Multifractionated image-guided and stereotactic intensity-modulated radiotherapy of paraspinal tumors: A preliminary report
ABSTRACT The use of image-guided and stereotactic intensity-modulated radiotherapy (IMRT) techniques have made the delivery of high-dose radiation to lesions within close proximity to the spinal cord feasible. This report presents clinical and physical data regarding the use of IMRT coupled with noninvasive body frames (stereotactic and image-guided) for multifractionated radiotherapy.
The Memorial Sloan-Kettering Cancer Center (Memorial) stereotactic body frame (MSBF) and Memorial body cradle (MBC) have been developed as noninvasive immobilizing devices for paraspinal IMRT using stereotactic (MSBF) and image-guided (MBC) techniques. Patients were either previously irradiated or prescribed doses beyond spinal cord tolerance (54 Gy in standard fractionation) and had unresectable gross disease involving the spinal canal. The planning target volume (PTV) was the gross tumor volume with a 1 cm margin. The PTV was not allowed to include the spinal cord contour. All treatment planning was performed using software developed within the institution. Isocenter verification was performed with an in-room computed tomography scan (MSBF) or electronic portal imaging devices, or both. Patients were followed up with serial magnetic resonance imaging every 3-4 months, and no patients were lost to follow-up. Kaplan-Meier statistics were used for analysis of clinical data.
Both the MSBF and MBC were able to provide setup accuracy within 2 mm. With a median follow-up of 11 months, 35 patients (14 primary and 21 secondary malignancies) underwent treatment. The median dose previously received was 3000 cGy in 10 fractions. The median dose prescribed for these patients was 2000 cGy/5 fractions (2000-3000 cGy), which provided a median PTV V100 of 88%. In previously unirradiated patients, the median prescribed dose was 7000 cGy (5940-7000 cGy) with a median PTV V100 of 90%. The median Dmax to the cord was 34% and 68% for previously irradiated and never irradiated patients, respectively. More than 90% of patients experienced palliation from pain, weakness, or paresthesia; 75% and 81% of secondary and primary lesions, respectively, exhibited local control at the time of last follow-up. No cases of radiation-induced myelopathy or radiculopathy have thus far been encountered.
Precision stereotactic and image-guided paraspinal IMRT allows the delivery of high doses of radiation in multiple fractions to tumors within close proximity to the spinal cord while respecting cord tolerance. Although preliminary, the clinical results are encouraging.
- SourceAvailable from: Beant Singh Gill
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- "With improved dose distributions and accuracy, SBRT has facilitated the safe painless delivery of high doses of radiation quickly to localized spine tumors. Multiple studies have confirmed the efficacy of SBRT with early symptomatic improvement seen in 86–96% of treated patients following delivery of one to five fractions (Gerszten et al., 2004,2007; Ryu et al., 2004,2008; Degen et al., 2005; Yamada et al., 2005,2008; Chang et al., 2007; Gibbs et al., 2007; Gagnon et al., 2009). Despite growing evidence supporting SBRT in poor prognosis, previously irradiated spine metastases patients, few studies have established local control rates for newly diagnosed relatively good prognosis patients with single VB metastases. "
ABSTRACT: This retrospective analysis examines the local control and toxicity of five-fraction fiducial-free CyberKnife stereotactic body radiation therapy (SBRT) for single vertebral body (VB) metastases. All patients had favorable performance status (ECOG 0-1), oligometastatic disease, and no prior spine irradiation. A prescribed dose of 30-35 Gy was delivered in five fractions to the planning target volume (PTV) using the CyberKnife with X-sight spine tracking. Suggested maximum spinal cord and esophagus point doses were 30 and 40 Gy, respectively. A median 30 Gy (IQR, 30-35 Gy) dose was delivered to a median prescription isodose line of 70% (IQR, 65-77%) to 20 patients. At 34 months median follow-up (IQR, 25-40 months) for surviving patients, the 1- and 2-year Kaplan-Meier local control estimates were 80 and 73%, respectively. Two of the five local failures were infield in patients