Repeated in-field radiosurgery for locally recurrent brain metastases: Feasibility, results and survival in a heavily treated patient cohort

Abstract

PurposeStereotactic radiosurgery (SRS) is an established primary treatment for newly diagnosed brain metastases with high local control rates. However, data about local re-irradiation in case of local failure after SRS (re-SRS) are rare. We evaluated the feasibility, efficacy and patient selection characteristics in treating locally recurrent metastases with a second course of SRS.MethodsWe retrospectively evaluated patients with brain metastases treated with re-SRS for local tumor progression between 2011 and 2017. Patient and treatment characteristics as well as rates of tumor control, survival and toxicity were analyzed.ResultsOverall, 32 locally recurrent brain metastases in 31 patients were irradiated with re-SRS. Median age at re-SRS was 64.9 years. The primary histology was breast cancer and non-small-cellular lung cancer (NSCLC) in respectively 10 cases (31.3%), in 5 cases malignant melanoma (15.6%). In the first SRS-course 19 metastases (59.4%) and in the re-SRS-course 29 metastases (90.6%) were treated with CyberKnife® and the others with Gamma Knife. Median planning target volume (PTV) for re-SRS was 2.5 cm3 (range, 0.1–37.5 cm3) and median dose prescribed to the PTV was 19 Gy (range, 12–28 Gy) in 1–5 fractions to the median 69% isodose (range, 53–80%). The 1-year overall survival rate was 61.7% and the 1-year local control rate was 79.5%. The overall rate of radiological radio-necrosis was 16.1% and four patients (12.9%) experienced grade ≥ 3 toxicities.ConclusionsA second course of SRS for locally recurrent brain metastases after prior local SRS appears to be feasible with acceptable toxicity and can be considered as salvage treatment option for selected patients with high performance status. Furthermore, this is the first study utilizing robotic radiosurgery for this indication, as an additional option for frameless fractionated treatment.

Retrospective analysis of salvage surgery for local progression of brain metastasis previously treated with stereotactic irradiation: diagnostic contribution, functional outcome, and prognostic factors

“…STI is the primary treatment for newly diagnosed brain metastases, especially if they are small and inaccessible. Local progression of brain metastases after upfront treatment with STI is seen more often now because of better survival of these patients, and the demand for salvage treatment is now more than ever [16]. In our study, salvage surgery was done for 20 cases in the first 9 years, and for 34 cases in the recent 9 years.…”

“…Toxicity was reported as overall necrosis rates 9.2 to 19% after the repeated SRS or SRT [25,26]. Necrosis after repeated STI was shown to be significantly associated with the irradiated volume and the cumulative dose [16]. For large lesions with surrounding edema, repeat SRS may lead to a risk of local progression as the majority of these lesions consist of a combination of radiation necrosis and cancer cells, surrounded by the injured brain.…”

Coregistration of Magnetic Resonance and [18F] Fludeoxyglucose–Positron Emission Tomography Imaging for Stereotactic Radiation Therapy Planning: Case Report in a Previously Irradiated Brain Metastasis With Recurrent Tumor and Radiation Necrosis

“…13 With reported 12month progression rates of 27.2% for unoperated 6 and 40% for resected BMs 5 after SRS, repeat irradiation is anticipated to be an increasingly used salvage therapy in this setting. 14,15 Combined with a reported occurrence of RN after initial SRS of 16% at 12 months with a plateaus at nearly 40% by 40 months, 7 these observations indicate that delineating recurrent tumor from RN in previously treated BM patients will become a more common clinical scenario. This distinction is of particular importance for clinical decision-making given that recurrent tumor can be effectively treated by reirradiation as noted earlier, or in the case of radiation necrosis, by other modalities such as laser interstitial thermal therapy.…”

Stereotactic radiosurgery combined with immune checkpoint inhibitors or kinase inhibitors for patients with multiple brain metastases of malignant melanoma

“…The LCR was 89.5% at 1 year ( Fig. 1a-c), and all local failures were re-treated with radiosurgery [15].…”