title: Gamma knife stereotactic radiosurgery in the treatment of brainstem metastases: The MD Anderson experience.
abstract: BACKGROUND
  Brainstem metastases (BSMs) represent a significant treatment challenge. Stereotactic radiosurgery (SRS) is often used to treat BSM. We report our experience in the treatment of BSM with Gamma Knife SRS (GK_SRS).
  
  
  METHODS
  The records of 1962 patients with brain metastases treated with GK_SRS between 2009 and 2013 were retrospectively reviewed. Seventy-four patients with 77 BSMs and follow-up brain imaging were identified. Local control (LC), overall survival (OS), progression-free survival (PFS), and toxicity were assessed.
  
  
  RESULTS
  Median follow-up was 5.5 months (range, 0.2-48.5 months). Median tumor volume was 0.13 cm3(range, 0.003-5.58 cm3). Median treatment dose was 16 Gy (range, 10-20 Gy) prescribed to 50% isodose line (range, 40%-86%). Crude LC was 94% (72/77). Kaplan-Meier estimate of median OS was 8.5 months (95% CI, 5.6-9.4 months). Symptomatic lesions and larger lesions, especially size ≥2 cm3, were associated with worse LC (HR = 8.70,P= .05; HR = 14.55,P= .02; HR = 62.81,P< .001) and worse OS (HR = 2.00,P= .02; HR = 2.14,P= .03; HR = 2.81,P= .008). Thirty-six percent of BSMs were symptomatic, of which 36% (10/28) resolved after SRS and 50% (14/28) had stable or improved symptoms. Actuarial median PFS was 3.9 months (95% CI, 2.7-4.9 months). Midbrain location was significant for worse PFS (HR = 2.29,P= .03). Toxicity was low (8%, 6/74), with size and midbrain location associated with increased toxicity (HR 1.57,P= .05; HR = 5.25,P= .045).
  
  
  CONCLUSIONS
  GK_SRS is associated with high LC (94%) and low toxicity (8%) for BSMs. Presence of symptoms or lesion size ≥ 2 cm3was predictive of worse LC and OS.
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Khinh Ranh
authors.initials: KR
authors.lastname: Voong
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Benjamin
authors.initials: B
authors.lastname: Farnia
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Qianghu
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Dershan
authors.initials: D
authors.lastname: Luo
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Mary F
authors.initials: MF
authors.lastname: McAleer
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Ganesh
authors.initials: G
authors.lastname: Rao
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Nandita
authors.initials: N
authors.lastname: Guha-Thakurta
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Anna
authors.initials: A
authors.lastname: Likhacheva
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Amol J
authors.initials: AJ
authors.lastname: Ghia
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Paul D
authors.initials: PD
authors.lastname: Brown
authors.affiliation: Department of Radiation Oncology , The University of Texas MD Anderson Cancer Center , Houston, Texas (K.R.V., B.F., Q.W., M.F.M., A.L., A.J.G., P.D.B., J.L.); Department of Radiation Physics , The University of Texas MD Anderson Cancer Center , Houston, Texas (D.L.); Department of Neurosurgery , The University of Texas MD Anderson Cancer Center , Houston, Texas (G.R.); Department of Radiology , The University of Texas MD Anderson Cancer Center , Houston, Texas (N.G.-T.).
authors.forename: Jing
authors.initials: J
authors.lastname: Li
keywords: Gamma Knife; brainstem metastases; radiosurgery