Salvage Surgical Resection After Linac-based Stereotactic Radiosurgery and Radiotherapy for Newly Diagnosed Brain Metastasis

Abstract Purpose: This study aimed to assess the clinical outcomes of salvage surgical resection (SSR) after stereotactic radiosurgery and fractionated stereotactic radiotherapy (SRS/fSRT) for brain metastasis.Methods: Between November 2009 and December 2018, we treated 427 consecutive patients with 919 lesions with SRS/fSRT for newly diagnosed brain metastasis at our hospital. During the follow-up period, we treated 19 consecutive patients who underwent 21 SSRs for recurrence, radiation necrosis (RN), and cyst formation after SRS/fSRT for newly diagnosed brain metastasis. Two patients underwent multiple surgical resections. Brain metastasis originated from the lung (n=15, 78.9%), breast (n=3, 15.7%), and colon (n=1, 5.2%). 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/SRT was 0.121–21.459 cm3 (median: 2.188 cm3). Histopathological diagnosis after SSR was recurrence, RN and cyst formation in 13 and 6 cases, respectively. The median survival time from SSR and from initial SRS/SRT was 17 months and 74 months, respectively. The cases with recurrence had a significantly shorter survival time than those without recurrence (p=0.0453).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.