Stereotactic body radiation therapy for spinal metastases: Tumor control probability analyses and recommended reporting standards Review


Authors: Soltys, S. G.; Grimm, J.; Milano, M. T.; Xue, J.; Sahgal, A.; Yorke, E.; Yamada, Y.; Ding, G. X.; Li, X. A.; Lovelock, D. M.; Jackson, A.; Ma, L.; El Naqa, I.; Gibbs, I. C.; Marks, L. B.; Benedict, S.
Review Title: Stereotactic body radiation therapy for spinal metastases: Tumor control probability analyses and recommended reporting standards
Abstract: Purpose: We sought to investigate the tumor control probability (TCP) of spinal metastases treated with stereotactic body radiation therapy (SBRT) in 1 to 5 fractions. Methods and Materials: PubMed-indexed articles from 1995 to 2018 were eligible for data extraction if they contained SBRT dosimetric details correlated with actuarial 2-year local tumor control rates. Logistic dose-response models of collected data were compared in terms of physical dose and 3-fraction equivalent dose. Results: Data were extracted from 24 articles with 2619 spinal metastases. Physical dose TCP modeling of 2-year local tumor control from the single-fraction data were compared with data from 2 to 5 fractions, resulting in an estimated α/β = 6 Gy, and this was used to pool data. Acknowledging the uncertainty intrinsic to the data extraction and modeling process, the 90% TCP corresponded to 20 Gy in 1 fraction, 28 Gy in 2 fractions, 33 Gy in 3 fractions, and (with extrapolation) 40 Gy in 5 fractions. The estimated TCP for common fractionation schemes was 82% at 18 Gy, 90% for 20 Gy, and 96% for 24 Gy in a single fraction, 82% for 24 Gy in 2 fractions, and 78% for 27 Gy in 3 fractions. Conclusions: Spinal SBRT with the most common fractionation schemes yields 2-year estimates of local control of 82% to 96%. Given the heterogeneity in the tumor control estimates extracted from the literature, with variability in reporting of dosimetry data and the definition of and statistical methods of reporting tumor control, care should be taken interpreting the resultant model-based estimates. Depending on the clinical intent, the improved TCP with higher dose regimens should be weighed against the potential risks for greater toxicity. We encourage future reports to provide full dosimetric data correlated with tumor local control to allow future efforts of modeling pooled data. © 2020 Elsevier Inc.
Keywords: radiotherapy; pathology; tumors; dosimetry; stereotactic body radiation therapy; extraction; spinal metastasis; tumor control probability; local tumor control; data mining; uncertainty analysis; methods and materials; transmission control protocol; reporting standards; dose-response models; modeling process
Journal Title: International Journal of Radiation Oncology, Biology, Physics
Volume: 110
Issue: 1
ISSN: 0360-3016
Publisher: Elsevier Inc.  
Date Published: 2021-05-01
Start Page: 112
End Page: 123
Language: English
DOI: 10.1016/j.ijrobp.2020.11.021
PUBMED: 33516580
PROVIDER: scopus
DOI/URL:
Notes: Article -- Export Date: 3 May 2021 -- Source: Scopus
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  1. Yoshiya Yamada
    479 Yamada
  2. Andrew Jackson
    253 Jackson
  3. Ellen D Yorke
    450 Yorke
  4. Dale M Lovelock
    183 Lovelock