Comparison of stereotactic body radiotherapy versus metastasectomy outcomes in patients with pulmonary metastases

Background: We compared the treatment outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy in patients with pulmonary metastases. Methods: Twenty-one patients received SBRT (total radiation doses 60 Gy in 3 fractions or 48 Gy in 4 fractions) and 30 underwent metastasectomy, most (93.3%) with wedge resection. The patients were followed for a median of 13.7 months. The tumor size in the SBRT group was larger than in the metastasectomy group (median 2.5 vs. 1.25 cm; P = 0.015). Patients with synchronous metastases were more likely to be treated with SBRT than with metastasectomy (P = 0.006). Results: There was no significant difference in the local control rates of the treatment groups (P = 0.163). Progression-free survival (PFS) was longer in the metastasectomy than in the SBRT group (P = 0.02), with one and two-year PFS rates of 51.1% and 46% versus 23.8% and 11.9%, respectively. The one and two-year overall survival (OS) rates were 95% and 81.8% in the metastasectomy group and 79.5% and 68.2%, in the SBRT group, respectively. In multivariate analysis, synchronous metastasis was related to poor PFS, and tumor size was the most significant factor affecting OS. There were no significant differences in PFS and OS between treatment groups after dividing patients according to the presence or absence of synchronous metastases. Conclusions: SBRT is considered a suitable local modality against pulmonary metastases; however, patients with synchronous metastases are only likely to obtain a small benefit from local treatment with either SBRT or surgery.