Spine Stereotactic Body Radiotherapy Research Articles

Positional uncertainties of cervical and upper thoracic spine in stereotactic body radiotherapy with thermoplastic mask immobilization.

PurposeTo investigate positional uncertainty and its correlation with clinical parameters in spine stereotactic body radiotherapy (SBRT) using thermoplastic mask (TM) immobilization.Materials and MethodsA total of 21 patients who underwent spine SBRT for cervical or upper thoracic spinal lesions were retrospectively analyzed. All patients were treated with image guidance using cone beam computed tomography (CBCT) and 4 degrees-of-freedom (DoF) positional correction. Initial, pre-treatment, and post-treatment CBCTs were analyzed. Setup error (SE), pre-treatment residual error (preRE), post-treatment residual error (postRE), intrafraction motion before treatment (IM1), and intrafraction motion during treatment (IM2) were determined from 6 DoF manual rigid registration.ResultsThe three-dimensional (3D) magnitudes of translational uncertainties (mean ± 2 standard deviation) were 3.7±3.5 mm (SE), 0.9±0.9 mm (preRE), 1.2±1.5 mm (postRE), 1.4±2.4 mm (IM1), and 0.9±1.0 mm (IM2), and average angular differences were 1.1°±1.2° (SE), 0.9°±1.1° (preRE), 0.9°±1.1° (postRE), 0.6°±0.9° (IM1), and 0.5°±0.5° (IM2). The 3D magnitude of SE, preRE, postRE, IM1, and IM2 exceeded 2 mm in 18, 0, 3, 3, and 1 patients, respectively. No association were found between all positional uncertainties and body mass index, pain score, and treatment location (p > 0.05, Mann-Whitney test). There was a tendency of intrafraction motion to increase with overall treatment time; however, the correlation was not statistically significant (p > 0.05, Spearman rank correlation test).ConclusionIn spine SBRT using TM immobilization, CBCT and 4 DoF alignment correction, a minimum residual translational uncertainty was 2 mm. Shortening overall treatment time and 6 DoF positional correction may further reduce positional uncertainties.

Postoperative re-irradiation using stereotactic body radiotherapy for metastatic epidural spinal cord compression.

OBJECTIVE This study aimed to clarify the outcomes of postoperative re-irradiation using stereotactic body radiotherapy (SBRT) for metastatic epidural spinal cord compression (MESCC) in the authors' institution and to identify factors correlated with local control. METHODS Cases in which patients with previously irradiated MESCC underwent decompression surgery followed by spine SBRT as re-irradiation between April 2013 and May 2017 were retrospectively reviewed. The surgical procedures were mainly performed by the posterior approach and included decompression and fixation. The prescribed dose for spine SBRT was 24 Gy in 2 fractions. The primary outcome was local control, which was defined as elimination, shrinkage, or no change of the tumor on CT or MRI obtained approximately every 3 months after SBRT. In addition, various patient-, treatment-, and tumor-specific factors were evaluated to determine their predictive value for local control. RESULTS Twenty-eight cases were identified in the authors' institutional databases as meeting the inclusion criteria. The histology of the primary disease was thyroid cancer in 7 cases, lung cancer in 6, renal cancer in 3, colorectal cancer in 3, and other cancers in 9. The most common previous radiation dose was 30 Gy in 10 fractions (15 cases). The mean interval since the most recent irradiation was 16 months (range 5-132 months). The median duration of follow-up after SBRT was 13 months (range 4-38 months). The 1-year local control rate was 70%. In the analysis of factors related to local control, Bilsky grade, number of vertebral levels in the treatment target, the interval between the latest radiotherapy and SBRT, recursive partitioning analysis (RPA), the prognostic index for spinal metastases (PRISM), and the revised Tokuhashi score were not significantly correlated with local control. The favorable group classified by the Rades prognostic score achieved a significantly higher 1-year local control rate than the unfavorable group (1-year local control rate: 100% vs 33%; p < 0.01). Radiation-induced myelopathy and vertebral compression fracture were observed in 1 and 3 patients, respectively. No other grade 3 or greater toxicities were encountered. CONCLUSIONS The results indicate that spine SBRT as postoperative re-irradiation was effective, and it was especially useful for patients classified as having a good survival prognosis according to the Rades score.

