ESTRO 2024 - Abstract Book

S595

Clinical - Breast

ESTRO 2024

Results:

The main tumour characteristics were T stage I (66.2%), N stage N0 (62.3%), Hormone receptor positive and HER2 negative tumour (74.9%), HER2 positive tumour (13.3%), tumour grade intermediate (45.6%). The median follow-up (FU) period was 7.7 years (interquartile range (IQR), 5.5-10.8) and in total 710 deaths (20.7%) (323 from BC (9.4%)), 134 patients with LRR (3.9%), and 396 patients with DM (11.6%), were observed. The median MHD was 1.80 Gy (IQR, 1.18-3.60), median MLD 4.70 Gy (IQR, 3.56-6.40) and median EDIC was 2.08 Gy (IQR, 1.64-2.72). The Kaplan-Meier curve showed that BCSS decreased by quartiles of MHD (Figure 1A, log-rank P < 0.001) and by quartiles of EDIC (Figure 1B, log-rank P < 0.001). In univariable and multivariable analysis, MHD, MLD and EDIC were associated with reduced BCSS, worse OS, more LRR and more DM (Table 1).

Conclusion: