ESTRO 2024 - Abstract Book

S5107

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2024

T3-4

45 (100%)

Chemotherapy

Yes

45 (100%)

Results:

The median OS was 15.5 months (95% CI: 13.2-20.6) and the median potential follow-up time was 19.8 months. The best-performing model based on cross-validation included two parameters, both derived from the DWI decomposition analysis. Specifically, the two parameters represented information from fraction one (Hazard ratio (HR) (95% CI): 2.51 (1.42-5.96)) and longitudinal DWI changes (HR (95% CI): 0.43 (0.21-0.64)), respectively. The C-Harrell index of the model was 0.754, indicating that the model was good at discriminating between patients with short and long survival times. The model could clearly separate patients into low-, intermediate- and high-risk groups (Figure 1). Noticeably, none of the clinical parameters showed any statistically significant association with OS.

Conclusion:

Longitudinal DWI demonstrated prognostic value in LAPC. Both information from fraction one and DWI changes during the course of SBRT were important for the prediction of OS. Interestingly, none of the clinical parameters were significantly associated with OS, indicating a superiority of longitudinal DWI over standard clinical parameters in the prediction of OS. Based on these results, it might be relevant to investigate whether signals in longitudinal DWI are also potential biomarkers for response to RT.