ESTRO 2024 - Abstract Book

S818

Clinical - CNS

ESTRO 2024

Other dose concepts

79 (7%)

Systemic Therapy (NSCLC)

n

ICI

256 (45%)

TT

63 (11%)

ICI and TT

20 (4%)

No documented ICI/TT

229 (40%)

Median number of sRTs per patient

2 (range 1-13)

Salvage-WBRT

131 (13%)

BM = brain metastases, sRT = stereotactic radiotherapy, ICI = immune checkpoint inhibition, TT = targeted therapy, WBRT = whole brain radiotherapy

Median OS (mOS) after the first sRT was 14.5 months. At time of first sRT, the number of BM was prognostic for mOS (1 BM vs. 2-4 BM vs. 5-10 BM with 19.0 vs. 13.1 vs. 9.0 months, p1 vs. 2-4 = 0.01, p1 vs. 5-10 < 0.001, p2-4 vs. 5 10 = 0.003, figure 1 A) as was progression within the first 3 months after sRT (15.0 months vs. 28.6 months; p < 0.001, figure 1 B). Patients with smaller PTVs (< 1cc) had a twice longer mOS compared to patients with PTVs > 1cc (20.4 vs. 10.9 months, p<0.001). Similarly, for patients with cavities, mOS was doubled for PTVs < 20 cc as compared to PTVs > 20 cc (37.7 vs. 19.2 months, p=0.02).

Figure 1: Overall survival of patients receiving sRT depending on the number of BM (A) and cerebral progression free survival until Re-sRT (B).

In NSCLC patients, administration of TT or ICI during the course of the disease was associated with an extended mOS after sRT (24.7 (TT) and 15.0 (ICI) vs. 8.0 (none) months, p = 0.003). For NSCLC patients, the number of BM at