| Autor: |
Redmond KJ; Department of Radiation Oncology and Molecular Radiation Sciences, The John Hopkins University, Baltimore, Maryland., Lo SS; Department of Radiation Oncology, University Hospitals Seidman Cancer Center, Case Comprehensive Cancer Center., Soltys SG; Department of Radiation Oncology, Stanford Cancer Institute, Stanford University, Stanford., Yamada Y; Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York., Barani IJ; Department of Radiation Oncology, University of California, San Francisco., Brown PD; Department of Radiation Oncology, MD Anderson Cancer Center., Chang EL; Department of Radiation Oncology, Norris Cancer Center and Keck School of Medicine at University of Southern California., Gerszten PC; Department of Neurological Surgery and Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania., Chao ST; Department of Radiation Oncology, Rose Ella Burkhardt Brain Tumor and Neurooncology Center, Cleveland Clinic, Cleveland, Ohio., Amdur RJ; Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida., De Salles AA; Department of Neurological Surgery, Brain Research Institute, University of California, Los Angeles, California., Guckenberger M; Department of Radiation Oncology, University of Zurich, Switzerland., Teh BS; Department of Radiation Oncology, Houston Methodist Hospital, Cancer Center and Research Institute, Weill Cornell Medical College, Houston, Texas., Sheehan J; Department of Neurological Surgery, University of Virginia Health System, Charlottesville., Kersh CR; Department of Radiation Oncology, Riverside Radiation Oncology Specialists, Newport News, Virginia., Fehlings MG; Division of Neurosurgery and Spine Program, Toronto Western Hospital, University of Toronto., Sohn MJ; Department of Neurological Surgery, Radiosurgery Center, Inje University Ilsan Paik Hospital, College of Medicine, Goyang; and., Chang UK; Department of Neurosurgery, Korea Institute of Radiological and Medical Sciences, Seoul, South Korea., Ryu S; Department of Radiation Oncology, Stony Brook Cancer Center, Stony Brook, New York., Gibbs IC; Department of Radiation Oncology, Stanford Cancer Institute, Stanford University, Stanford., Sahgal A; Department of Radiation Oncology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada. |
| Abstrakt: |
OBJECTIVE Although postoperative stereotactic body radiation therapy (SBRT) for spinal metastases is increasingly performed, few guidelines exist for this application. The purpose of this study is to develop consensus guidelines to promote safe and effective treatment for patients with spinal metastases. METHODS Fifteen radiation oncologists and 5 neurosurgeons, representing 19 centers in 4 countries and having a collective experience of more than 1300 postoperative spine SBRT cases, completed a 19-question survey about postoperative spine SBRT practice. Responses were defined as follows: 1) consensus: selected by ≥ 75% of respondents; 2) predominant: selected by 50% of respondents or more; and 3) controversial: no single response selected by a majority of respondents. RESULTS Consensus treatment indications included: radioresistant primary, 1-2 levels of adjacent disease, and previous radiation therapy. Contraindications included: involvement of more than 3 contiguous vertebral bodies, ASIA Grade A status (complete spinal cord injury without preservation of motor or sensory function), and postoperative Bilsky Grade 3 residual (cord compression without any CSF around the cord). For treatment planning, co-registration of the preoperative MRI and postoperative T1-weighted MRI (with or without gadolinium) and delineation of the cord on the T2-weighted MRI (and/or CT myelogram in cases of significant hardware artifact) were predominant. Consensus GTV (gross tumor volume) was the postoperative residual tumor based on MRI. Predominant CTV (clinical tumor volume) practice was to include the postoperative bed defined as the entire extent of preoperative tumor, the relevant anatomical compartment and any residual disease. Consensus was achieved with respect to not including the surgical hardware and incision in the CTV. PTV (planning tumor volume) expansion was controversial, ranging from 0 to 2 mm. The spinal cord avoidance structure was predominantly the true cord. Circumferential treatment of the epidural space and margin for paraspinal extension was controversial. Prescription doses and spinal cord tolerances based on clinical scenario, neurological compromise, and prior overlapping treatments were controversial, but reasonable ranges are presented. Fifty percent of those surveyed practiced an integrated boost to areas of residual tumor and density override for hardware within the beam path. Acceptable PTV coverage was controversial, but consensus was achieved with respect to compromising coverage to meet cord constraint and fractionation to improve coverage while meeting cord constraint. CONCLUSIONS The consensus by spinal radiosurgery experts suggests that postoperative SBRT is indicated for radioresistant primary lesions, disease confined to 1-2 vertebral levels, and/or prior overlapping radiotherapy. The GTV is the postoperative residual tumor, and the CTV is the postoperative bed defined as the entire extent of preoperative tumor and anatomical compartment plus residual disease. Hardware and scar do not need to be included in CTV. While predominant agreement was reached about treatment planning and definition of organs at risk, future investigation will be critical in better understanding areas of controversy, including whether circumferential treatment of the epidural space is necessary, management of paraspinal extension, and the optimal dose fractionation schedules. |
