title: Stereotactic ablative radiotherapy for comprehensive treatment of oligometastatic tumors (SABR-COMET): study protocol for a randomized phase II trial.
abstract: BACKGROUND
  Stereotactic ablative radiotherapy (SABR) has emerged as a new treatment option for patients with oligometastatic disease. SABR delivers precise, high-dose, hypofractionated radiotherapy, and achieves excellent rates of local control. Survival outcomes for patients with oligometastatic disease treated with SABR appear promising, but conclusions are limited by patient selection, and the lack of adequate controls in most studies. The goal of this multicenter randomized phase II trial is to assess the impact of a comprehensive oligometastatic SABR treatment program on overall survival and quality of life in patients with up to 5 metastatic cancer lesions, compared to patients who receive standard of care treatment alone.
  
  
  METHODS
  After stratification by the number of metastases (1-3 vs. 4-5), patients will be randomized between Arm 1: current standard of care treatment, and Arm 2: standard of care treatment + SABR to all sites of known disease. Patients will be randomized in a 1:2 ratio to Arm 1:Arm 2, respectively. For patients receiving SABR, radiotherapy dose and fractionation depends on the site of metastasis and the proximity to critical normal structures. This study aims to accrue a total of 99 patients within four years. The primary endpoint is overall survival, and secondary endpoints include quality of life, toxicity, progression-free survival, lesion control rate, and number of cycles of further chemotherapy/systemic therapy.
  
  
  CONCLUSIONS
  This study will provide an assessment of the impact of SABR on clinical outcomes and quality of life, to determine if long-term survival can be achieved for selected patients with oligometastatic disease, and will inform the design of a possible phase III study.
authors: Department of Radiation Oncology, London Regional Cancer Program, 790 Commissioners Rd, E, London, ON, Canada. david.palma@uwo.ca
authors: David A
authors: DA
authors: Palma
authors: Cornelis J A
authors: CJ
authors: Haasbeek
authors: George B
authors: GB
authors: Rodrigues
authors: Max
authors: M
authors: Dahele
authors: Michael
authors: M
authors: Lock
authors: Brian
authors: B
authors: Yaremko
authors: Robert
authors: R
authors: Olson
authors: Mitchell
authors: M
authors: Liu
authors: Jason
authors: J
authors: Panarotto
authors: Gwendolyn H M J
authors: GH
authors: Griffioen
authors: Stewart
authors: S
authors: Gaede
authors: Ben
authors: B
authors: Slotman
authors: Suresh
authors: S
authors: Senan
mesh_terms: D002985:Clinical Protocols; D006801:Humans; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000473:pathology* / Q000601:surgery*; D016634:Radiosurgery / Q000379:methods*