Predictors of survival in contemporary practice after initial radiosurgery for brain metastases.
OBJECTIVE
The number of brain metastases (BM) is a major consideration in determining patient eligibility for stereotactic radiosurgery (SRS), but the evidence for this popular practice is equivocal. The purpose of this study was to determine whether, following multivariate adjustment, the number and volume of BM held prognostic significance in a cohort of patients initially treated with SRS alone.


METHODS
A total of 251 patients with primary malignancies, including non-small cell lung cancer (34%), melanoma (30%), and breast carcinoma (16%), underwent SRS for initial treatment of BM. SRS was used as the sole management (62% of patients) or was combined with salvage treatment with SRS (22%), whole-brain radiation therapy (WBRT; 13%), or resection (3%). Median follow-up time was 9.4 months. Survival was determined using the Kaplan-Meier method. Cox regression was used to assess the effects of patient factors on distant brain failure (DBF), local control (LC), and overall survival (OS).


RESULTS
LC at 1 year was 94.6%, and median time to DBF was 10 months. Median OS was 11.1 months. On multivariate analysis, statistically significant predictors of OS were presence of extracranial disease (hazard ratio [HR], 4.2, P<.001), total tumor volume greater than 2 cm(3) (HR, 1.98; P<.001), age ≥60 years (HR, 1.67; P=.002), and diagnosis-specific graded prognostic assessment (HR, 0.71; P<.001). The presence of extracranial disease was a statistically significant predictor of DBF (HR, 2.15), and tumor volume was predictive of LC (HR, 4.56 for total volume >2 cm(3)). The number of BM was not predictive of DBF, LC, or OS.


CONCLUSIONS
The number of BM is not a strong predictor for clinical outcomes following initial SRS for newly diagnosed BM. Other factors including total treatment volume and systemic disease status are better determinants of outcome and may facilitate appropriate use of SRS or WBRT.
Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
Anna
A
Likhacheva
Chelsea C
CC
Pinnix
Neil R
NR
Parikh
Pamela K
PK
Allen
Mary F
MF
McAleer
Max S
MS
Chiu
Erik P
EP
Sulman
Anita
A
Mahajan
Nandita
N
Guha-Thakurta
Sujit S
SS
Prabhu
Daniel P
DP
Cahill
Dershan
D
Luo
Almon S
AS
Shiu
Paul D
PD
Brown
Eric L
EL
Chang
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality* / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery*; D001943:Breast Neoplasms; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D016371:Cranial Irradiation / Q000379:methods; D005260:Female; D006801:Humans; D008175:Lung Neoplasms; D008297:Male; D008545:Melanoma / Q000401:mortality / Q000532:radiotherapy / Q000556:secondary / Q000601:surgery; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D016634:Radiosurgery / Q000379:methods*; D016879:Salvage Therapy / Q000379:methods; D016019:Survival Analysis; D047368:Tumor Burden; D055815:Young Adult