Introduction: Surgery for spinal metastases can improve survival and reduce pain, but has high morbidity that can diminish the surgery benefits and hasten demise.1 With the limited prognostic ability of Tokuhashi and Tomita scores,2-4 new objective ways of predicting overall survival are necessary. Analytic morphometrics quantifies patient frailty and can predict overall survival in lung cancer patients with spine metastases.5 This study evaluates whether morphometrics is predictive of survival in prostate cancer patients with spinal metastasis.

Methods: Utilizing a retrospective registry of spinal metastases patients who have undergone stereotactic body radiation therapy, we identified females with primary prostate cancer. Morphometric measurements of the psoas muscle were taken from the most recent lumbar spine CT. Patients were stratified into lowest, middle, and highest tertiles based on psoas muscle area. The primary outcome measure was overall survival from the date of CT scan. Hazard ratios were estimated using cox proportional hazards regression analysis.

Results: A total of 92 patients were identified, 52% African American and 39% Caucasian. The median survival for all patients was 124 days (95%CI=98–197d). Patients in the smallest third for average psoas size had significantly shorter survival as compared to the largest third: 117 days vs 302, hazard ratio 2.42 (95%CI=1.32-4.43), p=0.004. The shorter survival was also true for the middle third as compared to the largest third of psoas size: 113 days vs 302, hazard ratio 2.31 (95%CI=1.25-4.25), p=0.007.

Conclusions: In prostate cancer patients with metastases to the spine, morphometric analysis of psoas muscle size can be used to identify patients who are at risk for shorter survival. This simple method has the potential to allow clinicians to accurately risk stratify patients based on expected survival. This can aid in surgical decision making by allowing surgeons to weigh a given patient’s expected survival and fitness versus the potential morbidity of intervention.

Patient Care: It will help identify Stage IV cancer patients who are at higher risk for demise. Identification of these patients will allow for more selective oncologic treatments, whether chemotherapy, radiation, surgery, or palliation.

Learning Objectives: By the conclusion of this session, participants will be able to: 1) Describe why it is important to predict outcomes in patients with spinal metastases 2) Discuss the role of morphometrics in predicting mortality in patients with spinal metastases 3) Apply morphometrics to stratify high risk and low risk patients

References: 1. Dea N, Versteeg A, Fisher C, Kelly A, Hartig D, Boyd M, et al: Adverse events in emergency oncological spine surgery: a prospective analysis. J Neurosurg Spine 21:698-703, 2014 2. Ghori AK, Leonard DA, Schoenfeld AJ, Saadat E, Scott N, Ferrone ML, et al: Modeling 1-year survival after surgery on the metastatic spine. Spine J 15:2345-2350, 2015 3. Quraishi NA, Manoharan SR, Arealis G, Khurana A, Elsayed S, Edwards KL, et al: Accuracy of the revised Tokuhashi score in predicting survival in patients with metastatic spinal cord compression (MSCC). Eur Spine J 22 Suppl 1:S21-26, 2013 4. Tabouret E, Cauvin C, Fuentes S, Esterni B, Adetchessi T, Salem N, et al: Reassessment of scoring systems and prognostic factors for metastatic spinal cord compression. Spine J 15:944-950, 2015 5. Zakaria HM, Basheer A, Boyce-Fappiano D, Elibe E, Schultz L, Lee I, et al: Application of morphometric analysis to patients with lung cancer metastasis to the spine: a clinical study. Neurosurg Focus 41:E12, 2016