title: Early volumetric change and treatment outcome of metastatic brain tumors after external beam radiotherapy: differential radiotherapy for brain metastasis.
abstract: OBJECTIVE
  To evaluate the treatment outcomes of low-dose whole brain radiation therapy (WBRT)-based differential radiation therapy (RT) for metastatic brain tumors.
  
  
  METHODS
  A total of 242 targets (metastatic brain lesions) were analyzed in the present study. Median WBRT dose and number of fractions were 25 (range 25-35) Gy and 10 (range 8-15) fractions, respectively. A median normalized total dose (NTD) of 1.8 Gy (NTD(1.8Gy)) to the metastatic lesion was 45 (range 27-64.8) Gy. We numbered and contoured each metastatic lesion sequentially using computed tomography fused with serial magnetic resonance imaging to evaluate volumetric changes.
  
  
  RESULTS
  The 6-month and 1-year freedom from remote intracranial failure rates were 87.7 and 58.5 %, respectively. The 6-month actuarial local control (LC) rate was 93.4 %. Tumor diameter was a major determinant for LC, and tumor histology was a significant parameter predicting the volume reduction rate. With overall complete response (CR) rate of 56.6 % after RT, CR rate, if the target was more than 1 cm in size, was 25 % with a median NTD(1.8Gy) of 45 Gy, requiring dose escalation to achieve better target regression.
  
  
  CONCLUSIONS
  Low-dose WBRT with selective boost was feasible and effective. Our results pose the rationale of future trial of differential radiation therapy (RT), which prescribes different radiation dose according to the tumor density in metastatic brain tumors.
authors: Department of Radiation Oncology, Yonsei Cancer Center, Severance Hospital, Yonsei University Health System, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea.
authors: D S
authors: DS
authors: Lee
authors: Y S
authors: YS
authors: Kim
authors: C G
authors: CG
authors: Lee
authors: J H
authors: JH
authors: Lim
authors: C-O
authors: CO
authors: Suh
authors: H J
authors: HJ
authors: Kim
authors: J
authors: J
authors: Cho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000556:secondary*; D016371:Cranial Irradiation; D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009369:Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult