Novel Approach In Treatment of Cholangiocarcinoma: A Review

Mauli Wagh*, Samarth Sitaphale, Suraj Hake, Nikita Shinde, Priti Kare, Nasir S. Shaikh, Dr. R.D Ingole

Department of Pharmacology, DJPS College of Pharmacy, Pathri Dist. Parbhani Maharashtra 431506.

*Correspondence: naaseerpharmacology@gmail.com;

DOI: https://doi.org/10.71431/IJRPAS.2025.4703 

INTRODUCTION

Cholangiocarcinoma is an aggressive malignancy of biliary epithelium that may arise anywhere in the biliary tract, from the intrahepatic biliary canaliculi to the terminus where the common bile duct enters the duodenum at the duodenal ampulla. Cholangiocarcinoma is classified by anatomical origin as intrahepatic cholangiocarcinoma (iCCA) or extrahepatic cholangiocarcinoma (eCCA); eCCA is subdivided into perihilar cholangiocarcinoma (pCCA) and distal cholangiocarcinoma (dCCA). More than 95% of cholangiocarcinomas are adenocarcinomas.

Several clinical conditions and premalignant lesions predispose to developing cholangiocarcinoma. The clinical presentation of cholangiocarcinoma will vary with the location and size of the tumor. Diagnosing cholangiocarcinoma can be difficult, particularly for extrahepatic lesions; available biopsy techniques lack diagnostic sensitivity. Surgical intervention is indicated even without a confirmatory tissue diagnosis in the appropriate clinical setting. All patients with suspected or confirmed cholangiocarcinoma should be evaluated for distant metastatic disease; almost 75% of patients have nonresectable or metastatic disease at presentation.

Cholangiocarcinoma is a rare cancer that starts in your.Bile ducts are thin tubes that bring bile (a fluid that helps you digest fats) from your liver and gall blader to your Small intestine

Cholangiocarcinoma is an aggressive cancer, which means it spreads fast. Most people receive a cholangiocarcinoma diagnosis after it’s already spread outside of their bile ducts. this point, bile duct cancer is difficult to treat, and the prognosis (chance of recovery) is usually poor.

Experts are continually researching and developing new treatments that can slow cancer spread and improve the outlook associated with cholangiocarcinoma.

Carbohydrate cell-surface antigen 19-9 (CA 19-9) is a tumor marker excreted by the biliary epithelium that assists with assessing disease severity and surveillance monitoring. The overall prognosis of cholangiocarcinoma is poor, given the aggressive nature of the tumor and the usually advanced stage at presentation. Surgery is the only curative treatment modality; radiation and chemotherapy serve as adjuncts. Recent investigations into the molecular mechanisms underlying cholangiocarcinoma have yielded various targeted therapies that have improved outcomes and will hopefully improve patient care in the future.

There are three types of cholangiocarcinoma:

• Intrahepatic cholangiocarcinoma is bile duct cancer inside your liver.
• Perihilar (hilar) cholangiocarcinoma is bile duct cancer in your hilum. The hilum is the area just outside your liver where the smaller bile ducts from inside your liver merge to form a larger duct called the common hepatic duct. It’s the most common form of cholangiocarcinoma. Another name for perihilar cholangiocarcinoma is a Kaltskintumor
• Distal cholangiocarcinoma is bile duct cancer that starts outside your liver, in the ducts closer to your small intestine.

Perihilar cholangiocarcinoma and distal cholangiocarcinoma are also known as extrahepatic bile duct cancers because they form outside your liver (“extra”-hepatic) instead of inside your liver (“intra”-hepatic).

Etiology

Cholangiocarcinoma frequently arises in the absence of genetic predisposition and without a clear etiology. However, certain risk factors that vary with ethnicity and geography predispose to cholangiocarcinoma in some patients. These predisposing risk factors include but are not limited to:

Parasitic infections: Infestation with liver flukes such as Clonorchis and Opisthorchiasis is strongly associated with cholangiocarcinoma. These infestations are endemic to Southeast Asian regions; the highest incidence rates are in northeast Thailand. Liver fluke infestation is due to the consumption of undercooked fish, and parasite-induced chronic biliary inflammation is the primary driver of malignant transformation.

Primary sclerosing cholangitis: Primary sclerosing cholangitis is a progressive autoimmune cholestatic liver disease. Individuals with primary sclerosing cholangitis have a significantly elevated risk, perhaps as much as 400 times the risk, of developing cholangiocarcinoma compared to the general population, especially with concomitant inflammatory bowel disease. For a comprehensive discussion of this disease process, please see our StatPearls' companion reference, "Primary Sclerosing Cholangitis."

Biliary tree calculi: Hepatolithiasis, cholelithiasis, and choledocholithiasis increase the risk of developing cholangiocarcinoma, especially with larger stones and a more prolonged illness duration. Hepatolithiasis is more common in Asia and may be associated with parasitic infections.

Cystic biliary lesions: Patients with choledochal cysts, biliary mucinous cystic neoplasms, or intraductal papillary biliary mucinous neoplasms are at a significantly increased risk of developing cholangiocarcinoma.

Choledochal cysts - All choledochal cysts are associated with an increased risk of cholangiocarcinoma; types I and IV confer the greatest risk. Prompt treatment of choledochal cysts is vital in reducing the risk of cholangiocarcinoma development. Please see StatPearls' companion reference, "Choledochal Cysts," for a thorough discussion of these lesions.

Biliary mucinous cystic neoplasms - Formerly identified as cystadenomas, biliary mucinous cystic neoplasms (B-MCNs) are predominately intrahepatic cystic lesions that are more common in young women. B-MCNs are frequently asymptomatic incidental findings, but large B-MCNs may cause signs or symptoms of compression or pain secondary to liver capsular distention. B-MCNs are usually septated with thickened internal walls and internal papillary projections, distinguishing them from simple liver cysts during imaging. Complete surgical resection is the preferred treatment for B-MCNs.

Intraductal papillary biliary mucinous neoplasms - These mucin-producing lesions, most commonly found in the left lobe of the liver, are analogous to pancreatic intraductal papillary mucinous neoplasms and are frequently asymptomatic. Cross-sectional imaging may reveal an associated solid component, and mucin may be distinguishable with magnetic resonance imaging. Approximately 80% of intraductal papillary biliary mucinous neoplasms harbor a malignancy, and surgical excision is recommended.

Chronic liver disease: Chronic infection with hepatitis B or C, hemochromatosis, metabolic dysfunction-associated steatotic liver disease (MASLD, formerly nonalcoholic fatty liver disease or NAFLD), and cirrhosis of any etiology are associated with an increased risk of cholangiocarcinoma.

Lifestyle, environmental, and metabolic factors: Type 2 diabetes, obesity, alcohol consumption, and cigarette smoking increase the risk of developing cholangiocarcinoma. Exposure to Thorotrast, a radioactive thorium dioxide contrast media widely used between 1920 and 1950, increases the risk of cholangiocarcinoma development. Exposure to asbestos and propylene dichloride (1,2-Dichoropropane) also confers an increased risk.

Genetic predisposition: Patients with hereditary nonpolyposis colorectal cancer (Lynch syndrome), BAP1-related tumor predisposition syndrome, multiple biliary papillomatosis, and cystic fibrosis carry an increased risk of cholangiocarcinoma development.

Epidemiology

Cholangiocarcinomas comprise about 3% of gastrointestinal malignancies, are the second most common primary liver tumors, and account for approximately 10% to 15% of all hepatobiliary malignancies. The incidence of intrahepatic cholangiocarcinoma has been rising, possibly due to improved diagnostic and classification techniques, while the incidence of extrahepatic lesions has been falling in recent years. The incidence of cholangiocarcinoma varies markedly according to the geographic area; the incidence rates are up to 50-fold higher in parts of Thailand than in the United States. The incidence of cholangiocarcinoma increases with age, is slightly more common in men, and is most commonly diagnosed between the ages of 50 and 70 years.

Perihilar cholangiocarcinoma is the most commonly encountered subtype, accounting for approximately 50% of cases. Distal (40%) and intrahepatic cholangiocarcinoma (10%) are less common.

Pathophysiology

Cholangiocarcinoma generally arises in the setting of chronic inflammation, either from precursor lesions or de novo. Mutations in various protooncogenes and tumor suppressor genes mediate carcinogenesis. While the specific molecular carcinogenic pathways have not been identified, cholangiocarcinomas typically harbor mutations RAS, BRAF, TP53, SMAD4, and more. K-ras and TP53 mutations are most commonly seen. However, genetic mutations will vary with the underlying disease etiology, especially for parasite-induced carcinogenesis.

Tumor Location and Morphology

The distinction between intrahepatic, perihilar, and distal cholangiocarcinoma is anatomical. Intrahepatic cholangiocarcinoma arises from the biliary epithelium proximal to the segmental bile ducts. Tumors arising from the left or right hepatic ducts or their confluence are termed perihilar cholangiocarcinoma. Tumors distal to the biliary confluence are distal cholangiocarcinoma.

Cholangiocarcinoma grows in 3 distinct morphologic forms; the Liver Cancer Study Group of Japan classifies cholangiocarcinoma into mass-forming, periductal infiltrating, and intraductal-growing types (see Table 1. Morphologic Cholangiocarcinoma Classification). See Image. Cholangiocarcinoma Tumor Location and Morphology.

HISTORY AND PHYSICAL

The clinical presentation of cholangiocarcinoma will depend on the location and size of the tumor. Intrahepatic cholangiocarcinoma typically presents with nonspecific symptoms, including abdominal pain, weight loss, and fatigue. Jaundice and cholangitis may occur in the presence of biliary obstruction. Frequently, symptoms occur late in the disease course; tumors can be large at the time of diagnosis.

Extrahepatic cholangiocarcinomas are symptomatic earlier in their clinical course due to biliary obstruction, leading to jaundice, pruritus, clay-colored stools, and dark-colored urine. There may be a palpable mass and ascites in advanced disease. Uncommonly, patients can present because of signs related to metastatic disease; metastatic disease may be an incidental finding of imaging studies.

The physical examination of a patient with suspected or known cholangiocarcinoma should evaluate nutritional status and liver function and include a focused abdominal exam. Rarely, a palpable mass in the right upper quadrant may be identified secondary to large intrahepatic tumors or with distal cholangiocarcinoma causing a biliary obstruction (Courvoisier sign). Signs of potentially unresectable disease include ascites or features of portal hypertension.

Evaluation

The presenting symptoms dictate the diagnostic evaluation, including laboratory, imaging, and interventional procedures. Obtaining a tissue diagnosis can be difficult depending on the location of the lesion; this is especially true for perihilar lesions. Modalities for obtaining tissue include brush cytology, fine needle aspiration, or image-guided biopsy. Despite improvement in diagnostic techniques, none of these modalities are sensitive enough to rule out cholangiocarcinoma effectively. In the appropriate clinical setting, surgery is indicated even without tissue confirmation.

Laboratory Studies

It is recommended that all patients undergo a comprehensive medical evaluation that includes a complete blood count (CBC), comprehensive metabolic profile (CMP) including liver function tests (LFTs), and coagulation studies to identify anemia, evidence of portal hypertension and hypersplenism, synthetic liver dysfunction, biliary obstruction, and renal dysfunction. Additionally, elevated transaminases may indicate hepatocyte injury. In tumors that cause biliary obstruction, direct hyperbilirubinemia and elevated alkaline phosphatase are common. Tumor biomarkers, including CA 19-9, carcinoembryonic antigen (CEA), and α-fetoprotein, should be measured. CA 19-9 is typically elevated in cholangiocarcinoma, but the results are unreliable in the presence of biliary obstruction.

Image study:

Abdominal ultrasonography: often the initial diagnostic tool in patients with suspected cholangiocarcinoma because it is easily performed, noninvasive, cost-effective, and carries no risk of radiation exposure. However, ultrasonography may not yield a conclusive diagnosis. Ultrasonography may reveal a liver mass, signs of intra- or extrahepatic biliary dilation, or gall bladder distention.

Computerized tomography (CT):

can identify liver anatomy and evaluate locoregional or metastatic disease. A triple-phase CT with arterial, venous, and portal venous phases is recommended to increase diagnostic accuracy. If the diagnosis is cholangiocarcinoma, a chest CT is recommended to evaluate for metastatic disease.

