Abstract Date: 5/2/2015
Deborah C. Marshall, BA
Teddy Kim, MD
Steven Goetsch, PhD
John Alksne, MD
Kenneth Ott, MD
David Hodgens, MD
Bob Carter, MD, PhD
Jona Hattangadi-Gluth, MD
Clark Chen, MD, PhD (San Diego, CA)
With escalating focus on cost containment, there is increasing scrutiny on the practice of sequential SRS for patients suffering multiple rounds of brain metastases. A major concern is that such recurrence pattern may be a prognostic indicator of poor overall survival.
We retrospectively analyzed outcomes of 788 consecutively treated patients with 2838 cerebral metastases at the San Diego Gamma Knife Center (SDGKC), comparing survival patterns of patients who underwent a single-round (n=644) versus multiple-rounds (n=144) of SRS for subsequent brain metastases distant to the initial tumor. Multivariate analyses were performed to control for known prognostic variables, including RPA class, tumor histology, number of metastases, and cumulative tumor volume.
Median survival of patients who underwent one round of SRS was 5 months from the time of SRS. For patients who underwent two or three rounds of SRS, the median survival from date of last SRS was 6 months and 5 months, respectively (p-value=0.11, log-rank test). Patients who underwent multiple-rounds of SRS tended to be younger, with systemic disease control, have melanoma histology, and harbor higher cumulative tumor volume (p-values 0.004, <0.001, and 0.009, respectively for Pearson chi-squared test). Median interval between treatments was 176 days (between first/second SRS) and 154 days (between second/third SRS).
For judiciously selected patients, no decrease in overall survival was observed in patients who underwent multiple rounds of SRS for new cerebral metastases. In light of the potential long-term toxicity of whole brain radiation therapy, serial SRS should be considered for select patient populations.
Article ID: AA-31548