AUTHOR=El Shafie Rami A. , Dresel Thorsten , Weber Dorothea , Schmitt Daniela , Lang Kristin , König Laila , Höne Simon , Forster Tobias , von Nettelbladt Bastian , Eichkorn Tanja , Adeberg Sebastian , Debus Jürgen , Rieken Stefan , Bernhardt Denise 

TITLE=Stereotactic Cavity Irradiation or Whole-Brain Radiotherapy Following Brain Metastases Resection—Outcome, Prognostic Factors, and Recurrence Patterns

JOURNAL=Frontiers in Oncology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.00693

DOI=10.3389/fonc.2020.00693

ISSN=2234-943X

ABSTRACT=<p><bold>Introduction:</bold> Following the resection of brain metastases (BM), whole-brain radiotherapy (WBRT) is a long-established standard of care. Its position was recently challenged by the less toxic single-session radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) of the resection cavity, reducing dose exposure of the healthy brain.</p><p><bold>Patients and Methods:</bold> We analyzed 101 patients treated with either SRS/FSRT (<italic>n</italic> = 50) or WBRT (<italic>n</italic> = 51) following BM resection over a 5-year period. Propensity score adjustment was done for age, total number of BM, timepoint of BM diagnosis, controlled primary and extracranial metastases. A Cox Proportional Hazards model with univariate and multivariate analysis was fitted for overall survival (OS), local control (LC) and distant brain control (DBC).</p><p><bold>Results:</bold> Median patient age was 61 (interquartile range, IQR: 56–67) years and the most common histology was non-small cell lung cancer, followed by breast cancer. 38% of the patients had additional unresected BM. Twenty-four patients received SRS, 26 patients received FSRT and 51 patients received WBRT. Median OS in the SRS/FSRT subgroup was not reached (IQR NA−16.7 months) vs. 12.6 months (IQR 21.3–4.4) in the WBRT subgroup (hazard ratio, HR 3.3, 95%-CI: [1.5; 7.2] <italic>p</italic> &lt; 0.002). Twelve-months LC-probability was 94.9% (95%-CI: [88.3; 100.0]) in the SRS subgroup vs. 81.7% (95%-CI: [66.6; 100.0]) in the WBRT subgroup (HR 0.2, 95%-CI: [0.01; 0.9] <italic>p</italic> = 0.037). Twelve-months DBC-probabilities were 65.0% (95%-CI: [50.8; 83.0]) and 58.8% (95%-CI: [42.9; 80.7]), respectively (HR 1.4, 95%-CI: [0.7; 2.7] <italic>p</italic> = 0.401). In propensity score-adjusted multivariate analysis, incomplete resection negatively impacted OS (HR 3.9, 95%-CI: [2.0;7.4], <italic>p</italic> &lt; 0.001) and LC (HR 5.4, 95%-CI: [1.3; 21.9], <italic>p</italic> = 0.018). Excellent clinical performance (HR 0.4, 95%-CI: [0.2; 0.9], <italic>p</italic> = 0.030) and better graded prognostic assessment (GPA) score (HR 0.4, 95%-CI: [0.2; 1.0], <italic>p</italic> = 0.040) were prognostic of superior OS. A higher number of BM was associated with a greater risk of developing new distant BM (HR 5.6, 95%-CI: [1.0; 30.4], <italic>p</italic> = 0.048). In subgroup analysis, larger cavity volume (HR 1.1, 95%-CI: [1.0; 1.3], <italic>p</italic> = 0.033) and incomplete resection (HR 12.0, 95%-CI: [1.2; 118.3], <italic>p</italic> = 0.033) were associated with inferior LC following SRS/FSRT.</p><p><bold>Conclusion:</bold> This is the first propensity score-adjusted direct comparison of SRS/FSRT and WBRT following the resection of BM. Patients receiving SRS/FSRT showed longer OS and LC compared to WBRT. Future analyses will address the optimal choice of safety margin, dose and fractionation for postoperative stereotactic RT of the resection cavity.</p>