The CT findings of cholangiocarcinoma will vary with the subtype:

• Intrahepatic-peripheral cholangiocarcinoma usually presents as a mass with irregular margins with or without hepatic capsule retraction and dilatation of the peripheral intrahepatic ducts. The lesion usually demonstrates thin, incomplete rim enhancement during the arterial and portal venous phases.
• Intrahepatic-intraductal disease can cause dilatation of the intrahepatic bile ducts with or without an intraductal polypoid mass or a lobar atrophy-hypertrophy complex. The neoplasm can present as irregular masses with markedly low attenuation, minimal peripheral enhancement, and focal dilatation of intrahepatic ducts around the tumor.
• Perihilar cholangiocarcinoma can present with dilated proximal bile ducts, affecting the liver segments proximal to the lesion. The right and left bile ducts can appear disconnected. A primary mass lesion may not be seen. Often, a biliary stricture is the only finding.
• Extrahepatic cholangiocarcinomas present as wall thickening of the extrahepatic duct, a mass at the porta hepatis, or proximal biliary dilatation in the periampullary region.

Magnetic resonance imaging (MRI): offers excellent imaging of the liver and, when combined with MR cholangiopancreatography (MRCP), provides the best noninvasive imaging of the biliary tree, allowing the identification of strictures, masses, and cysts (see Image. Cholangiocarcinoma). MRI with contrast, which is usually gadolinium-based, enables the visualization of intrahepatic masses and their relationship to hepatic vasculature (see Image. Axial T2 Haste and 20s, 3-minute, and 10-minute post-contrast).

Positron emission tomography (PET): may be used to assess for distant metastatic disease, but the National Comprehensive Cancer Network (NCCN) guidelines do not recommend the routine use of PET in the diagnosis and management of cholangiocarcinoma.

Interventional Procedures

Endoscopic techniques: endoscopic retrograde cholangiopancreatography (ERCP) is used for biliary decompression and tissue diagnosis. Extrahepatic cholangiocarcinoma may be amenable to ERCP-guided biopsy or cytologic brushing. Unfortunately, the sensitivity of current biopsy techniques is too low to rule out carcinoma effectively, and operative intervention is still recommended in the appropriate clinical scenario, even without a tissue diagnosis. ERCP for biliary drainage may be indicated for severe jaundice or in patients with cholangitis.

Endoscopic ultrasound (EUS): visualizes the portal structures and the surrounding lymph nodes. In addition, EUS-guided biopsies have a higher sensitivity than ERCP alone but remain inadequate in ruling out cholangiocarcinoma effectively.

Percutaneous transhepatic cholangiography (PTC): Percutaneous image-guided access to the biliary tree is possible, especially in patients with intrahepatic biliary dilation. PTC allows for decompression of dilated bile ducts without contaminating the biliary tree. In patients undergoing hepatectomy, draining the functional liver remnant (FLR) is essential in improving postoperative liver regeneration and reducing the risk of liver failure.

Treatment / Management

The management of cholangiocarcinoma is complex and dictated by the site, extent, and relationship of the neoplasm to surrounding structures. Surgery is the only definitive cure, either with resection or liver transplantation. Chemotherapy and radiation are adjunctive treatment modalities.

Preoperative Considerations

Biliary drainage

Biliary obstruction induces liver atrophy and impairs liver regeneration. Distal cholangiocarcinoma can cause biliary obstruction with dilation of the entire biliary tree. Preoperative biliary drainage, usually via ERCP and biliary stent placement, does not improve outcomes when compared to upfront surgery in patients with resectable disease and increases the risk of postoperative complications. Drainage may be beneficial in patients who undergo neoadjuvant therapy.

Biliary drainage in perihilar tumors is a more widely debated topic. Perihilar cholangiocarcinoma commonly causes biliary obstruction, with dilation of the ducts proximal to the tumor. Drainage via ERCP results in colonization of the biliary tract with intestinal organisms and has a higher rate of stent misplacement and replacement in more proximal obstruction. PTC has the advantage of biliary drainage without contamination. Routine biliary decompression is not indicated. Selective biliary decompression of the FLR in patients undergoing liver resection, especially in whom the FLR is less than 40%, is indicated, as this minimizes postoperative liver failure. Drainage is also recommended in those undergoing neoadjuvant chemotherapy or portal venous embolization.

Volumetric analysis

In patients with iCCA and pCCA who require liver resection, the calculation of liver volumes and the FLR is critical to operative planning. Generally, an FLR of greater than 30% in healthy patients and 40% in those with cirrhosis is required. FLR is calculated using CT-guided imaging with software that calculates liver volumes. Patients who have inadequate FLR require interventions to increase liver volumes. Portal venous embolization (PVE) is the most commonly utilized technique and involves preoperative embolization of the portal vein branches to the liver segments to be resected.Embolization results in hypertrophy of the FLR of up to 40%. The rate of hypertrophy, or the kinetic growth rate, is an important marker; a rate greater than 2.66% per week predicts lower postoperative liver failure and mortality.Less common techniques for inducing hypertrophy include liver partition and portal vein ligation for staged hepatectomy and liver venous deprivation.

