Hypofractionated spinal stereotactic body radiation therapy for high-grade epidural disease.

OBJECTIVE: To characterize the clinical outcomes when stereotactic body radiation therapy (SBRT) alone is used to treat high-grade epidural disease without prior surgical decompression, the authors conducted a retrospective cohort study of patients treated at the Memorial Sloan Kettering Cancer Center between 2014 and 2018. The authors report locoregional failure (LRF) for a cohort of 31 cases treated with hypofractionated SBRT alone for grade 2 epidural spinal cord compression (ESCC) with radioresistant primary cancer histology. METHODS: High-grade epidural disease was defined as grade 2 ESCC, which is notable for radiographic deformation of the spinal cord by metastatic disease. Kaplan-Meier survival curves and cumulative incidence functions were generated to examine the survival and incidence experiences of the sample level with respect to overall survival, LRF, and subsequent requirement of vertebral same-level surgery (SLS) due to tumor progression or fracture. Associations with dosimetric analysis were also examined. RESULTS: Twenty-nine patients undergoing 31 episodes of hypofractionated SBRT alone for grade 2 ESCC between 2014 and 2018 were identified. The 1-year and 2-year cumulative incidences of LRF were 10.4% (95% CI 0-21.9) and 22.0% (95% CI 5.5-38.4), respectively. The median survival was 9.81 months (95% CI 8.12-18.54). The 1-year cumulative incidence of SLS was 6.8% (95% CI 0-16.0) and the 2-year incidence of SLS was 14.5% (95% CI 0.6-28.4). All patients who progressed to requiring surgery had index lesions at the thoracic apex (T5-7). CONCLUSIONS: In carefully selected patients, treatment of grade 2 ESCC disease with hypofractionated SBRT alone offers a 1-year cumulative incidence of LRF similar to that in low-grade ESCC and postseparation surgery adjuvant hypofractionated SBRT. Use of SBRT alone has a favorable safety profile and a low cumulative incidence of progressive disease requiring open surgical intervention (14.5%).

Predicting tumor-specific survival in patients with spinal metastatic renal cell carcinoma: which scoring system is most accurate?

OBJECTIVE: Although several prognostic scores for spinal metastatic disease have been developed in the past 2 decades, the applicability and validity of these models to specific cancer types are not yet clear. Most of the data used for model formation are from small population sets and have not been updated or externally validated to assess their performance. Developing predictive models is clinically relevant as prognostic assessment is crucial to optimal decision-making, particularly the decision for or against spine surgery. In this study, the authors investigated the performance of various spinal metastatic disease risk models in predicting prognosis for spine surgery to treat metastatic renal cell carcinoma (RCC). METHODS: Data of patients who underwent surgery for RCC metastatic to the spine at 2 tertiary centers between 2010 and 2019 were retrospectively retrieved. The authors determined the prognostic value associated with the following scoring systems: the Tomita score, original and revised Tokuhashi scores, original and modified Bauer scores, Katagiri score, the Skeletal Oncology Research Group (SORG) classic algorithm and nomogram, and the New England Spinal Metastasis Score (NESMS). Regression analysis of patient variables in association with 1-year survival after surgery was assessed using Cox proportional hazard models. Calibration and time-dependent discrimination analysis were tested to quantify the accuracy of each scoring system at 3 months, 6 months, and 1 year. RESULTS: A total of 86 metastatic RCC patients were included (median age 64 years [range 29-84 years]; 63 males [73.26%]). The 1-year survival rate was 72%. The 1-year survival group had a good performance status (Karnofsky Performance Scale [KPS] score 80%-100%) and an albumin level > 3.5 g/dL (p < 0.05). Multivariable-adjusted Cox regression analysis showed that poor performance status (KPS score < 70%), neurological deficit (Frankel grade A-D), and hypoalbuminemia (< 3.5 g/dL) were associated with a higher risk of death before 1 year (p < 0.05). The SORG nomogram, SORG classic, original Tokuhashi, and original Bauer demonstrated fair performance (0.7 < area under the curve < 0.8). The NESMS differentiates survival among the prognostic categories with the highest accuracy (area under the curve > 0.8). CONCLUSIONS: The present study shows that the most cited and commonly used scoring systems have a fair performance predicting survival for patients undergoing spine surgery for metastatic RCC. The NESMS had the best performance at predicting 1-year survival after surgery.

