Comparison of surface-guided radiotherapy-based deep inspiration breath hold and continuous positive airway pressure techniques in left-sided breast cancer: dosimetric and workflow analysis

This study aimed to compare the clinical utility of two respiratory motion management techniques—deep inspiration breath hold (DIBH) and continuous positive airway pressure (CPAP)—both integrated with surface-guided radiotherapy (SGRT), in patients receiving radiotherapy for left-sided breast cancer. The objective was to evaluate their relative dosimetric benefits, setup accuracy, and workflow efficiency. Twenty patients treated between August 2023 and June 2024 were retrospectively analyzed. All underwent whole breast irradiation using either DIBH or CPAP with SGRT monitoring. Dosimetric comparisons included mean and maximum doses to the heart, left anterior descending artery (LAD), and left lung. Workflow metrics—setup time, beam-on time, and positioning accuracy—were assessed. The CPAP group showed significantly lower maximum LAD dose (1212.6 ± 562.0 cGy vs. 2219.1 ± 841.0 cGy, p = 0.004) and mean LAD dose (488.6 ± 175.0 cGy vs. 844.5 ± 301.0 cGy, p = 0.004). The mean heart dose was lower with CPAP (211.8 ± 81.0 cGy vs. 229.8 ± 74.0 cGy), though not statistically significant (p = 0.615). CPAP demonstrated shorter setup time (4.2 ± 2.6 min vs. 7.5 ± 3.2 min, p < 0.05) and reduced beam-on time. No significant differences were observed in translational or rotational offsets, except for a smaller longitudinal error with CPAP (p = 0.030). SGRT-based CPAP demonstrated superior dosimetric outcomes and better workflow efficiency compared to DIBH in left-sided breast cancer radiotherapy. These findings suggest that CPAP may serve as a clinically effective and efficient alternative to DIBH, particularly in scenarios where patient compliance with breath-hold is limited.