Gallbladder cancer and cholangiocarcinoma are aggressive biliary malignancies with poor prognoses, due to their insidious onset and late-stage diagnosis. Early detection is critical for improving survival outcomes yet remains challenging as early disease lacks specific symptoms and can mimic benign conditions. This article highlights the importance of risk stratification and multimodality imaging in the early identification of these cancers. Emerging strategies integrating artificial intelligence and deep learning models show promise in augmenting diagnostic accuracy. A multidisciplinary approach combining risk-based surveillance, standardized high-quality imaging, and novel diagnostic technologies is essential to bridge the gap in early detection and improve patient outcomes.
Key points
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Gallbladder cancer (GBC) and cholangiocarcinoma (CCA) have poor prognoses primarily due to late diagnosis; early detection is critical for improving outcomes.
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High-risk populations warrant targeted surveillance, particularly in geographic hotspots.
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Common risk factors include gallstones, polyps greater than 1 cm, primary sclerosing cholangitis (PSC) for GBC and PSC, choledochal cyst, and liver flukes for CCA.
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Multimodality imaging algorithms with ultrasound (US), contrast-enhanced US, computed tomography, and MR imaging/magnetic resonance cholangiopancreatography (MRCP) with diffusion weighted imaging provide complementary information for early detection.
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Advanced radiological techniques and endoscopic techniques, including endoscopic US, intraductal US, and intraductal cholangioscopy, with targeted sampling and genetic testing, improve diagnostic accuracy.
Abbreviations
| AUC | areas under the curve |
| BilIN | biliary intraepithelial neoplasia |
| CCA | cholangiocarcinoma |
| CEUS | contrast-enhanced ultrasound |
| CT | computed tomography |
| DECT | dual-energy computed tomography |
| EUS | endoscopic ultrasound |
| GBC | gallbladder cancer |
| GB-RADS | gallbladder reporting and data system |
| ICCA | intrahepatic cholangiocarcinoma |
| ICPN | intracholecystic papillary neoplasm |
| IDUS | intraductal ultrasound |
| IPNB | intraductal papillary neoplasm of the bile duct |
| PSC | primary sclerosing cholangitis |
| US | ultrasound |
| XGC | xanthogranulomatous cholecystitis |
Introduction
Gallbladder cancer (GBC) and cholangiocarcinoma (CCA) are aggressive biliary tract malignancies with low 5-year survival rates, primarily attributable to their insidious onset and silent clinical course. The diagnostic challenge lies in the lack of specific symptoms during early stages; GBC frequently develops against a background of chronic inflammation, where early flat lesions or precursor polyps are often overlooked on conventional imaging. , Consequently, over two-thirds of early GBCs are diagnosed incidentally during cholecystectomy performed for presumed benign conditions. Similarly, CCA typically manifests only after causing biliary obstruction, making early diagnosis difficult even in high-risk populations, such as those with primary sclerosing cholangitis (PSC).
While surgical resection remains the only curative treatment, the majority of patients present with unresectable disease due to late diagnosis. This underscores the urgent need for accurate risk stratification to identify individuals who would benefit most from surveillance. This article covers the epidemiology, risk factors, and clinical algorithms for the early detection of GBC and CCA. It evaluates current and emerging strategies, including multimodality imaging with ultrasound (US), computed tomography (CT), and MR imaging, to aid in early diagnosis and the differentiation of malignancy from benign conditions.
Epidemiology
GBC demonstrates particularly high incidence rates among indigenous populations in South America, northern India, and East Asia. The highest GBC incidence rates are found in women from India (21.5 per 100,000), Chile (18.1 per 100,000), Pakistan (13.8 per 100,000), and Ecuador (12.9 per 100,000). The age adjusted incidence rate in North America is 0.65 per 100,000. Similarly, CCA incidence shows global variation with the highest global incidence in Asian countries, especially North East Thailand (85 cases per 100,000), North and Central Thailand (14.5 cases per 100,000), and South Korea (8.8 cases per 100,000), while Western nations report significantly lower rates (range 0.5–3.4). This geographic disparity reflects the complex interplay of genetic, environmental, and lifestyle factors that contribute to disease development. Globally, there is increase in the incidence rates of CCA, partly attributable to increased risk factors for chronic liver disease, including alcohol consumption, tobacco smoking, chronic viral infections (hepatitis B and C viruses), and metabolic syndrome.
Risk stratification and high-risk populations
Gallbladder Cancer
GBC is most strongly associated with gallstones, present in up to 90% of cases at diagnosis, yet less than 1% of those with gallstones develop GBC, indicating additional cofactors are required for development of malignancy. Higher risk correlates with large stones (>3 cm), long disease duration, and chronic inflammation. Demographic factors—female gender (3:1), age over 50, lower socioeconomic status, and multiparity—further elevate risk. Environmental and geographic factors, including residence in high-incidence areas (Gangetic belt of India, Chile, and Bolivia), heavy metal contamination, and aflatoxin exposure, contribute to a fivefold increased risk. Lifestyle choices like mustard oil consumption, tobacco use, and physical inactivity also play a role. Porcelain gallbladder’s association with GBC is now considered modest (2%–3%), depending on calcification patterns. Gallbladder polyps have a low overall malignancy risk, although larger polyps (>10 mm) carry higher rates (unadjusted GBC rate per 100,000 person-years of 1.3 for polyps < 6 mm vs 128.2 for polyps ≥10 mm). ,,, A 20-year study found GBC rates per 100,000 person-years were 11.3 overall, increasing with polyp size, but rates were similar in patients with and without polyps. Anomalous pancreaticobiliary duct junction (defined as congenital malformation in which there is anomalous junction of the pancreatic and bile ducts outside the duodenal wall) fosters carcinogenesis via chronic reflux and inflammation.
Cholangiocarcinoma
PSC is the major risk factor for CCA in Western countries, conferring a 22-fold increased risk; annual incidence is 0.5% to 1.5%, lifetime risk up to 6% to 13%. Other risk factors include congenital anomalies (choledochal cysts, bile duct adenomas, and Caroli disease), hepatolithiasis, and chronic liver fluke infection (Opisthorchis viverrini and Clonorchis sinensis) in endemic regions. Additional contributors are prior thorotrast exposure, cirrhosis, chronic viral hepatitis, and bacterial infections such as Salmonella typhi and Helicobacter pylori . Recent studies link viral hepatitis, metabolic syndrome, and metabolic dysfunction-associated steatotic liver disease to increased intrahepatic CCA risk, though absolute risk remains low. Hepatitis B virus (HBV) and hepatitis C virus (HCV) seropositivity rates are significantly higher in patients with intrahepatic CCA compared to controls. , A systematic review reported odds ratio of 1.75 and 1.45 for CCA in patients with HBV and HCV, respectively. However, the association between HBV and intrahepatic cholangiocarcinoma (ICC) has not been consistently found in the studies on American population. ,
Risk-Based Surveillance Recommendations
In high-risk geographic areas for GBC, no formal screening guidelines exists, but investigation thresholds should be lower for symptomatic patients with gallstones or incidentally detected gallbladder wall thickening or polyps. Surveillance for gallbladder polyps should be stratified by size and US features. The gallbladder reporting and data system (GB-RADS) aids risk stratification of wall thickening by US. For PSC, the American Association for the Study of Liver Diseases recommends annual MR imaging or MRCP screening for CCA, with or without serum biomarkers. Other guidelines suggest surveillance every 6 to 12 months via MR imaging/MRCP.
Morphologic types of gallbladder cancer and cholangiocarcinoma
GBC manifests in several morphologic types.
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Mass-forming type: Large mass replacing the gallbladder, often invading liver.
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Wall-thickening type: Focal or diffuse wall thickening.
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Intraluminal polypoid type: Discrete polypoid lesion projecting into the lumen.
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Combined type: Features of both mass-forming and wall-thickening.
CCA is classified by anatomic location (intrahepatic, perihilar, and distal) and growth pattern (mass-forming, periductal infiltrating, and intraductal growing). Intrahepatic CCA (iCCA) arises within/proximal to second-order ducts; perihilar CCA (Klatskin tumor) from the hepatic duct/confluence; distal CCA from the common bile duct (CBD). Recent classifications distinguish large duct, small duct, parenchymal, and ductal types of iCCA. Large duct iCCA often shows mucinous/papillary features, while small duct iCCA presents as mass-forming lesions unrelated to chronic inflammation.
Imaging techniques optimized for early detection and imaging features
Early detection relies on a multimodal approach: high-resolution US, multiphasic CT, advanced MR imaging/MRCP and use of emerging endoscopic/radiomics modalities ( Table 1 ). Standardization of reporting systems are integral in early detection paradigm (GB-RADS, and Society of Radiologists in Ultrasound [SRU] polyp risk) to facilitate improved communication of findings with the referring providers and streamline effective management ( Table 2 ).
Table 1
Comparative utility of imaging modalities in biliary tract malignancy
| Diagnostic Task | Ultrasound | Contrast-Enhanced Ultrasound | Computed Tomography | MR Imaging/MRCP | PET/Computed Tomography |
|---|---|---|---|---|---|
| Initial screening | +++ | + | + | + | – |
| Gallbladder wall thickening characterization | +++ | +++ | ++ | +++ | + |
| Polyp characterization | +++ | +++ | ++ | +++ | + |
| Biliary extent | + | – | ++ | +++ | – |
| Vascular involvement | + | – | +++ | +++ | – |
| Lymph node assessment | + | + | ++ | ++ | +++ |
| Distant metastases | – | – | +++ | ++ | +++ |
| Treatment response | + | ++ | +++ | +++ | +++ |
– no utility; + limited utility; ++ moderate utility; +++ high utility.
Table 2
Gallbladder reporting and data system for gallbladder wall thickening on ultrasound
| Score | Risk Category | Lexicon Descriptors |
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| 0 | Inadequate evaluation |
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| 1 | Normal |
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| 2 | Benign |
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| 3 | Equivocal |
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| 4 | Malignancy is likely |
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| 5 | Malignancy is highly likely |
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Ultrasound
Transabdominal US is first-line modality for diagnosis early gallbladder and biliary lesions, with convex and high-frequency linear transducers, and harmonic imaging enhancing subtle wall assessment. Sensitivity varies with disease stage; wall-thickening types of GBC are challenging to diagnose accurately. GB-RADS standardizes evaluation of wall thickening by features such as intramural cysts, echogenic foci, and liver interface ( Fig. 1 , Table 3 ). Validation studies show improved sensitivity/specificity for diagnosing GBC when gray scale US is combined with color Doppler. ,, Doppler enhances detection of vascular flow. Malignant lesions show higher velocities (>20 cm/s), though quantification is challenging.
GB-RADS for gallbladder wall-thickening on US. ( A ) Axial US image shows diffuse gallbladder wall thickening with mural layering ( arrow ) (GB-RADS 2). ( B ) Sagittal US image shows mural thickening along the peritoneal aspect of body of gallbladder with intramural cyst ( arrow ) (GB-RADS) 2). ( C ) Axial US image shows diffuse mural thickening of the gallbladder body with extensive intramural echogenic foci. Based on the presence of intramural echogenic foci, the lesion can be classified as GB-RADS 2. However, note that there is indistinct interface with the adjacent liver parenchyma ( arrows ) suggesting that it is a GB-RADS 4 lesion. ( D–F ) Sagittal US image shows asymmetric diffuse mural thickening ( asterisk ). Note that the interface with the liver is distinct ( arrow ).
