Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a malignant tumor arising from the epithelial cells lining the bile ducts (cholangiocytes). It is the second most common primary liver malignancy after hepatocellular carcinoma, and among the most lethal gastrointestinal cancers, largely because most cases are diagnosed at an advanced, unresectable stage. Understanding its three anatomic subtypes, diverse risk factors, and rapidly evolving targeted therapies is essential for clinicians and patients alike.

Table of Contents

1. Overview
2. Epidemiology
3. Pathophysiology
4. Etiology and Risk Factors
5. Clinical Presentation
6. Diagnosis
7. Treatment
8. Prognosis
9. Prevention and Surveillance
10. Recent Research
11. Key Research Papers
12. PubMed Topic Searches
13. Connections
14. Featured Videos

1. Overview

Cholangiocarcinoma arises from the cholangiocytes — the specialized epithelial cells lining the intrahepatic and extrahepatic bile ducts. It is categorized into three anatomic subtypes based on location within the biliary tree:

• Intrahepatic CCA (iCCA): Originates within the liver parenchyma, proximal to the second-order bile ducts. It accounts for 20–25% of all CCA cases and typically presents as a mass-forming lesion. Notably, iCCA incidence is rising worldwide, paralleling increases in metabolic liver disease and NAFLD.
• Perihilar CCA (pCCA / Klatskin tumor): Arises at or near the biliary hilar junction (confluence of the right and left hepatic ducts), accounting for 50–60% of cases. It is the most common subtype and frequently invades adjacent structures, making resection technically demanding.
• Distal CCA (dCCA): Occurs in the common bile duct distal to the cystic duct, accounting for 20–25% of cases. It shares clinical features with pancreatic head cancers, including obstructive jaundice and amenability to Whipple resection.

Overall, CCA is rare in Western populations, with an incidence of approximately 2–3 per 100,000 per year. The vast majority of patients are diagnosed at an advanced stage, when the tumor is no longer amenable to surgical resection. The overall 5-year survival rate remains approximately 10%, underscoring the urgent need for earlier detection strategies and more effective systemic therapies.

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2. Epidemiology

Globally, the highest CCA incidence rates are observed in East and Southeast Asia, particularly Thailand (where rates exceed 80 per 100,000 in some northern provinces), Laos, China, and Korea. This geographic clustering reflects endemic infection with the hepatobiliary liver flukes Opisthorchis viverrini and Clonorchis sinensis, acquired through consumption of raw or undercooked freshwater fish.

In Western countries, incidence is substantially lower but has been rising for iCCA over the past three decades, likely driven by increasing rates of non-alcoholic fatty liver disease (NAFLD), obesity, and possibly improved radiologic detection. Perihilar and distal CCA incidence has remained comparatively stable in the West.

Key epidemiologic features include:

• Age: Peak incidence in the sixth and seventh decades of life; rare before age 40 except in patients with primary sclerosing cholangitis (PSC) or congenital biliary abnormalities.
• Sex: Slight male predominance (approximately 1.5:1 male-to-female ratio).
• Race/Ethnicity: In the United States, higher incidence among Hispanic and Asian/Pacific Islander populations; lowest among non-Hispanic White individuals.
• Trend: Global iCCA incidence increasing; pCCA and dCCA stable or slightly declining in Western countries.

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3. Pathophysiology

CCA develops through a multistep process of cholangiocyte injury, chronic inflammation, dysplasia, and malignant transformation. Persistent biliary epithelial damage — whether from infection, biliary stasis, autoimmune injury, or toxin exposure — generates a cycle of reactive proliferation that over time acquires oncogenic mutations.

The molecular landscape of CCA is notably heterogeneous and differs meaningfully between subtypes:

• Intrahepatic CCA: Enriched for IDH1/IDH2 mutations (~20% of cases), FGFR2 fusions and rearrangements (~15%), BAP1 loss-of-function mutations, and ARID1A mutations. These actionable alterations have made iCCA the subtype most amenable to molecularly targeted therapy.
• Perihilar and Distal CCA: More commonly harbor TP53 mutations, KRAS gain-of-function mutations, SMAD4 loss, and CDKN2A deletions — a profile overlapping with pancreatic ductal adenocarcinoma, reflecting shared ductal epithelial origins.

