ESTRO 2024 - Abstract Book

S14 ESTRO 2024 The use of automated QA for auto-segmentation models is at this moment not yet established in clinical practice. However, it could be of great importance during further expansion of adaptive radiotherapy since Invited Speaker

3298

Brachy/SBRT rationale

Piotr Wojcieszek

National Research Institute of Oncology, Gliwice Branch, Brachytherapy, Gliwice, Poland

Abstract:

Ultrahypofractionation is an unprecedented concept in the modern radiation oncologist's arsenal to cure cancer. The evolution of imaging, planning algorithms and precision of LINACs has brought us to the moment when we can ask ourselves if conventional means still 2Gy per fraction. Although classic radiotherapy (i.e., hiperfractionation, conventional, mild hypofractionation, and altered schedules) has saved many lives and has pushed our understanding up to today, we live now in the era of precisely delivered high fractions in short overall treatment time. Nevertheless, there is one method, also more than 100 years old, in which aficionados were fearless in using doses per fraction higher than those recognized as ultra-hypofractionated. This lecture aims to show where we are now with high-dose-rate (HDR) brachytherapy (interventional radiotherapy) and stereotactic body radiotherapy (SBRT). Such knowledge inspires an understanding of different radiotherapy techniques in clinical settings.

3299

Breast brachytherapy: Can we match EBRT hypofractionation?

Jean-Michel Hannoun-Levi

Antoine Lacassagne Cancer Center, Radiation Oncology, Nice, France

Abstract:

Regarding radiation therapy regimens, since the publication of the results of the “Boost versus no boost” EORTC phase 3 randomized trial, one of the main subjects related to adjuvant breast irradiation has been the investigation of new hypofractioned and accelerated regimens with the goal of shortening significantly the total treatment time. Moderate hypofractionation was first investigated in the START B prospective phase 3 randomized trial, which confirmed that 40 Gy in 15 fractions over 3 weeks was non-inferior in terms of local control compared to 50 Gy in 25 fractions over 5 weeks. IMPORT LOW trial was the first phase 3 randomized trial to show that APBI was possible in 3 weeks. More recently, FAST-Forward phase 3 randomized trial reported non-inferior local control rates after a moderate hypofractionated regimen (40 Gy/15 fractions/3 weeks) compared to accelerated-hypofractionated whole breast irradiation (26 Gy/5 fractions/1 week). In the framework of accelerated-hypofractionated adjuvant breast irradiation, and specifically for low-risk tumors, multicatheter interstitial brachytherapy (MIBT) is another validated option since the publication of the GEC-ESTRO phase 3 randomized trial results comparing whole versus accelerated and partial breast irradiation (APBI). In this trial, more than 80% of the APBI cohort were treated with high-dose rate