ESTRO 2024 - Abstract Book

S503

Clinical - Breast

ESTRO 2024

Conclusion:

The present case-cohort study of 1329 modernly treated BC patients with differing risk profiles shows 1) a significantly poorer survival in irradiated patients with ER- disease and “low TILs” as compared to “high TILs” and that 2) a similar association between TILs and OS is not present for irradiated patients with ER+ disease. The findings further support the hypothesis that 3) superior OS in patients with high TILs is mediated through distant tumor control rather than improved local control.

These results validate previous findings of the DBCG82bc study and show a robust biological association between TILs and ER-status in irradiated BC patients.