Introduction: Currently, prediction of survival for patients with cancer is by TNM staging. Identifying accurate prognostic markers of survival would allow better treatment stratification between more aggressive treatment strategies or palliation. This is especially relevant for patients with spinal metastases who all have identical TNM staging, and whose surgical decision-making is potentially complex. Analytic morphometrics quantifies patient frailty by measuring lean muscle mass and can predict risk for postoperative morbidity after lumbar spine surgery. This study evaluates whether morphometrics is predictive of survival in patients with spinal metastasis.
Methods: Utilizing a retrospective registry of spinal metastases patients who have undergone stereotactic body radiation therapy (SBRT), we identified patients with primary lung, breast, or prostate cancer. Morphometric measurements were taken of the psoas using CT of the lumbar spine at the time of SBRT. Patients were stratified into tertiles based on psoas muscle area. The primary outcome measure was overall survival from the date of CT scan. Cox proportional hazards regression analyses were done to estimate the hazard ratios.
Results: A total of 371 patients with cancer metastasis were included; 156 with lung cancer, 118 with breast cancer, and 97 with prostate cancer. The median survival for all patients was 156 days (95%CI=126-186 days). Patients in the smallest third for left psoas size had significantly shorter survival: 115 days versus 234 days, hazard ratio 1.79 (95%CI=1.36-2.25), p<0.001. Patients below the median psoas size also had significantly shorter survival: 124 days versus to 218 days, hazard ratio 1.49 (95%CI=1.20-1.86), p<0.001.
Conclusions: In patients with lung, breast, or prostate cancer metastases to the spine, morphometric analysis of psoas muscle size can be used to identify patients who are at risk for shorter survival. This information can be used to help with surgical decision making in patients with the same burden of disease.
Patient Care: My research will improve patient care because it will help identify patients who at high risk of mortality, allowing for more accurate surgical decision making in patients with spinal cancer metastases.
Learning Objectives: By the conclusion of this session, participants should 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 for surgery for spinal metastases
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