(OA26) Significance of Hormone Therapy & Bisphosphonate Use on Vertebral Compression Fracture (VCF) Incidence Following Spine Stereotactic Body Radiation Therapy (SBRT) for Breast Cancer Metastases

Spinal metastases are increasingly being treated with SBRT. Though effective, a potential toxicity of SBRT is VCF. Breast cancer (BC) is one of the most common primary sites to metastasize to the spine, & due to factors such as HT use, these patients may be at higher risk for VCF following SBRT. Our study aimed to determine the rate of SBRT induced VCF (S-VCF) in BC patients, & to understand if there is a significant relationship between hormone therapy (HT) & bisphosphonate (Bp) use on this risk. 335 vertebral bodies (VB) (n=131 patients) were treated with spine SBRT for BC metastases at a single institution between 06/2001 & 12/2014. EMRs were retrospectively reviewed in this IRB approved study, & data on the use of Bp, Selective Estrogen Receptor Modulators (SERMs), & Aromatase Inhibitors (AIs) were recorded. Development of a new VCF, progression of an existing VCF & requirement of stabilization surgery after SBRT were the primary endpoints of this study. These were evaluated using CT & MRI. Only VCF development/progression occurring in VB treated with SBRT were considered. VBs with concurrent tumor progression, or surgery prior to SBRT were not included. Statistical significance of VCF incidence, & the use of Bp & HT concurrent with, within 6 m, 1 yr, & 2 yrs of SBRT, was evaluated using the Chi-Square Test for Independence, & Fisher’s Exact Test. Follow up was available for 91 patients (69%) & 233 VB. Median survival post SBRT was 21 m. 58.8% of patients were Caucasian, 33.6% African American, & 7.6% were of other ethnicities. Bone density was low in 59% of patients. Median SBRT dose was 18 Gy/1 fx. Median tumor volume was 35.83 cc. Median follow-up was 15.6 m. 33 VCFs in 20 patients were observed. 48% were new, 24% progressed, & 27% were VB that required surgical stabilization after SBRT. The overall S-VCF rate was 14%. 70 patients (192 VB), 50 patients (146 VB), & 78 (221 VB) were exposed to AIs, SERMs, & Bp, with S-VCF rates of 14.6%, 14%, & 13% respectively. The following were found to be statistically significant in relation to S-VCF: SERM use concurrent (p= .003), within 6 m of (p= .028), & within 2 yrs of (p= .021) SBRT. Also significant was Bp use within 1 yr of SBRT (p< .0001). AI use was not found to be statistically significant for any of the time frames evaluated in our study. Rate of developing a VCF in our cohort was 14%. The overall rate of S-VCF in BC patients is not considerably higher than rates previously reported in non-histology specific series. We will further analyze our cohort to better understand the protective or adverse effects of HT & Bp use in BC patients receiving spine SBRT. To the best of our knowledge, this is the only reported series analyzing S-VCF in BC with an emphasis on the relation of Bp & HT use.

First Experience With Markerless Online 3D Spine Position Monitoring During SBRT Delivery Using a Conventional LINAC

The purpose was to report our initial experience with online markerless 3-dimensional (3D) spine position monitoring. We used template matching plus triangulation of fluoroscopic kilovoltage images acquired with the gantry-mounted imager during flattening filter-free volumetric modulated arc spine stereotactic body radiation therapy delivery on a conventional linear accelerator. Kilovoltage images were acquired at 7 frames per second and streamed to a stand-alone computer.Two-dimensional templates (1/°) containing the clinical target volume were generated from planning computed tomography (CT) data before the first fraction and matched to the (prefiltered) kilovoltage images during treatment.Each 2-dimensional registration was triangulated with multiple previous registrations, resulting in the 3D spine position offset from the planned position in realtime during treatment. If the offset was more than a certain threshold, the treatment was manually stopped and a cone beam CT scan was acquired to reposition the patient. During irradiation of 10 fractions in 3 patients, images were analyzed at an average rate of 1.0 to 1.3 frames per second; all other frames were excluded from the analysis because of limitations in processing speed. As a result of the start-up period of triangulation and poorer image quality at the start of treatment (lateral imaging angles), the first 3D position was determined after an average of 4.9seconds. On the basis of the position results, we interrupted the treatment beam 2 times for different patients. In all cases the spine position results corresponded well with the CT-cone beam CT match values used for subsequent repositioning. For the first time, we have determined the spine position during stereotactic body radiation therapy delivery on a standard linear accelerator using the gantry-mounted kilovoltage imager. This has the potential to increase confidence in the treatment, and the need for 2 treatment interruptions demonstrates the benefit of monitoring during irradiation. However, software improvements are needed to increase processing speed.

Population description and clinical response assessment for spinal metastases: part 2 of the SPIne response assessment in Neuro-Oncology (SPINO) group report.

Approximately 40% of metastatic cancer patients will develop spinal metastases. The current report provides recommendations for standardization of metrics used for spinal oncology patient population description and outcome assessment beyond local control endpoints on behalf of the SPIne response assessment in Neuro-Oncology (SPINO) group. The SPINO group survey was conducted in order to determine the preferences for utilization of clinician-based and patient-reported outcome measures for description of patients with spinal metastases. Subsequently, ClinicalTrials.gov registry was searched for spinal oncology clinical trials, and measures for patient description and outcome reporting were identified for each trial. These two searches were used to identify currently used descriptors and instruments. A literature search was performed focusing on the measures identified in the survey and clinical trial search in order to assess their validity in the metastatic spinal tumor patient population. References for this manuscript were identified through PubMed and Medline searches. Published literature, expert survey, and ongoing clinical trials were used to synthesize recommendations for instruments for reporting of spinal stability, epidural tumor extension, neurological and functional status, and symptom severity. Accurate description of patient population and therapy effects requires a combination of clinician-based and patient-reported outcome measures. The current report provides international consensus recommendations for the systematic reporting of patient- and clinician-reported measures required to develop trials applicable to surgery for spinal metastases and postoperative spine stereotactic body radiotherapy (SBRT).

Lead with Surgery, SBRT to Follow

This patient initially underwent radiation for T8 lytic renal cell cancer (RCC) metastases with a palliative total dose of 8 Gy delivered in 1 fraction and a field encompassing T7 to T9 (1). The patient now presents with complex spinal metastases involving T7-T8. The patient is oligometastatic with oligoprogression. The oligometastatic state has been reported to be prognostic for RCC patients with spinal metastases treated with spinal stereotactic body radiation therapy (SBRT) (2). I would be aggressive with re-irradiation SBRT, instead of further palliative conventional radiation.

Treatment plan quality and delivery accuracy assessments on 3 IMRT delivery methods of stereotactic body radiotherapy for spine tumors

Stereotactic body radiotherapy (SBRT) for spine tumors has demonstrated clinical effectiveness. The treatment planning and delivery techniques have evolved from dynamic conformal arc therapy, to fixed gantry angle intensity modulated radiotherapy (IMRT), and most recently to volumetric modulated arc therapy (VMAT). A hybrid-arc (HARC) planning and delivery method combining dynamic conformal arc therapy delivery with a number of equally spaced IMRT beams is proposed. In this study we investigated plan quality, delivery accuracy, and efficiency of 3 delivery techniques: IMRT, HARC, and VMAT. Patients who underwent spine SBRT treatments were randomly selected from an Institutional Review Board-approved registry. For each patient, the prescription dose was 14 to 16 Gy in a single fraction to cover >90% of the tumor (without planning margin) while constraining V10Gy ≤ 10% of the spinal cord and the maximum point dose (MPD) of the spinal cord ≤ 14 Gy. All cases were clinically treated with fixed gantry step-shoot IMRT plans and then re-planned with VMAT using Pinnacle 9.0 and with HARC using Brainlab iPlan 4.5. Student t-test was used to compare the dosimetric end points, including V16Gy to the planning target volume, homogeneity index, MPDPTV, the conformity index, V10Gy of the spinal cord, and MPDcord. To compare the accuracy of delivery, we delivered all plans on a phantom and conducted gamma index (GI) comparisons with 3 mm/3% and 2 mm/2% criteria. All plans met our clinical requirements. Among 3 techniques, there were no differences on dose coverage to the tumor volume, maximum dose to the spinal cord, and plan homogeneity index (p > 0.05). The average V10Gy of the spinal cord was 6.66 ± 0.03%, 5.49 ± 0.03%, and 4.76 ± 0.02% for IMRT, HARC, and VMAT plans, respectively. Accordingly, the conformity indices were 1.30 ± 0.11 and 1.29 ± 0.20, 1.53 ± 0.29, respectively. VMAT plans were significantly (p < 0.05) less conformal but significantly (p < 0.05) lower V10Gy of the spinal cord than those from HARC and IMRT plans. With delivery accuracy measured by GIs, the average GIs of 3%/3 mm were 92.6 ± 1.1%, 96.5 ± 2.7%, 99.0 ± 1.1% for IMRT, HARC, and VMAT plans, respectively. The differences were significant (p < 0.05). Accordingly, the average monitor units were 9238 ± 2242, 9853 ± 2548 and 5091 ± 910. The plan quality created from the 3 planning techniques can meet the clinical requirement. Adding arc beams in delivery such as in HARC and VMAT plans improves the delivery accuracy. VMAT is the most efficient delivery method.

Myositis following spine radiosurgery for metastatic disease: a case series.

OBJECTIVE Spinal stereotactic body radiation therapy (SBRT) has emerged as an attractive method to deliver high doses of radiation to oligometastatic spinal tumors with radioresistant histology. Because SBRT is a palliative therapy, attention to potential radiation toxicities is paramount when counseling patients. The objective of this study was to report radiation-induced myositis after SBRT, a previously undescribed complication. METHODS A total of 667 patients received 891 spine SBRT treatments (either 24 Gy in 1 fraction or 27 Gy in 3 fractions) from 2011 to 2016 and underwent retrospective review. Eleven patients were identified as having radiographic evidence of myositis following SBRT. Clinical and pathologic results were collected, including receipt of anti-vascular endothelial growth factor (VEGF) therapy, radiation dose, equivalent dose in 2-Gy fractions (EQD2), biologically effective dose (BED), and volume of muscle treated. Treatment toxicities were classified according to the Common Terminology Criteria for Adverse Events (CTCAE; version 4.03). Univariate statistical analyses were performed to evaluate the relationships between radiation fractionation schedule and myositis and between anti-VEGF therapy and myositis. RESULTS The cumulative incidence of myositis was 1.9% at 1 year. The median of the mean dose administered to muscle with myositis was 17.5 Gy. The median EQD2 was 55.1 Gy, and the median BED was 82.7 Gy. The median time to the development of clinical symptoms was 1.4 months, while the median time to imaging evidence was 4.7 months. Two patients (18.2%) had CTCAE grade 3 complications. Single-fraction spine SBRT (HR 4.5, 95% CI 1.2-16.9; p = 0.027) was associated with increased risk of developing myositis whereas receipt of anti-VEGF therapy was not (HR 2.2, 95% CI 0.6-7.1; p = 0.2). CONCLUSIONS Radiation myositis following spinal radiosurgery is a rare but important complication. Single-fraction treatment schedules may be associated with increased risk of myositis but should be validated in a larger series.

Early Tissue Effects of Stereotactic Body Radiation Therapy for Spinal Metastases

