A Phase I/II Trial to Evaluate the Safety and Efficacy of Continuous Positive Airway Pressure in Volumetric Modulated Arc Therapy for Breast Cancer.

PURPOSE: This phase I/II study aimed to evaluate the tolerability and the organ-sparing effects of continuous positive airway pressure (CPAP) in breast cancer radiotherapy (RT).

MATERIALS AND

METHODS

We conducted a prospective, single-institutional trial approved by the Ministry of Food and Drug Safety of South Korea. Patients with breast cancer who received postoperative RT underwent 4D-CT simulation and treatment planning under both free breathing (FB) and CPAP-assisted breathing (WC), with a target pressure of 20 cm H2O. Adverse events (AEs) were evaluated, and dosimetric parameters of organs at risk and heart position change were compared between the FB and WC arms.

RESULTS

Among 20 enrolled patients, four withdrew due to discomfort during simulation. During the trial, no CPAP-related AEs greater than grade 2 were observed. Compared to FB, CPAP reduced the mean heart dose by 33.8% (p < 0.001), as well as V5-V30 for both the left ventricle and left anterior descending artery (all p < 0.05). It also led to significant reductions in V5-V40 and the mean ipsilateral lung dose, including a 4.4% reduction in V20 (all p < 0.001). The heart centroid shifted rightward (4.8 mm), ventrally (8.1 mm), and caudally (16.3 mm) with CPAP, displacing the heart away from the RT field.

CONCLUSION

CPAP demonstrated both safety and efficacy for breast cancer RT, achieving significant reductions in cardiac and pulmonary radiation exposure. These findings support further investigation of CPAP as a novel respiratory motion management strategy. Future studies are warranted to identify optimal CPAP pressure levels to facilitate broader clinical implementation.