Choosing a Prescription Isodose in Stereotactic Radiosurgery for Brain Metastases: Implications for Local Control

Kara D. Romano, Daniel Trifiletti, Allison Garda, Zhiyuan Xu, David Schlesinger, William T. Watkins, Brian Neal, James M. Larner, Jason P. Sheehan

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Objective Stereotactic radiosurgery (SRS) achieves excellent local control (LC) with limited toxicity for most brain metastases. SRS dose prescription variables influence LC; therefore, we evaluated the impact of prescription isodose line (IDL) on LC after SRS. Methods A retrospective analysis of patients with brain metastases treated on a Gamma Knife platform from 2004 to 2014 was conducted. Clinical, toxicity, radiographic, and dosimetric data were collected. Cox proportional hazards regression was used to determine progression-free survival (PFS) and competing risks analysis was used to determine predictive factors for LC. Results A total of 134 patients with 374 brain metastases were identified with a median survival of 8.7 months (range, 0.2–64.8). The median tumor maximum dimension was 8 mm (range, 2–62 mm), median margin dose was 20 Gy (range, 5–24 Gy), and 12-month LC rate was 88.7%. On multivariate analysis, PFS improved with increasing IDL (P = 0.003) and decreased with non-non-small-cell lung cancer histology (P = 0.001). Margin dose, tumor size, conformality, and previous whole-brain irradiation failed to independently affect PFS. When adjusting for death as a competing risk, the cumulative likelihood of LC improved with higher IDL (P = 0.04). The rate of SRS-induced radiographic and clinical toxicity was low (16.6% and 1.5%, respectively), and neither was affected by IDL. Conclusions Our results confirm that SRS for brain metastases results in favorable LC, particularly for patients with smaller tumors. We noted that dose delivery to a higher prescription IDL is associated with small but measurable improvements in LC. This finding could be related to higher dose just beyond the radiographically apparent tumor.

Original languageEnglish (US)
Pages (from-to)761-767.e1
JournalWorld neurosurgery
Volume98
DOIs
StatePublished - Feb 1 2017
Externally publishedYes

Fingerprint

Radiosurgery
Prescriptions
Neoplasm Metastasis
Brain
Disease-Free Survival
Neoplasms
Lung Neoplasms
Histology
Multivariate Analysis
Survival

Keywords

  • Brain metastases
  • Isodose
  • Local control
  • Margin dose
  • Radiosurgery

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

Cite this

Choosing a Prescription Isodose in Stereotactic Radiosurgery for Brain Metastases : Implications for Local Control. / Romano, Kara D.; Trifiletti, Daniel; Garda, Allison; Xu, Zhiyuan; Schlesinger, David; Watkins, William T.; Neal, Brian; Larner, James M.; Sheehan, Jason P.

In: World neurosurgery, Vol. 98, 01.02.2017, p. 761-767.e1.

Research output: Contribution to journalArticle

Romano, KD, Trifiletti, D, Garda, A, Xu, Z, Schlesinger, D, Watkins, WT, Neal, B, Larner, JM & Sheehan, JP 2017, 'Choosing a Prescription Isodose in Stereotactic Radiosurgery for Brain Metastases: Implications for Local Control', World neurosurgery, vol. 98, pp. 761-767.e1. https://doi.org/10.1016/j.wneu.2016.11.038
Romano, Kara D. ; Trifiletti, Daniel ; Garda, Allison ; Xu, Zhiyuan ; Schlesinger, David ; Watkins, William T. ; Neal, Brian ; Larner, James M. ; Sheehan, Jason P. / Choosing a Prescription Isodose in Stereotactic Radiosurgery for Brain Metastases : Implications for Local Control. In: World neurosurgery. 2017 ; Vol. 98. pp. 761-767.e1.
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abstract = "Objective Stereotactic radiosurgery (SRS) achieves excellent local control (LC) with limited toxicity for most brain metastases. SRS dose prescription variables influence LC; therefore, we evaluated the impact of prescription isodose line (IDL) on LC after SRS. Methods A retrospective analysis of patients with brain metastases treated on a Gamma Knife platform from 2004 to 2014 was conducted. Clinical, toxicity, radiographic, and dosimetric data were collected. Cox proportional hazards regression was used to determine progression-free survival (PFS) and competing risks analysis was used to determine predictive factors for LC. Results A total of 134 patients with 374 brain metastases were identified with a median survival of 8.7 months (range, 0.2–64.8). The median tumor maximum dimension was 8 mm (range, 2–62 mm), median margin dose was 20 Gy (range, 5–24 Gy), and 12-month LC rate was 88.7{\%}. On multivariate analysis, PFS improved with increasing IDL (P = 0.003) and decreased with non-non-small-cell lung cancer histology (P = 0.001). Margin dose, tumor size, conformality, and previous whole-brain irradiation failed to independently affect PFS. When adjusting for death as a competing risk, the cumulative likelihood of LC improved with higher IDL (P = 0.04). The rate of SRS-induced radiographic and clinical toxicity was low (16.6{\%} and 1.5{\%}, respectively), and neither was affected by IDL. Conclusions Our results confirm that SRS for brain metastases results in favorable LC, particularly for patients with smaller tumors. We noted that dose delivery to a higher prescription IDL is associated with small but measurable improvements in LC. This finding could be related to higher dose just beyond the radiographically apparent tumor.",
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AU - Romano, Kara D.