Stereotactic body radiation therapy (SBRT) is a highly effective and potentially ablative treatment for complex spinal metastases. Recent data have suggested radiobiologic effects of SBRT that expand beyond the traditional concept of DNA damage. Antitumor immunity, vascular damage leading to tumor necrosis, and increased rates of tumor apoptosis have been implied; however, in-human evidence remains scarce. The present study reports unique pathologic confirmation of SBRT-induced biological effects within spinal metastases treated with preoperative SBRT. Ten patients with spinal metastases secondary to various solid tumors were treated with preoperative single-fraction SBRT (18Gy) to the magnetic resonance imaging-defined macroscopic metastasis, followed by spinal stabilization within 24hours. Perioperative samples of spinal metastases were obtained, and 6 patients also had a pre-SBRT biopsy specimen available for a matched comparison. The samples were stained for tumor necrosis on routine hematoxylin-eosin-stained slices and, subsequently, immunohistochemical staining for T cells (CD3+, CD4+, CD8+), natural killer cells (CD56+), endothelium (CD31+), and apoptotic activity (caspase-3). Perioperative biopsy specimens were obtained ∼6hours (range 4.5-7.5) or 21hours (range 18.5-22.5) after SBRT. Necrosis was observed in 83% of the 21-hour post-SBRT samples (5 of 6) compared with 0% of pre-SBRT biopsies (0 of 6) and 6-hour post-SBRT biopsies (0 of 4). Tumor cell apoptosis had increased greatly in the 21-hour post-SBRT samples compared with before and 6hours after SBRT. The CD31+vessel counts decreased after SBRT, as did mitotic activity. Both of the renal cell metastases displayed major decreases in vessel density. Desmoplastic reaction was visible in 67% (4 of 6) of the pre-SBRT samples compared with 100% (10 of 10) the post-SBRT samples. The T-cell and natural killer cell counts were relatively unaffected. High-dose single-fraction SBRT induced tumor necrosis, desmoplasia, and tumor apoptosis and decreased tumor vessel density within 24hours, even in renal cell metastases. The role of immune cells seems limited in this early phase. These first-in-human results imply direct vascular and DNA damage mechanisms important in the clinical efficacy specific to spinal SBRT.

Improving Quality and Consistency in NRG Oncology Radiation Therapy Oncology Group 0631 for Spine Radiosurgery via Knowledge-Based Planning

Touse knowledge-based planning (KBP) as a method of producing high-quality, consistent, protocol-compliant treatment plans in a complex setting of spine stereotactic body radiation therapy on NRG Oncology Radiation Therapy Oncology Group (RTOG)0631. An internally developed KBP model was applied to an external validation cohort of 22 anonymized cases submitted under NRG Oncology RTOG 0631. The original and KBP plans were compared via their protocol compliance, target conformity and gradient index, dose to critical structures, and dose to surrounding normal tissues. The KBP model generated plans meeting all protocol objectives in a single optimization when tested on both internal and protocol-submitted NRG Oncology RTOG 0631 cases. Two submitted plans that were considered to have a protocol-unacceptable deviation were made protocol compliant through the use of the model. There were no statistically significant differences in protocol spinal cord metrics (D10% and D0.03cc) between the manually optimized plans and the KBP plans. The volume of planning target volume receiving prescription dose increased from 93.3%±3.2% to 98.3%±1.4% (P=.01) when using KBP. High-dose spillage to surrounding normal tissues (V105%) showed no significant differences (2.1±7.3cm3 for manual plans to 1.8±0.6cm3 with KBP), and dosimetric outliers with large amounts of spillage were eliminated through the use of KBP. Knowledge-based planning plans were also found to be significantly more consistent in several metrics, including target coverage and high dose outside of the target. Incorporation of KBP models into the clinical trial setting may have a profound impact on the quality of trial results, owing to the increase in consistency and standardization of planning, especially for treatment sites or techniques that are nonstandard.

Stereotactic Body Radiotherapy for Spinal Metastases: Clinical Experience in 134 Cases From a Single Japanese Institution.