A comparison of spinal laser interstitial thermotherapy with open surgery for metastatic thoracic epidural spinal cord compression.

OBJECTIVE: The proximity of the spinal cord to compressive metastatic lesions limits radiosurgical dosing. Open surgery is used to create safe margins around the spinal cord prior to spinal stereotactic radiosurgery (SSRS) but carries the risk of potential surgical morbidity and interruption of systemic oncological treatment. Spinal laser interstitial thermotherapy (SLITT) in conjunction with SSRS provides local control with less morbidity and a shorter interval to resume systemic treatment. The authors present a comparison between SLITT and open surgery in patients with metastatic thoracic epidural spinal cord compression to determine the advantages and disadvantages of each method. METHODS: This is a matched-group design study comprising patients from a single institution with metastatic thoracic epidural spinal cord compression that was treated either with SLITT or open surgery. The two cohorts defined by the surgical treatment comprised patients with epidural spinal cord compression (ESCC) scores of 1c or higher and were deemed suitable for either treatment. Demographics, pre- and postoperative ESCC scores, histology, morbidity, hospital length of stay (LOS), complications, time to radiotherapy, time to resume systemic therapy, progression-free survival (PFS), and overall survival (OS) were compared between groups. RESULTS: Eighty patients were included in this analysis, 40 in each group. Patients were treated between January 2010 and December 2016. There was no significant difference in demographics or clinical characteristics between the cohorts. The SLITT cohort had a smaller postoperative decrease in the extent of ESCC but a lower estimated blood loss (117 vs 1331 ml, p < 0.001), shorter LOS (3.4 vs 9 days, p < 0.001), lower overall complication rate (5% vs 35%, p = 0.003), fewer days until radiotherapy or SSRS (7.8 vs 35.9, p < 0.001), and systemic treatment (24.7 vs 59 days, p = 0.015). PFS and OS were similar between groups (p = 0.510 and p = 0.868, respectively). CONCLUSIONS: The authors' results have shown that SLITT plus XRT is not inferior to open decompression surgery plus XRT in regard to local control, with a lower rate of complications and faster resumption of oncological treatment. A prospective randomized controlled study is needed to compare SLITT with open decompressive surgery for ESCC.

Stent screw-assisted internal fixation (SAIF): clinical report of a novel approach to stabilizing and internally fixating vertebrae destroyed by malignancy.

OBJECTIVE: Severe lytic cancerous lesions of the spine are associated with significant morbidity and treatment challenges. Stabilization and restoration of the axial load capability of the vertebral body (VB) are important to prevent or arrest vertebral collapse. Percutaneous stent screw-assisted internal fixation (SAIF), which anchors a VB stent/cement complex with pedicular screws to the posterior vertebral elements, is a minimally invasive, image-guided, 360° internal fixation technique that can be utilized in this patient cohort. The purpose of this study was to assess the feasibility, safety, and stabilization efficacy of VB reconstruction via the SAIF technique in a cohort of patients with extensive lytic vertebral lesions, who were considered to have an unstable or potentially unstable spine according to the Spinal Instability Neoplastic Score (SINS). METHODS: This study was a retrospective assessment of a prospectively maintained database of a consecutive series of patients with neoplastic extensive extracompartmental osteolysis (Tomita type 4-6) of the VB treated with the SAIF technique. VB reconstruction was assessed on postprocedure plain radiographs and CT by two independent raters. Technical and clinical complications were recorded. Clinical and imaging follow-ups were assessed. RESULTS: Thirty-five patients with extensive osteolytic metastatic lesions of the VB underwent 36 SAIF procedures. SAIF was performed as a stand-alone procedure in 31/36 cases and was associated with posterior surgical fixation in 5/36 (4/5 with decompressive laminectomy). In 1 case an epidural cement leak required surgical decompression. VB reconstruction was categorized as satisfactory (excellent or good rating) by the two raters in 34/36 cases (94.5%) with an interrater reliability of 94.4% (Cohen's kappa of 0.8). Follow-up, ranging from 1 to 30 months, was available for 30/36 levels. Long-term follow-up (6-30 months, mean 11.5 months) was available for 16/36 levels. Stability during follow-up was noted in 29/30 cases. CONCLUSIONS: SAIF provides 360° nonfusion internal fixation that stabilizes the VB in patients with extensive lytic lesions that would otherwise be challenging to treat.

