Stereotactic ablative radiation therapy for brain metastases with volumetric modulated arc therapy and flattening filter free delivery: feasibility and early clinical results
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For selected patients with brain metastases (BMs), the role of stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (SFRT) is well recognized. The recent introduction of flattening filter free (FFF) delivery during linac-based SRS or SFRT allows shorter beam-on-time, improving patients’ comfort and facility workflow. Nevertheless, limited experiences evaluated the impact of FFF linac-based SRS and SFRT in BMs treatment. Aim of the current study was to analyze SRS/SFRT linac-based FFF delivery for BMs in terms of dosimetric and early clinical results.
Materials and methods
Patients with life expectancy >3 months, number of BMs <5, diameter <3 cm, and controlled or synchronous primary tumor received SRS/SFRT. The prescribed total dose and fractionation, based on BMs size and proximity to organs at risk, ranged from 15 Gy in 1 fraction to 30 Gy in 5 fractions. A FFF volumetric modulated arc therapy (VMAT) plan was generated with one or two coplanar partial arcs. Toxicity was assessed according to CTCAE v4.0.
From April 2014 to February 2016, 45 patients (89 BMs) were treated with SRS/SFRT linac-based FFF delivery. The mean beam-on-time was 140 s for each lesion (range 90–290 s) and the average brain Dmean was 1 Gy (range 0.1–4.8 Gy). At the time of analysis, local control was reported in 93.2% (83/89 BMs). With a median follow-up time of 12 months (range 1–27 months), the median overall survival was 14 months and the 6-month overall survival was 77%. Finally, the median intracranial disease control was 11 months. Acute and late toxicities were acceptable without severe events (no adverse events ≥G2 were recorded).
These preliminary results highlighted the feasibility and safety of linac-based SRS/SFRT with FFF mode for BMs patients. A longer follow-up is necessary to confirm the efficacy of this treatment modality in BM patients.
KeywordsBrain metastases Radiotherapy Stereotactic radiotherapy Stereotactic fractionated radiotherapy
Compliance with ethical standards
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of interest
The authors declare that they have no conflict of interest. Informed consent was obtained from all individual participants included in the study.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
- 4.NCCN guide lines (2016) https://www.nccn.org/professionals/physician_gls/f_guidelines.asp. Accessed 30 Oct 2016
- 6.Soffietti R, Kocher M, Abacioglu UM et al (2013) A European organisation for research and treatment of cancer phase III trial of adjuvant whole-brain radiotherapy versus observation in patients with one to three brain metastases from solid tumors after surgical resection or radiosurgery: quality-of-life result. J Clin Oncol 31:65–72. doi: 10.1200/JCO.2011.41.0639 CrossRefPubMedGoogle Scholar
- 7.Brown PD, Jaeckle K, Ballman KV et al (2016) Effect of radiosurgery alone vs radiosurgery with whole brain radiation therapy on cognitive function in patients with 1 to 3 brain metastases: a randomized clinical trial. JAMA 316:401–409. doi: 10.1001/jama.2016.9839 CrossRefPubMedPubMedCentralGoogle Scholar
- 15.Abacioglu U, Ozen Z, Yilmaz M et al (2014) Critical appraisal of RapidArc radiosurgery with flattening filter free photon beams for benign brain lesions in comparison to GammaKnife: a treatment planning study. Radiat Oncol 9:119. doi: 10.1186/1748-717X-9-119 CrossRefPubMedPubMedCentralGoogle Scholar
- 32.Minniti G, Scaringi C, Paolini S et al (2016) Single-fraction versus multifraction (3 × 9 Gy) stereotactic radiosurgery for large (>2 cm) brain metastases: a comparative analysis of local control and risk of radiation-induced brain necrosis. Int J Radiat Oncol Biol Phys 95:1142–1148. doi: 10.1016/j.ijrobp.2016.03.013 CrossRefPubMedGoogle Scholar
- 36.Navarria P, Ascolese AM, Mancosu P et al (2013) Volumetric modulated arc therapy with flattening filter free (FFF) beams for stereotactic body radiation therapy (SBRT) in patients with medically inoperable early stage non small cell lung cancer (NSCLC). Radiother Oncol 107:414–418. doi: 10.1016/j.radonc.2013.04.016 CrossRefPubMedGoogle Scholar
- 38.Zwahlen DR, Lang S, Hrbacek J et al (2012) The use of photon beams of a flattening filter-free linear accelerator for hypofractionated volumetric modulated arc therapy in localized prostate cancer. Int J Radiat Oncol Biol Phys 83:1655–1660. doi: 10.1016/j.ijrobp.2011.10.019 CrossRefPubMedGoogle Scholar