ESTRO 2024 - Abstract Book

S2222

Clinical - Upper GI

ESTRO 2024

Results:

The median JCI for the arterial and venous phases were 0.50 (range, 0.17-0.64) and 0.41 (range, 0.23-0.61) (p=0.10), respectively. The JCI seemed to be higher when the GTV of the gold standard (gsGTV) increased at the arterial phase and at the venous phase (R² = 0.30, p=0.01 and R² = 0.32, p=0.01, respectively). The median gsGTV was significantly smaller compared to the operators’ GTV at the arterial (p<0.0001) and venous phases (p<0.001), respectively. The GMI were low with few tumors missed for all patients with a median GMI of 0.07 (range 0.03-0.15) and 0.05 (range 0.02- 012) at the arterial and venous phases, respectively (p=0.15). In only one case, the GMI was ≥0.5 which corresponds to at least 50% of the tumor being missed. There was a moderate agreement between the operators with a median kappa index of 0.52 (range 0.38-0.57) on the arterial phase, and 0.52 (range 0.36-0.57) on the venous phase (p=0.08). The intra-observer variability for GTV delineation was lower at the venous phase than at the arterial phase for the two operators. There was no significant difference between the arterial and the venous phases regarding the dose-volume histogram for the operators.

Conclusion:

JCI for the GTV at arterial phase was higher than at the venous phase, but the difference was not statistically significant. The use of both phases should be encouraged. Our findings suggest the need to provide training for radiation oncologists in pancreatic imaging and to collaborate within a multidisciplinary team.

Keywords: pancreatic cancer, interobserver variability