Advances in the treatment of metastatic spine tumors: the future is not what it used to be.

An improved understanding of tumor biology, the ability to target tumor drivers, and the ability to harness the immune system have dramatically improved the expected survival of patients diagnosed with cancer. However, many patients continue to develop spine metastases that require local treatment with radiotherapy and surgery. Fortunately, the evolution of radiation delivery and operative techniques permits durable tumor control with a decreased risk of treatment-related toxicity and a greater emphasis on restoration of quality of life and daily function. Stereotactic body radiotherapy allows delivery of ablative radiation doses to the majority of spine tumors, reducing the need for surgery. Among patients who still require surgery for decompression of the spinal cord or spinal column stabilization, minimal access approaches and targeted tumor excision and ablation techniques minimize the surgical risk and facilitate postoperative recovery. Growing interdisciplinary collaboration among scientists and clinicians will further elucidate the synergistic possibilities among systemic, radiation, and surgical interventions for patients with spinal tumors and will bring many closer to curative therapies.

Spinal Instability Neoplastic Score component validation using patient-reported outcomes.

OBJECTIVE: The Spinal Instability Neoplastic Score (SINS) correlates with preoperative disability and response to stabilization, with patients with higher scores experiencing greater relief after surgery. However, there is a paucity of data demonstrating the extent to which each component contributes to preoperative clinical status and response to stabilization surgery. The objectives of this study were 2-fold. First, to determine how SINS components correlate with pre- and postoperative patient-reported outcomes (PROs). Second, to determine whether patients with higher SINS (10-12) in the "indeterminate" group respond differently to surgery compared to patients with lower SINS (7-9). METHODS: SINS and PROs were prospectively collected in 131 patients undergoing stabilization surgery for metastatic spinal disease. Association of SINS components and their individual scores with preoperative symptom burden and PRO symptom change after surgery was analyzed using the Spearman rank correlation coefficient (rho) and the Kruskal-Wallis test. SINS and association with preoperative PRO scores and mean differences in post- and preoperative PRO scores were compared for 2 SINS categories within the indeterminate group (7-9 vs 10-12) using the Wilcoxon 2-sample test and Wilcoxon signed-rank test. RESULTS: The presence of mechanical pain, followed by metastatic location, correlated most strongly with preoperative functional disability measures and lower disability PRO scores following surgical stabilization. Blastic rather than lytic bone lesions demonstrated stronger association with pain reduction following stabilization. Following surgery, patients with SINS 10-12 demonstrated markedly greater improvement in pain and disability PRO scores nearly across the board compared to patients with SINS 7-9. CONCLUSIONS: The presence of mechanical pain has the strongest correlation with preoperative disability and improvement in pain and disability PRO scores after surgery. Radiographic components of SINS also correlate with preoperative symptom severity and postoperative PRO, supporting their utilization in evaluation of spinal instability. Among patients with indeterminate SINS, patients with higher scores experience greater reduction in pain and disability PRO scores following surgical stabilization, suggesting that the indeterminate-SINS group includes distinct populations.

Interbody distraction and vertebral body reconstruction with polymethylmethacrylate for the treatment of pathological fractures.

