ESTRO 2024 - Abstract Book

S690

Clinical - Breast

ESTRO 2024

20 patients were enrolled, of whom 4 withdrew because of discomfort during simulation. Thus, a total of 16 patients were analyzed, with a median age of 53 years. CPAP increased lung volume by 48.1 % (mean, 2687.0 cm 3 to 3979.6 cm 3 in the FB arm to CPAP arm, respectively; p< .001) and decreased heart volume by 9.1% (mean, 581.9 cm 3 to 528.7 cm 3 ; p < .001). CPAP was associated with significant benefits in lung dosimetric parameters V 5 , V 10 , V 20 , V 30 , V 40 (V x = the percentage of the structure volume exceeding x Gy) and mean dose (13.96 Gy vs. 11.96 Gy in the FB arm vs. CPAP arm; all p < .001). Mean heart dose (7.45 Gy vs. 4.87 Gy) ( Figure 1 ) and V 5 , V 10 , V 15 , and the maximum dose of left ventricle and left anterior descending artery were significantly decreased (all p < .05) ( Figure 2 ). The mean vector of heart centroid showed a consistent displacement to right (4.8 mm), ventral (8.1 mm), and caudal (16.3 mm) direction with CPAP, moving away from the radiation field. In the trial, grade 1 dry mouth (25%) was the most common adverse event, which was followed by dyspnea (12.5%) and headache (6.2%). No more than grade 2 adverse events were observed.

Conclusion:

In this prospective trial, CPAP demonstrated notable improvements in dosimetric parameters, minimizing radiation exposure to adjacent organs for breast cancer patients who underwent postoperative radiotherapy. Once started properly, CPAP proved to be safe, easily implementable, and well-tolerated for patients with no severe toxicity.