Initial UK Experience of Stereotactic Body Radiotherapy for Extracranial Oligometastases: Can We Change the Therapeutic Paradigm?
OBJECTIVE
To retrospectively review the toxicity and early outcome data from patients who have received stereotactic body radiotherapy (SBRT) for extracranial oligometastases at a single UK institution.


METHODS
Eligible patients had ≤3 extracranial metastases and performance status ≤2. Prior systemic therapy and radical treatment of oligometastastic relapse with any standard treatment modality was permitted. Patients with synchronous metastatic disease were excluded unless they had evidence of controlled primary disease after radical therapy. Follow-up consisted of clinical examination, biochemical and radiological assessments in accordance with standard clinical care. Progression events were defined using RECIST. Toxicity was evaluated using CTCAE v4.0. Local control, progression-free survival (PFS), freedom from widespread distant metastasis (defined as disease not amenable to further radical salvage therapy) and overall survival were calculated.


RESULTS
Between July 2011 and April 2014, 73 patients with 87 metastases received SBRT (range 1-3 per patient). The median follow-up was 14.5 months (range 0-26.4). The median PFS was 14.5 months (1 year PFS 57%, 2 year 28%); 1 year overall survival 96%, 2 year 79.8%; 2 year local control 88%. At 2 years, 46% of patients were free from widespread distant metastases. No ≥ grade 3 acute or late toxicity was observed.


CONCLUSIONS
At this time point, observed toxicity is minimal with excellent local control rates. This promising treatment paradigm requires further investigation in the context of a randomised controlled trial to establish if the addition of SBRT to standard care improves survival outcomes.
Department of Radiotherapy, Royal Marsden Hospital, London, UK. Electronic address: katharine.aitken@rmh.nhs.uk.
K
K
Aitken
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
A
A
Tree
Department of Statistics, Royal Marsden Hospital, London, UK.
K
K
Thomas
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
C
C
Nutting
Gray Institute for Radiation Oncology and Biology, University of Oxford, Oxford, UK.
M
M
Hawkins
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
D
D
Tait
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
H
H
Mandeville
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
M
M
Ahmed
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
S
S
Lalondrelle
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
A
A
Miah
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
A
A
Taylor
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
G
G
Ross
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
V
V
Khoo
Department of Radiotherapy, Royal Marsden Hospital, London, UK.
N
N
van As
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000532:radiotherapy* / Q000628:therapy; D016634:Radiosurgery; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D006113:United Kingdom; D055815:Young Adult
Extracranial oligometastases; SBRT; stereotactic radiotherapy