The First-line Treatment of RCLM With RAS Mutation Was Local Short-course Radiotherapy (SCRT) + PD-1+ Standard Therapy

To explore the efficacy and safety of radiotherapy followed by PD-1+ standard chemotherapy in the first-line treatment of initial unresectable rectal cancer liver metastases

Inclusion Criteria:Histologically confirmed adenocarcinoma of the rectum；The clinical stage evaluated by MRI was T3-4 and/or N+ and M1a(only liver metastasis)；ECOG PS 0-2；CHild Pugh A；Estimated survival ≥3 months;Women of childbearing age should comply with contraceptive measures if pregnancy test is negative;Adequate organ and bone marrow functions, ecg, blood, biochemical and other basic tests are not contraindications of chemotherapy;Adherence to scheduled visits, treatment plans, laboratory tests, and other study procedures Willingness and ability.Exclusion Criteria:Pregnant or lactating women;No previous antitumor therapy；No previous liver local therapy；No contraception during the reproductive period;patients known to have a history of allergy to any study drug, similar drug or excipient;Patients with risk of massive gastrointestinal bleeding or gastrointestinal obstruction;Patients with a history of thromboembolism, except those caused by PICC;Patients with active infection;Other conditions that the investigator determines are not suitable for inclusion in the study.