title: Image-guided stereotactic ablative radiotherapy for the liver: a safe and effective treatment.
abstract: OBJECTIVE
  Stereotactic ablative body radiotherapy (SABR) is a non-invasive treatment option for inoperable patients or patients with irresectable liver tumors. Outcome and toxicity were evaluated retrospectively in this single-institution patient cohort.
  
  
  METHODS
  Between 2010 and 2014, 39 lesions were irradiated in 33 consecutive patients (18 male, 15 female, median age of 68 years). All the lesions were liver metastases (n = 34) or primary hepatocellular carcinomas (n = 5). The patients had undergone four-dimensional respiration-correlated PET-CT for treatment simulation to capture tumor motion. We analyzed local control with a focus on CT-based response at three months, one year and two years after treatment, looking at overall survival and the progression pattern.
  
  
  RESULTS
  All patients were treated with hypofractionated image-guided stereotactic radiotherapy. The equivalent dose in 2 Gy fractions varied from 62.5 Gy to 150 Gy, delivered in 3-10 fractions (median dose 93.8 Gy, alpha/beta = 10). The CT-based regression pattern three months after radiotherapy revealed partial regression in 72.7% of patients with a complete remission in 27.3% of the cases. The site of first progression was predominantly distant. One- and two-year overall survival rates were 85.4% and 68.8%, respectively. No toxicity of grade 2 or higher according to the NCI Common Terminology Criteria for Adverse Events v4.0 was observed.
  
  
  CONCLUSIONS
  SABR is a safe and efficient treatment for selected inoperable patients or irresectable tumors of the liver. Future studies should combine SABR with systemic treatment acting in synergy with radiation, such as immunological interventions or hypoxic cell radiosensitizers to prevent distant relapse.
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands. Electronic address: Lien.vandevoorde@maastro.nl.
authors.forename: L
authors.initials: L
authors.lastname: Van De Voorde
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Vanneste
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Houben
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Damen
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van den Bogaard
authors.affiliation: Department of Radiation Oncology, Mediclin Robert Janker Klinik, Bonn, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Lammering
authors.affiliation: Department of Surgery, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Dejong
authors.affiliation: Department of Internal Medicine, Medical Oncology Division, GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: de Vos-Geelen
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Buijsen
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Öllers
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Berbée
authors.affiliation: Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Centre +, Maastricht, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Lambin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000601:surgery*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000175:diagnosis / Q000556:secondary / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009068:Movement; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011829:Radiation Dosage; D015642:Radiology, Interventional; D016634:Radiosurgery / Q000009:adverse effects; D012119:Respiration; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed
keywords: Hepatocellular carcinoma; Liver metastases; Local control; Overall survival; Stereotactic ablative body radiotherapy