Local Therapies

Local therapies are the recommended treatment for intrahepatic cholangiocarcinoma when the tumor is unresectable, or the patient is not fit for surgery. There are various techniques available, but their detailed discussion is beyond the scope of this activity. The techniques are not mutually exclusive and can be used in combination depending on the size and location of the tumor and available expertise. Local therapies for cholangiocarcinoma are extremely important as the majority of patients die from liver failure due to intrahepatic metastases. Delaying the onset of liver failure can significantly improve patient survival and quality of life. For an overview of local therapies for the treatment of cholangiocarcinoma, please see . Local Therapies for Cholangiocarcinoma.

Transarterial chemoembolization

Transarterial chemoembolization (TACE) employs chemotherapeutic agents directly instilled into the hepatic artery, followed by embolization of the artery, thereby depriving the tumor of its arterial supply. Doxorubicin and platinum agents are most commonly used. The chemotherapeutic agent may be emulsified or incorporated into beads or microspheres and deployed via angiography into the hepatic artery branches that supply the tumor. The procedure is well-tolerated in most patients and can significantly shrink tumors.

Transarterial radioembolization

Transarterial radioembolization (TARE) is a newer technique that installs yttrium 90 (90Y) in either resin or glass microspheres via the hepatic artery directly into the tumor, followed by vessel embolization. This results in a high dose of radiation in the immediate vicinity of the tumor and is performed similarly to TACE.

Ablative techniques

Tumor ablation using radiofrequency or microwave energy is an option for local control in patients with unresectable disease or who are not fit to undergo surgical resection.[38] These techniques can be done using image guidance and are much better tolerated than surgery. Both techniques rely on the application of energy, and the electrode is placed in the center of the tumor. The effectiveness is inversely proportional to size; tumors larger than 3 cm are much less likely to be entirely ablated. These techniques should be used cautiously near larger blood vessels or bile ducts. Ablation can be repeated as often as needed.

Hepatic artery infusion

Hepatic artery infusion is a technique whereby chemotherapy is instilled directly into the hepatic artery proper via a subcutaneously placed pump. The catheter is threaded into the hepatic artery via the gastroduodenal artery; this requires a surgical procedure to accomplish. Chemotherapy is then infused over the ensuing weeks and can result in significant downstaging of the tumor. When hepatic artery infusion is performed at institutions with extensive experience, the overall results are promising. Hepatic artery infusion is not yet a widely adopted treatment modality.

Differential Diagnosis

Since the signs and symptoms of cholangiocarcinoma, including jaundice, abdominal pain, and fatigue, are very nonspecific, the differential diagnosis can be vast. Some possible differential diagnoses include:

• Choledocholithiasis
• Pancreatic cancer
• Primary sclerosing cholangitis
• Primary biliary cirrhosis
• Hepatocellular carcinoma
• Cholangitis
• Cholecystitis

Surgical Oncology

The general principles of liver surgery apply to cholangiocarcinoma. Maintaining an adequate FLR and hepatic inflow and outflow while obtaining microscopically negative margins is critical to good outcomes. Diagnostic laparoscopy should always be performed before laparotomy; as many as 30% of patients may have radiographically occult metastatic disease that would preclude resection.

Radiation Oncology

Adjuvant Therapy

Radiotherapy (RT) may be used in the adjuvant setting for cholangiocarcinoma.There is typically no role for radiotherapy for patients who undergo a complete resection with microscopically negative margins. RT, usually in combination with chemotherapy, is generally utilized to reduce local recurrence in patients with a microscopically or grossly positive surgical margin. The radiation dose depends on the tumor location, the tolerance of surrounding organs, and underlying liver function. Image-guided techniques, such as three-dimensional conformal and intensity-modulated RT, improve targeting and reduce toxicity. The radiation field should include the operative bed and the regional lymph nodes, including the portal, celiac, para-aortic, superior mesenteric artery, and others. Typical doses range from 40 Gy to 45 Gy to the lymph nodes and 55 Gy to 60 Gy to the tumor site. There is no definitive data to suggest a survival benefit. Patients with node-positive disease may also receive radiotherapy. External beam radiotherapy with a chemosensitizing agent such as capecitabine or gemcitabine is typically used.