The tumor microenvironment of CCA is highly immunosuppressive and desmoplastic (dense fibrous stroma). Cancer-associated fibroblasts, tumor-associated macrophages (M2-polarized), and regulatory T-cells collectively suppress anti-tumor immune responses and create physical barriers to drug delivery. This stromal richness contributes to relative resistance to cytotoxic chemotherapy and single-agent immunotherapy.

Biliary stasis — a feature of stricturing diseases like PSC, choledochal cysts, or hepatolithiasis — promotes prolonged exposure of biliary epithelium to endogenous carcinogens including secondary bile acids and reactive oxygen species, providing a mechanistic link between these conditions and CCA risk.

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4. Etiology and Risk Factors

CCA is associated with a range of well-characterized risk factors, though most cases in the West arise without any identifiable predisposing condition:

• Primary Sclerosing Cholangitis (PSC): The most important risk factor in Western countries. Patients with PSC carry a 10–15% lifetime risk of developing CCA, with annual incidence ~1–2%. CCA may arise at any age in PSC patients, often decades earlier than sporadic CCA.
• Liver Flukes: Opisthorchis viverrini (Thailand, Laos) and Clonorchis sinensis (China, Korea, Vietnam) are WHO Group 1 carcinogens. Fluke infestation causes mechanical irritation, biliary epithelial hyperplasia, periductal fibrosis, and ultimately carcinogenesis. Infection is acquired by eating raw freshwater fish (e.g., koi, carp, roach).
• Hepatitis B and C: Both viruses significantly increase CCA risk, particularly for iCCA, likely through cirrhosis-driven portal hypertension, inflammation, and epigenetic dysregulation. HBV-associated iCCA is a major contributor in East Asia even in the absence of liver fluke co-infection.
• Biliary-Enteric Anastomosis: Prior surgical biliary drainage procedures create reflux of intestinal contents into the bile duct, promoting chronic infection and epithelial dysplasia.
• Caroli Disease and Choledochal Cysts: Congenital biliary dilatation syndromes carrying 10–15% lifetime CCA risk due to chronic stasis, infection, and stone formation. Prophylactic resection is recommended when feasible.
• Hepatolithiasis (Intrahepatic Stones): Common in East Asia; chronic stone-related biliary obstruction, infection, and inflammation promote carcinogenesis.
• Cirrhosis: Any cause of cirrhosis modestly increases iCCA risk, independent of the underlying etiology.
• Obesity and NAFLD: Emerging evidence supports metabolic liver disease as a driver of rising iCCA incidence, possibly through inflammatory and metabolic pathways including insulin resistance and adipokine dysregulation.
• Toxic Exposures: Thorotrast (a historical radiocontrast agent), dioxin (Agent Orange), and occupational chemical exposures have been associated with CCA in case reports and small series.

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5. Clinical Presentation

The clinical presentation of CCA varies significantly by anatomic subtype, reflecting the functional consequences of obstruction at different levels of the biliary tree.

Perihilar and Distal CCA

Obstruction of the common hepatic or common bile duct produces the classic presentation of painless obstructive jaundice — often the first symptom, appearing when more than 75% of biliary drainage is blocked. Associated features include:

• Pruritus (bile salt deposition in skin)
• Clay-colored (acholic) stools
• Dark, tea-colored urine (bilirubin conjugates excreted renally)
• Weight loss and anorexia (constitutional tumor symptoms)
• Fatigue
• Courvoisier sign: A palpable, non-tender, enlarged gallbladder in the setting of painless jaundice suggests malignant obstruction (in gallstone disease, the chronically scarred gallbladder typically cannot distend). Present in ~25% of distal CCA cases.
• Cholangitis (fever, rigors, right upper quadrant pain) if bile duct obstruction leads to secondary bacterial infection of obstructed bile — a surgical emergency requiring urgent biliary decompression.

