Brain Metastasis Velocity: A Novel Prognostic Metric Predictive of Overall Survival and Freedom From Whole-Brain Radiation Therapy After Distant Brain Failure Following Upfront Radiosurgery Alone

作者：Farris Michael^*; McTyre Emory R; Cramer Christina K; Hughes Ryan; Randolph David M; Ayala Peacock Diandra N; Bourland J Daniel; Ruiz Jimmy; Watabe Kounosuke; Laxton Adrian W; Tatter Stephen B; Zhou Xiaobo; Chan Michael D

来源：International Journal of Radiation Oncology, Biology, Physics, 2017, 98(1): 131-141.

DOI：10.1016/j.ijrobp.2017.01.201

Purpose: Prior statistical models attempted to identify risk factors for time to distant brain failure (DBF) or time to salvage whole-brain radiation therapy (WBRT) to predict the benefit of early WBRT versus stereotactic radiosurgery (SRS) alone. We introduce a novel clinical metric, brain metastasis velocity (BMV), for predicting clinical outcomes after initial DBF following upfront SRS alone.
Methods and Materials: BMV was defined as the cumulative number of new brain metastases that developed over time since first SRS in years. Patients were classified by BMV into low-, intermediate-, and high-risk groups, consisting of <4, 4 to 13, and >13 new metastases per year, respectively. Histology, number of metastases at the time of first SRS, and systemic disease status were assessed for effect on BMV.
Results: Of 737 patients treated at our institution with upfront SRS without WBRT, 286 had >= 1 DBF event. A lower BMV predicted for improved overall survival (OS) following initial DBF (log-rank P<.0001). Median OS for the low, intermediate, and high BMV groups was 12.4 months (95% confidence interval [CI], 10.4-16.9 months), 8.2 months (95% CI, 5.0-9.7 months), and 4.3 months (95% CI, 2.6-6.7 months), respectively. Multivariate analysis showed that BMV remained the dominant predictor of OS, with a hazard ratio of 2.75 for the high BMV group (95% CI, 1.94-3.89; P<.0001) and a hazard ratio of 1.65 for the intermediate BMV group (95% CI, 1.182.30; P<.004). A lower BMV was associated with decreased rates of salvage WBRT (P = .02) and neurologic death (P = .008). Factors predictive for a higher BMV included >= 2 initial brain metastases (P = .004) and melanoma histology (P = .008).
Conclusions: BMVis a novel metric associated with OS, neurologic death, and need for salvage WBRT after initial DBF following upfront SRS alone.

• 出版日期2017-5-1
• 单位上海生物信息技术研究中心