Radiation myelopathy following stereotactic body radiation therapy for spine metastases

Ong, Wee Loon; Wong, Shun; Soliman, Hany; Myrehaug, Sten; Tseng, Chia‐Lin; Detsky, Jay; Husain, Zain; Maralani, Pejman; Ma, Lijun; Lo, Simon S.; Sahgal, Arjun

doi:10.1007/s11060-022-04037-0

Cited by 14 publications

(10 citation statements)

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“…Concerning other adverse events, we observed no case of RM although ∼54% of the segments had received more than 1 course of radiation and ∼26% had received 2 courses of spine SBRT. Our spinal cord PRV and thecal sac constraints were initially conservative with a Dmax of 23 Gy in nonradiated and 14 Gy in reirradiated segments as recommended by Sahgal et al 23,29 But after sufficient clinical experience and no cases of RM, they were subsequently increased to the upper threshold of 25.3 to 26.2 Gy in nonradiated patients 23,24 and 19.4 to 21.3 Gy in selected reirradiated cases. Although no RM cases were observed, we report a 5.2% risk of brachial or lumbosacral plexopathy.…”

Section: Discussionmentioning

confidence: 99%

“…Spinal cord PRV and thecal sac constraints were the same and were based on reported thresholds that maintain the risk of myelopathy or cauda equina necrosis <1% to 5%. 23,24,29,30 Over the years, the constraints were refined based on updated recommendations and our institutional practices such that the point maximum dose (Dmax) within de novo critical neural organs at risk typically ranged from an absolute dose of 23 to 25.3 Gy and, most recently, to 26.2 Gy in 4 fractions. 23,24 In the reirradiation scenario, 23,30 the absolute Dmax typically ranged from 14 to 19.4 Gy, and most recently to 21.3 Gy, depending on cumulative spinal cord PRV/thecal sac EQD2 (a/b = 2).…”

Section: Treatment Techniquementioning

confidence: 99%

“…23,24,29,30 Over the years, the constraints were refined based on updated recommendations and our institutional practices such that the point maximum dose (Dmax) within de novo critical neural organs at risk typically ranged from an absolute dose of 23 to 25.3 Gy and, most recently, to 26.2 Gy in 4 fractions. 23,24 In the reirradiation scenario, 23,30 the absolute Dmax typically ranged from 14 to 19.4 Gy, and most recently to 21.3 Gy, depending on cumulative spinal cord PRV/thecal sac EQD2 (a/b = 2). For example, when a significant previous radiation dose was delivered (SBRT or EQD2 of 50 Gy 2 ), the Dmax was limited to 14 Gy/4 fractions to maintain the cumulative EQD2 ≤70 Gy 2 .…”

Section: Treatment Techniquementioning

confidence: 99%

“…Finally, patients undergoing reirradiation may also be at an increased risk of radiation-induced myelopathy (RM) after 1- to 2-fraction SBRT, given that the risk of late adverse effects increases with the dose per fraction; therefore, more fractionated courses of SBRT are typically applied in these situations. 21-24…”

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confidence: 99%

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30 Gy in 4 Stereotactic Body Radiotherapy Fractions for Complex Spinal Metastases: Mature Outcomes Supporting This Novel Regimen

