PCSK9 Inhibitor and PD-1 Inhibitor Combined With Neoadjuvant Chemoradiotherapy for pMMR/MSS Locally Advanced Rectal Cancer

"1. Neoadjuvant Treatment 1.1 Short-Course Radiotherapy (SCRT) Total Dose: 25 Gy in 5 fractions over 5 days. Interval: 1-week rest before the next stage. 1.2 Chemotherapy and Immunotherapy Regimen: Start 1 week after SCRT with 6 cycles of CAPOX chemotherapy combined with PD-1 inhibitor immunotherapy (3 weeks per cycle).~ 1.3 PCSK9 Inhibitor Administration: Subcutaneous injection every 4 weeks during neoadjuvant therapy (6 cycles total).~2. Multidisciplinary Team (MDT) Discussion Timing: 2 weeks after completing neoadjuvant therapy.~Approach:~Patients achieving clinical complete response (cCR): Watch-and-wait strategy. Others: Surgery based on MDT evaluation."