ESTRO 2024 - Abstract Book

S1840

Clinical - Mixed sites, palliation

ESTRO 2024

With a median follow-up of 23 months post-treatment, 8 of 13 patients had disease progression (62%). The median, 6-month and 12-month PFS were 3.6 months, 33.8% and 11.3%, respectively. The median, 6-month, and 12-month OS were 13.8 months, 73%, and 62%, respectively. Four patients received at least one line of systemic therapy after radiotherapy (7.7%): FOLFIRI and FOLFOX, Palbociclib, Zoladex and Casodex and Enzalutamide, Carboplatin, and paclitaxel. Five patients (38%) received further radiation including additional SBRT treatments, whole brain radiotherapy and conventional palliative radiotherapy for symptom control.

Conclusion:

To our knowledge, this is the first in human study to evaluate SABR in patients with more than 10 metastases. The ARREST study demonstrated that SABR treatment to all sites of polymetastatic disease is feasible in selected patients. Doses up to 30 Gy in 5 fractions were delivered with minimal acute toxicity noted. There was a trend towards decreased post-treatment QoL in this study, which could be attributed to metastatic disease progression or radiation treatment sequalae. A phase II/III randomized study, ARREST-2, is underway to evaluate the efficacy, survival characteristics and QoL impacts of SABR for polymetatstatic disease.

Keywords: Polymetastatic, SABR, Palliation

References:

[1] Palma, D.A., Olson, R., Harrow, S., Correa, R.J., Schneiders, F., Haasbeek, C.J., Rodrigues, G.B., Lock, M., Yaremko, B.P., Bauman, G.S. and Ahmad, B., 2019. Stereotactic ablative radiotherapy for the comprehensive treatment of 4 – 10 oligometastatic tumors (SABR-COMET-10): study protocol for a randomized phase III trial. BMC cancer, 19(1), pp.1-15.