MET-5 Salvage surgical resection after linac-based stereotactic radiosurgery and radiotherapy for brain metastasis

Methods: Between November 2009 and December 2018, 335 consecutive patients with 1085 brain metastases were treated with SRS/fSRT for newly diagnosed brain metastasis at our hospital. Nineteen of 335 patients (5.6%) and 19 of 1044 brain metastases (1.8%) went on to receive SSR after SRS/fSRT during this study period. Two patients underwent multiple surgical resections. Nineteen consecutive patients underwent 21 SSRs. Results: The median time from initial SRS/fSRT to SSR was 14 months (range: 2–96 months). The median follow-up after SSR was 15 months (range: 2–76 months). The range of tumor volume at initial SRS/fSRT was 0.12–21.46 cm3 (median: 2.19 cm3). Histopathological diagnosis after SSR was recurrence, radiation necrosis (RN) and cyst formation in 13 and 6 cases, respectively. The time from SRS/fSRT to SSR were shorter in the recurrence than in the RNs and cyst formation, but these differences did not reach statistical significance (p = 0.07). The median survival time from SSR and from initial SRS/fSRT was 17 months and 74 months, respectively. The cases with recurrence had a significantly shorter survival time from initial SRS/fSRT than those without recurrence (p=0.045).Conclusion: The patients treated with SRS/fSRT for brain metastasis need long-term follow-up. SSR is a safe and effective treatment for the recurrence, RN, and cyst formation after SRS/fSRT for brain metastasis.