Fractionated stereotactic radiosurgery for locally recurrent brain metastases after failed stereotactic radiosurgery

There is scant data on the utility of repeated radiosurgery for management of locally recurrent brain metastases after upfront stereotactic radiosurgery (SRS). Most studies have used single-fraction SRS for repeated radiosurgery, and the use of fractionated stereotactic radiosurgery (f-SRS) in this setting has been poorly addressed. In this study, we assessed the utility of f-SRS for the management of locally recurrent brain metastases after failed upfront single-fraction SRS and report our single-center experience.

A total of 30 patients receiving f-SRS for locally recurrent brain metastases after upfront single-fraction SRS at our department between September 2011 and September 2017 were retrospectively evaluated for local control (LC), toxicity, and overall survival outcomes.

Median age and Karnofsky performance status were 57 (range: 38-78 years) and 80 (range: 70-100) at repeated radiosurgery (SRS2). The median time interval between the two radiosurgery applications was 13.5 months (range: 3.7-49 months). LC after SRS2 was 83.3%. Radionecrosis developed in 4 of the 30 lesions after SRS2, and total rate of radionecrosis was 13.3%. Statistical analysis revealed that the volume of planning target volume (PTV) at SRS2 was significantly associated with radionecrosis (P = 0.014). The volume of PTV was >13 cm³ at SRS2 in all patients with radionecrosis.

A repeated course of radiosurgery in the form of f-SRS may be a viable therapeutic option for the management of locally recurrent brain metastases after failed upfront SRS with high LC rates and an acceptable toxicity profile despite the need for further supporting evidence.