open access

Vol 24, No 2 (2019)
Original research articles
Published online: 2019-03-01
Submitted: 2018-05-07
Get Citation

Local control rates in stereotactic body radiotherapy (SBRT) of lung metastases associated with the biologically effective dose

Daniel Zucca Aparicio, Ovidio Hernando Requejo, Miguel Ángel de Julián, Carmen Rubio Rodríguez, Pedro Fernández Letón
DOI: 10.1016/j.rpor.2019.01.001
·
Rep Pract Oncol Radiother 2019;24(2):142-150.

open access

Vol 24, No 2 (2019)
Original research articles
Published online: 2019-03-01
Submitted: 2018-05-07

Abstract

Aim

To evaluate dose differences in lung metastases treated with stereotactic body radiotherapy (SBRT), and the correlation with local control, regarding the dose algorithm, target volume and tissue density.

Background

Several studies showed excellent local control rates in SBRT for lung metastases, with different fractionation schemes depending on the tumour location or size. These results depend on the dose distributions received by the lesions in terms of the tissue heterogeneity corrections performed by the dose algorithms.

Materials and methods

Forty-seven lung metastases treated with SBRT, using intrafraction control and respiratory gating with internal fiducial markers as surrogates (ExacTrac, BrainLAB AG), were calculated using Pencil Beam (PB) and Monte Carlo (MC) (iPlan, BrainLAB AG).

Dose differences between both algorithms were obtained for the dose received by 99% (D99%) and 50% (D50%) of the planning treatment volume (PTV). The biologically effective dose delivered to 99% (BED99%) and 50% (BED50%) of the PTV were estimated from the MC results. Local control was evaluated after 24 months of median follow-up (range: 3–52 months).

Results

The greatest variations (40.0% in ΔD99% and 38.4% in ΔD50%) were found for the lower volume and density cases. The BED99% and BED50% were strongly correlated with observed local control rates: 100% and 61.5% for BED99%>85Gy and <85Gy (p<0.0001), respectively, and 100% and 58.3% for BED50%>100Gy and <100Gy (p<0.0001), respectively.

Conclusions

Lung metastases treated with SBRT, with delivered BED99%>85Gy and BED50%>100Gy, present better local control rates than those treated with lower BED values (p=0.001).

Abstract

Aim

To evaluate dose differences in lung metastases treated with stereotactic body radiotherapy (SBRT), and the correlation with local control, regarding the dose algorithm, target volume and tissue density.

Background

Several studies showed excellent local control rates in SBRT for lung metastases, with different fractionation schemes depending on the tumour location or size. These results depend on the dose distributions received by the lesions in terms of the tissue heterogeneity corrections performed by the dose algorithms.

Materials and methods

Forty-seven lung metastases treated with SBRT, using intrafraction control and respiratory gating with internal fiducial markers as surrogates (ExacTrac, BrainLAB AG), were calculated using Pencil Beam (PB) and Monte Carlo (MC) (iPlan, BrainLAB AG).

Dose differences between both algorithms were obtained for the dose received by 99% (D99%) and 50% (D50%) of the planning treatment volume (PTV). The biologically effective dose delivered to 99% (BED99%) and 50% (BED50%) of the PTV were estimated from the MC results. Local control was evaluated after 24 months of median follow-up (range: 3–52 months).

Results

The greatest variations (40.0% in ΔD99% and 38.4% in ΔD50%) were found for the lower volume and density cases. The BED99% and BED50% were strongly correlated with observed local control rates: 100% and 61.5% for BED99%>85Gy and <85Gy (p<0.0001), respectively, and 100% and 58.3% for BED50%>100Gy and <100Gy (p<0.0001), respectively.

Conclusions

Lung metastases treated with SBRT, with delivered BED99%>85Gy and BED50%>100Gy, present better local control rates than those treated with lower BED values (p=0.001).

Get Citation

Keywords

SBRT; Local control; Biologically effective dose; Lung metastases

About this article
Title

Local control rates in stereotactic body radiotherapy (SBRT) of lung metastases associated with the biologically effective dose

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 24, No 2 (2019)

Pages

142-150

Published online

2019-03-01

DOI

10.1016/j.rpor.2019.01.001

Bibliographic record

Rep Pract Oncol Radiother 2019;24(2):142-150.

Keywords

SBRT
Local control
Biologically effective dose
Lung metastases

Authors

Daniel Zucca Aparicio
Ovidio Hernando Requejo
Miguel Ángel de Julián
Carmen Rubio Rodríguez
Pedro Fernández Letón

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By "Via Medica sp. z o.o." sp.k., ul. Świętokrzyska 73, 80–180 Gdańsk, Poland
tel.:+48 58 320 94 94, fax:+48 58 320 94 60, e-mail: journals@viamedica.pl