Molecular mechanisms of TAM-regulated tumorigenesis and progression in various types of radiotherapy and future prospects of radiation-immunotherapy combinations

Although conventional photon radiotherapy can eradicate tumors, the presence of radioresistance has limited treatment efficacy. Nowadays the multiple radiotherapies carried out around different physics beam types will provide more options for tumor treatment. Under the current trend of anti-tumor immunotherapy, tumor-associated macrophages (TAMs), as an important component of the tumor microenvironment, significantly influence tumor progression and prognosis of comprehensive tumor therapy through reciprocal regulation with radiotherapy. The aim of this review is to summarize the influence of radiotherapy with various beam types on the biological effects of TAMs, and to explore the physiological basis for the conjunction of radiotherapy and immunotherapy based on TAMs. Ultimately, these data will provide an evidence-based medical rationale and translational research basis for optimizing the combination of radiotherapy and immunotherapy as a treatment modality for tumors in the future.