title: Stereotactic body radiotherapy for oligo-metastatic liver disease - Influence of pre-treatment chemotherapy and histology on local tumor control.
abstract: Stereotactic body radiation therapy (SBRT) is applied in the oligometastatic setting to treat liver metastases. However, factors influencing tumor control probability (TCP) other than radiation dose have not been thoroughly investigated. Here we set out to investigate such factors with a focus on the influence of histology and chemotherapy prior to SBRT using a large multi-center database from the German Society of Radiation Oncology.
  
  
  
  452 SBRT treatments in 363 patients were analyzed after collection of patient, tumor and treatment data in a multi-center database. Histology was considered through random effects in semi-parametric and parametric frailty models. Dose prescriptions were parametrized by conversion to the maximum biologically effective dose using alpha/beta of 10Gy (BEDmax).
  
  
  
  After adjusting for histology, BEDmaxwas the strongest predictor of TCP. Larger PTV volumes, chemotherapy prior to SBRT and simple motion management techniques predicted significantly lower TCP. The model predicted a BED of 209±67Gy10necessary for 90% TCP at 2years with no prior chemotherapy, but 286±78Gy10when chemotherapy had been given. Breast cancer metastases were significantly more responsive to SBRT compared to other histologies with 90% TCP at 2years achievable with BEDmaxof 157±80Gy10or 80±62Gy10with and without prior chemotherapy, respectively.
  
  
  
  Besides dose, histology and pretreatment chemotherapy were important factors influencing local TCP in this large cohort of liver metastases. After adjusting for prior chemotherapy, our data add to the emerging evidence that breast cancer metastases do respond better to hypofractionated SBRT compared to other histologies.
authors.affiliation: Leopoldina Hospital Schweinfurt, Department of Radiation Oncology, Germany.
authors.forename: R J
authors.initials: RJ
authors.lastname: Klement
authors.affiliation: University Hospital Zürich, Department of Radiation Oncology, University of Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Guckenberger
authors.affiliation: Strahlentherapie Bautzen, Radiation Oncology, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Alheid
authors.affiliation: Krankenhaus Barmherzige Brüder, Radiation Oncology, Regensburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Allgäuer
authors.affiliation: RadioChirurgicum CyberKnife Südwest, Radiation Oncology, Göppingen, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Becker
authors.affiliation: Universitätsklinikum Schleswig-Holstein, Radiation Oncology, Kiel/Lübeck, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Blanck
authors.affiliation: University Hospital Mannheim, Radiation Oncology, University of Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Boda-Heggemann
authors.affiliation: University Hospital Freiburg, Radiation Oncology, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Brunner
authors.affiliation: Klinikum rechts der Isar- Technische Universität München, Radiation Oncology, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Duma
authors.affiliation: Department of Radiation Oncology, University of Munich - LMU Munich, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Gerum
authors.affiliation: University Hospital Heidelberg, Radiation Oncology, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Habermehl
authors.affiliation: University Hospital Rostock, Radiation Oncology, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Hildebrandt
authors.affiliation: University Hospital Würzburg, Radiation Oncology, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Lewitzki
authors.affiliation: University Hospital Halle, Radiation Oncology, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ostheimer
authors.affiliation: University Hospital Basel, Radiation Oncology, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Papachristofilou
authors.affiliation: University Medical Center Hamburg-Eppendorf, Radiation Oncology, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Petersen
authors.affiliation: Strahlenzentrum Hamburg, Radiation Oncology, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schneider
authors.affiliation: University Hospital of Cologne, Radiation Oncology, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Semrau
authors.affiliation: Klinikum Passau, Radiation Oncology, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Wachter
authors.affiliation: University Hospital Zürich, Department of Radiation Oncology, University of Zurich, Switzerland. Electronic address: nicolaus.andratschke@usz.ch.
authors.forename: N
authors.initials: N
authors.lastname: Andratschke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000556:secondary; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D016634:Radiosurgery / Q000379:methods*; D055815:Young Adult
keywords: Frailty models; Liver metastases; SBRT; Stereotactic radiotherapy; Tumor control probability modeling