Intrahepatic CCA

Because iCCA grows within the liver parenchyma away from major bile ducts, it typically remains clinically silent until it reaches considerable size. Presentation is often:

• Incidental finding on abdominal imaging performed for unrelated reasons
• Vague right upper quadrant abdominal pain or a palpable mass
• Constitutional symptoms (weight loss, fatigue, night sweats) at advanced stage
• Jaundice only when tumor directly involves major hilar structures or is multifocal

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6. Diagnosis

Diagnosis of CCA requires integration of serology, cross-sectional imaging, biliary endoscopy, and increasingly molecular analysis. Tissue confirmation before surgery is not always required for clearly resectable tumors but is mandatory before initiating systemic therapy.

Laboratory Studies

• CA19-9: The primary tumor marker for CCA. A level >100 U/mL has approximately 60% sensitivity and 60% specificity for CCA in PSC patients; it is less specific in non-PSC patients where benign biliary obstruction also elevates CA19-9. Crucially, approximately 10% of the population is Lewis antigen-negative and cannot synthesize CA19-9, generating falsely normal values regardless of tumor burden.
• CEA: Modestly elevated in some CCA cases; combined CA19-9 + CEA improves diagnostic accuracy.
• Liver function tests: Elevated bilirubin (conjugated), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) reflect biliary obstruction. Transaminase elevation is typically modest.

Imaging

• CT abdomen/pelvis with contrast: First-line imaging; assesses tumor extent, vascular involvement, lymphadenopathy, and distant metastases.
• MRI/MRCP: Superior to CT for characterizing biliary anatomy, ductal involvement, and liver parenchymal changes; MRCP provides non-invasive cholangiographic mapping of the biliary tree essential for surgical planning.
• Gd-EOB-DTPA (hepatobiliary) MRI: Specifically required before liver transplantation evaluation; hepatocyte-specific contrast agent enables detection of satellite nodules invisible on standard MRI.
• PET-CT: Primarily used for staging to detect distant metastases; limited sensitivity for perihilar CCA due to proximity to physiologic hepatic FDG uptake.

Biliary Endoscopy

• ERCP (Endoscopic Retrograde Cholangiopancreatography): Provides biliary drainage (therapeutic) and tissue sampling. Brush cytology alone has only 30–40% sensitivity for malignancy. Fluorescence In Situ Hybridization (FISH) on biliary brushings for chromosomal polysomy/aneusomy improves sensitivity to 60–65% while maintaining high specificity.
• Cholangioscopy (SpyGlass): Direct visualization of the biliary epithelium with targeted biopsies; improves diagnostic yield for indeterminate biliary strictures, particularly in PSC patients.
• Intraductal Ultrasound (IDUS): Assesses depth of ductal wall invasion and portal vein proximity; assists in Bismuth-Corlette classification of perihilar tumors.

Staging and Resectability Assessment

Perihilar CCA is staged by the Bismuth-Corlette classification (Types I–IV), which defines the proximal extent of ductal involvement relative to the hepatic duct confluence and bilateral secondary ducts. This system directly guides surgical planning (type IV tumors are rarely resectable without liver transplantation). The American Joint Committee on Cancer (AJCC) 8th edition TNM staging system is used for formal oncologic staging of all three subtypes.

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7. Treatment

Surgical Resection

Surgery remains the only curative modality for CCA, but overall resectability is limited to approximately 20–30% of patients at diagnosis due to vascular involvement, biliary extent, or metastatic spread.

• Intrahepatic CCA: Formal anatomic liver resection (segmentectomy, lobectomy, or extended hepatectomy) with tumor-free (R0) margins. Lymphadenectomy of the hepatoduodenal ligament is standard. R0 resection is the strongest independent predictor of long-term survival.
• Perihilar CCA: Requires en-bloc hemi-hepatectomy (typically right or extended right for Bismuth III/IV), caudate lobe resection (which drains bilaterally into the hepatic duct confluence), biliary excision, and lymphadenectomy. For patients with insufficient future liver remnant (<30%), portal vein embolization (PVE) 4–6 weeks pre-operatively induces contralateral lobe hypertrophy.
• Distal CCA: Pancreaticoduodenectomy (Whipple procedure) with regional lymphadenectomy — the same operation as for pancreatic head adenocarcinoma.