OBJECTIVE Treatment of epidural spinal cord compression (ESCC) caused by tumor includes surgical decompression and stabilization followed by postoperative radiation. In the case of severe axial loading impairment, anterior column reconstruction is indicated. The authors describe the use of interbody distraction to restore vertebral body height and correct kyphotic angulation prior to reconstruction with polymethylmethacrylate (PMMA), and report the long-term durability of such reconstruction. METHODS A single institution, prospective series of patients with ESCC undergoing single-stage decompression, anterior column reconstruction, and posterior instrumentation from 2013 to 2016 was retrospectively analyzed. Several demographic, perioperative, and radiographic measurements were collected. Descriptive statistics were compiled, in addition to postoperative changes in anterior height, posterior height, and kyphosis. Paired Student t-tests were performed for each variable. Overall survival was calculated using the techniques described by Kaplan and Meier. RESULTS Twenty-one patients underwent single-stage posterior decompression with interbody distraction and anterior column reconstruction using PMMA. The median age and Karnofsky Performance Scale score were 61 years and 70, respectively. Primary tumors included renal cell (n = 8), lung (n = 4), multiple myeloma (n = 2), prostate (n = 2), and other (n = 5). Eighteen patients underwent a single-level vertebral body reconstruction and 3 underwent multilevel transpedicular corpectomies. The median survival duration was 13.3 months. In the immediate postoperative setting, statistically significant improvement was noted in anterior body height (p = 0.0017, 95% confidence interval [CI] -4.15 to -1.11) and posterior body height (p = 0.0116, 95% CI -3.14 to -0.45) in all patients, and improved kyphosis was observed in those with oblique endplates (p = 0.0002, 95% CI 11.16-20.27). In the median follow-up duration of 13.9 months, the authors observed 3 cases of asymptomatic PMMA subsidence. One patient required reoperation in the form of extension of fusion. CONCLUSIONS In situ interbody distraction allows safe and durable reconstruction with PMMA, restores vertebral height, and corrects kyphotic deformities associated with severe pathological fractures caused by tumor. This is accomplished with minimal manipulation of the thecal sac and avoiding an extensive 360° surgical approach in patients who cannot tolerate extensive surgery.

Image guidance based on MRI for spinal interstitial laser thermotherapy: technical aspects and accuracy.

OBJECTIVE Image guidance for spinal procedures is based on 3D-fluoroscopy or CT, which provide poor visualization of soft tissues, including the spinal cord. To overcome this limitation, the authors developed a method to register intraoperative MRI (iMRI) of the spine into a neuronavigation system, allowing excellent visualization of the spinal cord. This novel technique improved the accuracy in the deployment of laser interstitial thermal therapy probes for the treatment of metastatic spinal cord compression. METHODS Patients were positioned prone on the MRI table under general anesthesia. Fiducial markers were applied on the skin of the back, and a plastic cradle was used to support the MRI coil. T2-weighted MRI sequences of the region of interest were exported to a standard navigation system. A reference array was sutured to the skin, and surface matching of the fiducial markers was performed. A navigated Jamshidi needle was advanced until contact was made with the dorsal elements; its position was confirmed with intraoperative fluoroscopy prior to advancement into a target in the epidural space. A screenshot of its final position was saved, and then the Jamshidi needle was exchanged for an MRI-compatible access cannula. MRI of the exact axial plane of each access cannula was obtained and compared with the corresponding screenshot saved during positioning. The discrepancy in millimeters between the trajectories was measured to evaluate accuracy of the image guidance RESULTS Thirteen individuals underwent implantation of 47 laser probes. The median absolute value of the discrepancy between the location predicted by the navigation system and the actual position of the access cannulas was 0.7 mm (range 0-3.2 mm). No injury or adverse event occurred during the procedures. CONCLUSIONS This study demonstrates the feasibility of image guidance based on MRI to perform laser interstitial thermotherapy of spinal metastasis. The authors' method permits excellent visualization of the spinal cord, improving safety and workflow during laser ablations in the epidural space. The results can be extrapolated to other indications, including biopsies or drainage of fluid collections near the spinal cord.

Spinal stereotactic body radiotherapy following intralesional curettage with separation surgery for initial or salvage chordoma treatment.

