Involved Versus Elective Target SSRS for Spinal Metastases

The spine is a common metastatic site for malignancy and it can lead to serious and devastating events, including pain, neurological dysfunction, and reduction in quality of life. The radiotherapy (RT) has been the mainstay for palliating painful spinal metastases for the past decades. It is utilized to arrest the tumor growth, control pain, and stabilize or improve skeletal and/or neurological function. One of the limitations of the conventional radiotherapy is that radiation dose intensification is not achievable with conventional RT techniques due to the dose-limiting spinal cord, which is close to the vertebral body and sometimes encased by epidural lesion. The management of patients with spine metastasis has undergone a great deal of change in the past 10 years. The concept of radiosurgery, a high dose of radiation targeted to a pathological entity and delivered in 1-5-fractions, has proven so successful at treating both benign and malignant lesions that it changed the paradigm for radiation therapy. Clinical experiences with high dose spine stereotactic radiosurgery (SSRS) for spinal metastases demonstrated both safety and efficacy. Nontheless, the patterns of clinical practice of SSRS varies considerably regarding the dose fractionation, target delineation, and dosimetry. There is lack of evidence-based recommedations for SSRS. In our prior clinical trial comparing single fraction and multiple fractions SSRS (NCT02608866), single-fraction with 16 Gy is the preferred regimen for further evaluation since it met the predefined primary endpoint and has lower risk of treatment failure compared to the multiple-fraction arm. Regarding the target volume definition, the International Spine Radiosurgery Consortium published concensus guidelines based on expert opinions and limited case series. We proposed this randomized study to determine the preferred or acceptable definition of target volume delineation in SSRS and to evaluate their toxicity, efficacy, and patterns of failure. Our analysis will provide evidence-based recommendations as well as predictive factors regarding the clinical practice of SSRS.

Sex

All

Minimum age

20 Years

Inclusion Criteria:

* Patients with a histologic diagnosis of non-hematopoietic malignancy
* Radiographic evidence of localized spine metastases without leptomeningeal involvement or intramedullary lesion
* Maximum four separate sites with a maximal involvement of two continuous vertebral levels
* Patients do not have prior radiotherapy to the index spine(s)
* Age ≥ 20 years
* Karnofsky performance status (KPS) ≥ 60%.
* Life expectancy of ≥ 6 month.
* Women of childbearing potential and male participants must practice adequate contraception
* Patients must be able to comply with the study protocol and follow- up schedules and provide study-specific informed consent

Exclusion Criteria:

* Prior radiotherapy to the index spine(s)
* Serum creatinine \> 2.0 mg/dL within 90 days prior registration
* Contraindication to MR imaging such as implanted metal devices or foreign bodies, severe claustrophobia
* Patients with leptomeningeal involvement or intramedullary metastasis
* Inability to tolerate treatment procedure
* Bony retropulsion causing neurologic abnormality
* Severe, active comorbidities which, in the judgment of the investigator, would make the patient inappropriate for entry into this study or interfere significantly with the proper assessment of safety and adverse events of the protocol, or limit compliance with study requirements
* Will receive any other investigational agent or chemotherapy and/or target therapies during treatment
* Women of childbearing potential and male participants who are sexually active and not willing/able to use medically acceptable forms of contraception; this exclusion is necessary because the radiation treatment involved in this study may be significantly teratogenic
* Pregnant or breast-feeding women