Outcomes of hypofractionated stereotactic radiotherapy for brain metastases: do we treat patients or lesions?
摘要
Hypofractionated stereotactic radiotherapy (HFSRT) is increasingly preferred over whole-brain radiotherapy (WBRT) for patients with limited brain metastases, aiming to balance durable local control with neurocognitive preservation, and it can be applied both to intact tumors and in the postoperative period. The objective of this study was to retrospectively evaluate the clinical and dosimetric outcomes of stereotactic radiosurgery (SRS) in patients with brain metastases, treated either in the intact tumor setting or postoperatively.
MethodsWe retrospectively reviewed a total of 70 lesions in 58 consecutive adults (KPS ≥ 70) treated with linear accelerator–based (LINAC-based) image-guided HFSRT between January 2021 and August 2024 for either intact metastases (i-HFSRT) or postoperative resection cavities (r-HFSRT). Standard prescriptions were 30 Gy/5 fractions (alternate-day delivery); 25 Gy/5 fractions was used at physician’s discretion (large volume, prior WBRT, proximity to organs at risk). For the evaluation of overall survival, patients were stratified according to extracranial disease status (present vs. absent), timing of brain metastases presentation, and receipt of systemic therapies with central nervous system penetration (yes vs. no). Outcomes included local control (LC), distant brain progression (DBP), leptomeningeal disease (LMD), radiation necrosis (RN), and overall survival (OS). The volumes of brain parenchyma receiving 24 Gy (V24 Gy) and 30 Gy (V30 Gy) were evaluated.
ResultsFifty-eight patients were included (median age 55; 55.2% male); 40 lesions (57.1%) received i-HFSRT and 30 (42.9%) r-HFSRT. Lung (50%) and breast (24%) cancer were the most common primaries. Median follow-up was 13 months (range 4–38). Overall survival was significantly prolonged in patients who received systemic therapies with central nervous system penetration compared to those who did not. Local failure occurred in 4 lesions (5.7%) 2 in i-HFSRT group, 2 in r-HFSRT group. DBP occurred in 23 (39.7%) patients 12 in i-HFSRT group, 11 in r-HFSRT group. LMD developed in 3 patients (5.2%), all in the r-HFSRT cohort at a median of 7 months. RN occurred in 5 lesions (7.1%): 4 i-HFSRT, 1 r-HFSRT. None of these outcomes differed significantly between groups. Median OS was 18 months (95% CI, 9.6–26.4). Despite statistically significant larger GTV/PTV volumes and higher V24/V30 in r-HFSRT, RN did not increase versus i-HFSRT.
ConclusionsFive-fraction LINAC-based HFSRT (25–30 Gy) was effective in both groups, with necrosis more frequent in the intact group and leptomeningeal dissemination confined to the operated group, though not statistically significant, emphasizing that, in this patient population with limited overall survival, surgery should be reserved for appropriately selected patients to avoid treatment-related time toxicity.