ESTRO 2025 - Abstract Book

S553

Clinical - Breast

ESTRO 2025

1 SSD Radioterapia, Ospedale Michele e Pietro Ferrero-AslCn2, Verduno, Italy. 2 SSC Radioterapia, Università degli Studi di Genova, Genova, Italy. 3 SSD Fisica Sanitaria, Ospedale Michele e Pietro Ferrero-AslCn2, Verduno, Italy. 4 SSC Fisica Sanitaria, Università degli Studi di Torino, Torino, Italy Purpose/Objective: The aim of this work is to evaluate the impact on reproducibility and on treatment radiotherapy (RT) session time of respiratory training (TRN) in left breast cancer patients(pts) who underwent adjuvant RT using Deep Inspiratory Breath-Hold technique (DIBH-t). Material/Methods: We analyzed 20 pts who underwent RT for left breast cancer with DIBH-t at our Radiotherapy Department. 10 pts treated from April to December 2022 without TRN for DIBH-t and 10 pts treated from July to October 2023 with TRN. Medium age was 59.2 years for no-TRN-group (range 47-76) and 57.7 years for TRN-group (range 44-74). All pts underwent two sequential CT simulations in supine position: the first in free breathing and the second in DIBH. The impact of TRN in clinical practice was evaluated analysing the difference of a series of parameters between the 2 groups (Tab1). The useful time to process the pre-treatment images is the processing time. All these data were provided directly by the ARIA software. The analysis was made using unpaired T-test, after verifying normality distributions with the Shapiro-Wilk test. Results: Session treatment time were seen differences not statistically significant between two groups and the same was for CBCT acquisition time in BH. Instead the data showed a statistically significant difference for the following parameters: CBCT + processing time with a median time of 4.6 minutes for the TRN-group versus 7.5 minutes for no-TRN-group (P-value 0.0034); MV + processing time with a median time of 2.8 minutes for the TRN-group versus 3.9 minutes for no-TRN-group (P-value 0.0327); treatment + imaging processing time with an average difference of 1.6 minutes between the 2 groups(P-value 0.046) (Tab1). The useful time to process the pre-treatment images is the processing time. For both groups we found a progressive temporal reduction of the RT-session time during RT.

Conclusion: From our preliminary data it seems that TRN for DIBH-t RT is useful for optimizing patients' reproducibility and interpretation of daily imaging dedicated to complex treatment-planning such as CBCT. This data is indirectly confirmed by progressive temporal reduction of RT-session time during treatment for both groups of pts. While a useful reduction in the overall session time clearly did not emerge from our analysis, probably due to limited number of pts. Respiratory training in left breast cancer patients who underwent adjuvant RT using DIBH-t has become clinical practice in our Centre.

Keywords: breast radiotherapy breath hold training