OBJECTIVE Chordoma is a rare malignant tumor for which en bloc resection with wide margins is advocated as primary treatment. Unfortunately, due to anatomical constraints, en bloc resection to achieve wide or marginal margins is not feasible for many patients as the resulting morbidity would be prohibitive. The objective of this study was to evaluate the efficacy of intralesional curettage and separation surgery followed by spinal stereotactic body radiation therapy (SBRT) in patients with chordomas in the mobile spine. METHODS The authors performed a retrospective chart review of all patients with chordoma in the mobile spine treated from 2004 to 2016. Patients were identified from a prospectively collected database. Initially 22 patients were identified with mobile spine chordomas. With inclusion criteria of cytoreductive separation surgery followed closely by SBRT and a minimum of 6 months of follow-up imaging, 12 patients were included. Clinical and pathological characteristics of each patient were collected and data were analyzed. Patients were divided into two cohorts-those undergoing intralesional resection followed by SBRT as initial chordoma treatment at Memorial Sloan Kettering Cancer Center (MSKCC) (Cohort 1) and those undergoing salvage treatment following recurrence (Cohort 2). Treatment toxicities were classified according to the Common Terminology Criteria for Adverse Events version 4.03. Overall survival was analyzed using Kaplan-Meier analysis. RESULTS The 12 patients had a median post-SBRT follow-up time of 26 months. Cohort 1 had 5 patients with median post-SBRT follow-up time of 65.9 months and local control rate of 80% at last follow-up. Only one patient had disease progression, at 48.2 months following surgery and SBRT. Cohort 2 had 7 patients who had been treated at other institutions prior to undergoing both surgery and SBRT (salvage therapy) at MSKCC. The local control rate was 57.1% and the median follow-up duration was 10.7 months. One patient required repeat irradiation. Major surgery- and radiation-related complications occurred in 18% and 27% of patients, respectively. Epidural spinal cord compression scores were collected for each patient pre- and postoperatively. CONCLUSIONS The combination of surgery and SBRT provides excellent local control following intralesional curettage and separation surgery for chordomas in the mobile spine. Patients who underwent intralesional curettage and spinal SBRT as initial treatment had better disease control than those undergoing salvage therapy. High-dose radiotherapy may offer several biological benefits for tumor control.

Percutaneous surgery for treatment of epidural spinal cord compression and spinal instability: technical note.

OBJECTIVE An emerging paradigm for treating patients with epidural spinal cord compression (ESCC) caused by metastatic tumors is surgical decompression and stabilization, followed by stereotactic radiosurgery. In the setting of rapid progressive disease, interruption or delay in return to systemic treatment can lead to a negative impact in overall survival. To overcome this limitation, the authors introduce the use of spinal laser interstitial thermotherapy (sLITT) in association with percutaneous spinal stabilization to facilitate a rapid return to oncological treatment. METHODS The authors retrospectively reviewed a consecutive series of patients with ESCC and spinal instability who were considered to be poor surgical candidates and instead were treated with sLITT and percutaneous spinal stabilization. Demographic data, Spine Instability Neoplastic Scale score, degree of epidural compression before and after the procedure, length of hospital stay, and time to return to oncological treatment were analyzed. RESULTS Eight patients were treated with thermal ablation and percutaneous spinal stabilization. The primary tumors included melanoma (n = 3), lung (n = 3), thyroid (n = 1), and renal cell carcinoma (n = 1). The median Karnofsky Performance Scale score before and after the procedure was 60, and the median hospital stay was 5 days (range 3-18 days). The median Spine Instability Neoplastic Scale score was 13 (range 12-16). The mean modified postoperative ESCC score (2.75 ± 0.37) was significantly lower than the preoperative score (4.5 ± 0.27) (Mann-Whitney test, p = 0.0044). The median time to return to oncological treatment was 5 days (range 3-10 days). CONCLUSIONS The authors present the first cohort of sLITT associated with a percutaneous spinal stabilization for the treatment of ESCC and spinal instability. This minimally invasive technique can allow a faster recovery without prejudice of adjuvant systemic treatment, with adequate local control and spinal stabilization.

Prognostic factors associated with pain palliation after spine stereotactic body radiation therapy.

