Preventive effects of combined live Bifidobacterium, Lactobacillus, Enterococcus, and Bacillus cereus tablets on radiation pneumonitis-associated with cyberknife treatment for pulmonary malignancies

This prospective trial was registered retrospectively (after patient enrollment began) because of delays in institutional approval processes. The retrospective registration was approved by the Ethics Committee of The First Hospital of Hebei Medical University (Approval No. [2025]074). The trial is registered at: WHO-primary registry ChiCTR (No. ChiCTR2500104615; Date: 19-Jun-2025), accessible via WHO ICTRP ( https://trialsearch.who.int/ ); China's National Public Health Security Information Platform (No. MR-13-25-043029; Date: 09-Jun-2025). All study procedures followed the original protocol without modifications.