Table 3
SRU guidelines for risk stratification and management of gallbladder polyps
| Risk Category | Morphology | Polyp Size | Management |
|---|---|---|---|
| Extremely low-risk |
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≤ 9 mm | No follow-up |
| 10–14 mm | Follow-up US at 6, 12, 24 mo | ||
| ≥ 15 mm | Surgical consult | ||
| Low-risk |
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≤ 6 mm | No follow-up |
| 7–9 mm | Follow-up US at 12 mo | ||
| 10–14 mm | Follow-up US at 6, 12, 24, 36 mo vs surgical consult | ||
| ≥ 15 mm | Surgical consult | ||
| Indeterminate-risk |
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≤ 6 mm | Follow-up US at 6, 12, 24, 36 mo vs surgical consult |
| ≥ 7 mm | Surgical consult |
High-resolution US differentiates benign from malignant thickening and polyps and assesses invasion depth. Benign features include echogenic foci and preserve layering; indistinct liver interface favors malignancy. The cervix sign—mural thickening at the gallbladder neck—appears in malignant neck thickening ( Fig. 2 ), reported in 64% of malignant versus 2.7% benign cases. Polyps are stratified by size/morphology, with low-risk (pedunculated, ball-on-wall) requiring less intensive follow-up ( Fig. 3 , Table 4 ). For CCA, US is primary imaging modality for workup of jaundice and allows high fidelity detection of biliary dilatation with high accuracy for distal CCA (80%–95%) but lower for perihilar CCA. Its main role is exclusion of benign obstruction.
Sonographic cervix sign in malignant thickening of the gallbladder neck. Axial US image shows mural thickening of the neck of the gallbladder ( asterisk ) giving the appearance of cervical canal. There is infiltration into the adjacent liver parenchyma ( thin arrows ) causing biliary obstruction ( thick arrow ).
Gallbladder polyp risk stratification on ultrasound. ( A ) Extremely low risk polyp (5 mm) with ball-on-wall morphology ( arrow ). ( B ) Extremely low risk polyps (7–8 mm) ( arrow ) with ball-on-wall morphology. ( C ) Low-risk sessile polyp (9 mm) ( arrow ) along the hepatic aspect of the body of the gallbladder. There is a calculus in the lumen of gallbladder neck ( short arrow ). ( D ) Indeterminate risk polyp with adjacent mural thickening along the peritoneal aspect of the gallbladder ( arrow ).
Table 4
Advanced endoscopic imaging for cholangiocarcinoma detection
| Technique | Equipment | Protocol Highlights | Diagnostic Value |
|---|---|---|---|
| IDUS | Miniprobe (12–30 MHz) via ERCP | Insertion through working channel beyond stricture | Detailed biliary wall layers, improved T-staging |
| POC | SpyGlass or direct cholangioscope | Direct visualization with targeted biopsies | Visual diagnosis of indeterminate strictures |
| CLE | Probe-based CLE via ERCP | IV fluorescein (2.5 mL, 10%) 2–5 min before imaging | Real-time histologic assessment |
| Endoscopic Optical Coherence Tomography | Probe-based system via ERCP | Automated pullback (1–2 cm/s) | Microscopic cross-sectional imaging |
Abbreviation: CLE, confocal laser endomicroscopy.
Shear wave elastography quantifies tissue stiffness, with limited literature in GBC/CCA. ,, One study identified a cutoff of 2.7 m/s for GBC (sensitivity/specificity 100%/91.3%). GBC shows higher stiffness (mean 34.99 ±17.77 kPa) than chronic cholecystitis (12.27 ±4.13 kPa).
Contrast-Enhanced Ultrasound
Contrast enhanced US (CEUS) characterizes lesions by real-time evaluation of microvascularization. Malignant features include irregular vascularity, inhomogeneous arterial hyperenhancement, early washout (<40–60 s), mucosal destruction, and branched vessels. Benign lesions have continuous enhancement and delayed washout (>80 s). CEUS with GB-RADS achieves sensitivity/specificity of 90% to 100%/90% to 95% for early GBC, distinguishing indeterminate thickening or differentiating GBC from xanthogranulomatous cholecystitis (XGC) or adenomyomatosis. For polyps, fast wash-in/out, hyperenhancement, and wall destruction indicate malignancy with sensitivity/specificity up to 94%/93%). In chronic liver disease, CEUS aids differentiation of iCCA from hepatocellular carcinoma (HCC) using liver imaging reporting and data system (LI-RADS), though overlap with metastases is a limitation. CEUS also distinguishes tumefactive sludge from polypoidal lesions.
