Local Control Outcomes of Patients With Brain Metastases From Small Cell Lung Cancer Treated With Stereotactic Radiosurgery.

[OBJECTIVES] Stereotactic radiosurgery (SRS) is increasingly used for brain metastases (BM) from small cell lung cancer (SCLC), either after whole brain radiation therapy (WBRT) or upfront. We report institutional outcomes for patients with SCLC treated with SRS for BM.

[METHODS] Patients who underwent single-fraction SRS for intact BM from 2002 to 2025 were identified from a single-institution. The primary endpoint was local control (LC); secondary endpoints were freedom from distant brain failure (FFDBF) and overall survival (OS).

[RESULTS] The study included 135 patients with 429 BM. Median follow-up was 6 months. Median prescription dose was 22 Gy (IQR: 20 to 24 Gy). Eighty-five BM with median size 2.6 cm (IQR: 2.1 to 3.4 cm) received <20 Gy. Of these, 22 (26%) BM underwent staged SRS to 30 Gy. Twenty-six patients with 63 BM (15%) underwent upfront SRS, 43 patients with 105 BM (24%) had prior prophylactic cranial irradiation (PCI), 64 patients with 249 BM (58%) had prior WBRT, and 2 patients with 12 BM (3%) had both PCI and WBRT. Thirty-two patients with 112 BM (26%) received concurrent systemic therapy. One-year LC, FFDBF, and OS were 89%, 21%, and 26%, respectively. For BM receiving ≥20 Gy, 30 Gy (staged), and <20 Gy, 1-year LC was 92%, 87%, and 68%, respectively. Prescription dose ≥20 Gy or staged SRS (P=0.01) was associated with improved LC, while prior PCI/WBRT and concurrent systemic therapy were not.

[CONCLUSIONS] SRS provides high LC for SCLC BM, including post-PCI/WBRT recurrences. OS remains limited by systemic progression. Prescription dose ≥20 Gy or staged SRS should be considered when feasible.