Routine Cancer Imaging Detects Risk of Metastatic Spinal Cord Compression and Time to Fracture
My Nguyen1, Jerome Graber2
1University of Washington, 2Neurology, University of Washington
Objective:
The purpose of my retrospective study is to determine whether the Spinal Instability Neoplastic Score (SINS) can be applied to routine cancer restaging imaging with predictive power, potentially allowing for earlier interventions such as radiation, bone-strengthening chemotherapy, or vertebroplasty to reduce risk of compression.
Background:
Metastatic epidural spinal cord compression (MESCC) occurs in 5-10% of all metastatic cancer patients, and delayed treatment risks paralysis and decreased survival. Treatments for MESCC (surgery, radiation) decrease risk of paralysis and death. Early detection of MESCC collapse risk and preventive approaches are preferred, and several have been validated based on imaging and clinical factors, but are not routinely applied to cancer patients having routine restaging imaging.
Design/Methods:
I reviewed 153 patient charts with spinal metastasis from breast, lung and kidney cancer who received MRI, CT, or PET imaging routinely done as part of their cancer monitoring before MESCC occurred. SINS scores were assigned using routine cancer imaging. For patients with a compression fracture, time elapsed between the initial spinal metastasis diagnosis and the fracture occurrence were calculated. Kaplan-Meier Survival Analysis evaluated whether there was a difference in time before MESCC occurrence among the different subgroups of SINS stability category.
Results:
MESCC occurrence was 100% in the Unstable category (SINS 13-18), 67% in Potentially Unstable (SINS 7-12) and 4% in Stable (SINS 0-6). The Potentially Unstable median survival times were 45, 17, and 3 months for SINS 7-8, 9-10, and 11-12 groups, respectively.
Conclusions:
The SINS classification system has power in establishing time to compression fracture and MESCC occurrence in secondary spine metastases from breast, kidney, and lung cancer. This may allow preventive screening in at risk patients and guide urgency of treatment interventions to prevent MESCC and associated paralysis and death.