Computed Tomography
Multiphasic contrast-enhanced CT is standard for characterization and staging, using thin-section acquisition and multiplanar reconstruction. Early GBC on CT shows focal/asymmetric mural thickening, indistinct liver interface, and enhancement patterns—2-layered enhancement (thick inner, weak outer) or single-layered heterogeneous enhancement (see Fig. 3 ). Focal thickening with heterogeneous enhancement suggests malignancy ( Fig. 4 ). Benign thickening features continuous mucosal line, intramural cysts/nodules, and preserved liver interface ( Fig. 5 ). Signs such as pearl-necklace , hour-glass , and cotton ball suggest adenomyomatosis, better seen on MR imaging.
Enhancement characteristics of malignant gallbladder wall thickening. ( A ) Axial CT image shows mural thickening of the body and fundus of the gallbladder ( arrow ) with layered appearance with thin enhancing inner layer ( short arrow ). ( B ) Axial CT image of another patient shows heterogeneously enhancing mural thickening of the body of the gallbladder ( arrow ) with indistinct liver interface. The peritoneal aspect of the thickening shows layered appearance ( short arrow ).
Features of focal malignant gallbladder wall thickening. ( A ) Axial T2-weighted MR imaging shows mural thickening of the gallbladder body with indistinct liver interface ( arrow ). ( B ) Diffusion weighted imaging (b = 800) shows diffusion restriction ( arrow ). ( C ) Axial postcontrast T1-weighted MR imaging shows heterogeneous contrast enhancement ( arrow ).
The role of Dual-energy CT’s (DECT) in early GBC is limited ( Fig. 6 ). Despite GBC demonstrating higher mean iodine density (1.35 mg/mL) than XGC (0.85 mg/mL) it is not statistically significant. In a prospective study, DECT features did not significantly differ between benign/malignant wall thickening, except that 140 keV late arterial phase attenuation was different between XGC and GBC. CT is preferred for initial CCA assessment and staging, with excellent resolution for extent, vascular involvement, and resectability ( Fig. 7 ). Multiphase CT distinguishes stones from tumor but is less accurate for proximal perihilar CCA. For iCCA, DECT-based iodine density distinguishes iCCA from HCC (threshold 2.33 mg/dL, sensitivity 89.4%, specificity 76.6%). DECT improves choledocholithiasis detection and sludge differentiation.
Dual energy CT in gallbladder wall thickening type of gallbladder cancer. ( A ) Axial contrast enhanced CT image at 80 keV shows diffuse asymmetrical mural thickening of the gallbladder ( arrow ) with heterogeneous enhancement and mural layering with thick enhancing inner layer. ( B ) Iodine map shows heterogenous iodine uptake in the thickening.
CT in intrahepatic cholangiocarcinoma. ( A ) Axial arterial phase CT image shows a heterogenous mass with necrotic component ( arrow ) in the right lobe of liver. ( B ) Portal venous phase CT image shows the extent of the mass better ( arrow ). The mass extends till the liver capsule and involves the liver hilum. The left ductal system is decompressed by a percutaneous biliary drainage catheter. ( C ) Delayed phase CT image shows progressive enhancement of the mass ( arrow ).
MR Imaging and MRCP
Contrast-enhanced MR imaging/MRCP provides superior soft tissue contrast and biliary mapping for GBC/CCA staging. MR imaging is superior to CT for gallbladder wall thickening characterization and mural enhancement ( Figs. 8 and 9 ). Early GBC shows loss of 3-layer pattern, indistinct liver interface, diffusion restriction, and early wall enhancement. Diffusion weighted imaging (DWI) improves detection of wall thickening. , Enhancement patterns—heterogeneous single-layered or 2-layered thick inner layer—suggest diffuse thickening GBC. Malignant polyps show lower apparent diffusion coefficient (ADC) and prolonged enhancement. Multiparametric MR imaging (DWI, diffusion tensor imaging [DTI], intravoxel incoherent motion [IVIM], and dynamic contrast-enhanced [DCE]) improves detection over conventional MR imaging ( Fig. 10 ). Scoring systems using morphologic/enhancement features aid detection.
