Stereotactic Body Radiotherapy for Lesions of the Spine and Paraspinal Regions

Nelson, John W.; Yoo, David S.; Sampson, John H.; Isaacs, Robert E.; Larrier, Nicole A.; Marks, Lawrence B.; Yin, Fang-Fang; Wu, Q. Jackie; Wang, Zhiheng; Kirkpatrick, John P.

doi:10.1016/j.ijrobp.2008.06.1949

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Volume 73, Issue 5 , Pages 1369-1375, 1 April 2009

Stereotactic Body Radiotherapy for Lesions of the Spine and Paraspinal Regions

John W. Nelson, M.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
David S. Yoo, M.D., Ph.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
John H. Sampson, M.D., Ph.D.
- Department of Surgery, Duke University Medical Center, Durham, NC
Robert E. Isaacs, M.D.
- Department of Surgery, Duke University Medical Center, Durham, NC
Nicole A. Larrier, M.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
Lawrence B. Marks, M.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
Fang-Fang Yin, Ph.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
Q. Jackie Wu, Ph.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
Zhiheng Wang, Ph.D
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
John P. Kirkpatrick, M.D., Ph.D.
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC
- Reprint requests to: John P. Kirkpatrick, M.D., Ph.D., Department of Radiation Oncology, Duke University Medical Center, Box 3085, Durham, NC 27710. Tel: (919) 668-5213; Fax: (919) 668-7345

Received 13 May 2008; received in revised form 13 June 2008; accepted 20 June 2008. published online 11 November 2008.

Purpose

To describe our experience and clinical strategy for stereotactic body radiotherapy (SBRT) of spinal lesions.

Methods and Materials

Thirty-two patients with 33 spinal lesions underwent computed tomography–based simulation while free breathing. Gross/clinical target volumes included involved portions of the vertebral body and paravertebral/epidural tumor. Planning target volume (PTV) expansion was 6 mm axially and 3 mm radially; the cord was excluded from the PTV. Biologic equivalent dose was calculated using the linear quadratic model with α/β = 3 Gy. Treatment was linear accelerator based with on-board imaging; dose was adjusted to maintain cord dose within tolerance. Survival, local control, pain, and neurologic status were monitored.

Results

Twenty-one patients are alive at 1 year (median survival, 14 months). Median follow-up is 6 months for all patients (7 months for survivors). Mean previous radiotherapy dose to 22 patients was 35 Gy, and median interval was 17 months. Renal (31%), breast, and lung (19% each) were the most common histologic sites. Three SBRT fractions (range, one to four fractions) of 7 Gy (range, 5–16 Gy) were delivered. Median cord and target biologic equivalent doses were 70 Gy₃ and 34.3 Gy₁₀, respectively. Thirteen patients reported complete and 17 patients reported partial pain relief at 1 month. There were four failures (mean, 5.8 months) with magnetic resonance imaging evidence of in-field progression. No dosimetric parameters predictive of failure were identified. No treatment-related toxicity was seen.

Conclusions

Spinal SBRT is effective in the palliative/re-treatment setting. Volume expansion must ensure optimal PTV coverage while avoiding spinal cord toxicity. The long-term safety of spinal SBRT and the applicability of the linear-quadratic model in this setting remain to be determined, particularly the time-adjusted impact of prior radiotherapy.

Spinal cord, Spine radiosurgery, Stereotactic body radiotherapy, Normal tissue tolerance