A Combination Therapy Including Anti-PD-1 Immunotherapy in MSS Rectal Cancer With Resectable Distal Metastasis

"Patients will receive tislelizumab in combination with neoadjuvant radiotherapy and chemotherapy, and will be evaluated 2-3 weeks after completion of the treatment. Those patients who achieve complete clinical regression of the lesion can choose observation, but for those without CCR, surgical resection (TME of the primary lesion, surgical resection of metastases or other destructive local treatment) will be applied. Patients will continue to receive tislelizumab for one year after surgery or during observation.~For liver/pulmonary metastasis, the treatment plan is to implement large fraction radiotherapy for 4-8 times. For primary rectum lesion, short-course radiotherapy regimen through intensity-modulated radiotherapy will be applied with dose of 25Gy/5Fx.~Immunotherapy contains anti-PD-1 monoclonal antibody, Tislelizumab(200mg, d1, q3w x6, i.v). Chemotherapy adopts CAPEOX plan, including Capecitabine(1000mg/m2 bid, d1-14, p.o) and oxaliplatin(130mg/m2, d1, i.v)."