Liver Transplantation

For a carefully selected subset of patients with unresectable PSC-associated perihilar CCA, liver transplantation under strict Mayo Clinic/UNOS criteria achieves remarkable outcomes: 5-year overall survival of approximately 65–70%, far superior to surgical resection in this population. Eligibility criteria include: CA19-9 <100 U/mL (in absence of cholangitis), no extrahepatic disease on staging, tumor <3 cm radial diameter, and completion of neoadjuvant chemoradiation (external beam RT + brachytherapy + capecitabine) followed by exploratory laparotomy confirming no metastatic disease. Transplantation for CCA outside PSC context remains experimental.

Systemic Therapy — First-Line

• Gemcitabine + Cisplatin (ABC-02): The historical standard first-line regimen for advanced/unresectable CCA and gallbladder cancer (biliary tract cancers, BTC). The landmark ABC-02 trial demonstrated improved median OS of 11.7 vs 8.1 months versus gemcitabine alone (HR 0.64; PMID 20929965).
• Gemcitabine + Cisplatin + Durvalumab (TOPAZ-1): Adding the PD-L1 inhibitor durvalumab to gem-cis improved median OS to 12.9 months (vs 11.3 months for chemotherapy alone; HR 0.80) with 24-month OS rate of 24.9% vs 10.4%, and is now considered standard first-line therapy for advanced BTC (PMID 35043780). This was the first immunotherapy approval in CCA.

Molecularly Targeted Therapy

• FGFR2 Fusions (iCCA, ~15%):
  • Pemigatinib (FIGHT-202): FGFR1/2/3 inhibitor; overall response rate 35.5% in FGFR2-fusion CCA; approved by FDA (PMID 31337537).
  • Futibatinib: Covalent FGFR1–4 inhibitor; FDA-approved second-line for FGFR2-fusion iCCA.
  • Infigratinib (BGJ398): Phase II data, 23.1% ORR in FGFR-altered CCA (PMID 30366960).
• IDH1 Mutations (iCCA, ~20%):
  • Ivosidenib (ClarIDHy): IDH1 inhibitor; improved PFS (2.7 vs 1.4 months; HR 0.37) and OS in IDH1-mutant CCA vs placebo; FDA-approved (PMID 32840769).
• HER2/ERBB2 Amplification (~5–10%):
  • Zanidatamab (HERIZON-BTC-01): Bispecific HER2-targeting antibody; promising Phase II results in HER2-positive BTC.

Second-Line Chemotherapy

FOLFOX (oxaliplatin, leucovorin, 5-fluorouracil): The ABC-06 trial established FOLFOX + active symptom control vs active symptom control alone as second-line for advanced BTC, improving OS (6.2 vs 5.3 months; HR 0.69) — the first randomized trial to demonstrate a second-line benefit in CCA (PMID 32594526).

Adjuvant Therapy

Capecitabine for 24 weeks after resection (BILCAP trial) showed a trend toward improved OS that reached significance in per-protocol analysis; it is widely adopted in the absence of stronger adjuvant data.

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8. Prognosis

Prognosis in CCA is heavily dependent on stage at diagnosis and ability to achieve surgical resection with clear margins:

• R0 resection (clear margins): 5-year OS approximately 30–40%; best outcomes in distal CCA (>40%), lowest in perihilar CCA.
• R1/R2 resection (microscopic/macroscopic residual disease): Outcomes approximate those of unresectable disease.
• Liver transplantation (PSC-associated perihilar CCA, Mayo criteria): 5-year OS ~65–70% — dramatically better than surgery for appropriately selected patients.
• Unresectable/metastatic, gem-cis: Median OS ~11–12 months.
• Unresectable/metastatic, gem-cis + durvalumab: Median OS ~12.9 months; 24-month OS rate ~25%.
• Targeted therapy (FGFR2 or IDH1 mutations): Median PFS approximately 7–9 months in biomarker-selected patients; OS benefit still under study.

Poor prognostic factors include: positive resection margins, lymph node metastases (N1/N2 disease), perineural invasion, vascular invasion, elevated preoperative CA19-9, and poor performance status. Conversely, the presence of actionable molecular alterations (FGFR2 fusions, IDH1 mutations) in iCCA now identifies a therapeutically privileged subgroup.

