(S049) Salvage Stereotactic Radiosurgery for Locally Recurrent Brain Metastases Treated Previously With Stereotactic Radiosurgery

Douglas E. Holt, BS, Beant S. Gill, MD, David A. Clump, MD, PhD, Steven A. Burton, MD, John C. Flickinger, MD, Jonathan A. Engh, MD, Nduka Amankulor, MD, PhD, Dwight E. Heron, MD; University of Pittsburgh Medical Center

PURPOSE AND OBJECTIVES: Patients with local recurrence of brain metastases following prior stereotactic radiosurgery (SRS) can be challenging to manage. Given the concerns of neurotoxicity with whole-brain radiotherapy (WBRT), we evaluated the efficacy of repeat SRS (rSRS) for patients with locally recurrent brain metastases after initial SRS (iSRS).

MATERIALS AND METHODS: A retrospective review from 2004 to 2014 identified 108 patients (133 lesions) who received rSRS due to locally recurrent brain metastases after iSRS. Among these patients, 19.4% had WBRT prior to rSRS, with 40.6% of the lesions previously treated with surgical resection. Kaplan-Meier estimates were calculated from rSRS for overall survival (OS), local control (LC), and distant brain failure (DBF), as well as radiation-related toxicity. Cox proportional hazards modeling was conducted to establish predictive factors for OS, LC, DBF, and toxicity (P < .05) from the time of rSRS.

RESULTS: With a median follow-up time of 12.0 months (range: 0.03–65.7 mo) from rSRS, the median OS was 14.2 months (range: 0.33–65.2 mo), with 12- and 18-month OS rates of 56.6% and 44.3%, respectively. On univariate analysis, inferior survival was associated with lower Karnofsky performance status (KPS) score (P = .038), presence of extracranial metastases at iSRS (P = .003), new metastases at the time of rSRS (P = .027), having rSRS < 9 months from iSRS (P = .019), and melanoma histology (P = .015). For all metastases from rSRS, the 12- and 18-month LC rates were 77.5% and 71.6%, respectively. Univariate analysis for local failure showed no significant association. Regarding DBF, the 12- and 18-month estimates were 52.8% and 62.9%, respectively. Univariate analysis for DBF was significant for melanoma (P < .01) and persistent systemic disease at rSRS (P = .012). Multivariate analysis showed a significant association for DBF with melanoma (hazard ratio [HR] = 22.34; P value < .00), presence of extracranial disease at rSRS (HR = 2.89; P = .07), and having at least one new brain metastasis at rSRS (HR = 3.32; P = .03), with an overall model P value < .00. Twelve patients (11.1%) had grade 3 radiation toxicities following rSRS at a median time of 4.0 months (range: 1.2–10.6 mo). The grade 3 toxicities consisted of radiation necrosis (10), seizure (3), headache (3), and an optic nerve disorder. No grade 4 or 5 toxicities were seen. Neither a dose nor volume relationship with toxicity was observed.

CONCLUSIONS: Repeat SRS represents a potential salvage therapy for patients with locally recurrent brain metastases, providing additional tumor control with acceptable toxicity, even in the setting of prior SRS, surgical resection, and/or WBRT. Repeat SRS may also be reasonable to use to either avoid or delay the treatment of WBRT.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org