Unresectable Disease

RT may be used in unresectable disease to provide local control and symptom relief. Both external beam RT and stereotactic body RT (SBRT) may be used. SBRT allows very high doses of radiation to target lesions with a high degree of accuracy and provides local control rates that appear to be better than conventional fractionated external beam radiotherapy. Radiotherapy is almost always administered with concurrent radiosensitizing chemotherapy. Typical doses in this setting are higher than those in adjuvant therapy.

Medical Oncology

Adjuvant Therapy

Postoperative therapy should be offered within 8 to 12 weeks and requires preinitiation baseline laboratory tests and imaging. Adjuvant treatment may be delayed in cases where there are significant surgical complications or other patient-related factors decreasing the ability to tolerate chemotherapy. In general, the efficacy of adjuvant therapy decreases as the time to initiation increases.

After resection, adjuvant therapy should be offered to patients with positive surgical margins, positive lymph nodes, or vascular involvement. The role of adjuvant chemotherapy in patients with completely resected specimens with microscopically negative margins is unclear. The benefit of adjuvant therapy is based on 2 trials, including the Biliary Tract Cancer (BILCAP) trial and a randomized trial from Japan employing single-agent adjuvant treatment. In the BILCAP trial, adjuvant capecitabine improved overall survival without chemotherapy, although this trend was not statistically significant. This is currently accepted as a standard of care after resection. Two negative trials have reported no benefit to gemcitabine-based regimens, which are presently discouraged.The lack of randomized trials plagues trial data on cholangiocarcinoma, which is a rare cancer; most trials combined gallbladder carcinoma with all biliary tract cancers. Some of the benefits of adjuvant chemotherapy may be in the population of patients with gallbladder carcinoma, which has a higher rate of distant metastatic disease.

Neoadjuvant setting

Neoadjuvant chemotherapy is currently used in borderline resectabletumors. Some patients may have an adequate response that allows for resection. In addition, neoadjuvant chemotherapy and radiation may be used as part of the Mayo protocol in preparation for liver transplant in patients with hilar cholangiocarcinoma. For patients with upfront resectable disease, there is no currently available data to support the routine use of neoadjuvant chemotherapy.

Locally advanced or metastatic setting

Chemotherapy can significantly extend survival in patients with metastatic disease, and immunotherapy has improved this benefit more recently. Based on the recent TOPAZ-1 trial, the combination of durvalumab with gemcitabine and cisplatin was superior to gemcitabine and cisplatin alone. Pembrolizumab, in combination with gemcitabine and cisplatin, has also been shown to be superior to chemotherapy alone. In general, these regimens are considered the standard of care.

Chemotherapy alone remains the standard of care in several settings where immunotherapy may not be available. Multiple second- and third-line regimens exist for patients with poor performance status, persistent hyperbilirubinemia, or other considerations. With the identification of an increased number of specific tumor mutations and the availability of targeted agents, several targeted agents are now available based on the tumor mutational profile of these cancers.

Chemotherapy:

Chemotherapy is a treatment that uses medicines to destroy cancer cells. There are many different types of chemo. They don’t all work exactly the same way, so different types of chemo might be used for different types of cancer. Most are given as an infusion into a vein (IV), but some are given as an injection, taken as pills, or applied to the skin.

Radiation Therapy:

Radiation therapy is one of the most common treatments for cancer. Radiation may be used alone or with other treatments, such as surgery, chemotherapy, hormones, or targeted therapy. If your treatment plan includes radiation therapy, knowing how it works and what to expect can often help you prepare for treatment and make informed decisions about your care.

Liver Transplant:

Liver transplantation or hepatic transplantation is the replacement of a diseased liver with the healthy liver from another person. Liver transplantation is a treatment option for end-stage liver disease and acute liver failure, although availability of donor organs is a major limitation.

Immunotherapy:

Immunotherapy is treatment that uses a person's own immune system to fight cancer. Immunotherapy can boost or change how the immune system works so it can find and attack cancer cells.  If your treatment plan includes immunotherapy, knowing how it works and what to expect can often help you prepare for treatment and make informed decisions about your care. 