Object:This study aimed to clarify the outcomes of stereotactic body radiotherapy for spinal metastases with a uniform dose fractionation schedule in our institution.Materials and Methods:Patients treated with spine stereotactic body radiotherapy were retrospectively reviewed. The prescribed dose was 24 Gy in 2 fractions. End points were local control, pain control, and adverse events. Local control was defined as elimination, shrinkage, or stable disease in the tumor on imaging evaluations. Pain status was measured on a scale of 0 to 10 by patients’ self-reports, and pain response was defined as the time at which pain scale score decreased by 2 or more from the baseline score without increase in analgesics. In addition, various treatment- and tumor-specific factors were evaluated to determine predictive values for local and pain control.Results:This study included 134 lesions in 131 patients, with: lesion histopathology, lung/colorectal/thyroid/renal/breast/prostate/sarcoma/other cancer, 24/22/18/14/12/10/6/25; reirradiation stereotactic body radiotherapy, 82 (61.2%) cases; and postoperative stereotactic body radiotherapy for epidural spinal cord compression, 45 (33.6%) cases. Median follow-up after stereotactic body radiotherapy was 9 months. The 1-year local control rate was 72.3%. Seventy (79.5%) of the 88 cases with pain from spinal metastases achieved pain response. The 1-year pain progression-free rate was 61.7%. Regarding metastases from colorectal cancer, local and pain control rates at 1 year were significantly lower compared with other cancer types (local control rate, 34.1% vs 81.8%; P < .01; pain progression-free rate, 36.9% vs 69.9%; P = .02). On multivariate analysis, colorectal cancer metastases and radiation history were identified as independent predictors of lower local and pain control rates. Radiation-induced myelopathy, radiculopathy, and vertebral compression fractures were observed in 0, 2 (1.5%), and 16 (11.9%) cases, respectively.Conclusions:This study showed that spine stereotactic body radiotherapy achieved good local and pain control, with a clinically acceptable safety profile. However, stereotactic body radiotherapy may be less effective against spinal metastases from colorectal cancer.

Dosimetric impact of translational and rotational setup errors for spine stereotactic body radiotherapy: A phantom study

This study aimed to investigate experimentally the effect of translational and rotational setup errors on 3-dimensional dose distributions by using the gamma index and dose volumetric indices for spine stereotactic body radiotherapy. Treatment plans were designed in accordance with the Radiation Therapy Oncology Group (RTOG) 0631 protocol. Measurements were taken using a Delta4 phantom (ScandiDos, Uppsala, Sweden). Setup errors were generated using the HexaMotion 6D moving platform (ScandiDos). Dose distributions in the presence of setup errors were evaluated, according to the γ passing rate with the 3% and 2 mm criteria (γ3%/2 mm) and dose volumetric indices (D90 for the target volume and D2 for the spinal cord), using the Delta4 device (ScandiDos). The sensitivity coefficient, which represented the correlation between the γ3%/2 mm passing rate and dose volumetric indices, was determined to assess robustness against setup errors. Rotational setup errors of 2° were equivalent to translational setup errors of 2 mm for the γ3%/2 mm passing rate, D90 for the target, and D2 for the spinal cord. D90 for the target had low robustness against a translational setup error in the vertical direction and a rotational setup error in the pitch direction. D2 for the spinal cord was sensitive to a translational setup error in the lateral direction and a rotational setup error in the roll direction. The positioning accuracy of the rotational setup error, corresponding to the tolerance level of image-guided radiotherapy in the RTOG 0631 protocol, was required to be ≤ 2°.

18. Metallic implants management in radiotherapy treatment planning process

Introduction Treatment planning in the presence of metallic implants may lead to several issues from contouring to dose calculation. The aim of this study was to control if extended CT scale technique (−10240 UH; 30710 HU) is a suitable alternative to standard CT scale technique for dose calculation in presence of high-Zmaterials. Then the efficiencies of two commercially available dose prediction algorithms, Accuros XB™ (AXB) and Analytical Anisotropic Algorithm™ (AAA) (Varian Medical Systems) were compared in this condition. This work will use for implementation of spinal stereotactic body radiation therapy (SBRT) with metallic fixations. Methods First an extended scale Hounsfield units (HU) conversion curve to relative electron density and to mass density was created based on density phantom (CIRS model 062). Uniformity, noise, low contrast and spatial resolution were evaluated for extended CT scale technique with manufactured CT phantom (GE Healthcare). Images were analyzed with ImageJ. Then measurements were performed using a True Beam™ linac (Varian Medical Systems) with energies of 6 MV flattening filter and flattening filter free for static fields and VMAT. Deposited dose through a titanium implant included in a water-equivalent phantom was evaluated. Two dimensional measurements were also performed at different depths in RW3’s plates with the implant placed above it. Calculations dose were made with Eclispe TPS (Varian Medical Systems) using AXB and AAA. EBT3 radiochromic films (Gafchromic) and liquid-filled ionization chamber array SRS 1000 (PTW Freiburg) were used. Analyses were performed with FilmQAPro (Ashland) et VeriSoft (PTW Freiburg). Results The extended scale HU conversion curve to relative electron density and to mass density show a good agreement to standard scale with 2% maximum variance. Image quality was steady. However low contrast detectability slightly decreased without significant clinical influence. AXB agrees better with measurements than AAA in presence of metallic implant. Conclusions Using extended CT scale technique can potentially improve efficiency in presence of metallic implants in the treatment planning process. In this condition, AXB improves dose calculation in comparison to AAA.

