Surgical resection of epidural disease improves local control following postoperative spine stereotactic body radiotherapy

Al-Omair, Ameen; Masucci, Laura; Masson-Côté, Laurence; Campbell, Mikki; Atenafu, Eshetu G.; Parent, Amy; Létourneau, D.; Yu, Eugene; Rampersaud, Raja; Massicotte, Eric M.; Lewis, Stephen J.; Yee, Albert; Thibault, Isabelle; Fehlings, Michael G.; Sahgal, Arjun

doi:10.1093/neuonc/not101

Cited by 159 publications

(129 citation statements)

References 20 publications

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“…The most common primary histology was sarcoma, comprising 35% of treated patients. The 2-year overall survival and freedom from local progression were 57% and 73%, respectively, with inferior local control possibly related to relatively gentle median dose / fractionation schedule of 30Gy in 5 fractions as compared to our 24Gy in 2 fractions, as previously described by Saghal et al [21] It is interesting that outcomes achieved in our study were similar to those achieved with SABR for other body sites where much higher doses are usually required. A threshold dose of BED10 > 100 Gy is often quoted as being required to achieve optimal local control in lung and liver metastases [22,23], which is much higher than the doses employed in this cohort.…”

Section: Discussionsupporting

confidence: 72%

Stereotactic Ablative Body Radiotherapy for the Treatment of Spinal Oligometastases

et al. 2017

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After the embargo period via non-commercial hosting platforms such as their institutional repository  via commercial sites with which Elsevier has an agreement In all cases accepted manuscripts should: link to the formal publication via its DOI  bear a CC-BY-NC-ND license -this is easy to do, click here to find out how  if aggregated with other manuscripts, for example in a repository or other site, be shared in alignment with our hosting policy  not be added to or enhanced in any way to appear more like, or to substitute for, the published journal article This cohort warrants further investigation in clinical trials of SABR.

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Section: Discussionsupporting

confidence: 72%

Stereotactic Ablative Body Radiotherapy for the Treatment of Spinal Oligometastases

et al. 2017

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“…The outcomes and technique applied to this cohort have been previously reported. 1 In that report, we also provided a detailed summary of the dosimetric outcomes and doses to the spinal cord and thecal sac (i.e., critical neural tissues). Of note regarding the original series, the only predictors for local control were the epidural disease grade and prescribed dose, and none of the dosimetric outcomes-including the dose to the critical neural tissues-were predictive.…”

Section: Methodsmentioning

confidence: 99%

“…13 There is growing evidence demonstrating the efficacy of spine SBRT, with excellent local control and pain control rates in patients receiving de novo treatment, retreatment after prior radiation, and, more recently, postoperative adjuvant therapy following resection. 1,6,15,16 Postoperative spine SBRT is growing in practice, as it fits with the rationale that if we are going to subject a patient to a major operation, then we should deliver an effective and philosophically equivalent adjuvant therapy intended to maximize local control. 10 Imaging-based local control rates after conventional palliative radiation therapy have not been well defined.…”

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confidence: 99%

“…5,8 In the limited literature on postoperative spine SBRT, the rates of local control are highly promising, as 1-year local control rates of approximately 80% to 90% have been reported. 1,6,7 Surgery for spinal metastases is often performed for decompression of the spinal cord and involves resection of epidural disease. However, a major area of uncertainty is related to the most appropriate clinical target volume (CTV) for postoperative spine SBRT.…”

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confidence: 99%

“…This has been common practice at the University of Toronto, per our previously published report specific to postoperative spine SBRT. The purpose of this investigation was to perform, as an extension of our previous outcome analysis, 1 a detailed pattern-of-failure analysis focused on the epidural space. In addition, we sought to determine if any relationship with epidural progression is observable that influences CTV delineation based on both the preoperative and postoperative epidural disease characteristics.…”

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Patterns of epidural progression following postoperative spine stereotactic body radiotherapy: implications for clinical target volume delineation

