SCAP and pulmonary fibrosis: RP, as one of the more common complications of radiotherapy for esophageal cancer, is the interaction of a variety of cells and molecules, which causes a large number of fibroblasts to accumulate, proliferate, and differentiate, cause excessive extracellular matrix deposition, and ultimately lead to pulmonary fibrosis and cause the pathology of the sCAP physiological process [12].