who had received irradiation to the gross tumor volume and three were paravertebral failures just outside the PTV in patients with prior corpectomy. No local failures occurred in patients who completed VB radiation alone. The 1- and 2-year Kaplan-Meier overall survival estimates were 80 and 57%, respectively. Most deaths were attributed to metastatic disease; one death was attributed to local recurrence. The mean maximum point doses were 26.4 Gy (SD, 5.1 Gy) to the spinal cord and 29.1 Gy (SD, 8.9 Gy) to the esophagus. Patients receiving maximum esophagus point doses greater than 35 Gy experienced acute dysphagia (Grade I/II). No spinal cord toxicity was documented. Five-fraction fiducial-free CyberKnife SBRT is an acceptable treatment option for newly diagnosed VB metastases with promising local control rates and minimal toxicity despite the close proximity of such tumors to the spinal cord and esophagus. A prospective study aimed at further enhancing local control by targeting the intact VB and escalating the total dose is planned.Frontiers in Oncology 04/2012; 2:39. DOI:10.3389/fonc.2012.00039
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- "Current therapies include surgical resection, radiation, and chemotherapy. In addition, with recent advances using intensity-modulated, proton and carbon-ion radiotherapy, radiation doses can be safely administered to microscopic residual tumor (10–12). "
ABSTRACT: We report a very rare case of a high grade osteosarcoma of the cervical spine in a 62-year-old woman. She presented with a relatively short history of a swelling in the posterior neck and cervical lymphadenopathy. This was associated with hoarseness of the voice, significant weight loss, and right upper arm radicular symptoms initially, progressing to paraplegia. Based on MR and CT imaging of the neck and an excision biopsy of an enlarged right supraclavicular lymph node, the histology revealed a high grade primary osteosarcoma of the cervical spine.02/2012; 1(1). DOI:10.1258/arsr.2012.110028
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- "Previously irradiated lesions were treated with a mean maximum dose of 20 Gy (range 12.5-25 Gy)11), a median dose 35 Gy (range 20-50.4 Gy)3), a median dose of 20 Gy in 5 fractions (range 20-30 Gy)43), and a median dose 20 Gy (range 10-30 Gy) in 1-5 fractions (median 2). "
ABSTRACT: The incidence and prevalence of spinal metastases are increasing, and although the role of radiation therapy in the treatment of metastatic tumors of the spine has been well established, the same cannot be said about the role of stereotactic radiosurgery. Herein, the authors present a systematic review regarding the value of spinal stereotactic radiosurgery in the management of spinal metastasis. A systematic literature search for stereotactic radiosurgery of spinal metastases was undertaken. Grades of Recommendation, Assessment, Development, and Education (GRADE) working group criteria was used to evaluate the qualities of study datasets. Thirty-one studies met the study inclusion criteria. Twenty-three studies were of low quality, and 8 were of very low quality according to the GRADE criteria. Stereotactic radiosurgery was reported to be highly effective in reducing pain, regardless of prior treatment. The overall local control rate was approximately 90%. Additional asymptomatic lesions may be treated by stereotactic radiosurgery to avoid further irradiation of neural elements and further bone-marrow suppression. Stereotactic radiosurgery may be preferred in previously irradiated patients when considering the radiation tolerance of the spinal cord. Furthermore, residual tumors after surgery can be safely treated by stereotactic radiosurgery, which decreases the likelihood of repeat surgery and accompanying surgical morbidities. Encompassing one vertebral body above and below the involved vertebrae is unnecessary. Complications associated with stereotactic radiosurgery are generally self-limited and mild. In the management of spinal metastasis, stereotactic radiosurgery appears to provide high rates of tumor control, regardless of histologic diagnosis, and can be used in previously irradiated patients. However, the quality of literature available on the subject is not sufficient.Journal of Korean Neurosurgical Society 01/2012; 51(1):1-7. DOI:10.3340/jkns.2012.51.1.1 · 0.64 Impact Factor