Low-Dose Total Body Irradiation Can Enhance Systemic Immune Related Response Induced by Hypo-Fractionated Radiation

Area of Science:

• Oncology
• Immunology
• Radiotherapy

Background:

• Systemic immune-related effects (SIME) from radiotherapy on metastatic tumors are observed but yield poor clinical outcomes.
• Novel therapeutic strategies are needed to enhance SIME and improve patient prognosis.

Purpose of the Study:

• To investigate the efficacy of combining hypo-fractionated radiation therapy (H-RT) with low-dose total body irradiation (L-TBI) in a syngeneic mouse model.
• To evaluate the potential of this combination therapy to enhance systemic immune responses against metastatic breast and colon carcinoma.

Main Methods:

• Utilized a syngeneic mouse model for breast and colon carcinoma.
• Administered a combination of H-RT and L-TBI.
• Assessed immune cell infiltration (CD8+ T cells) and cytokine production (IFN-γ) in tumor microenvironments.

Main Results:

• The combination of H-RT and L-TBI potentially enhanced SIME.
• Observed increased infiltration of CD8+ T cells and modulation of the immunosuppressive microenvironment in non-irradiated tumors.
• IFN-γ producing CD8+ T cells significantly inhibited secondary tumor growth in both breast and colon cancer models.

Conclusions:

• Low-dose total body irradiation (L-TBI) shows potential as a therapeutic agent for metastatic breast and colon cancer.
• The combination of L-TBI with H-RT significantly enhances therapeutic potential by stimulating anti-tumor immunity.