title: Follow-up results of brain metastasis patients undergoing repeat Gamma Knife radiosurgery.
abstract: OBJECTIVE Stereotactic radiosurgery (SRS) without upfront whole-brain radiotherapy (WBRT) has influenced recent treatment recommendations for brain metastasis patients. However, in brain metastasis patients who undergo SRS alone, new brain metastases inevitably appear with relatively high incidences during post-SRS follow-up. However, little is known about the second SRS results. The treatment results of second SRS were retrospectively reviewed, mainly for newly developed or, uncommonly, for recurrent brain metastases in order to reappraise the efficacy of this treatment strategy with a special focus on the maintenance of neurological status and safety. METHODS This was an institutional review board-approved, retrospective cohort study that used a prospectively accumulated database, including 3102 consecutive patients with brain metastases who underwent SRS between July 1998 and June 2015. Among these 3102 patients, 859 (376 female patients; median age 64 years; range 21-88 years) who underwent a second SRS without WBRT were studied with a focus on overall survival, neurological death, neurological deterioration, local recurrence, salvage SRS, and SRS-induced complications after the second SRS. Before the second SRS, the authors also investigated the clinical factors and radiosurgical parameters likely to influence these clinical outcomes. For the statistical analysis, the standard Kaplan-Meier method was used to determine post-second SRS survival and neurological death. A competing risk analysis was applied to estimate post-second SRS cumulative incidences of local recurrence, neurological deterioration, salvage SRS, and SRS-induced complications. RESULTS The post-second SRS median survival time was 7.4 months (95% CI 7.0-8.2 months). The actuarial survival rates were 58.2% and 34.7% at 6 and 12 months after the second SRS, respectively. Among 789 deceased patients, the causes of death could not be determined in 24 patients, but were confirmed in the remaining 765 patients to be nonbrain diseases in 654 (85.5%) patients and brain diseases in 111 (14.5%) patients. The actuarial neurological death-free survival rates were 94.4% and 86.6% at 6 and 12 months following the second SRS. Multivariable analysis revealed female sex, Karnofsky Performance Scale score of 80% or greater, better modified recursive partitioning analysis class, smaller tumor numbers, and higher peripheral dose to be significant predictive factors for longer survival. The cumulative incidences of local recurrence were 11.2% and 14.9% at 12 and 24 months after the second SRS. The crude incidence of neurological deterioration was 7.1%, and the respective cumulative incidences were 4.5%, 5.8%, 6.7%, 7.2%, and 7.5% at 12, 24, 36, 48, and 60 months after the second SRS. SRS-induced complications occurred in 25 patients (2.9%) after a median post-second SRS period of 16.8 months (range 0.6-95.0 months; interquartile range 5.6-29.3 months). The cumulative incidences of complications were 1.4%, 2.0%, 2.4%, 3.0%, and 3.0% at 12, 24, 36, 48, and 60 months after the second SRS, respectively. CONCLUSIONS Carefully selected patients with recurrent tumors-either new or locally recurrent-are favorable candidates for a second SRS, particularly in terms of neurological status maintenance and the safety of this treatment strategy.
authors.affiliation: Katsuta Hospital Mito GammaHouse, Hitachinaka.|Department of Neurosurgery, Faculty of Medicine, University of Tsukuba.
authors.forename: Takao
authors.initials: T
authors.lastname: Koiso
authors.affiliation: Katsuta Hospital Mito GammaHouse, Hitachinaka.|Department of Neurosurgery, Tokyo Women's Medical University Medical Center East, Tokyo.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Kyoto Prefectural University of Medicine Graduate School of Medical Sciences, Kyoto.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kawabe
authors.affiliation: Department of Neurosurgery, National Hospital Organization Mito Medical Center, Mito; and.
authors.forename: Shinya
authors.initials: S
authors.lastname: Watanabe
authors.affiliation: Clinical Research Center and.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Higuchi
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, University of Tsukuba.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Faculty of Medicine, University of Tsukuba.
authors.forename: Akira
authors.initials: A
authors.lastname: Matsumura
authors.affiliation: Department of Neurosurgery, Tokyo Women's Medical University Medical Center East, Tokyo.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Kasuya
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Gamma Knife; HR = hazard ratio; IQR = interquartile range; KPS = Karnofsky Performance Scale; M-RPA = modified recursive partitioning analysis; MST = median survival time; RTOG = Radiation Therapy Oncology Group; SRS = stereotactic radiosurgery; WBRT = whole-brain radiotherapy; brain metastases; oncology; radiosurgery; re-treatment; stereotactic radiosurgery