Metastatic colorectal cancer (mCRC) frequently results in complex hilar biliary strictures and obstructive jaundice. When cannulation is difficult or standard approaches fail, alternative endoscopic drainage strategies may be required. Evidence in the mCRC population remains limited. This study evaluated the feasibility, safety, and early effectiveness of endoscopic biliary drainage in these patients.

We retrospectively evaluated all consecutive patients with mCRC and malignant biliary obstruction who underwent endoscopic biliary drainage between 01.01.2020 and 30.09.2025 at our tertiary referral center. We collected demographic data, information about drainage procedure type, unilateral or bilateral drainage and application of combined endoscopic approaches. Technical success was defined as successful stent placement with documented bile drainage. Clinical success was defined as a ≥10% reduction in serum bilirubin within the first 3 days. Adverse events and predictors of outcome were also explored.

Forty-seven patients were included (median age 65 years, IQR 58–73; 70.2% male). The ECOG performance status was ≥2 in 88.9% of cases. Technical success was achieved in 93.6% of cases (44/47). Clinical success was achieved in 70.2% (33/47) of patients. ERCP was performed in 35 patients (74.5%), EUS-based biliary drainage in 8 patients (17.0%), and combined ERCP + EUS drainage in 3 patients (6.4%); no cases required percutaneous drainage. Clinical success was comparable between unilateral and bilateral drainage (66.7% vs. 72.4%, p = 0.75). AEs occurred in 27.7% (13/47), mainly cholangitis (25.5%), with one hepatic abscess. ROC analysis identified baseline bilirubin >224 µmol/L as predictive of lower clinical success (AUC 0.61), whereas metastatic burden and drainage pattern were not associated with outcome. Clinical success did not differ by drainage modality (ERCP: 66.7%; EUS-BD: 75.0%; combined: 100%; p = 0.46).

Endoscopic biliary drainage in patients with mCRC-related malignant obstruction achieved high technical success and acceptable early biochemical response across all drainage modalities. Most adverse events were manageable. Elevated baseline bilirubin was the only factor associated with reduced early clinical success, while drainage approach and metastatic burden showed no significant impact. These findings support a flexible endoscopic strategy tailored to anatomy and expertise, as outcomes were comparable across procedure types.