et al. 2023

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BACKGROUND AND OBJECTIVES: We designed a 30 Gy in 4 fractions stereotactic body radiotherapy protocol, as an alternative option to our standard 2-fraction approach, for primarily large volume, multilevel, or previously radiated spinal metastases. We report imaging-based outcomes of this novel fractionation scheme. METHODS: The institutional database was reviewed to identify all patients who underwent 30 Gy/4 fractions from 2010 to 2021. Primary outcomes were magnetic resonance–based vertebral compression fracture (VCF) and local failure per treated vertebral segment. RESULTS: We reviewed 245 treated segments in 116 patients. The median age was 64 years (range, 24-90). The median number of consecutive segments within the treatment volume was 2 (range, 1-6), and the clinical target volume (CTV) was 126.2 cc (range, 10.4-863.5). Fifty-four percent had received at least 1 previous course of radiotherapy, and 31% had previous spine surgery at the treated segment. The baseline Spinal Instability Neoplastic Score was stable, potentially unstable, and unstable for 41.6%, 51.8%, and 6.5% of segments, respectively. The cumulative incidence of local failure was 10.7% (95% CI 7.1-15.2) at 1 year and 16% (95% CI 11.5-21.2) at 2 years. The cumulative incidence of VCF was 7.3% (95% CI 4.4-11.2) at 1 year and 11.2% (95% CI 7.5-15.8) at 2 years. On multivariate analysis, age ≥68 years (P = .038), CTV volume ≥72 cc (P = .021), and no previous surgery (P = .021) predicted an increased risk of VCF. The risk of VCF for CTV volumes <72 cc/≥72 cc was 1.8%/14.6% at 2 years. No case of radiation-induced myelopathy was observed. Five percent of patients developed plexopathy. CONCLUSION: 30 Gy in 4 fractions was safe and efficacious despite the population being at increased risk of toxicity. The lower risk of VCF in previously stabilized segments highlights the potential for a multimodal treatment approach for complex metastases, especially for those with a CTV volume of ≥72 cc.

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Section: Discussionmentioning

confidence: 99%

Section: Treatment Techniquementioning

confidence: 99%

Section: Treatment Techniquementioning

confidence: 99%

mentioning

confidence: 99%

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30 Gy in 4 Stereotactic Body Radiotherapy Fractions for Complex Spinal Metastases: Mature Outcomes Supporting This Novel Regimen

et al. 2023

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“…The risk of radiation myelopathy is low, but it can have a huge negative impact on the quality of life and prognosis. Symptoms can include di culty walking, numbness, limb weakness, loss of bladder and bowel control, and death [7,8]. Therefore, to prevent radiation myelopathy, it is important to reduce the dose to the spinal cord and cauda equina as much as possible.…”

Section: Introductionmentioning

confidence: 99%

Progressive resolution optimizer (PRO) predominates over photon optimizer (PO) in sparing of spinal cord for spine SABR VMAT plans

Son

Park²

2022

Preprint

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Background: we assessed the performance of the optimization algorithms by comparing volumetric modulated arc therapy generated by a progressive resolution optimized (VMATPRO) and photon optimizer (VMATPO) in terms of plan quality, MU reduction, sparing of the spinal cord (or cauda equina), and plan complexity.Methods: Fifty-seven patients who received spine stereotactic ablative radiotherapy (SABR) with tumors located in the cervical, thoracic, and lumbar spine were retrospectively selected. For each patient, VMATPRO and VMATPO with two full arcs were generated with using the PRO and PO algorithms. For dosimetric evaluation, the dose-volumetric (DV) parameters of the planning target volume (PTV), organs at risk (OARs), the corresponding planning organs at risk (PRV), and 1.5-cm ring structure surrounding the PTV (Ring1.5 cm) were calculate for all VMAT plans. The total number of monitor units (MUs) and the modulation complexity score for the VMAT (MCSv) were compared. To investigate the correlations of OAR sparing to plan complexity, Pearson’s and Spearman’s correlation tests were conducted between the two algorithms (PO – PRO, denoted as Δ) in the DV parameters for normal tissues, total MUs, and MCSv.Results: For the PTVs, Target conformity and dose homogeneity in the PTVs of VMATPRO were better than those of VMATPO with statistical significance. For the spinal cords (or cauda equine) and corresponding PRVs, all of the DV parameters for VMATPRO were markedly lower than those for VMATPO, with statistical significance (all p < 0.0001). Among them, the difference in the maximum dose to the spinal cord between VMATPRO and VMATPO was remarkable (9.04 Gy vs 11.08 Gy with p < 0.0001). For Ring1.5 cm, no significant difference in V115% for VMATPRO and VMATPO was observed.Conclusions: The use of VMATPRO resulted in coverage and uniformity of dose to the PTV, as well as OARs sparing, compared with that of VMATPO for cervical, thoracic, and lumbar spine SABR. Better dosimetric plan quality generated by the PRO algorithm was observed to result in higher total MUs and plan complexity. Therefore, careful evaluation of its deliverability should be performed with caution during the routine use of the PRO algorithm.

