Phase II Study of Toripalimab Plus Stereotactic Body Radiotherapy in Colorectal Cancer Patients With Oligometastasis

Metastatic colorectal cancer is one of the common malignant tumors and the overall prognosis is poor. The introduction of immune-checkpoint inhibition (ICI) has led to a paradigm shift in the treatment of patients with metastatic cancer. Stereotactic body radiation therapy (SBRT) delivers a large dose of radiation to the tumor target with high precision while sparing irradiation of the surrounding normal tissues. It is suggested that SBRT could be the most appropriate radiotherapy modality to be combined with immunotherapy since it induces the expression of a series of cytokines and new tumour-associated antigens (TAAs) and is more likely to cause intense immune response and exert an abscopal effect than conventional radiotherapy. Thus, this study is to explore the use of SBRT in combination with ICI in colorectal cancer patients with oligometastasis, in order to get better local and systemic tumor control and improve progress-free survival (PFS).