ESTRO 2021 Abstract Book

S713

ESTRO 2021

pattern of first site of failure between SCC and AC was confirmed in the validation cohort (Figure 2). Patients with SCC present higher loco-regional failure rates (p<0.001) and lower intra-cranial and extra-cranial distant failure rates (p=0.006 and p<0.001) than patients with AC.

Conclusion The risks of local and distant failure in the independent external cohort were consistent with the statistical uncertainty of the model predictions. The differences in recurrence patterns for SCC and AC were confirmed. Such an externally validated model of failure type could support more personalized treatment strategies.

PD-0877 Radiological prediction model of lung radiation pneumonitis based on dose line segmentation P. Yang 1 , X. Peng 2 , H. Jin 3 , Y. Jin 3 , J. Cheng 4 , H. Elhalawani 5 , J. Liu 4 , J. Wang 4 , A. Mohamed 6 , Y. Shi 3 , C.