ESTRO 2024 - Abstract Book

S2135

Clinical - Upper GI

ESTRO 2024

The median OS for the entire cohort of HCC patients treated with SBRT was 27.3 months (95% CI: 22.5-34.7 months). After SBRT, 13 (12.1%) patients developed radiation-induced severe lymphopenia (no pre-treatment severe lymphopenia). Univariate analysis showed that previous TACE, BCLC stage, macrovascular invasion, baseline Child Pugh score, baseline severe thrombocytopenia, newly developed severe radiation-induced lymphopenia, larger gross tumour volume and higher liver mean dose were associated with poor survival. In the multivariate analysis, only BCLC stage (BCLC-B: HR: 2.30, 95% CI: 1.36-3.88, p=0.002; BCLC-C: HR: 3.18, 95% CI: 1.61-6.25, p=0.001) and newly developed radiation-induced severe lymphopenia (HR:2.21, 95% CI: 1.12-4.35, p=0.029) remained as poor prognostic variables. Compared to those who did not develop severe radiation-induced lymphopenia, patients with severe radiation-induced lymphopenia had an inferior overall survival (28.1 vs. 15.8 months, p=0.01). Subsequent logistic regressions showed that radiation prescription parameters such as larger liver volume receiving more than 5Gy (i.e. Liver V5Gy, OR for every 10cc increased, 1.03, 95% CI: 1.01-1.06, p=0.016) or 10Gy (i.e. Liver V10Gy, OR for every 10cc increased, 1.04, 95% CI: 1.01-1.07, p=0.014) were associated with severe radiation-induced lymphopenia.

Table 1. Multivariate Cox Proportional Hazard Model for Overall Survival

HR (95% CI)

p-value

BCLC

stage

(ref:

0/A)

B C

2.30

(1.36-3.88)

0.002 0.001

3.18 (1.61-6.25)

Child

Pugh

grade

(ref:

A)

B

1.93 (0.95-3.96)

0.071

Baseline grade 3 thrombocytopenia

2.54 (0.87-7.39)

0.087

Newly developed grade 3 lymphopenia

2.21 (1.12-4.35)

0.029

Figure 1. Kaplan-Meier curve showing inferior overall survival in patients with newly developed post-radiation grade 3 lymphopenia