Short interactive workshops reduce variability in contouring treatment volumes for spine stereotactic body radiation therapy: Experience with the ESTRO FALCON programme and EduCase™ training tool

We report the results of 4, 2-h contouring workshops on target volume definition for spinal stereotactic radiotherapy. They combined traditional teaching methods with a web-based contouring/contour-analysis platform and led to a significant reduction in delineation variability. Short, interactive workshops can reduce interobserver variability in spine SBRT target volume delineation.

Spinal Stereotactic Body Radiotherapy in the United States: A Decade-Long Nationwide Analysis of Patient Demographics, Practice Patterns, and Trends Over Time

Abstract Nationwide utilization of spinal stereotactic body radiotherapy (SBRT) is not known; to address this void, the National Cancer Data Base (NCDB) from 2004 to 2013 was used for analysis. Spinal SBRT was defined as 1–5 fractions (14–32 Gy) delivered to the cervical, thoracic, lumbar or sacral spine. From 2004 to 2013, 1044 patients received spinal SBRT, most commonly in single-fraction (38%), three-fraction (26%) and five-fractions (25%). Metastatic spinal disease most commonly originated from the lung (34%), kidney (14%), and blood (9%). The most common insurance status receiving spinal SBRT was private (44%) followed by Medicare (43%), with Medicaid (8%) a distant third. Fifty-six percent of patients were male, and 55% of patients were younger than age 65. 80% of patients were Caucasian, with 13% being African-American. The vast majority (74%) of patients had no Charlson/Deyo comorbidities. The incidence of spinal SBRT gradually increased over time, rising from 2% to 20% of cases from 2004 to 2013. Comprising only 1.4% of spinal metastases radiation in 2004, SBRT rose to a 5.8% share in 2013. In conclusion, SBRT for spine metastases in the United States has more than quadrupled in utilization over a recent ten-year span. Although the majority of spinal SBRT is multi-fraction, the most popular fractionation scheme was single-fraction. It has been most commonly used for Caucasian men under age 65 with private/Medicare insurance and no comorbidities. By far the most common origin of spinal metastases treated by SBRT was the lung, followed by renal cancer. These results provide a baseline for further prospective investigation.

Postoperative Reirradiation Using Stereotactic Body Radiation Therapy for Metastatic Epidural Spinal Cord Compression: Selection of Eligible Cases

This study aimed to clarify the outcomes of postoperative re-irradiation using stereotactic body radiotherapy (SBRT) for metastatic epidural spinal cord compression (MESCC), and to clarify factors correlated with local control. Patients with MESCC and a history of radiotherapy who had been treated with decompression surgery and spine SBRT were retrospectively reviewed. The prescribed dose for spine SBRT was 24 Gy in 2 fractions. Local control, ambulatory function and adverse events were evaluated. The correlation between local control and some factors including degree of compression, interval between last radiotherapy and SBRT, and prognostic scores were analyzed. Twenty-six patients were selected from our database: mean age, 63 years (range, 33-76); 18 men, 8 women; ECOG performance status 0-1/2/3, 17/7/2; lesion histopathology, thyroid/lung/renal/colorectal/other cancer, 7/6/3/3/7; mean interval since last irradiation, 25 months (range, 5-132). Median follow-up after SBRT was 14 months (range, 3-37). The 1-year local control rate was 73%. Bilsky grade, interval between last radiotherapy and SBRT, RPA and PRISM were not significantly correlated with local control. One-year local control of favorable survival prognosis group and intermediate/poor survival prognosis group by Rades score were 100% and 0% (p<.001). Comparing ambulatory functions between pre-treatment and 1 year after SBRT, improvement/no change/worsening was seen in 3/7/5 cases, respectively. Grade 3 acute and late adverse events were observed in 0 and 1 (myelopathy) patients. No grade 4 or greater toxicities were encountered. Spine SBRT appears meaningless as postoperative re-irradiation for patients with poor survival prognosis, and Rades score seems useful for selecting eligible cases.