OBJECT The number of patients with spinal tumors is rapidly increasing; spinal metastases develop in more than 30% of cancer patients during the course of their illness. Such lesions can significantly decrease quality of life, often necessitating treatment. Stereotactic radiosurgery has effectively achieved local control and symptomatic relief for these patients. The authors determined prognostic factors that predicted pain palliation and report overall institutional outcomes after spine stereotactic body radiation therapy (SBRT). METHODS Records of patients who had undergone treatment with SBRT for either primary spinal tumors or spinal metastases from June 2008 through June 2013 were retrospectively reviewed. Data were collected at the initial visit just before treatment and at 1-, 3-, 6-, and 12-month follow-up visits. Collected clinical data included Karnofsky Performance Scale scores, pain status, presence of neurological deficits, and prior radiation exposure at the level of interest. Radiation treatment plan parameters (dose, fractionation, and target coverage) were recorded. To determine the initial extent of epidural spinal cord compression (ESCC), the authors retrospectively reviewed MR images, assessed spinal instability according to the Bilsky scale, and evaluated lesion progression after treatment. RESULTS The study included 99 patients (mean age 60.4 years). The median survival time was 9.1 months (95% CI 6.9-17.2 months). Significant decreases in the proportion of patients reporting pain were observed at 3 months (p < 0.0001), 6 months (p = 0.0002), and 12 months (p = 0.0019) after treatment. Significant decreases in the number of patients reporting pain were also observed at the last follow-up visit (p = 0.00020) (median follow-up time 6.1 months, range 1.0-56.6 months). Univariate analyses revealed that significant predictors of persistent pain after intervention were initial ESCC grade, stratified by a Bilsky grade of 1c (p = 0.0058); initial American Spinal Injury Association grade of D (p = 0.011); initial Karnofsky Performance Scale score, stratified by a score of 80 (p = 0.002); the presence of multiple treated lesions (p = 0.044); and prior radiation at the site of interest (p < 0.0001). However, when multivariate analyses were performed on all variables with p values less than 0.05, the only predictor of pain at last follow-up visit was a prior history of radiation at the site of interest (p = 0.0038), although initial ESCC grade trended toward significance (p = 0.073). Using pain outcomes at 3 months, at this follow-up time point, pain could be predicted by receipt of radiation above a threshold biologically effective dose of 66.7 Gy. CONCLUSIONS Pain palliation occurs as early as 3 months after treatment; significant differences in pain reporting are also observed at 6 and 12 months. Pain palliation is limited for patients with spinal tumors with epidural extension that deforms the cord and for patients who have previously received radiation to the same site. Further investigation into the optimal dose and fractionation schedule are needed, but improved outcomes were observed in patients who received radiation at a biologically effective dose (with an a/b of 3.0) of 66.7 Gy or higher.

Utilization of laser interstitial thermotherapy guided by real-time thermal MRI as an alternative to separation surgery in the management of spinal metastasis.

OBJECT: High-grade malignant spinal cord compression is commonly managed with a combination of surgery aimed at removing the epidural tumor, followed by spinal stereotactic radiosurgery (SSRS) aimed at local tumor control. The authors here introduce the use of spinal laser interstitial thermotherapy (SLITT) as an alternative to surgery prior to SSRS. METHODS: Patients with a high degree of epidural malignant compression due to radioresistant tumors were selected for study. Visual analog scale (VAS) scores for pain and quality of life were obtained before and within 30 and 60 days after treatment. A laser probe was percutaneously placed in the epidural space. Real-time thermal MRI was used to monitor tissue damage in the region of interest. All patients received postoperative SSRS. The maximum thickness of the epidural tumor was measured, and the degree of epidural spinal cord compression (ESCC) was scored in pre- and postprocedure MRI. RESULTS: In the 11 patients eligible for study, the mean VAS score for pain decreased from 6.18 in the preoperative period to 4.27 within 30 days and 2.8 within 60 days after the procedure. A similar VAS interrogating the percentage of quality of life demonstrated improvement from 60% preoperatively to 70% within both 30 and 60 days after treatment. Imaging follow-up 2 months after the procedure demonstrated a significant reduction in the mean thickness of the epidural tumor from 8.82 mm (95% CI 7.38-10.25) before treatment to 6.36 mm (95% CI 4.65-8.07) after SLITT and SSRS (p = 0.0001). The median preoperative ESCC Grade 2 was scored as 4, which was significantly higher than the score of 2 for Grade 1b (p = 0.04) on imaging follow-up 2 months after the procedure. CONCLUTIONS: The authors present the first report on an innovative minimally invasive alternative to surgery in the management of spinal metastasis. In their early experience, SLITT has provided local control with low morbidity and improvement in both pain and the quality of life of patients.

Stereotactic radiosurgery for spinal metastases with or without separation surgery.

