Concept-verification Clinical Trial on the Inhibition of Breast Cancer Lung Metastasis Progression by Hyperbaric Oxygen

Breast cancer is prone to distant metastasis, with the lungs being one of the most common target sites. Tumor hypoxia (a low-oxygen microenvironment) is a key factor promoting tumor progression and metastasis, and it can also reduce the efficacy of conventional treatments. HBOT delivers 100% oxygen at a pressure of 2.0-2.5 atmospheres absolute, which effectively improves tissue oxygenation, modifies the tumor microenvironment, and may suppress tumor growth by inhibiting cell migration and invasion and inducing tumor cell death. This study aims to verify the potential of HBOT as an adjuvant therapy to slow or block breast cancer lung metastasis progression. Eligible participants (aged 18-75 years with pathologically confirmed breast cancer accompanied by lung metastasis and no prior HBOT contraindications) will receive standard breast cancer treatment (including surgery, chemotherapy, radiotherapy, or targeted therapy as appropriate) combined with HBOT. The HBOT regimen will consist of 6 sessions per week for 2 consecutive weeks, with each session lasting 120 minutes, including 15 minutes for increasing pressure and 15 minutes for reducing pressure, at 2.5 ATA and 100% oxygen. Over a 6-month follow-up period, participants will undergo regular assessments including chest CT (to monitor lung metastasis lesions), serum tumor marker tests, and quality of life evaluations. The primary outcome is the objective response rate (ORR) of tumors evaluated according to the RECIST version 1.1 criteria: the proportion of subjects with complete response (CR) + partial response (PR), and secondary outcomes include changes in progression-free survival, the number and viability of circulating tumor cells and safety indicators. Participants may benefit from potential inhibition of lung metastasis progression and access to a well-tolerated adjuvant therapy. HBOT-related side effects are usually mild and temporary, such as ear discomfort or pressure changes, which will be closely monitored and managed by the study team throughout the treatment process. This research is significant as it explores a clinically available, safe therapy for addressing breast cancer lung metastasis-a major challenge affecting patient prognosis. If proven effective, HBOT could become an important part of comprehensive breast cancer treatment, helping to improve patient outcomes and quality of life.