Evaluation of Predictive Risk Factors of Nausea for Patients Treated with Spine Stereotactic Body Radiation Therapy

Evaluation of Predictive Risk Factors of Nausea for Patients Treated with Spine Stereotactic Body Radiation Therapy

Clinical Outcomes of a Multileaf Collimator-Based Frameless Robotic Radiosurgery System for Spine Stereotactic Body Radiation Therapy

Clinical Outcomes of a Multileaf Collimator-Based Frameless Robotic Radiosurgery System for Spine Stereotactic Body Radiation Therapy

Single Fraction Spine Stereotactic Ablative Body Radiotherapy (SABR) with Volumetric Modulated Arc Therapy (VMAT): A Single Institution Experience

Single Fraction Spine Stereotactic Ablative Body Radiotherapy (SABR) with Volumetric Modulated Arc Therapy (VMAT): A Single Institution Experience

Oligometastatic Disease State Is Associated with Improved Local Control in Patients Undergoing 3 or 5 Fraction Spine Stereotactic Body Radiotherapy

Stereotactic body radiotherapy (SBRT) is an increasingly utilized treatment modality for patients with spine metastases. The objective of our study was to describe the local control (LC) outcomes with 3 or 5 fraction SBRT to the spine and identify predictors for improved LC. We retrospectively reviewed outcomes of patients treated with SBRT for vertebral body metastases. No patients had prior surgical intervention or spinal cord compression. All patients were treated with 3 (median dose 27 Gy; range 24-30 Gy) or 5 fraction (median dose 35 Gy, range 25-40 Gy) SBRT. The Kaplan-Meier method and SPINO criteria were used to determine LC. Patients were classified as having an oligometastatic disease state (< 5 systemic metastases) or polymetastatic disease state (≥ 5 metastases). Univariate analysis (UVA) was performed using the log-rank test to predict for clinical factors associated with LC. Multivariable analysis (MVA) was conducted using the cox proportional hazards model and included all covariates with p < 0.1 on UVA. Predictors of compression fracture were also evaluated using logistic regression. We included 56 patients with a total of 64 distinct SBRT targets. Median follow-up time was 9 months. Fifteen targets and 49 targets were treated with 3 and 5 fractions, respectively. Thirteen patients (20%) had prior radiotherapy to the SBRT area. Twenty-one patients (33%) had an oligometastatic disease state. One year LC was 82% (100% for 3 fraction, 77% for 5 fraction, p = 0.11). On UVA, polymetastases (1 year LC 76% vs. 100%; p = 0.038), prior radiotherapy to the SBRT target (65% vs. 87%; p = 0.041), and inclusion of greater than 2 vertebral levels in the target (63% vs. 86%; p < 0.01) were associated with worse LC. Male sex (84% vs. 87%; p = 0.091) had a trend toward worse LC at one year. Pseudoprogression occurred in 3 patients (5%) and was not associated with LC on UVA (p = 0.470). On MVA, patients with a polymetastatic state (hazard ratio 21.3, 95% confidence interval 1.21-373.73; p = 0.036) and prior radiotherapy to the SBRT target (HR 7.01, 95% confidence interval 1.46-33.6; p = 0.015) had worse LC. Sex and number of treated vertebral levels were not statistically significant (p = 0.395 and p = 0.233, respectively). Eight patients had grade 1 toxicity, and 1 patient had grade 2 toxicity. Vertebral body compression fractures occurred in 11 (17%) patients. Five fractions was associated with a higher risk of compression fracture (22% versus 0%, p=0.044), while increasing biologically effective dose (p = 0.110) and prior radiotherapy (p = 0.328) were not associated with an increased risk of compression fracture. LC of vertebral body metastases is encouraging with 3 or 5 fraction SBRT. Our study is hypothesis-generating in that patients with an oligometastatic disease state appear to have improved LC following SBRT, suggesting there may be a biologic advantage with local therapy in this group of patients not seen in patients with polymetastatic disease.