Graduate School of Medicine, Division of Health Sciences
Radiotherapy (RT) has achieved great control of local tumor, but the survival time of cancer patients failed to extend because of low control of tumors outside of the irradiation field. In clinical situations, a shrunk of tumors outside of the irradiation field, called “abscopal effect”, has been rarely observed. This phenomenon is rare, though, the underlying mechanisms have been investigated and some researchers reported that abscopal effect is an immune-mediated systemic antitumor effect. Our previous studies have shown that abscopal effect could be induced by RT combined with immune checkpoint inhibitors (ICI), but not induced by RT monotherapy.
I have studied the abscopal effect induced by RT combined with ICI for mice with subcutaneously transplanted pancreatic ductal adenocarcinoma (PDAC). PDAC has been known to have a unique immune environment and almost half of PDAC patients are diagnosed with metastasis, therefore PDAC is a very intractable cancer.
Some reports have shown that subcutaneously transplanted mouse models cannot imitate the unique immune environment of PDAC. I plan to verify whether the combination therapy evokes not only local control but also abscopal effect even in a mouse model with orthotopic cancer, which has a similar immune environment as a clinical PDAC to search for the optimal treatment to induce the abscopal effect.