Stereotactic Radiosurgery for Thalamic Brain Metastases: A Retrospective Analysis and Literature Review

The thalamus, a neural processor and integrator for forebrain activities, is an uncommon site for metastatic lesions. Stereotactic radiosurgery (SRS) has become a noninvasive treatment for brain metastases. This study assesses the efficacy, safety, and outcomes of SRS in patients with thalamic metastases, focusing on local control, overall survival (OS), progression-free survival, neurological outcomes, and treatment response factors.

We retrospectively reviewed cases of thalamic brain metastases treated with SRS at our institute between 2002 and 2024. A total of 49 lesions from 47 patients were included. Statistical analyses were performed logistic regression, the χ² test, the t-test, and the Mann-Whitney U test. Survival outcomes were assessed using Kaplan-Meier analysis, and model performance was evaluated using receiver operating characteristic analysis. A literature review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines supplemented the analysis.

The median OS was 18 months (95% CI, 9.4-26.6). The median age at diagnosis was 60 years; 61.7% were female. Primary tumor histology included non-small cell lung cancer (46.8%), breast cancer (14.9%), and small cell lung cancer (10.6%), among others. The median size of metastases was 1.0 cm with a mean volume of 2 cm³. The median prescribed dose was 22 Gy. Higher maximum radiation doses were associated with lower tumor recurrence (P = .042). Cumulative 6-, 9-, 12-, and 24-month local control rates were 100%, 90%, 82.5%, and 78%. OS rates were 78.7%, 70.8%, 68.2%, and 40.4%, respectively.

Our results showed sufficient local control after treatment. SRS demonstrates efficacy and safety in managing thalamic metastases, with high local control rates over time, supporting its role as an effective treatment option.