Association of subcutaneous adiposity with survival outcomes in advanced biliary tract cancer treated with gemcitabine, cisplatin, and immune checkpoint inhibitor.

Stage cholangiocarcinoma with multiphasic MRI/MRCP plus CT chest/abdomen/pelvis, obtain tissue via ERCP brush cytology with FISH, cholangioscopy-directed biopsy, or EUS-FNA (avoiding primary perihilar tumor sampling if liver transplant is being considered due to theoretical seeding risk), and manage through a multidisciplinary tumor board with treatment stratified by tumor location: resect (anatomic hepatectomy for intrahepatic, hemihepatectomy with bile duct resection for perihilar, Whipple for distal) with adjuvant capecitabine (category 1, per BILCAP) when resectable. For unresectable or metastatic disease, first-line systemic therapy is gemcitabine plus cisplatin combined with a PD-L1/PD-1 checkpoint inhibitor, either durvalumab (TOPAZ-1) or pembrolizumab (KEYNOTE-966), both listed as category 1 preferred options by NCCN; comprehensive molecular/genomic profiling is recommended for all unresectable/metastatic candidates for systemic therapy to identify actionable targets (e.g., FGFR2 fusions, IDH1 mutations, HER2 amplification) for later-line therapy. Selected unresectable early-stage perihilar tumors may undergo neoadjuvant chemoradiation and liver transplant per the Mayo Clinic protocol at experienced centers, and jaundice or cholangitis is managed with biliary drainage (ERCP preferred over PTC).