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Stereotactic ablative radiotherapy for comprehensive treatment of oligometastatic tumors (SABR-COMET): Study protocol for a randomized phase II trial

David A Palma1*, Cornelis J A Haasbeek2, George B Rodrigues1, Max Dahele2, Michael Lock1, Brian Yaremko1, Robert Olson3, Mitchell Liu3, Jason Panarotto4, GwendolynHMJ Griffioen2, Stewart Gaede1, Ben Slotman2 and Suresh Senan2

Author Affiliations

1 Department of Radiation Oncology, London Regional Cancer Program, 790 Commissioners Rd. E, London, ON, Canada, N6A4L6

2 Department of Radiation Oncology, VU University Medical Center, Amsterdam, Netherlands

3 Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, Canada

4 Department of Radiation Oncology, Ottawa Regional Cancer Centre, Ottawa, Canada

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BMC Cancer 2012, 12:305  doi:10.1186/1471-2407-12-305

Published: 23 July 2012



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.


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.


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.

Trial registration identifier: NCT01446744

Oligometastases; Stereotactic radiotherapy; Quality of life; Cancer; Survival