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AU - Garda, Allison

AU - Xu, Zhiyuan

AU - Schlesinger, David

AU - Watkins, William T.

AU - Neal, Brian

AU - Larner, James M.

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N2 - Objective Stereotactic radiosurgery (SRS) achieves excellent local control (LC) with limited toxicity for most brain metastases. SRS dose prescription variables influence LC; therefore, we evaluated the impact of prescription isodose line (IDL) on LC after SRS. Methods A retrospective analysis of patients with brain metastases treated on a Gamma Knife platform from 2004 to 2014 was conducted. Clinical, toxicity, radiographic, and dosimetric data were collected. Cox proportional hazards regression was used to determine progression-free survival (PFS) and competing risks analysis was used to determine predictive factors for LC. Results A total of 134 patients with 374 brain metastases were identified with a median survival of 8.7 months (range, 0.2–64.8). The median tumor maximum dimension was 8 mm (range, 2–62 mm), median margin dose was 20 Gy (range, 5–24 Gy), and 12-month LC rate was 88.7%. On multivariate analysis, PFS improved with increasing IDL (P = 0.003) and decreased with non-non-small-cell lung cancer histology (P = 0.001). Margin dose, tumor size, conformality, and previous whole-brain irradiation failed to independently affect PFS. When adjusting for death as a competing risk, the cumulative likelihood of LC improved with higher IDL (P = 0.04). The rate of SRS-induced radiographic and clinical toxicity was low (16.6% and 1.5%, respectively), and neither was affected by IDL. Conclusions Our results confirm that SRS for brain metastases results in favorable LC, particularly for patients with smaller tumors. We noted that dose delivery to a higher prescription IDL is associated with small but measurable improvements in LC. This finding could be related to higher dose just beyond the radiographically apparent tumor.

AB - Objective Stereotactic radiosurgery (SRS) achieves excellent local control (LC) with limited toxicity for most brain metastases. SRS dose prescription variables influence LC; therefore, we evaluated the impact of prescription isodose line (IDL) on LC after SRS. Methods A retrospective analysis of patients with brain metastases treated on a Gamma Knife platform from 2004 to 2014 was conducted. Clinical, toxicity, radiographic, and dosimetric data were collected. Cox proportional hazards regression was used to determine progression-free survival (PFS) and competing risks analysis was used to determine predictive factors for LC. Results A total of 134 patients with 374 brain metastases were identified with a median survival of 8.7 months (range, 0.2–64.8). The median tumor maximum dimension was 8 mm (range, 2–62 mm), median margin dose was 20 Gy (range, 5–24 Gy), and 12-month LC rate was 88.7%. On multivariate analysis, PFS improved with increasing IDL (P = 0.003) and decreased with non-non-small-cell lung cancer histology (P = 0.001). Margin dose, tumor size, conformality, and previous whole-brain irradiation failed to independently affect PFS. When adjusting for death as a competing risk, the cumulative likelihood of LC improved with higher IDL (P = 0.04). The rate of SRS-induced radiographic and clinical toxicity was low (16.6% and 1.5%, respectively), and neither was affected by IDL. Conclusions Our results confirm that SRS for brain metastases results in favorable LC, particularly for patients with smaller tumors. We noted that dose delivery to a higher prescription IDL is associated with small but measurable improvements in LC. This finding could be related to higher dose just beyond the radiographically apparent tumor.

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KW - Radiosurgery

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