Application of morphometric analysis to patients with lung cancer metastasis to the spine: a clinical study.

OBJECTIVE Predicting the survival rate for patients with cancer is currently performed using the TNM Classification of Malignant Tumors (TNM). 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. Analytical 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 can be predictive of survival in patients with spinal metastases. METHODS Utilizing a retrospective registry of patients with spinal metastases who had undergone stereotactic body radiation therapy, the authors identified patients with primary lung cancer. Morphometric measurements were taken of the psoas muscle using CT of the lumbar spine. Additional morphometrics were taken of the L-4 vertebral body. Patients were stratified into tertiles based on psoas muscle area. The primary outcome measure was overall survival, which was measured from the date of the patient's CT scan to date of death. RESULTS A total of 168 patients were identified, with 54% male and 54% having multiple-level metastases. The median survival for all patients was 185.5 days (95% confidence interval [CI] 146-228 days). Survival was not associated with age, sex, or the number of levels of metastasis. Patients in the smallest tertile for the left psoas area had significantly shorter survival compared with a combination of the other two tertiles: 139 days versus 222 days, respectively, hazard ratio (HR) 1.47, 95% CI 1.06-2.04, p = 0.007. Total psoas tertiles were not predictive of mortality, but patients whose total psoas size was below the median size had significantly shorter survival compared with those greater than the median size: 146 days versus 253.5 days, respectively, HR 1.43, 95% CI 1.05-1.94, p = 0.025. To try to differentiate small body habitus from frailty, the ratio of psoas muscle area to vertebral body area was calculated. Total psoas size became predictive of mortality when normalized to vertebral body ratio, with patients in the lowest tertile having significantly shorter survival (p = 0.017). Left psoas to vertebral body ratio was also predictive of mortality in patients within the lowest tertile (p = 0.021). Right psoas size was not predictive of mortality in any calculations. CONCLUSIONS In patients with lung cancer metastases to the spine, morphometric analysis of psoas muscle and vertebral body size can be used to identify patients who are at risk for shorter survival. This information should be used to select patients who are appropriate candidates for surgery and for the tailoring of oncological treatment regimens.

Sarcopenia Predicts Overall Survival in Patients with Lung, Breast, Prostate, or Myeloma Spine Metastases Undergoing Stereotactic Body Radiation Therapy (SBRT), Independent of Histology.

BACKGROUND: Predicting survival of patients with spinal metastases would help stratify treatments from aggressive to palliation. OBJECTIVE: To evaluate whether sarcopenia predicts survival in patients with lung, breast, prostate, or multiple myeloma spinal metastases. METHODS: Psoas muscle measurements in patients with spinal metastasis were taken from computed tomography scans at 2 time points: at first episode of stereotactic body radiation therapy (SBRT) and from the most recent scan available. Overall survival and hazard ratios were calculated with multivariate cox proportional hazards regression analyses. RESULTS: In 417 patients with spinal metastases, 40% had lung cancer, 27% breast, 21% prostate, and 11% myeloma. Overall survival was not associated with age, sex, ethnicity, levels treated, or SBRT volume. Multivariate analysis showed patients in the lowest psoas tertile had shorter survival (222 d, 95% CI = 185-323 d) as compared to the largest tertile (579 d, 95% CI = 405-815 d), (HR1.54, P = .005). Median psoas size as a cutoff value was also strongly predictive for survival (HR1.48, P = .002). Survival was independent of tumor histology. The psoas/vertebral body ratio was also successful in predicting overall survival independent of tumor histology and gender (HR1.52, P < .01). Kaplan-Meier survival curves visually represent survival (P = .0005). CONCLUSION: In patients with spine metastases, psoas muscle size as a hallmark of frailty/sarcopenia is an objective, simple, and effective way to identify patients who are at risk for shorter survival, regardless of tumor histology. This information can be used to help with surgical decision making in patients with advanced cancer, as patients with small psoas sizes are at higher risk of death.

Stereotactic radiosurgery for primary tumors of the spine and spinal cord†.

PURPOSE: The purpose of this study was to evaluate the role of stereotactic radiosurgery in the treatment of primary tumors of the spine and spinal cord. METHODS: An Institutional Review Board approved retrospective analysis of 30 patients with primary spine tumors treated at a single institution was performed. Post-treatment pain, neurological, and radiographic responses were the endpoints. RESULTS: Nine patients were treated for benign tumors, and 21 patients were treated for malignant tumors. The median dose delivered was 16 Gy in one fraction. Median follow up was 13.13 months (range, 1 month-84 months). Pain relief was 88% initially. Pain recurred in five patients with a median time to recurrence of 5 months (range, 3.6 months - 80 months). Neurological improvement was achieved in 65% of patients. Three patients experienced a recurrence in their neurological deficit (at 3.6 months, 1.6 years, and 3.7 years after SRS). Radiographic control was achieved in 77% of sites treated with SRS. Thirteen of the treated sites recurred with a median time of 9.9 months. Two long-term toxicities were observed (asymptomatic radio-necrosis of the erector spinae muscle and foot drop). CONCLUSIONS: Our results suggest that SRS is a safe and effective treatment option for primary tumors of the spine and spinal cord.

