Stereotactic radiosurgery (SRS) is being used increasingly for brain metastases to prevent central nervous system (CNS) toxicity, and new findings published in Clinical Genitourinary Cancer demonstrate that it is a highly effective procedure for brain metastases from renal cell carcinoma (RCC).
In this study, the 1-year local control rate was more than 90% and durability of control was up to 2 years. SRS appears to be the most efficacious for smaller metastases, while escalated dosing or fractionation are needed to effectively treat larger lesions.
In metastatic RCC, the incidence of brain metastases is as high as 15%, and while surgical resection is associated with an improved survival compared with whole brain radiotherapy alone, for patients who are not candidates for resection, SRS is an alternative option. For this study, the authors sought to determine outcomes after treatment with SRS for brain metastases in 268 patients with metastatic RCC who were treated between 2006 and 2015 at a single institution.
Of this group, 38 patients were identified with brain metastases and a total of 243 lesions were treated with SRS, reported Zabi Wardak, MD, and his associates.
The median lesion size was 0.6 cm (0.2-3.1) and patients received a median SRS treatment dose of 18 Gy (12-24). The median age of patients was 65 years and the most common histology was clear cell RCC. Three quarters (74%) of patients received only one GammaKnife session, with a median number of two lesions treated at each session. The most common intracranial location for metastases was the frontal lobe (39% of lesions) followed by the parietal and temporal lobes (15% of lesions). The median size of treated metastases was 0.6 cm (0.2-3.1), reported Dr. Wardak, of the University of Texas UT Southwestern Medical Center, Dallas, and his associates.
At 1 year, local control rates were 91.8% (95% confidence interval, 85.7-95.4) and at 2 years, 86.1% (77.1-91.7). The median overall survival after a diagnosis of brain metastases was 13.8 months (95% CI, 8.1-28.0), with a 1-year survival of 57.5% (95% CI, 40.2-71.4). For patients with a single brain metastasis, 1-year overall survival was 56.3% (95% CI, 29.5-76.2) and for those with multiple lesions, 59.1% (95% CI, 36.1-76.2).
“Patients with multiple brain metastases (greater than five lesions) from RCC did not have a worse survival and should be considered for SRS to achieve intracranial tumor control while avoiding neurological decline,” wrote Dr. Wardak and his associates.
Coauthor James Brugarolas is supported by a grant from the National Institutes of Health. No other study funding was disclosed. The other authors have no disclosures.
SOURCE: Wardak Z et al. Clin Genitourin Cancer. 2018 Nov 20. .