ESTRO 2024 - Abstract Book

S817

Clinical - CNS

ESTRO 2024

retrospective analysis of factors influencing OS of patients after sRT for BM, in order to accurately assess the prognosis for patients receiving immune checkpoint inhibition (ICI) and targeted therapies (TT).

Material/Methods:

In a retrospective single center analysis, demographic, clinical and radiation treatment parameters of 1127 patients undergoing sRT for BM with CyberKnife were evaluated from 03/2016 to 10/2022. sRT was prescribed as either single-fraction (18-20 Gy at the 70% isodose) or fractionated sRT (6-7 fractions of 5 Gy at the 70% isodose). Survival data were retrospectively collected through the German cancer registry. Re-irradiation, number of BMs, planning target volume (PTV) were integrated with the data. Moreover, influence of TT/ICI treatments on prognosis was analyzed in a subgroup of patients with non-small cell lung cancer (NSCLC) (n=568).

Results:

Cohort characteristics are depicted in Table 1.

Table 1: Clinical and treatment characteristics

Patients/number of BM

1127/3841

Gender (m:w)

526:601

Median age at sRT in years 63 (range 18-89) Median number of BM in primary sRT 2 (range 1-15) Entities n

NSCLC

568 (50%)

Breast cancer

153 (14%)

Melanoma

121 (11%)

SCLC

70 (6%)

Renal cell cancer

50 (4%)

Others

165 (15%)

Primary sRT

n

BM

1 x 20 Gy / 1 x 18 Gy

733 (65%)

6 x 5 Gy

178 (16%)

Cavities (+/- simultaneous RT of BM)

7x5Gy

137 (12%)