Morphometrics predicts overall survival in patients with multiple myeloma spine metastasis: A retrospective cohort study.

Background: Treatment strategies for spinal metastases for myeloma range from conservative measures (radiation and chemotherapy) to invasive (surgical). Identifying better predictors of overall survival (OS) would help in surgical decision making. Analytic morphometrics has been shown to predict survival in oncologic patients, and our study evaluates whether morphometrics is predictive of survival in patients with multiple myeloma (MM) spinal metastases. Methods: For this observational retrospective cohort study, we identified 46 patients with MM spinal metastases who had undergone stereotactic body radiation therapy. OS was the primary outcome measure. Morphometric analysis of the psoas muscle was performed using computed tomography scans of the lumbar spine. Results: OS was statistically correlated with age (P = 0.025), tumor burden (P = 0.023), and number of levels radiated (P = 0.029), but not with gender. Patients in the lowest tertile of average psoas size had significantly shorter survival compared to the highest tertile, hazard ratio (HZ) 6.87 (95% CI = 1.65-28.5, P = 0.008). When calculating the psoas size to vertebral body ratio and correlating this measure to OS, the lowest tertile again had significantly shorter OS compared to the highest tertile, HZ 6.87 (95% CI = 1.57-29.89, P = 0.010); the middle tertile also showed significantly shorter OS compared to the highest tertile, HZ 5.07 (95% CI = 1.34-19.10, P = 0.016). Kaplan-Meier survival curves were used to visually illustrate the differences in survival between different tertiles (Log-rank test P = 0.006). Conclusions: Morphometric analysis successfully predicts long-term survival in patients with MM. More research is needed to validate these results and to see if these methodologies can be applied to other cancer histologies.

Application of morphometrics as a predictor for survival in female patients with breast cancer spinal metastasis: a retrospective cohort study.

BACKGROUND CONTEXT: The current standard of care for prediction of survival of cancer staging is based on TNM staging. However, for patients with spinal metastasis, who all have identical stage IV disease, identifying accurate prognostic markers of survival would allow better treatment stratification between more aggressive treatment strategies or palliation. Analytical morphometrics enables physicians to quantify patient frailty by measuring lean muscle mass. Morphometrics also predicts survival in patients with lung cancer metastases to the spine. PURPOSE: Our study evaluates whether morphometrics is predictive of survival in patients with breast cancer spinal metastasis. DESIGN: This is an observational retrospective cohort study. PATIENT SAMPLE: This study includes female patients with breast cancer spinal metastases and patients who have undergone stereotactic body radiation therapy. OUTCOME MEASURES: Overall survival was the primary outcome measure. METHODS: Morphometric measurements of the psoas muscle were taken using computed tomography scans of the lumbar spine. We then stratified patients into tertiles based on the psoas muscle area. RESULTS: We identified 118 patients, with a median survival of 104 days (95% confidence interval [CI]=73-157 days). Overall survival was not associated with age, chemotherapy, or number of levels radiated. Patients in the lowest tertile of psoas size had significantly shorter survival compared with the highest tertile (68 days versus 148 days, hazard ratio 1.76 [95% CI=1.08-2.89], p=.024). The shorter survival was also true for the lowest tertile versus the middle tertile (68 days versus 167 days, hazard ratio 1.95 [95% CI=1.19-3.19], p=.007). Kaplan-Meier survival curves were used to visually illustrate the differences in survival between different tertiles. CONCLUSIONS: Morphometric analysis of the psoas muscle size in patients with breast cancer metastases to the spine was effective in identifying patients at risk of shorter survival. Further research is needed to validate these results, as well as to see if these methodologies can be applied to other cancer histologies.

Application of Morphometrics as a Predictor for Survival in Patients with Prostate Cancer Metastasis to the Spine.

