Stereotactic Radiosurgery for Treatment of Spinal Metastases Recurring in Close Proximity to Previously Irradiated Spinal Cord

Choi, Chang-Hoon; Adler, John R.; Gibbs, Iris C.; Chang, Steven D.; Jackson, Paul; Minn, A. Yuriko; Lieberson, Robert E.; Soltys, Scott G.

doi:10.1016/j.ijrobp.2009.07.1727

Cited by 111 publications

(58 citation statements)

References 29 publications

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“…Although minimum target dose and degree of epidural disease have been reported as predictors in various series, there has been no consistent predictive factor to guide treatment planning. 1,7,13 With respect to OS, the majority of patients died within the follow-up period (21 of 37, 57%). Our analysis identified a significantly prolonged survival in patients with oligometastatic disease compared with patients with more widely disseminated disease (Fig.…”

Section: 1115mentioning

confidence: 99%

Spine stereotactic body radiotherapy for renal cell cancer spinal metastases: analysis of outcomes and risk of vertebral compression fracture

Thibault

Al-Omair

Masucci³

et al. 2014

SPI

125

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Object The aim of this study was to evaluate local control (LC) and the risk of vertebral compression fracture (VCF) after stereotactic body radiotherapy (SBRT) in patients with renal cell cancer spinal metastases. Methods Prospectively collected data on 71 spinal segments treated with SBRT in 37 patients were reviewed. The median follow-up was 12.3 months (range 1.2–55.4 months). The LC rate was assessed based on each spinal segment treated and overall survival (OS) according to each patient treated. Sixty of 71 segments (85%) were radiation naive, 11 of 71 (15%) were previously irradiated, and 10 of 71 (14%) were treated with postoperative SBRT. The median SBRT total dose and number of fractions were 24 Gy and 2, respectively. The VCF analysis also included evaluation of the Spinal Instability Neoplastic Score criteria. Results The 1-year OS and LC rates were 64% and 83%, respectively. Multivariate analysis identified oligometastatic disease (13 of 37 patients) as a positive prognostic factor (p = 0.018) for OS. Of 61 non-postoperative spinal segments treated, 10 (16%) developed VCFs; 3 of 10 were de novo VCFs and 7 of 10 occurred as progression of an existing VCF. The 1-year VCF-free probability rate was 82%. Multivariate analysis identified single-fraction SBRT and baseline VCF as significant predictors of SBRT-induced VCF (p = 0.028 and p = 0.012, respectively). Conclusions Spine SBRT yields high rates of local tumor control in patients with renal cell cancer. Baseline VCF and 18–24 Gy delivered in a single fraction were predictive of further collapse. Patients with oligometastatic disease may benefit most from such aggressive local therapy, given the prolonged survival observed.

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Section: 1115mentioning

confidence: 99%

Spine stereotactic body radiotherapy for renal cell cancer spinal metastases: analysis of outcomes and risk of vertebral compression fracture

Thibault

Al-Omair

Masucci³

et al. 2014

SPI

125

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“…Given the prior fractionated irradiation to the spinal cord, a conservative target dose of 21 Gy in 3 fractions with strict limits for the spinal cord (

{normalV}_{14 Gy} < 2 cc

{normalV}_{18 Gy} < 0.1 cc

) was chosen. Higher target doses of 27‐30 Gy in 3 fractions may have been led to higher local control; 19 , 20 however, the given limitations for the spinal cord due to multiple preirradiations did not allow a higher dose for this patient. A secondary defined constraint was the dose to the kidney (

{normalD}_{max} < 22 Gy

).…”

Section: Methodsmentioning

confidence: 95%

“…We selected a single complex‐shaped tumor surrounding a critical structure to demonstrate that, even for such a challenging case, simple planning methods can lead to high‐quality treatment plans, allowing the planning guidelines to be potentially applicable to simple cases, as well. One may also argue that the whole spine could have been included in the PTV (37) and the dose chosen for this treatment may be low for spine SBRT, 19 , 20 but as noted earlier, the patient had received preirradiation to this area limiting the spinal cord dose significantly. We believe that across the 10 treatment plans, the range of treatment plan qualities for this case was reasonably covered.…”

Section: Discussionmentioning

confidence: 99%

Inverse treatment planning for spinal robotic radiosurgery: an international multi‐institutional benchmark trial

