ESTRO 2021 Abstract Book

S681

ESTRO 2021

GTV volumes (p=0.24) were observed. Concomitant chemotherapy was administered more frequently in the ART group (78% compared to 64% preART), p<0.001. The reduction in PTV volumes was reflected in significantly reduced mean doses to the lungs (median, preART 16.4 [1.9;24.7] Gy, ART 12.1 [1.7;19.4] Gy, p<0.001) and heart (median, preART 8.0 [0.1;32.1] Gy, ART 4.4 [0.1;33.9] Gy, p<0.001). The incidence of RP at nine months decreased significantly with ART, see Figure 1 (from 50% to 20% for symptomatic RP (≥G2), from 21% to 7% for severe RP (≥G3), from 6% to 0.4% for lethal RP (G5), all p<0.001).

Slight differences in loco-regional failure and distant metastasis rates did not reach statistical significance (p=0.2, HR ART =0.84 [0.63,1.12], p=0.8, HR ART =1.03 [0.78,1.36]), respectively. The two-year progression free survival increased from 22% (preART) to 30% (ART), while the overall survival increased from 43% (preART) to 56% (ART), see Figure 2. The median overall survival time increased from 20 (preART) to 28 months (ART).

Conclusion