BACKGROUND: Surgery for spinal metastases can improve survival but has high morbidity that can potentially diminish benefits. New objective methods of predicting overall survival would be beneficial for surgical decision making. Morphometrics quantifies patient frailty and has been successfully used to predict overall survival in patients with lung cancer spinal metastases. This study evaluated whether morphometrics can predict survival in patients with prostate cancer spinal metastases. METHODS: Using a retrospective registry of patients with spinal metastases who underwent stereotactic body radiation therapy, we identified patients with primary prostate cancer. Morphometric measurements of the psoas muscle were taken from most recent lumbar spine computed tomography. Patients were stratified into lowest, middle, and highest tertiles based on psoas muscle area. Primary outcome measure was overall survival from the date of computed tomography scan. RESULTS: We identified 92 patients. Median survival for all patients was 124 days (95% confidence interval, 98-197 days). Patients in the smallest third for average psoas size had significantly shorter survival compared with patients in the largest third: 117 days versus 302 days (hazard ratio 2.42; 95% confidence interval, 1.32-4.43; P = 0.004). Patients in the middle third for average psoas size also had shorter survival compared with patients in the largest third: 113 days versus 302 days (hazard ratio 2.31; 95% confidence interval, 1.25-4.25; P = 0.007). CONCLUSIONS: In patients with prostate cancer spinal metastases, morphometric analysis of psoas muscle size can identify patients at risk for shorter survival. This technique can aid in surgical decision making by weighing expected survival and fitness versus potential morbidity of intervention.

Reirradiation of the spine with stereotactic radiosurgery: Efficacy and toxicity.

PURPOSE: To determine the potential benefits and adverse effects associated with reirradiating the spinal cord when at least 1 course of radiation therapy (RT) is stereotactic radiosurgery (SRS). METHODS AND MATERIALS: This institutional review board-approved retrospective review included 162 patients (237 reirradiated spine lesions). All patients received SRS at our institution between 2001 and 2013. Electronic medical records were reviewed for clinical exams and radiologic tests (computed tomography/magnetic resonance imaging). Primary endpoints were pain, neurological, radiographic responses, and the development of adverse effects. RESULTS: A total of 120 patients (74.1%) were deceased with a median survival of 13 months. Time between courses of RT was a median of 10.2 months. Median SRS dose was 16 Gy in 1 fraction, whereas the median conventional external beam radiation therapy (cEBRT) dose was 30 Gy in 10 fractions. The median tumor equivalent dose in 2-Gy fractions (EQD2) for SRS doses was 34.7 Gy, whereas the median tumor EQD2 for cEBRT was 32.5 Gy, providing a median total tumor EQD2 of 69.3 Gy (22-145.6 Gy). The median critical nervous tissue EQD2 for SRS and cEBRT was 56 Gy and 37.5 Gy, respectively, resulting in a median total critical nervous tissue EQD2 of 93.5 Gy. Overall pain, neurological, and radiographic response rates were 81%, 82%, and 71%, respectively. Adverse effects occurred in 11 (6.8%) patients. Seventy-seven vertebral compression fractures were observed, 22 (9.3%) of which may be attributed to RT. CONCLUSIONS: Our results demonstrate that reirradiation achieves favorable response rates with minimal toxicity if recommended dose constraints to the spinal cord with SRS are carefully observed. To the best of our knowledge, this is the largest reported single-institution experience analyzing the efficacy and toxicity of reirradiation of the spine when at least 1 course of RT is stereotactic radiosurgery.

Analysis of the Factors Contributing to Vertebral Compression Fractures After Spine Stereotactic Radiosurgery.

PURPOSE: To determine our institutional vertebral compression fracture (VCF) rate after spine stereotactic radiosurgery (SRS) and determine contributory factors. METHODS AND MATERIALS: Retrospective analysis from 2001 to 2013 at a single institution was performed. With institutional review board approval, electronic medical records of 1905 vertebral bodies from 791 patients who were treated with SRS for the management of primary or metastatic spinal lesions were reviewed. A total of 448 patients (1070 vertebral bodies) with adequate follow-up imaging studies available were analyzed. Doses ranging from 10 Gy in 1 fraction to 60 Gy in 5 fractions were delivered. Computed tomography and magnetic resonance imaging were used to evaluate the primary endpoints of this study: development of a new VCF, progression of an existing VCF, and requirement of stabilization surgery after SRS. RESULTS: A total of 127 VCFs (11.9%; 95% confidence interval [CI] 9.5%-14.2%) in 97 patients were potentially SRS induced: 46 (36%) were de novo, 44 (35%) VCFs progressed, and 37 (29%) required stabilization surgery after SRS. Our rate for radiologic VCF development/progression (excluding patients who underwent surgery) was 8.4%. Upon further exclusion of patients with hematologic malignancies the VCF rate was 7.6%. In the univariate analyses, females (hazard ratio [HR] 1.54, 95% CI 1.01-2.33, P=.04), prior VCF (HR 1.99, 95% CI 1.30-3.06, P=.001), primary hematologic malignancies (HR 2.68, 95% CI 1.68-4.28, P<.001), thoracic spine lesions (HR 1.46, 95% CI 1.02-2.10, P=.02), and lytic lesions had a significantly increased risk for VCF after SRS. On multivariate analyses, prior VCF and lesion type remained contributory. CONCLUSIONS: Single-fraction SRS doses of 16 to 18 Gy to the spine seem to be associated with a low rate of VCFs. To the best of our knowledge, this is the largest reported experience analyzing SRS-induced VCFs, with one of the lowest event rates reported.