Laser interstitial thermal therapy (LITT) for brain metastases: a systematic review and pooled analysis of Efficacy/Safety and the role of combination treatments.

purposeLaser interstitial thermal therapy (LITT) has been used for brain metastases (BM), particularly for recurrent lesions and radiation necrosis after stereotactic radiosurgery (SRS). As SRS is increasingly used, differentiating tumor recurrence from radiation necrosis has become a frequent clinical problem. Recently, LITT has also been combined with other treatments to improve outcomes. However, prior reviews have primarily focused on LITT monotherapy and have provided limited evaluation of emerging multimodal strategies. We aim to summarize the current literature on LITT for BM, with particular attention to local control, safety, factors associated with outcomes, and the potential role of combination treatment strategies.

methodsPubMed, Scopus, and Web of Science were searched following PRISMA guidelines. We included studies reporting local control outcomes following LITT for BM or radiation necrosis secondary to previously treated BM. We used a combination of the following terms: ("laser interstitial thermal therapy" OR "LITT" OR "laser ablation") AND ("brain" OR "cerebral" OR "intracranial") AND ("metastases" OR "metastasis"). Graphical data were extracted using WebPlotDigitizer. A proportional meta-analysis was conducted to estimate pooled LTC rates at 6 and 12 months following treatment.

resultsA total of 254 studies were identified after duplicate removal, of which 30 met the inclusion criteria. These included 26 studies on LITT monotherapy and 4 on combination therapies, comprising 972 patients. Median age ranged from 51 to 69 years and median tumor volume from 2.2 to 8.5 cm. SRS was the most common prior treatment. Among patients treated with LITT monotherapy, pooled 6- and 12-month LTC rates were 74.4% and 67.9%, respectively. In subgroup analyses, corresponding rates were 74.0% and 67.9% for brain tumor metastases, and 76.6% and 65.7% for radiation necrosis. Studies of combination therapy reported local control rates of 76% for LITT+SRT (stereotactic radiotherapy), 94.7% for LITT+ICB (immune checkpoint blockade), and 100% at 12 months in both studies for LITT+cSRS (consolidation SRS). Transient neurological deficits were the most common adverse events, whereas permanent deficits were less frequent and procedure-related complications were reported in 20 patients. Significant predictive factors for better local control included greater extent of ablation, smaller pre-treatment tumor volume, pathology consistent with radiation necrosis and post-LITT chemotherapy.

conclusionsCurrent evidence suggests that LITT may provide favorable local control with an acceptable safety profile in selected patients, and combination approaches may further improve outcomes. However, the available evidence remains largely retrospective and heterogeneous, and further prospective studies are needed to better define the role of LITT and combination treatment strategies.