Workup steps (12)

• 1lab Complete Blood Count with Differential
  Baseline cytopenia assessment and ongoing monitoring of myelosuppression.
• 2lab Comprehensive Metabolic Panel
  Електроліти (Na, K, Cl, HCO3), креатинін + BUN (renal function), глюкоза, кальцій, альбумін, total protein. Базова метаболічна оцінка перед будь-якою терапією + основа TLS risk + dosing adjustments.
• 3lab Liver Function Tests
  Assess hepatic function — baseline + during BR cycles + DAA therapy + HBV reactivation monitoring.
• 4lab Carcinoembryonic antigen (serum)
  CRC tumor marker — baseline + monitoring; >5 ng/mL pre-resection associated with worse prognosis.
• 5imaging Full colonoscopy with biopsy
  Diagnostic colonoscopy to cecum + biopsy of any lesion. Mandatory for CRC diagnosis + screening synchronous lesions (~3-5%).
• 6imaging CT chest + abdomen + pelvis with IV contrast
  CRC staging — detects nodal and distant (liver, lung, peritoneal) metastases.
• 7imaging MRI rectum (high-resolution pelvic MRI for rectal cancer staging)
  Rectal cancer mrT/N staging + circumferential resection margin (CRM) prediction. Determines neoadjuvant CRT vs upfront surgery.
• 8histology MSI status by PCR or NGS
  Detect microsatellite instability — treatment-defining in mCRC + Lynch syndrome screening for all CRCs.
• 9histology MMR proteins IHC (MLH1 / MSH2 / MSH6 / PMS2)
  Functional equivalent of MSI for treatment decisions. Loss of any protein → dMMR.
• 10histology RAS extended panel (KRAS exons 2-4 + NRAS exons 2-4)
  Mandatory before anti-EGFR therapy in mCRC — RAS mutation precludes cetuximab/panitumumab benefit.
• 11histology BRAF V600E mutation testing
  Prognostic + predictive in mCRC: V600E confers poor prognosis + precludes anti-EGFR; eligibility for encorafenib + cetuximab (BEACON) 2L+.
• 12histology HER2 IHC + reflex ISH (gastric scoring criteria)
  HER2 amplification status — actionable in CRC ~3% of RAS-WT (trastuzumab+tucatinib MOUNTAINEER) + gastric/GEJ standard.

MDT brief