Stereotactic Radiosurgery for Treatment of Spinal Metastases Recurring in Close Proximity to Previously Irradiated Spinal Cord

Journal Article · Fri Oct 01 04:00:00 EDT 2010 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2009.07.1727· OSTI ID:21436194

Choi, Clara Y.H.; Adler, John R ^[1]; Gibbs, Iris C ^[2]; Chang, Steven D; Jackson, Paul S ^[1]; Minn, A Yuriko ^[2]; Lieberson, Robert E ^[1]

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1. Department of Neurosurgery, Stanford University Medical Center, Stanford, CA (United States)
2. Department of Radiation Oncology, Stanford University Medical Center, Stanford, CA (United States)

Purpose: As the spinal cord tolerance often precludes reirradiation with conventional techniques, local recurrence within a previously irradiated field presents a treatment challenge. Methods and Materials: We retrospectively reviewed 51 lesions in 42 patients treated from 2002 to 2008 whose spinal metastases recurred in a previous radiation field (median previous spinal cord dose of 40 Gy) and were subsequently treated with stereotactic radiosurgery (SRS). Results: SRS was delivered to a median marginal dose of 20 Gy (range, 10-30 Gy) in 1-5 fractions (median, 2), targeting a median tumor volume of 10.3 cm{sup 3} (range, 0.2-128.6 cm{sup 3}). Converting the SRS regimens with the linear quadratic model ({alpha}/{beta} = 3), the median spinal cord maximum single-session equivalent dose (SSED) was 12.1 Gy{sub 3} (range, 4.7-19.3 Gy{sub 3}). With a median follow-up of 7 months (range, 2-47 months), the Kaplan-Meier local control and overall survival rates at 6/12 months were 87%/73% and 81%/68%, respectively. A time to retreatment of {<=}12 months and the combination of time to retreatment of {<=}12 months with an SSED of <15 Gy{sub 10} were significant predictors of local failure on univariate and multivariate analyses. In patients with a retreatment interval of <12 months, 6/12 month local control rates were 88%/58%, with a SSED of >15 Gy{sub 10}, compared to 45%/0% with <15 Gy{sub 10}, respectively. One patient (2%) experienced Grade 4 neurotoxicity. Conclusion: SRS is safe and effective in the treatment of spinal metastases recurring in previously irradiated fields. Tumor recurrence within 12 months may correlate with biologic aggressiveness and require higher SRS doses (SSED >15 Gy{sub 10}). Further research is needed to define the partial volume retreatment tolerance of the spinal cord and the optimal target dose.

• OSTI ID: 21436194
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 2 Vol. 78; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BODY
CENTRAL NERVOUS SYSTEM
DISEASES
DOSES
MEDICINE
METASTASES
NEOPLASMS
NERVOUS SYSTEM
NUCLEAR MEDICINE
ORGANS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
SKELETON
SPINAL CORD
SURGERY
THERAPY
TOLERANCE
VERTEBRAE