Effect Of Timing Of Adjuvant Radiosurgery On Local Control For Brain Metastases

Abstract

rates of OS and DMFS were similar with 45 Gy and <45 Gy but 2-and 5-year EFS rates were significantly higher with 45 Gy (82% and 66% vs. 76% and 50% with <45 Gy, p Z 0.006). The rates of OS, DMFS, and EFS were significantly lower in patients with a tumor diameter 8 mm. In patients with a tumor depth 8 mm, the rates of DMFS and EFS were significantly lower. In patients with a tumor volume <600 mm 3 , the rates of OS, DMFS, and EFS were significantly higher. Among patients that received 45 Gy, the ones with a tumor volume <600 cm 3 had significantly higher rates of DMFS and EFS but OS was similar. In multivariate analysis, no prognostic factors were found for DMFS. However, for OS and EFS >8 mm basal tumor diameter (relative risk [RR] Z 1.6, 95% confidence interval [CI] Z 1.92-3.12, p Z 0.09; and RR Z 1.8, 95% CI Z 1.15-2.81, p Z 0.01), for EFS >8 mm depth (RR Z 1.6, 95% CI Z 1.03-2.4, p Z 0.03), and 45 Gy dose (RR Z 1.4, 95% CI Z 0.9-2.08, p Z 0.06) were negative prognostic factors. SRS/FSRT-related late toxicity was significantly higher in patients with a basal tumor diameter >8 mm and depth >8 mm (p Z 0.001 and p Z 0.04, respectively). Conclusion: Total SRS/FSRT dose and tumor diameter and depth were found prognostic factors for EFS. Toxicity rate was higher in patients with a higher tumor depth and basal diameter.