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

Although patients with locally advanced rectal cancer and resectable liver/pulmonary metastasis could benefit from surgery resection, these patients still have a poorer prognosis compared to those without distal metastasis. Based on previous studies, there is no confirmation of whether these patients could benefit from preoperative immunotherapy combined with conventional chemoradiotherapy. This study proposes a combination therapy, preoperative short-course radiotherapy followed by neoadjuvant chemotherapy and anti-PD-1 immunotherapy, for microsatellite-stable patients with locally advanced rectal cancer and resectable liver/pulmonary metastasis, to assess its impact on tumor retreat, decline of postoperative metastasis and recurrence, and the disease-free survival and overall survival of patients. Besides, this study will provide high-level medical evidence for future clinical treatment of patients with advanced rectal cancer.