Background: Surgical resection and stereotactic radiosurgery (SRS) are well-established treatment options for selected patients with oligo-brain metastases (BMs). The dynamics of edema resolution with each treatment method have not been well characterized.
Methods: Of 389 patients treated for BMs between 2012 and 2014, this study retrospectively identified 107 patients (150 metastases) who underwent either surgery or SRS as a single treatment method for BMs. The two groups of patients were matched for clinical parameters. Volumetric assessments of the tumor and associated edema were performed before treatment and then 2-3 months after treatment.
Results: In this study, 76 surgical cases were compared with 74 cases treated with SRS. The volume of the tumor and surrounding edema was significantly greater in the surgery group than in the SRS group. However, resolution of edema was significantly more rapid in the surgical group (p < 0.0001), accompanied by faster weaning from steroids. After a matching process based on the propensity of a patient to receive SRS, a subgroup cohort was analyzed (mean maximal diameter: 21 mm in the surgical group vs 20.8 mm in the SRS group; p = 0.9). At diagnosis, edema volume, but not tumor volume, was significantly greater in the surgical group. The resolution of edema 2-3 months after treatment was better in the surgical group than in the SRS group (89.6% vs 71.1% of baseline, respectively; p = 0.09), although this difference did not reach the level of significance.
Conclusions: Resolution of tumor-associated edema in BMs suitable for either surgery or SRS was significantly faster after surgical resection than after SRS. Accordingly, when both treatment options are suitable, surgery appears to induce faster resolution of the edema.