1. T-cell Activation (Normal Function):

T cells become activated when they recognize cancer antigens presented by antigen-presenting cells (APCs).

2. Immune Suppression by Tumors:

Tumor cells often express PD-L1 or PD-L2, which bind to PD-1 receptors on T cells.

This binding inhibits T-cell activity, allowing the tumor to evade immune attack.

3. Pembrolizumab Action:

Pembrolizumab binds to the PD-1 receptor on T cells.

This prevents interaction with PD-L1/PD-L2 on tumor cells.

As a result, T cells remain active and can attack tumor cells.

Targeted Therapies:

Targeted therapy is a type of cancer treatment that uses drugs or other substances to precisely identify and attack certain types of cancer cells. A targeted therapy can be used by itself or in combination with other treatments, such as traditional or standard chemotherapy, surgery, or radiation therapy. If your treatment plan includes targeted therapy, knowing how it works and what to expect can often help you prepare for treatment and make informed decisions about your care.

Targeted Therapy for FGFR2 Mutations:

FGFR inhibitors,like derazantinib, are being studied for their effectiveness in patients with CCA and FGFR2 gene fusion or mutation.

Darazantinib is a pan-FGFR inhibitor, meaning it inhibits FGFR1, FGFR2, and FGFR3 tyrosine kinases. These receptors are involved in key cellular processes, such as:

Cell proliferation

Survival

Migration

Angiogenesis (formation of new blood vessels)

Therapeutic Target

Darazantinib is especially relevant in cancers where FGFR pathways are genetically altered, such as:

FGFR2 fusions in intrahepatic cholangiocarcinoma (iCCA)

FGFR amplifications or mutations in other tumors (e.g., bladder, breast, and gastric cancers)

⚙️ Secondary Mechanisms

Darazantinib also shows inhibitory activity against:VEGFRs (vascular endothelial growth factor receptors)

RET kinase

Other kinases involved in tumor angiogenesis and growth

This multi-targeted approach may enhance its anti-tumor and anti-angiogenic effects.

Clinical Development

Darazantinib is being studied in clinical trials, particularly for cholangiocarcinoma and urothelial carcinoma, and may be used alone or in combination (e.g., with atezolizumab, an immune checkpoint inhibitor).

Targeted Therapy for IDH1 Mutations:

Ivosidenib, an IDH1 inhibitor, has been approved for the treatment of CCA with IDH1 mutation.

Combination Therapies:

The combination of chemotherapy immunotherapy, and targated therapies is being explored to maximize treatment effectiveness and potentially improve survival outcomes.

Drugs used in Cholangiocarcinoma

• Gemcitabine

Gemcitabine is a nucleoside analog and a chemotherapeutic agent. It was originally investigated for its antiviral effects, but it is now used as an anticancer therapy for various cancers.¹ Gemcitabine is a cytidine analog with two fluorine atoms replacing the hydroxyl on the ribose.³ As a prodrug, gemcitabine is transformed into its active metabolites that work by replacing the building blocks of nucleic acids during DNA elongation, arresting tumour growth and promoting apoptosis of malignant cells.The structure, metabolism, and mechanism of action of gemcitabine are similar to cytarabine, but gemcitabine has a wider spectrum of antitumour activity.

Gemcitabine is marketed as Gemzar and it is available as intravenous injection. It is approved by the FDA to treat advanced ovarian cancer in combination with carboplatin, metastatic breast cancer in combination with paclitaxel, non-small cell lung cancer in combination with cisplatin, and pancreatic cancer as monotherapy.⁴ It is also being investigated in other cancer and tumour types.

CONCLUSION

Cholangiocarcinoma remains a complex and lethal malignancy with a dismal prognosis due to late diagnosis and limited curative options. Surgical resection continues to be the mainstay of treatment for early-stage disease, while chemotherapy and radiation provide modest benefits in advanced cases. However, the advent of precision medicine—incorporating immunotherapy and molecularly targeted therapies—has revolutionized the therapeutic landscape. Agents such as pembrolizumab and ivosidenib, along with FGFR inhibitors like derazantinib, demonstrate encouraging clinical activity, particularly in biomarker-selected populations. Continued research into molecular pathways, early diagnostic tools, and personalized therapeutic regimens is essential for improving long-term outcomes. This review underscores the importance of integrating novel treatment strategies with existing modalities to pave the way for more effective and individualized management of cholangiocarcinoma.

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