Radiation therapy is a highly effective modality for managing localized solid tumors and has become a fundamental component of treating unresectable hepatocellular carcinoma. Our previous preclinical investigation revealed that radiotherapy can initiate immunogenic cell death and facilitate the cross-presentation of tumor antigens by antigen-presenting cells, thereby augmenting systemic anti-tumor T cell responses in murine tumor models. However, this immune response subsequent to irradiation has not been comprehensively evaluated in clinical trials involving hepatocellular carcinoma patients. Given that radiotherapy represents a standard therapeutic approach for unresectable hepatocellular carcinoma, our ongoing phase II non-randomized trial aims to prospectively assess immunological responses and dose-volumetric parameters, while identifying predictors of clinical outcomes in patients undergoing definitive radiotherapy for hepatocellular carcinoma.

Inclusion Criteria:

1. Participants must have diagnosis of HCC. Participants may have multiple lesions. Diagnosis should be confirmed by at least 1 criteria listed below:

   • Histologically or cytologically proven diagnosis of HCC.
   • Typical arterial enhancement and delayed washout on multiphasic CT or MRI.

2. Age ≥18 years at the time of signing informed consent document.

3. ECOG performance status 0-2.

4. Child-Pugh score 5-9 liver function within 28 days of study registration.

5. Documented virology status of hepatitis B virus (HBV), as confirmed by screening HBV serology test.

6. Documented virology status of hepatitis C virus (HCV), as confirmed by screening HCV serology test.

7. Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

1. Presence of distant metastases that cannot be encompassed by radiotherapy
2. Pregnancy or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception
3. Inability to treat all sites of disease by radiotherapy
4. Known HIV infection.

Patients undergoing routine radiotherapy using photons or protons for HCC

Sharing individual participant data (IPD) with other researchers requires IRB review and approval. Presently, we do not have a plan to provide IPD to other researchers