Blanck

Wang

Baus

et al. 2016

J Applied Clin Med Phys

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Stereotactic radiosurgery (SRS) is the accurate, conformal delivery of high‐dose radiation to well‐defined targets while minimizing normal structure doses via steep dose gradients. While inverse treatment planning (ITP) with computerized optimization algorithms are routine, many aspects of the planning process remain user‐dependent. We performed an international, multi‐institutional benchmark trial to study planning variability and to analyze preferable ITP practice for spinal robotic radiosurgery. 10 SRS treatment plans were generated for a complex‐shaped spinal metastasis with 21 Gy in 3 fractions and tight constraints for spinal cord (normalV14Gy<2 cc, normalV18Gy<0.1 cc) and target (coverage >95%). The resulting plans were rated on a scale from 1 to 4 (excellent‐poor) in five categories (constraint compliance, optimization goals, low‐dose regions, ITP complexity, and clinical acceptability) by a blinded review panel. Additionally, the plans were mathematically rated based on plan indices (critical structure and target doses, conformity, monitor units, normal tissue complication probability, and treatment time) and compared to the human rankings. The treatment plans and the reviewers' rankings varied substantially among the participating centers. The average mean overall rank was 2.4 (1.2‐4.0) and 8/10 plans were rated excellent in at least one category by at least one reviewer. The mathematical rankings agreed with the mean overall human rankings in 9/10 cases pointing toward the possibility for sole mathematical plan quality comparison. The final rankings revealed that a plan with a well‐balanced trade‐off among all planning objectives was preferred for treatment by most participants, reviewers, and the mathematical ranking system. Furthermore, this plan was generated with simple planning techniques. Our multi‐institutional planning study found wide variability in ITP approaches for spinal robotic radiosurgery. The participants', reviewers', and mathematical match on preferable treatment plans and ITP techniques indicate that agreement on treatment planning and plan quality can be reached for spinal robotic radiosurgery.PACS number(s): 87.55.de

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“…The rising interest in frame‐less stereotactic radiotherapy to body sites with image guidance has presented new challenges for quality assurance of linear accelerators. The requirement of placing high‐dose gradients in extreme proximity to critical structures, such as stereotactic radiotherapy of spine malignancies and the spinal cord, 20 , 21 , 22 , 23 , 24 , 25 has resulted in more stringent AAPM guidelines for treatment accuracy and the development of precision methods to characterize performance (26) …”

Section: Discussionmentioning

confidence: 99%

Improved accuracy for noncoplanar radiotherapy: an EPID‐based method for submillimeter alignment of linear accelerator table rotation with MV isocenter

Nyflot

Cao

Meyer

et al. 2014

J Applied Clin Med Phys

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Accurate alignment of linear accelerator table rotational axis with radiation isocenter is critical for noncoplanar radiotherapy applications. The purpose of the present study is to develop a method to align the table rotation axis and the MV isocenter to submillimeter accuracy. We developed a computerized method using electronic portal imaging device (EPID) and measured alignment stability over time. Mechanical and radiation isocenter coincidence was measured by placing a steel ball bearing at radiation isocenter using existing EPID techniques. Then, EPID images were acquired over the range of table rotation. A MATLAB script was developed to calculate the center of rotation, as well as the necessary adjustment to move the table rotational axis to MV isocenter. Adjustment was applied via torque to screws at the base of the linac table. Stability of rotational alignment was measured with 49 measurements over 363 days on four linacs. Initial rotational misalignment from radiation isocenter ranged from 0.91−2.11 mm on the four tested linacs. Linac‐A had greatest error false(>2 mmfalse) and was adjusted with the described method. After adjustment, the error was significantly decreased to 0.40±0.12 mm. The adjustment was stable over the course of 15 measurements over 231 days. Linac‐B was not adjusted, but tracked from time of commissioning with 27 measurements over 363 days. No discernible shift in couch characteristics was observed (mean error 1.40±0.22 mm). The greater variability for Linac‐B may relate to the interchangeable two‐piece couch, which allows more lateral movement than the one‐piece Linac‐A couch. Submillimeter isocenter alignment was achieved by applying a precision correction to the linac table base. Table rotational characteristics were shown to be stable over the course of twelve months. The accuracy and efficiency of this method may make it suitable for acceptance testing, annual quality assurance, or commissioning of highly‐conformal noncoplanar radiotherapy programs.PACS number: 87

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Stereotactic Radiosurgery for Treatment of Spinal Metastases Recurring in Close Proximity to Previously Irradiated Spinal Cord

Cited by 111 publications

References 29 publications

Spine stereotactic body radiotherapy for renal cell cancer spinal metastases: analysis of outcomes and risk of vertebral compression fracture

Spine stereotactic body radiotherapy for renal cell cancer spinal metastases: analysis of outcomes and risk of vertebral compression fracture

Inverse treatment planning for spinal robotic radiosurgery: an international multi‐institutional benchmark trial

Improved accuracy for noncoplanar radiotherapy: an EPID‐based method for submillimeter alignment of linear accelerator table rotation with MV isocenter

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