title: A new grading system focusing on neurological outcomes for brain metastases treated with stereotactic radiosurgery: the modified Basic Score for Brain Metastases.
abstract: OBJECTIVE
  The Basic Score for Brain Metastases (BSBM) proposed by Lorenzoni and colleagues is one of the best grading systems for predicting survival periods after stereotactic radiosurgery (SRS) for brain metastases. However, it includes no brain factors and cannot predict neurological outcomes, such as preservation of neurological function and prevention of neurological death. Herein, the authors propose a modified BSBM, adding 4 brain factors to the original BSBM, enabling prediction of neurological outcomes, as well as of overall survival, in patients undergoing SRS.
  
  
  METHODS
  To serve as neurological prognostic scores (NPSs), the authors scored 4 significant brain factors for both preservation of neurological function (qualitative survival) and prevention of neurological death (neurological survival) as 0 or 1 as described in the following: > 10 brain tumors = 0 or ≤ 10 = 1, total tumor volume > 15 cm(3) = 0 or ≤ 15 cm(3) = 1, MRI findings of localized meningeal dissemination (yes = 0 or no = 1), and neurological symptoms (yes = 0 or no = 1). According to the sum of NPSs, patients were classified into 2 subgroups: Subgroup A with a total NPS of 3 or 4 and Subgroup B with an NPS of 0, 1, or 2. The authors defined the modified BSBM according to the NPS subgroup classification applied to the original BSBM groups. The validity of this modified BSBM in 2838 consecutive patients with brain metastases treated with SRS was verified.
  
  
  RESULTS
  Patients included 1868 with cancer of the lung (including 1604 with non-small cell lung cancer), 355 of the gastrointestinal tract, 305 of the breast, 176 of the urogenital tract, and 134 with other cancers. Subgroup A had 2089 patients and Subgroup B 749. Median overall survival times were 2.6 months in BSBM 0 (382 patients), 5.7 in BSBM 1 (1143), 11.4 in BSBM 2 (1011) and 21.7 in BSBM 3 (302), and pairwise differences between the BSBM groups were statistically significant (all p < 0.0001). One-year qualitative survival rates were 64.6% (modified BSBM 0A, 204 patients), 45.0% (0B, 178), 82.5% (1A, 825), 63.3% (1B, 318), 86.4% (2A, 792), 73.7% (2B, 219), 91.4% (3A, 268), and 73.5% (3B, 34). One-year neurological survival rates were 82.6% (0A), 52.4% (0B), 90.5% (1A), 78.1% (1B), 91.1% (2A), 83.2% (2B), 93.9% (3A), and 76.3% (3B), where A and B identify the subgroup. Statistically significant differences in both qualitative and neurological survivals between Subgroups A and B were detected in all BSBM groups.
  
  
  CONCLUSIONS
  The authors' new index, the modified BSBM, was found to be excellent for predicting neurological outcomes, independently of life expectancy, in SRS-treated patients with brain metastases.
authors.affiliation: Tokyo Gamma Unit Center, Tsukiji Neurological Clinic, Tokyo;
authors.forename: Toru
authors.initials: T
authors.lastname: Serizawa
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Osamu
authors.initials: O
authors.lastname: Nagano
authors.forename: Shinji
authors.initials: S
authors.lastname: Matsuda
authors.forename: Junichi
authors.initials: J
authors.lastname: Ono
authors.forename: Naokatsu
authors.initials: N
authors.lastname: Saeki
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Hirai
authors.forename: Akifumi
authors.initials: A
authors.lastname: Miyakawa
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
mesh_terms: D000368:Aged; D001926:Brain Death; D001932:Brain Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D001943:Breast Neoplasms / Q000473:pathology; D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000556:secondary / Q000601:surgery; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000473:pathology; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D060787:Neoplasm Grading; D011237:Predictive Value of Tests; D016634:Radiosurgery / Q000401:mortality*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D014565:Urogenital Neoplasms / Q000473:pathology
keywords: ADL = activity of daily living; BSBM = Basic Score for Brain Metastases; GKS = Gamma Knife surgery; GPA = graded prognostic assessment; Gamma Knife surgery; KPS = Karnofsky performance status; MD = meningeal dissemination; NPS = neurological prognostic score; RPA = recursive partitioning analysis; SIR = score index for stereotactic radiosurgery; SRS = stereotactic radiosurgery; WBRT = whole-brain radiation therapy; brain metastases; preservation of neurological function; prevention of neurological death; stereotactic radiosurgery