A Klatskin tumor is a cancer that forms where the two main bile ducts of the liver meet, a junction point called the hepatic hilum. It accounts for 50% to 70% of all bile duct cancers (cholangiocarcinomas), making it the most common subtype. The tumor grows within about 2 cm of this junction and tends to block the flow of bile from the liver into the intestines, which is why jaundice is almost always the first sign something is wrong.
Where Klatskin Tumors Develop
Your liver produces bile, a fluid that helps digest fats. Bile drains from the liver through two main channels: the right and left hepatic ducts. These ducts merge at a Y-shaped junction called the hepatic hilum before continuing as a single duct toward the small intestine. A Klatskin tumor grows right at that junction, which is why it’s also called hilar cholangiocarcinoma or perihilar cholangiocarcinoma.
This location is what makes Klatskin tumors particularly challenging. Because the tumor sits at a critical crossroads in the bile drainage system, even a small growth can block bile flow from one or both sides of the liver. The tumor can extend into either the right or left hepatic duct, or both, and may wrap around nearby blood vessels that supply the liver.
Symptoms and Early Warning Signs
Jaundice, the yellowing of skin and eyes, is the presenting complaint in almost all cases. It happens because the tumor obstructs bile flow, causing a pigment called bilirubin to build up in the blood. Along with the visible yellowing, you may notice dark urine, pale or clay-colored stools, and intense itching (a result of bile salts depositing in the skin).
Other symptoms are less specific. Weight loss, abdominal pain (typically in the upper right area), fatigue, and loss of appetite can all occur, but these tend to develop gradually. Because the tumor grows slowly and the early symptoms mimic more common conditions like gallstones or hepatitis, Klatskin tumors are often diagnosed at an advanced stage.
Risk Factors
The strongest known risk factor is primary sclerosing cholangitis (PSC), a chronic condition that causes inflammation and scarring of the bile ducts. People with PSC carry roughly a 25-fold increased risk of developing extrahepatic bile duct cancers, including Klatskin tumors. PSC is often associated with inflammatory bowel disease, particularly ulcerative colitis.
Other conditions that increase risk include chronic bile duct infections, bile duct cysts (choledochal cysts), liver fluke infections (more common in Southeast Asia), and chronic hepatitis B or C. However, many patients diagnosed with a Klatskin tumor have no identifiable risk factors at all.
How Klatskin Tumors Are Diagnosed
Diagnosis typically starts with blood tests showing elevated bilirubin and liver enzymes consistent with bile duct obstruction. A tumor marker called CA 19-9 is commonly checked. At a standard cutoff level, it has a sensitivity of about 77% and a specificity of roughly 85% for cholangiocarcinoma. That means it catches most cases but can miss about one in four, and it can also be falsely elevated in non-cancerous bile duct conditions. It’s useful as a supporting clue but not definitive on its own.
Imaging is the cornerstone of diagnosis. Magnetic resonance cholangiopancreatography (MRCP) has become the preferred initial imaging tool because it’s noninvasive, radiation-free, and produces detailed 3D images of the bile ducts and surrounding tissue. It can show exactly where the blockage is, how far the tumor extends, and whether it’s invading nearby structures.
Endoscopic retrograde cholangiopancreatography (ERCP) remains the gold standard for directly visualizing the bile ducts and has the added benefit of allowing tissue samples to be taken during the procedure. However, it requires sedation, involves radiation, and carries a 1% to 7% complication rate including inflammation of the pancreas, bleeding, and infection. For this reason, ERCP is increasingly reserved for situations where a tissue sample is needed or when a stent must be placed to relieve the blockage, rather than being used purely for diagnosis.
The Bismuth-Corlette Classification
Once imaging defines the tumor’s extent, doctors classify it using the Bismuth-Corlette system. This classification describes how far along the bile ducts the tumor has spread, which directly affects treatment options:
- Type I: The tumor sits in the common hepatic duct below the junction, without reaching the point where the two ducts meet.
- Type II: The tumor reaches the junction but does not extend into either the right or left hepatic duct.
- Type IIIa or IIIb: The tumor extends from the junction into either the right (IIIa) or left (IIIb) hepatic duct.
- Type IV: The tumor involves the junction and extends into both the right and left hepatic ducts.
Types I and II are generally more amenable to surgical removal. Type IV tumors, which involve both sides, are the most difficult to treat surgically because removing the tumor may not leave enough functional liver behind.
Surgical Treatment
Surgery to completely remove the tumor offers the best chance of long-term survival. The goal is what surgeons call an R0 resection, meaning no cancer cells are visible at the cut edges of the removed tissue. Achieving this often requires removing part of the liver along with the affected bile ducts and reconstructing the remaining drainage system.
Whether a tumor is operable depends on several factors. A tumor is considered clearly resectable when there’s no significant involvement of blood vessels supplying the portion of liver that will remain after surgery, and when a complete removal of the cancerous bile duct tissue appears feasible. Tumors are clearly unresectable when blood vessels to the remaining liver are involved in a way that can’t be repaired, or when a complete removal isn’t possible. Many patients fall into a borderline category where resectability is uncertain and requires evaluation by a specialized surgical team.
Even after aggressive surgery, the five-year survival rate ranges from 14% to 48% depending on factors like tumor stage, margin status, and lymph node involvement. A recent single-center study reported one-, three-, and five-year survival rates of 82.8%, 53.7%, and 35.8% for patients who underwent surgery.
Liver Transplantation for Select Patients
For patients whose tumors can’t be surgically removed, or whose cancer arose in the setting of primary sclerosing cholangitis, liver transplantation following a course of chemotherapy and radiation has shown promising results. A protocol developed at the Mayo Clinic selects patients with early-stage tumors no larger than 3 cm, with no evidence of cancer spread inside or outside the liver. Patients with cancer that has spread to lymph nodes, the lining of the abdomen, or that involves the liver tissue itself are not eligible.
Among patients who completed this protocol and received a transplant, five-year survival reached 71%. Even when counting all patients who started the protocol (including those who became ineligible before transplant), five-year survival was 55%. These results are notably better than surgical resection alone, though the strict selection criteria mean only a small subset of patients qualify.
Palliative Options When Surgery Isn’t Possible
For patients with advanced disease, the primary goal shifts to relieving the bile duct blockage, which alleviates jaundice, itching, and the risk of bile duct infections. This is done by placing a stent, a small tube that props open the narrowed duct and allows bile to flow again.
Two types of stents are used: plastic and metal. Metal stents (self-expanding metal stents, or SEMS) tend to stay open longer and have a significantly lower rate of early complications. One multicenter study found the one-month adverse outcome rate was 11.8% with metal stents compared to 39.3% with plastic stents. Metal stents also maintained patency better at six months, with 81% still functioning well compared to significantly lower rates for plastic stents. However, metal stents cost more and are permanent once placed, so the choice depends on the patient’s overall prognosis and treatment plan.
Chemotherapy, sometimes combined with radiation, is also used in advanced cases to slow tumor growth. These treatments can extend survival and improve quality of life, though they are not curative in the palliative setting.