Evaluation of The Efficacy And Safety of PD-1 + IL-2 Combined With Capox Treatment After Loop Colostomy Surgery in Left-sided Colorectal Cancer Patients Complicating Acute Obstruction

Inclusion Criteria:

* Males and females aged between 40 and 75 years;
* ECOG (Eastern Cooperative Oncology Group) performance status score of 0 or 1;
* Tumor tissue samples obtained and histologically confirmed as colon or rectal adenocarcinoma;
* Adequate hematological, liver, and kidney functions: neutrophil count ≥ 1.5×10\^9/L; platelet count ≥ 75×10\^9/L; serum total bilirubin ≤ 1.5× upper limit of normal (UNL); aspartate aminotransferase ≤ 2.5× UNL; alanine aminotransferase ≤ 2.5× UNL; serum creatinine ≤ 1.5× UNL.

Exclusion Criteria:

* Metastatic disease (Stage IV);
* Recurrent colorectal cancer;
* Concurrent active bleeding, perforation, or other complex situations that cannot be addressed with emergency colostomy surgery alone;
* Previous systemic anti-cancer treatment for colorectal cancer;
* Coexistence of other non-colorectal cancer malignancies;
* Patients with any active autoimmune diseases, or a history of needing steroids or immunosuppressive drugs;
* Patients with interstitial lung disease, non-infectious pneumonia, or uncontrolled systemic diseases (e.g., diabetes, hypertension, pulmonary fibrosis, and acute pneumonia);
* Previous treatment-induced any grade 2 or above toxicity reaction (according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5 classification) that has not subsided (excluding anemia, hair loss, and skin pigmentation);
* Previous treatment with anti-programmed death receptor-1 (PD-1) or its ligand (PD-L1) antibodies, anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibodies;
* Pregnant or breastfeeding women;
* Known or tested positive for human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS);
* Known or suspected allergy history to any drugs used in the trial;
* Pregnant or breastfeeding women.