Stereotactic radiosurgery (SRS) is a mainstay treatment option for brain metastasis (BM). While guidelines for SRS use have been outlined by professional societies, consideration of these guidelines should be weighed in the context of emerging literature, novel technology platforms, and contemporary treatment paradigms. Here, we review recent advances in prognostic scale development for SRS-treated BM patients and survival outcomes as a function of the number of BM and cumulative intracranial tumor volume. Focus is placed on the role of stereotactic laser thermal ablation in the management of BM that recur after SRS and the management of radiation necrosis. Neoadjuvant SRS prior to surgical resection as a means of minimizing leptomeningeal spread is also discussed.

Introduction In independent clinical trials, ~30% of brain metastases recur locally after radiosurgery (BMRS). For these lesions, treatment with stereotactic laser ablation (SLA, also known as laser interstitial thermal therapy (LITT)) alone achieves a 12-month local control (LC12) of 54–85% while repeat SRS achieved LC12 of 54–79%. Here, we report favorable outcomes for BMRS treated with SLA followed by consolidation radiosurgery (SLA/cSRS). Methods Clinical outcome of 18 patients with 19 histologically confirmed BMRS treated with SLA followed by consolidation SRS and >3 months follow-up were collected retrospectively across three institutions. Local control was defined as stability or decrease in contrast-enhancing (CE) and FLAIR volume. Results SLA achieved ablation of 73–100% of the BMRS CE volumes. Consolidation hypo-fractionated radiosurgery (5 Gy x 5 or 6 Gy x 5) was carried out 16–40 days post-SLA (median of 26 days). With a median follow-up of 185 days (range: 93–1367 days) and median overall survival (OS) of 185 days (range: 99–1367 days), 100% LC12 was achieved. 13/18 (72%) patients that required steroid therapy prior to SLA/cSRS were successfully weaned off steroid by three months post-SLA/cSRS. Post-SLA, KPS declined for 3/19 (16%) patients and improved for 1/19 (5%) patients. No KPS changes occurred subsequent to consolidation SRS. There were no 30-day mortalities or wound complications. Two patients required re-admission within 30 days of SRS (severe headache that resolved with steroid therapy (n=1) and new-onset seizure (n=1)). Except for two patients who suffered histologically confirmed, local failure at 649 and 899 days, all other patients are either alive (n=5) or died from systemic disease progression (n=11). None of the treated patients developed symptomatic radiation necrosis. Conclusions This collaborative institutional experience support efficacy and safety of SLA followed by consolidation SRS as a treatment for BMRS. The treatment strategy warrants further investigations.

INTRODUCTION In independent clinical trials, ~30% of brain metastases recur locally after radiosurgery (BMRS). For these lesions, treatment with stereotactic laser ablation (SLA, also known as laser interstitial thermal therapy (LITT)) alone achieves a 12-month local control (LC12) of 54-85% while repeat SRS achieved LC12 of 54-79%. Here, we report favorable outcomes for BMRS treated with SLA followed by consolidation radiosurgery (SLA/cSRS). METHODS Clinical outcome of 18 patients with 19 histologically confirmed BMRS treated with SLA followed by consolidation SRS and >3 months follow-up were collected retrospectively across three institutions. Local control was defined as stability or decrease in contrast-enhancing (CE) and FLAIR volume. RESULTS SLA achieved ablation of 73-100% of the BMRS CE volumes. Consolidation hypo-fractionated radiosurgery (5 Gy x 5 or 6 Gy x 5) was carried out 16-40 days post-SLA (median of 26 days). With a median follow-up of 185 days (range: 93-1367 days) and median overall survival (OS) of 185 days (range: 99-1367 days), 100% LC12 was achieved. 13/18 (72%) patients that required steroid therapy prior to SLA/cSRS were successfully weaned off steroid by three months post-SLA/cSRS. Post-SLA, KPS declined for 3/19 (16%) patients and improved for 1/19 (5%) patients. No KPS changes occurred subsequent to consolidation SRS. There were no 30-day mortalities or wound complications. Two patients required re-admission within 30 days of SRS (severe headache that resolved with steroid therapy (n=1) and new-onset seizure (n=1)). Except for two patients who suffered histologically confirmed, local failure at 649 and 899 days, all other patients are either alive (n=6) or died from systemic disease progression (n=10). None of the treated patients developed symptomatic radiation necrosis. CONCLUSIONS This collaborative institutional experience support efficacy and safety of SLA followed by consolidation SRS as a treatment for BMRS. The treatment strategy warrants further investigations.