Stereotactic Laser Ablation as Treatment of Brain Metastases Recurring after Stereotactic Radiosurgery: A Systematic Literature Review

Background: The optimal treatment of brain metastases recurring after radiosurgery (BMRS) remains an area of active investigation. Stereotactic laser ablation (SLA, also known as laser interstitial thermal therapy) has recently emerged as a potential treatment option.

Objective: To summarize the available literature on SLA as treatment of BMRS and synthesize findings on local control, overall survival, neurologic outcome, imaging findings, morbidity, and postprocedure clinical course.

Methods: We performed a comprehensive search of PubMed for articles investigating SLA as treatment of BMRS.

Results: Thirteen peer-reviewed publications met our search criteria. Local control was a function of the percentage of tumor that was thermally ablated. In completely ablated tumors, 3-month local control was 80%-100%. Median survival ranged from 5.8 to 19.8 months. About two-thirds of treated lesions showed postablation expansion of contrast-enhancing volume and fluid-attenuated inversion recovery volume. Expansion could start within an hour of treatment, and resolution typically occurred within 6 months. Notably, maximal expanded contrast-enhancing volume could reach >3-fold the preoperative lesion volume. The incidence of SLA-related permanent neurologic injuries was <10%. The most common complications were hemorrhage, thermal injury causing neurologic deficit, and malignant cerebral edema. Nearly all patients were treated with dexamethasone, but there was variability in the dose and duration of therapy. Median hospital stay was 1-2 days (range, 1-5 days), and most treated patients were discharged home (range, 59.5%-100%).

Conclusion: Our analysis provides support for continued development of SLA as a treatment of BMRS. Standardization of periprocedural management will be needed.