Long-course Chemoradiotherapy or Short-course Radiotherapy Combined With CAPOX, PD-1antibody, and COX-2 Inhibitor for MSS Locally Advanced Rectal Cancer (SERRAC)

Inclusion criteria

• Age 18-75 years, gender not limited
• Pathologically confirmed rectal adenocarcinoma
• ≤10 cm from the anus
• Baseline stage T3-4/N+
• No distant metastasis
• MSI/MMR status MSS/pMMR
• Karnofsky performance status score ≥70
• No prior chemotherapy or other anti-cancer treatment prior to enrollment
• No prior immunotherapy prior to enrollment
• Ability to comply with the study protocol
• Written informed consent

Exclusion criteria

• Pregnancy or breast-feeding women;
• Known history of other malignancies within 5 years;
• Known history of previous anti-tumor treatment, including radiotherapy, chemotherapy, immune checkpoint inhibitors, T cell-related therapy, etc;
• Known history of severe neurological or mental illness (such as schizophrenia, dementia or epilepsy);
• Current severe cardiac disease (cardiac dysfunction and arrhythmia), renal dysfunction and liver dysfunction;
• Acute cardiac infarction or cerebral ischemic stroke occurred within 6 months before recruitment;
• Uncontrolled infection which needs systemic therapy;
• Active autoimmune disease or immunodeficiencies, known history of organ transplantation or systematic use of immunosuppressive agents;
• Known history of human immunodeficiency virus (HIV) infection (i.e., HIV 1 to 2 antibody positive), active syphilis infection, active pulmonary tuberculosis infection
• Allergic to any component of the therapy.