Charged Particle and Conventional Radiotherapy: Current Implications as Partner for Immunotherapy

Area of Science:

• Oncology
• Immunology
• Radiation Oncology

Background:

• Radiotherapy (RT) modulates inflammatory signals and enhances tumor immunogenicity, potentially improving immunotherapy efficacy.
• Combinations of RT with immune checkpoint inhibition (ICI) show clinical success but do not achieve curative outcomes for most cancers.
• Charged particle RT (PRT) offers unique properties that may further enhance tumor immunogenicity compared to conventional RT.

Purpose of the Study:

• To review the immunological effects of RT in the tumor microenvironment for immunotherapy combinations.
• To examine immunotherapeutic interventions co-administered with RT.
• To explore the theoretical basis and evidence for PRT's enhanced immunogenicity.

Main Methods:

• Literature review of preclinical and clinical studies on RT and immunotherapy combinations.
• Analysis of immunological effects of different RT modalities.
• Evaluation of immunotherapeutic strategies combined with RT.

Main Results:

• Optimal RT dose fractionation for maximizing immunogenic potential is still inconclusive.
• Multimodal therapies beyond ICI combined with RT are underrepresented.
• PRT presents a theoretical advantage for enhancing tumor immunogenicity.

Conclusions:

• Further investigation is needed to determine if PRT combined with immunotherapy yields superior antitumor effects.
• Understanding RT's immunological impact is crucial for optimizing combination therapies.
• PRT warrants further study for its potential in cancer immunotherapy.