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Radiation Myelitis Risk After Hypofractionated Spine Stereotactic Body Radiation Therapy

Jackson,

Boe,

Zhang

et al. 2024

JAMA Oncol

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ImportanceStereotactic body radiation therapy (SBRT) for spinal metastases improves symptomatic outcomes and local control compared to conventional radiotherapy. Treatment failure most often occurs within the epidural space, where dose is constrained by the risk of radiation myelitis (RM). Current constraints designed to prevent RM after spine SBRT are derived from limited data.ObjectiveTo characterize the risk of RM after spine SBRT and to update the dosimetric constraints for preventing it.Design, Setting, and ParticipantsThis cohort study was conducted in a single tertiary cancer care center with patients treated for spinal metastases from 2014 to 2023. All included participants had undergone spine SBRT, had a minimum of 1-month follow-up with magnetic resonance imaging (MRI), a maximal cord dose to a voxel (Dmax) greater than 0 Gy, and no overlapping prior radiotherapy. In all, 2051 patients received SBRT to 2835 spinal metastases (levels C1-L2) during the study period.ExposuresThree-fraction spine SBRT to a prescription dose of 27 to 36 Gy.Main Outcomes and MeasuresRM defined as radiographic evidence of spinal cord injury in the treatment field, classified as grade (G) 1 to G4 or G3 to G4 per the Common Terminology Criteria for Adverse Events, version 5.0. Multiple dosimetric parameters of the true spinal cord structure were assessed for an association with risk of RM to determine the important covariates associated with this toxicity.ResultsThe analysis included 1423 patients (mean [SD] age, 61.6 [12.9] years; 695 [48.8%] females and 728 [51.1%] males) who received SBRT for 1904 spinal metastases. Among them, 30 cases of RM were identified, 19 of which were classified as G3 to G4. Two years after SBRT, the rate of G1 to G4 RM was 1.8% (95% CI, 1.2%-2.5%) and the rate of G3 to G4 RM was 1.1% (95% CI, 0.7%-1.7%). The minimum dose to the 0.1 cm3 of spinal cord receiving the greatest dose (D0.1cc) was the most important covariate on univariable cause-specific hazards regression for RM (for G3 to G4: hazard ratio, 2.14; 95% CI, 1.68-2.72; P &lt; .001). A true cord D0.1cc of 19.1 Gy and Dmax of 20.8 Gy estimated a 1.0% risk (95% CI, 0.3%-1.6% and 0.4%-1.6%, respectively) of G3 to G4 RM 2 years after SBRT.Conclusions and RelevanceThe findings of this cohort study indicate that a cord (myelogram or MRI-derived) D0.1cc constraint of 19.1 Gy and a Dmax constraint of 20.8 Gy correspond with a 1.0% risk of G3 to G4 RM at 2 years.

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Radiation myelopathy following stereotactic body radiation therapy for spine metastases

Cited by 14 publications

References 73 publications

30 Gy in 4 Stereotactic Body Radiotherapy Fractions for Complex Spinal Metastases: Mature Outcomes Supporting This Novel Regimen

30 Gy in 4 Stereotactic Body Radiotherapy Fractions for Complex Spinal Metastases: Mature Outcomes Supporting This Novel Regimen

Progressive resolution optimizer (PRO) predominates over photon optimizer (PO) in sparing of spinal cord for spine SABR VMAT plans

Radiation Myelitis Risk After Hypofractionated Spine Stereotactic Body Radiation Therapy

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