Faculty Collaboration Database

Cystic Brain Metastasis Outcomes After Gamma Knife Radiation Therapy. Adv Radiat Oncol 2024 Jan;9(1):101304

Date

01/23/2024

Pubmed ID

38260234

Pubmed Central ID

PMC10801666

DOI

10.1016/j.adro.2023.101304

Scopus ID

2-s2.0-85167453267 (requires institutional sign-in at Scopus site)

Abstract

PURPOSE: The response of cystic brain metastases (BMets) to radiation therapy is poorly understood, with conflicting results regarding local control, overall survival, and treatment-related toxicity. This study aims to examine the role of Gamma Knife (GK) in managing cystic BMets.

METHODS AND MATERIALS: Volumetric analysis was conducted to measure tumor and edema volume at the time of GK and follow-up magnetic resonance imaging studies. Survival was described using the Kaplan-Meier method, and the cumulative incidence of progression was described using the Aalen-Johansen estimator. We evaluated the association of 4 variables with survival using Cox regression analysis.

RESULTS: Between 2016 and 2021, 54 patients with 83 cystic BMets were treated with GK at our institution. Lung cancer was the most common pathology (51.9%), followed by breast cancer (13.0%). The mean target volume was 2.7 cm³ (range, 0.1-39.0 cm³), and the mean edema volume was 13.9 cm³ (range, 0-165.5 cm³). The median prescription dose of single-fraction and fractionated GK was 20 Gy (range, 14-27.5 Gy). With a median follow-up of 8.9 months, the median survival time (MST) was 11.1 months, and the 1-year local control rate was 75.9%. Gamma Knife was associated with decreased tumor and edema volumes over time, although 68.5% of patients required steroids after GK. Patients whose tumors grew beyond baseline after GK received significantly more whole-brain radiation therapy (WBRT) before GK than those whose tumors declined after GK. Higher age at diagnosis of BMets and pre-GK systemic therapy were associated with worse survival, with an MST of 7.8 months in patients who received it compared with 23.3 months in those who did not.

CONCLUSIONS: Pre-GK WBRT may select for BMets with increased radioresistance. This study highlights the ability of GK to control cystic BMets with the cost of high posttreatment steroid use.

Author List

Amidon RF, Livingston K, Kleefisch CJ, Martens M, Straza M, Puckett L, Schultz CJ, Mueller WM, Connelly JM, Noid G, Morris K, Bovi JA

Authors

Jennifer M. Connelly MD Professor in the Neurology department at Medical College of Wisconsin
Christopher J. Kleefisch MD Assistant Professor in the Radiology department at Medical College of Wisconsin
Michael Martens PhD Assistant Professor in the Data Science Institute department at Medical College of Wisconsin
Wade M. Mueller MD Professor in the Neurosurgery department at Medical College of Wisconsin
Lindsay L. Puckett MD Associate Professor in the Radiation Oncology department at Medical College of Wisconsin
Christopher J. Schultz MD Chair, Professor in the Radiation Oncology department at Medical College of Wisconsin