ESTRO 2024 - Abstract Book

S2006

Clinical - Mixed sites, palliation

ESTRO 2024

The 1-year LC rate was 94.3% [95% CI: 89 – 100%] after a median follow-up of 12.1 months (95% CI: 11.9 – 12.5). The 1-year overall and progression-free survival were 92% (90-100%) and 55% (44 – 69%).

Within 1-year follow-up, no patients experienced grade (G4) or more TRAEs, three (4.5 %) had G3, and 11 (16%) had G2 TRAEs. The recorded grade 3 TRAEs were vertebra compression fractures (n=2) and an episode with urinary retention (n=1). All grade 3 TRAEs required instrumentation. The most common grade 2 TRAEs were pain (n=6, 9%) and fatigue (n=4, 6%).

Of the patients with a pain intensity ≥1 at baseline, 46% had a complete pain response after 36 weeks and 34% after a year. Initial pain flare was registered in eight (12%) patients.

The overall 1-year fracture rate was 10.9% (95% CI 2.6 – 18.5%), 15.5% (95% CI: 0 – 29%, n = 4) in spine targets, and 7.5% (95% CI: 0 – 15.6%, n = 3) in non-spine targets, see Figure 1. An additional patient had a G3 vertebra compression fracture after 13 months of follow-up. Five of the eight fractures were asymptomatic, and four of these were diagnosed by the radiologist during the central assessment

Conclusion:

In patients with oligometastatic bony metastases, risk-adapted SABR provided a high 1-year local control rate with an acceptable toxicity profile. However, longer follow-up is needed to evaluate the full extent of SABR-related toxicity.