Chan¹,

Thibault²,

Atenafu³

et al. 2016

SPI

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OBJECT The authors performed a pattern-of-failure analysis, with a focus on epidural disease progression, in patients treated with postoperative spine stereotactic body radiotherapy (SBRT). METHODS Of the 70 patients with 75 spinal metastases (cases) treated with postoperative spine SBRT, there were 26 cases of local disease recurrence and 25 cases with a component of epidural disease progression. Twenty-four of the 25 cases had preoperative epidural disease with subsequent epidural disease progression, and this cohort was the focus of this epidural-specific pattern-of-failure investigation. Preoperative, postoperative, and follow-up MRI scans were reviewed, and epidural disease was characterized based on location according to a system in which the vertebral anatomy is divided into 6 sectors, with the anterior compartment comprising Sectors 1, 2, and 6, and the posterior compartment comprising Sectors 3, 4, and 5. RESULTS Patterns of epidural progression are reported specifically for the 24 cases with preoperative epidural disease and subsequent epidural progression. Epidural disease progression within the posterior compartment was observed to be significantly lower in those with preoperative epidural disease confined to the anterior compartment than in those with preoperative epidural disease involving both anterior and posterior compartments (56% vs 93%, respectively; p = 0.047). In a high proportion of patients with epidural disease progression, treatment failure was found in the anterior compartment, including both those with preoperative epidural disease confined to the anterior compartment and those with preoperative epidural disease involving both anterior and posterior compartments (100% vs. 73%, respectively). When epidural disease was confined to the anterior compartment on the preoperative and postoperative MRIs, no epidural disease progression was observed in Sector 4, which is the most posterior sector. Postoperative epidural disease characteristics alone were not predictive of the pattern of epidural treatment failure. CONCLUSIONS Reviewing the extent of epidural disease on preoperative MRI is imperative when planning postoperative SBRT. When epidural disease is confined to the anterior epidural sectors pre- and postoperatively, covering the entire epidural space circumferentially with a prophylactic “donut” distribution may not be needed.

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Commissioning and validation of a Monte Carlo algorithm for spine stereotactic radiosurgery

Knill¹,

Sandhu²,

Loughery³

et al. 2023

J Applied Clin Med Phys

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PurposeA 6FFF Monte Carlo (MC) dose calculation algorithm was commissioned for spine stereotactic radiosurgery (SRS). Model generation, validation, and ensuing model tuning are presented.MethodsThe model was generated using in‐air and in‐water commissioning measurements of field sizes between 10 and 400 mm2. Commissioning measurements were compared to simulated water tank MC calculations to validate output factors, percent depth doses (PDDs), profile sizes and penumbras. Previously treated Spine SRS patients were re‐optimized with the MC model to achieve clinically acceptable plans. Resulting plans were calculated on the StereoPHAN phantom and subsequently delivered to the microDiamond and SRSMapcheck to verify calculated dose accuracy. Model tuning was performed by adjusting the model's light field offset (LO) distance between physical and radiological positions of the MLCs, to improve field size and StereoPHAN calculation accuracy. Following tuning, plans were generated and delivered to an anthropomorphic 3D‐printed spine phantom featuring realistic bone anatomy, to validate heterogeneity corrections. Finally, plans were validated using polymer gel (VIPAR based formulation) measurements.ResultsCompared to open field measurements, MC calculated output factors and PDDs were within 2%, profile penumbra widths were within 1 mm, and field sizes were within 0.5 mm. Calculated point dose measurements in the StereoPHAN were within 0.26% ± 0.93% and −0.10% ± 1.37% for targets and spinal canals, respectively. Average SRSMapcheck per‐plan pass rates using a 2%/2 mm/10% threshold relative gamma analysis was 99.1% ± 0.89%. Adjusting LOs improved open field and patient‐specific dosimetric agreement. Anthropomorphic phantom measurements were within −1.29% ± 1.00% and 0.27% ± 1.36% of MC calculated for the vertebral body (target) and spinal canal, respectively. VIPAR gel measurements confirmed good dosimetric agreement near the target‐spine junction.ConclusionValidation of a MC algorithm for simple fields and complex SRS spine deliveries in homogeneous and heterogeneous phantoms has been performed. The MC algorithm has been released for clinical use.

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Surgical resection of epidural disease improves local control following postoperative spine stereotactic body radiotherapy

Abstract: Postoperative SBRT with high total doses ranging from 18 to 26 Gy delivered in 1-2 fractions predicted superior LC, as did postoperative epidural grade.

Cited by 159 publications

References 20 publications

Stereotactic Ablative Body Radiotherapy for the Treatment of Spinal Oligometastases

Stereotactic Ablative Body Radiotherapy for the Treatment of Spinal Oligometastases

Patterns of epidural progression following postoperative spine stereotactic body radiotherapy: implications for clinical target volume delineation

Commissioning and validation of a Monte Carlo algorithm for spine stereotactic radiosurgery

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