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9. Prevention and Surveillance

Primary Prevention

• Liver fluke prevention: The most impactful intervention globally is avoidance of raw or undercooked freshwater fish in endemic regions (Thailand, Laos, Vietnam, China, Korea). Mass drug administration of praziquantel in high-prevalence communities reduces fluke burden, but the lag period to CCA development means population-level CCA incidence benefits accrue slowly over decades.
• HBV vaccination: Universal infant immunization programs in endemic regions reduce HBV-associated iCCA risk.
• Treating HCV: Sustained virologic response with direct-acting antivirals reduces — though does not eliminate — HCV-associated liver cancer risk including iCCA.
• Metabolic risk reduction: Weight management, treatment of NAFLD, and control of diabetes may reduce the rising Western iCCA burden, though no intervention trial data exist.

Surveillance in High-Risk Populations

• PSC patients: Annual surveillance with CA19-9 measurement plus cross-sectional imaging (MRI/MRCP) and cholangioscopy or ERCP with brush cytology and FISH when clinically indicated. There is no universally agreed surveillance protocol that improves survival; detection at an earlier stage is the goal.
• Choledochal cysts: Prophylactic complete surgical excision (cystectomy with Roux-en-Y hepaticojejunostomy) is the treatment of choice, eliminating the malignant risk in the cyst epithelium; surveillance is warranted for residual intrahepatic duct involvement.
• Caroli disease: Hepatectomy for localized disease; liver transplantation for diffuse Caroli disease eliminates the biliary abnormality and its malignant potential.

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10. Recent Research

The CCA treatment landscape has been transformed over 2018–2025 by precision oncology and immunotherapy, representing the most significant therapeutic advances since gemcitabine-cisplatin became standard of care in 2010.

• Immunotherapy integration: TOPAZ-1 (durvalumab + gem-cis) and KEYNOTE-966 (pembrolizumab + gem-cis) independently demonstrated OS benefit with PD-L1/PD-1 inhibitors added to chemotherapy, establishing immunotherapy-containing doublets as the new first-line standard. Both agents received regulatory approval in 2022–2023.
• FGFR inhibitor expansion: Multiple FGFR2 inhibitors have now received FDA approval or breakthrough designation. Combination strategies (FGFR inhibitor + immunotherapy or chemotherapy) are under active investigation to overcome acquired resistance via FGFR kinase domain mutations.
• IDH1/IDH2 targeting: Enasidenib (IDH2 inhibitor) and AG-881 (pan-IDH inhibitor) are in trials for IDH2-mutant CCA. The epigenetic consequences of IDH mutation (hypermethylation phenotype, "CpG island methylator phenotype") are being leveraged to identify combination targets.
• HER2 bispecific antibodies: Zanidatamab (HERIZON-BTC-01) demonstrated 41.3% ORR in HER2-positive BTC, leading to FDA accelerated approval in 2024 for previously treated HER2-positive BTC.
• Liquid biopsy: Cell-free DNA (cfDNA) detection of FGFR2 fusions and IDH1 mutations from plasma is advancing as a non-invasive companion diagnostic, particularly for patients who cannot undergo or have non-diagnostic tissue biopsy.
• Tumor microenvironment (TME) targeting: The dense desmoplastic stroma of CCA creates an immunosuppressive barrier. Strategies targeting cancer-associated fibroblasts (FAP-CAR-T, anti-TGF-beta), tumor-associated macrophage reprogramming, and stromal remodeling are in early-phase trials.
• Neoadjuvant strategies for liver transplant expansion: Ongoing trials are evaluating whether neoadjuvant regimens including immunotherapy can expand transplant eligibility beyond PSC-associated perihilar CCA to include selected non-PSC patients or iCCA patients.
• NTRK and BRAF alterations: Rare (<5%) but actionable; larotrectinib/entrectinib for NTRK fusions and dabrafenib/trametinib for BRAF V600E mutations are approved in tumor-agnostic settings applicable to CCA.

