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KEY CONCEPTS
Biliary tract cancers are rare tumors (prevalence <6/100,000 persons/year) with significant geographic variability.
Risk factors include cholelithiasis, polyps, porcelain gallbladder, chronic inflammatory states such as inflammatory bowel disease, primary sclerosing cholangitis and nonalcoholic steatohepatitis, genetic syndromes (Peutz-Jeghers or Gardner syndrome), and chronic infection (Salmonella typhi carriers, Opisthorchis viverrine, and Clonorchis sinensis, particularly in Southeast Asia, hepatitis B and C).
Five-year overall survival rates post R0 resection range from 40% to 50%. High-risk features include positive lymph nodes/margins, vascular invasion, and multifocal disease.
In localized disease, a multimodality approach is often used:
In early-stage intrahepatic cholangiocarcinoma, surgical resection with nodal dissection is followed by adjuvant capecitabine or gemcitabine-cisplatin; radiation therapy is given postoperatively for positive margins.
Neoadjuvant chemotherapy is considered for high-risk features.
In clinical practice, combination chemotherapy (gemcitabine-cisplatin or gemcitabine-capecitabine) is used adjuvantly, particularly in node-positive disease or R1 resection.
Systemic therapy in metastatic disease is guided largely by molecular profiling and actionable targets. FGFR, IDH1, HER2, and BRAF alterations are among the most enriched, and numerous clinical trial options are available for these patients.
Cholangiocarcinoma has low rates of high microsatellite instability and programmed cell death ligand 1 positivity. It remains overall a “cold tumor,” though methods to improve immune cell infiltration and predict responders to immunotherapy are underway.
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Biliary Tract Cancers
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Biliary tract cancers include gallbladder carcinoma and cholangiocarcinoma, both of which arise from the ductal epithelium. Cholangiocarcinomas are further classified based on their anatomic site as intrahepatic, perihilar, and distal types (Fig. 29–1). Intrahepatic cholangiocarcinoma (ICC) occurs in the bile ducts proximal to the confluence of the right and left hepatic ducts. Perihilar cholangiocarcinoma includes the ductal confluence up to the origin of the cystic duct from the common bile duct, whereas distal cholangiocarcinoma includes the bile duct below the cystic duct origin to the ampulla of Vater. The incidence of these anatomic types varies—perihilar cholangiocarcinoma occurs most frequently, followed by the extrahepatic distal and intrahepatic types. Cholangiocarcinoma has been subclassified by the Liver Cancer Study Group of Japan according to the growth pattern and macroscopic appearance of the tumor into three types as mass-forming, periductal-infiltrating, and intraductal growth types.1 The mass-forming type has an expansive pattern of growth, whereas the periductal-infiltrating type of tumor extends toward the portal pedicle. The intraductal type spreads along the mucosal layer and is associated with abundant mucin production.
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At a microscopic level, cholangiocarcinoma is adenocarcinoma consisting of tubules, acini, solid nests, or trabeculae embedded within a desmoplastic stroma.2 Other types are exceedingly rare and include adenosquamous and squamous carcinomas that arise in metaplastic epithelium and from liver cysts. Adenocarcinoma, particularly ICC, is radiologically indistinguishable from metastatic tumors ...