. The median time to any metastasis was 0.5 (0-6.7), to the brain was 14.9 (0.6-42.7), to the osseous spine was 19.4 (0.7-38.9), and to the intradural spine was 29.5 (14.0-52.6) months. Targetable mutations were noted in 46.4% of primary lesions and such patients trended towards improved OS (51.7 months, 31.2-105.2) compared to patients without (30.1 months, 12.6-58.9, p = 0.072). Actionable mutations are present in nearly 50% of patients who develop spinal intradural disease, and so regular molecular characterization and sequencing of this space (e.g. CSF liquid biopsy) could have a clinically meaningful impact on these patients. Further, surveillance imaging of patients concerning for spinal intradural disease can miss >25% of intradural spinal disease if MRI of only one part of the spine is regularly imaged.