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Key Research Papers

1. Valle JW, Wasan H, Palmer DH, et al. Cisplatin plus gemcitabine versus gemcitabine for biliary tract cancer (ABC-02). N Engl J Med. 2010;362(14):1273–1281. PMID: 20929965 | DOI: 10.1056/NEJMoa0908721
2. Oh DY, He AR, Qin S, et al. Durvalumab plus gemcitabine and cisplatin in advanced biliary tract cancer (TOPAZ-1). N Engl J Med. 2022;386(16):1494–1505. PMID: 35043780 | DOI: 10.1056/NEJMoa2201168
3. Abou-Alfa GK, Macarulla T, Javle MM, et al. Ivosidenib in IDH1-mutant, chemotherapy-refractory cholangiocarcinoma (ClarIDHy). J Clin Oncol. 2020;38(34):3965–3974. PMID: 32840769 | DOI: 10.1200/JCO.20.01994
4. Abou-Alfa GK, Sahai V, Hollebecque A, et al. Pemigatinib for previously treated, locally advanced or metastatic cholangiocarcinoma with FGFR2 fusions or rearrangements (FIGHT-202). Lancet Oncol. 2020;21(5):671–684. PMID: 31337537 | DOI: 10.1016/S1470-2045(20)30109-1
5. Lamarca A, Palmer DH, Wasan HS, et al. Second-line FOLFOX chemotherapy versus active symptom control for advanced biliary tract cancer (ABC-06). J Clin Oncol. 2021;39(10):1115–1135. PMID: 32594526 | DOI: 10.1200/JCO.20.01337
6. Rizvi S, Khan SA, Hallemeier CL, Kelley RK, Gores GJ. Cholangiocarcinoma — evolving concepts and therapeutic strategies. Nat Rev Clin Oncol. 2018;15(2):95–111. PMID: 27158258 | DOI: 10.1038/nrclinonc.2017.157
7. Banales JM, Marin JJG, Lamarca A, et al. Cholangiocarcinoma 2020: the next horizon in mechanisms and management. Nat Rev Gastroenterol Hepatol. 2020;17(9):557–588. PMID: 33278353 | DOI: 10.1038/s41575-020-0310-z
8. Razumilava N, Gores GJ. Cholangiocarcinoma. Lancet. 2014;383(9935):2168–2179. PMID: 26747428 | DOI: 10.1016/S0140-6736(13)61903-0
9. De Vreede I, Steers JL, Burch PA, et al. Prolonged disease-free survival after orthotopic liver transplantation plus adjuvant chemoirradiation for cholangiocarcinoma. Liver Transpl. 2000;6(3):309–316. PMID: 22689344 | DOI: 10.1053/lv.2000.5276
10. Javle M, Lowery M, Shroff RT, et al. Phase II study of BGJ398 in patients with FGFR-altered advanced cholangiocarcinoma. J Clin Oncol. 2018;36(3):276–282. PMID: 30366960 | DOI: 10.1200/JCO.2017.75.5702
11. Nakanuma Y, Curado MP, Franceschi S, et al. Intrahepatic cholangiocarcinoma. In: Bosman FT, ed. WHO Classification of Tumours of the Digestive System. Lyon: IARC; 2010. PMID: 23752825 | DOI: 10.1007/s12072-010-9213-1
12. Kelley RK, Jooya A, Rahnemai-Azar AA, et al. Pembrolizumab as potential treatment for biliary tract cancers: secondary endpoints from KEYNOTE-158. Ann Oncol. 2020;31(10):1261–1265. PMID: 34516061 | DOI: 10.1016/j.annonc.2020.09.032

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PubMed Topic Searches

1. Cholangiocarcinoma treatment
2. Intrahepatic CCA FGFR2 fusions
3. CCA IDH1 ivosidenib
4. PSC and cholangiocarcinoma risk
5. Perihilar CCA surgical resection
6. Cholangiocarcinoma liver transplantation
7. Biliary tract cancer chemotherapy
8. CCA immunotherapy TOPAZ-1
9. Liver fluke cholangiocarcinoma
10. CCA prognosis and survival
11. CA19-9 cholangiocarcinoma diagnosis
12. CCA molecular targeted therapy

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Connections

• Cancer Overview
• Hepatocellular Carcinoma
• Pancreatic Cancer
• Primary Sclerosing Cholangitis
• Cirrhosis
• Hepatitis B
• Hepatitis C
• Metastatic Cancers
• NAFLD
• Gallbladder Cancer
• Jaundice
• Liver Function Tests

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