Three-year update of outcomes for SABR-treated extracranial oligometastases: A real world experience
Abutaleb, MohamedKhalid Croxford, William Fatimilehin, Abiola Bowen Jones, Sarah Bewley, Michelle Colaco, Rovel J Hall, R. Whitehurst, Philip Wooder, Rachael Radhakrishna, Ganesh
Abutaleb, MohamedKhalid
Croxford, William
Fatimilehin, Abiola
Bowen Jones, Sarah
Bewley, Michelle
Colaco, Rovel J
Hall, R.
Whitehurst, Philip
Wooder, Rachael
Radhakrishna, Ganesh
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Abstract
Purpose or Objective
We present real-world data from a single institution demonstrating longer term treatment outcomes in patients who have
received SABR for oligometastases in addition to standard of care management. We compared our treatment outcomes and
safety and safety against published data.
Materials and Methods
We retrospectively collated 5-year outcomes for patients with oligomatastases treated with SABR from February 2016 to
September 2021. Inclusion criteria were as per the UK SABR Consortium Guidelines1. Prescribed doses ranged between 25-
60Gy in 3-8 alternate day fractions. The primary endpoints were: local in-field control rate (LC), distant relapse (DR) for
Years 1, 2 and 3, median overall survival (OS), progression free survival (PFS) and median time to further subsequent
treatment (TFST). Tumour biologically effective dose (BED) was calculated using α/β ratio of 10. When applicable,
endpoints were estimated from SABR treatment end date. Toxicity data (≥ G3) was collected and assessed using CTCAE
v5.0.
Results
A total of 142 patients received 152 treatments (10 patients had SABR for 2 sites). Patients’ characteristics are shown in
table-1. Mean tumour BED was 96.4 Gy (range 43.2-180) for the prescribed doses.
Median follow up was 33 months (range 0-65), Median LC for years 1, 2 and 3 was 89.4%, 83.5% and 82.2% respectively. OS
for years 1, 2 and 3 was: 89.1%, 77.8% and 72.4% respectively. Median OS is not yet reached (Fig-1). DR was 66.4%, 52.6%
and 47.3% for years 1, 2 and 3 respectively. Median times to: local in-field recurrence (LR) and DR were 10 and 9 months
respectively. Median local and distant PFS was 19 months. Median TFST was 12 months (range 0-36). G3 toxicities observed
in 1.4% (2/142) (spinal fracture and fatigue). No ≥G4 toxicities. Conclusion
Our cohort showed that SABR for oligometastases offers high rates of local control with minimal toxicity. Our outcomes for
LC, OS and PFS are consistent with the UK NHS CtE registry study2 and SABR COMET3. In our series, we have shown that
SABR delayed subsequent treatment by a median of 12 months. Ongoing trial results are awaited to further determine the
benefit of adding SABR to the standard-of-care therapy for oligometastases.
Description
Date
2022
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Abutaleb MK, Croxford W, Fatimilehin A, Bowen-Jones S, Bewley M, Colaco R, et al. Three-year update of outcomes for SABR-treated extracranial oligometastases: A real world experience. Radiotherapy and Oncology. 2022 May;170:S55-S6. PubMed PMID: WOS:000806759200053.