OBJECT: In patients with significant epidural spinal cord compression, initial surgical decompression and stabilization of spinal metastases, as opposed to radical oncological resection, provides a margin around the spinal cord that facilitates subsequent treatment with high-dose adjuvant stereotactic radiosurgery (SRS). If a safe margin exists between tumor and spinal cord on initial imaging, then high-dose SRS may be used as the primary therapy, eliminating the need for surgery. Selecting the appropriate approach has shown greater efficacy of tumor control, neurological outcome, and duration of response when compared with external beam radiotherapy, regardless of tumor histology. This study evaluates the efficacy of this treatment approach in a series of 57 consecutive patients. METHODS: Patients treated for spinal metastases between 2007 and 2011 using the Varian Trilogy Linear Accelerator were identified retrospectively. Each received SRS, with or without initial surgical decompression and instrumentation. Medical records were reviewed to assess neurological outcome and surgical or radiation-induced complications. Magnetic resonance images were obtained for each patient at 3-month intervals posttreatment, and radiographic response was assessed as stability/regression or progression. End points were neurological outcome and local radiographic disease control at death or latest follow-up. RESULTS: Fifty-seven patients with 69 lesions were treated with SRS for spinal metastases. Forty-eight cases (70%) were treated with SRS alone, and 21 (30%) were treated with surgery prior to SRS. A single fraction was delivered in 38 cases (55%), while a hypofractionated scheme was used in 31 (45%). The most common histological entities were renal cell, breast, and lung carcinomas. Radiographically, local disease was unchanged or regressed in 63 of 69 tumors (91.3%). Frankel score improved or remained stable in 68 of 69 cases (98.6%). CONCLUSIONS: SRS, alone or as an adjunct following surgical decompression, provides durable local radiographic disease control while preserving or improving neurological function. This less-invasive alternative to radical spinal oncological resection appears to be effective regardless of tumor histology without sacrificing durability of radiographic or clinical response.

Factors affecting survival in 37 consecutive patients undergoing de novo stereotactic radiosurgery for contiguous sites of vertebral body metastasis from renal cell carcinoma.

OBJECT: Palliative resection of renal cell carcinoma (RCC) spinal metastasis is indicated in cases of neurological compromise or mechanical instability, whereas conventional external beam radiotherapy (EBRT) is commonly used for pain control. Recently, spinal stereotactic radiosurgery (SRS) has emerged as a safe alternative, delivering higher therapeutic doses of radiation to spinal metastases. To better understand factors affecting survival in patients undergoing spinal SRS for metastatic RCC, the authors performed a retrospective analysis of a consecutive series of cases at a tertiary cancer center. METHODS: Patients harboring contiguous sites of vertebral body involvement from metastatic RCC who received upfront spinal SRS treatment at The University of Texas MD Anderson Cancer Center between 2005 and 2012 were identified. Demographic data, pain scores, radiographic data, overall survival, complications, status of systemic disease, neurological and functional status, and time between primary diagnosis and diagnosis of metastasis (systemic and spinal) were analyzed to determine their influence on survival. RESULTS: Thirty-seven patients receiving treatment for 40 distinct, contiguous sites of disease were included. The median overall survival after spinal SRS was 16.3 months (range 7.4-25.3 months). Univariate analysis revealed several factors significantly associated with improved overall survival. Local progression after spinal SRS was associated with worse overall survival compared with sustained local control (HR 3.4, 95% CI 1.6-7.4, p = 0.002). Median survival in patients with a Karnofsky Performance Scale (KPS) score ≥ 70 was longer than in patients with a KPS score < 70 (HR 4.7, 95% CI 2.1-10.7, p < 0.001). Patients with neurological deficits at the time of spinal SRS had a shorter median survival than those without (HR 4.2, 95% CI 1.4-12.0, p = 0.008). Individuals with nonprogressive systemic disease at the time of spinal SRS had a longer median survival than those with systemic progression at the time of treatment (HR 8.3, 95% CI 3.3-20.7, p < 0.001). Median survival in patients experiencing any metastasis < 12 months after primary RCC diagnosis was shorter than in patients experiencing any metastasis > 12 months after primary diagnosis, a difference that approached but did not attain significance (HR 1.9, 95% CI 0.90-4.1, p = 0.09). On multivariate analysis, local progression of disease after spinal SRS, metastasis < 12 months after primary, KPS score ≤ 70, and progression of systemic disease at time of spinal SRS all remained significant factors influencing survival (respectively, HR 3.7, p = 0.002; HR 2.6, p = 0.026; HR 4.0, p = 0.002; and HR 13.2, p < 0.001). CONCLUSIONS: We identified several factors associated with survival after spinal SRS for RCC metastases, including local progression, time between first metastasis and primary RCC diagnosis, KPS score, presence of neurological deficits, and progressive metastatic disease. These factors should be taken into consideration when considering a patient for spinal SRS for RCC metastases.