Abstract
BACKGROUND
Laser interstitial thermal therapy (LITT) is a minimally invasive surgical treatment being employed frequently for radiographically progressive brain metastases (BM). Considerable interest exists in combining LITT-mediated in situ vaccination to license immune checkpoint blockade (ICB) and activate an anti-tumor immune response. However, LITT also disrupts the blood-brain barrier, causing transient peritumoral edema. Accordingly, information on safety and feasibility of this combination in BM is needed.
METHODS
All patients receiving LITT for radiographically progressive non-small cell lung carcinoma (NSCLC) BM at a single center from 2015 – 2023 were retrospectively reviewed. Combination therapy was defined as ICB within 6 weeks of LITT. Clinical data, post-LITT freedom from local progression (FFLP), and overall survival (OS) were collected. Adverse events (AEs) were evaluated according to Common Terminology Criteria.
RESULTS
Eighteen patients received LITT + ICB to a total of 19 lesions. Median time between therapies was 2.29 weeks (range 0.85 – 5.98). In comparison to NSCLC patients receiving LITT alone (n = 25), there was no decrement in % ablation (98 vs 95%, P = 0.1), length of stay (1 vs 1 days, P = 0.91), home discharge (100 vs 92%, P = 0.5), or 30-day readmissions (15.8 vs 16%, P = 0.99). Despite decreased preoperative steroid use (P = 0.0098), patients receiving LITT + ICB discontinued steroids at a median of 11 (4 – 147) days post-LITT vs. 24 (3 – 242) days for patients receiving LITT alone (P = 0.62). At study cutoff, 18/19 (94.7%) lesions in the LITT + ICB group and 22/25 (88.0%) in the LITT only group were locally controlled. There were 3 and 5 AEs ≥ Grade 3 in the LITT + ICB and LITT alone group, respectively.
CONCLUSIONS
Combination LITT and ICB does not compromise procedural outcomes and may favorably impact local control in NSCLC. Prospective studies are needed to assess biomarkers of immune response.