Systematic review and meta-analysis of stereotactic body radiotherapy without systemic therapy for oligometastatic cancer

Metastasis-directed stereotactic body radiotherapy (SBRT) may be a viable strategy to defer systemic therapy in patients with oligometastatic cancer (≤ 5 metastases). Systematic review and meta-analysis of studies published between 2009 and July 10, 2024, evaluated metastasis-directed SBRT without upfront systemic therapy for oligometastatic cancer. Of 29 studies (2074 patients) included in the systematic review, 13 (984 patients) contributed data to the meta-analysis. SBRT alone was associated with pooled 1- and 2-year systemic therapy-free survival (STFS) of 70% across cancer types. Subgroup analyses revealed the highest STFS rates in renal cell (87%) and prostate (78%) cancer, with lower STFS rates in other cancer types. The authors conclude that these findings suggest that metastasis-directed SBRT for oligometastatic disease was associated with meaningful STFS, particularly in selected patients with renal cell or prostate cancer.