Experimental: modified FOLFOXIRI plus target therapy

* Pre-Treatment Medications:~ 1. Atropine SC: Administered before irinotecan infusion to prevent side effects.~ 2. High-Risk Anti-Emetics Regimen: Used to prevent acute and delayed vomiting.~* Chemotherapy Regimen: All eligible patients will receive the modified FOLFOXIRI regimen as follows:~ * Oxaliplatin: 85 mg/m² IV over 2 hours (Day 1)~ * Irinotecan: 150 mg/m² IV over 90 minutes (Day 1)~ * 5-FU: 2400 mg/m² IV over 48 hours infusion (Days 1)~* Targeted Therapy: Administered according to NRAS/KRAS status and the location of the primary tumor:~ * KRAS/NRAS/BRAF Wild-Type (Left-Sided Tumor): Anti-EGFR treatment with either Panitumumab (6 mg/kg over 60 minutes, Day 1) or Cetuximab (500 mg/m², Day 1).~ * KRAS/NRAS Mutant or Right-Sided Tumor: Bevacizumab at a dose of 5 mg/kg IV over 30 to 90 minutes (Day 1).~* Treatment Schedule: The treatment will be administered biweekly for a maximum of 12 cycles (6 months).