Background <p>Seroma formation is a common postoperative complication of breast cancer surgery, leading to delayed wound healing, infection, patient discomfort, and repeated outpatient visits. In severe cases, it can cause skin flap necrosis, imposing physical, psychological, and financial burdens on patients. Applying compression bandaging to the patient’s postoperative wound with a chest strap is an effective measure to prevent seroma formation. However, the commonly used elastic chest straps cannot provide specific compression values, limiting their use. Therefore, we aim to compare the efficacy of standard elastic chest straps versus controlled localised air-balloon compression chest straps in preventing seroma formation following breast cancer surgery.</p> Methods <p>This is a superiority, single-blind randomised controlled trial conducted at a tertiary hospital in Guizhou Province, China, involving female breast cancer patients undergoing mastectomy. Eligible participants will be recruited by attending surgeons during routine preoperative consultations. Patients aged 18&#xa0;years or older diagnosed with unilateral breast cancer who meet the criteria for mastectomy (including modified radical mastectomy and/or simple mastectomy) and provide informed consent will be eligible for inclusion. Exclusion criteria include patients with severe concomitant diseases before surgery, those with chest deformities or trauma, those with chest strap allergies, and those with psychiatric disorders who are unable to cooperate. Sixty patients were randomly assigned to two groups (control group and intervention group) in a 1:1 ratio, without stratification. Patients in the control group received postoperative compression bandaging with standard elastic chest bandages. In contrast, those in the intervention group received postoperative compression bandaging with a controlled-pressure local air-balloon chest bandage, with pressure sensors measuring the air-balloon inflation level. The air-balloon inflation period lasted one week, with inflation values ranging from 4 to 8&#xa0;kPa. Both sets of chest straps were worn for one month. Safety measures to be collected include adverse events, postoperative complications (seroma, wound infection), and device-related skin reactions or discomfort. Primary outcomes included seroma incidence, postoperative drainage volume, and drainage tube retention time. Secondary outcomes encompassed quality of life, comfort, and satisfaction with the chest straps.</p> Discussion <p>Postoperative wound compression dressing is essential for promoting flap-to-chest wall adhesion, reducing cavities, preventing seroma formation, and facilitating wound healing. By applying the Controlled Local Air-Balloon Compression Chest Belt, we aim to reduce postoperative complications, improve postoperative comfort, and promote patient recovery.</p> Trial registration <p>Chinese Clinical Trial Registry (ChiCTR), ChiCTR 2500105194.</p> <p>Date of first planned enrolment: February 2025.</p> <p>June 30, 2025 (Clinical Trial Registration Date, retrospectively registered).</p> <p><a href="https://www.chictr.org.cn/showproj.html?proj=277304">https://www.chictr.org.cn/showproj.html?proj=277304</a></p>