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How perihilar bile duct cancer is staged: Bismuth-Corlette and TNM | CION Cancer Clinics
The Bismuth-Corlette classification sorts a perihilar bile duct cancer into types I to IV by how far it reaches up the ducts below the liver. Surgeons use it to plan an operation. It is not the stage, which is described separately by TNM. This page explains each type, how the two systems fit together, and which tests your team uses. At CION Cancer Clinics in Hyderabad, our oncologists explain liver cancer in plain words and plan care around you and your family.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed October 2026, next review due October 2027
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On this page
- What is the Bismuth-Corlette classification?
- What do Bismuth types I, II, IIIa, IIIb and IV mean?
- How is Bismuth-Corlette different from the TNM stage?
- Which tests are used to stage a perihilar tumour?
- What do families often misread in a staging report?
- What can this page not tell you?
- Common questions about staging perihilar bile duct cancer
The short answer
What is the Bismuth-Corlette classification?
The Bismuth-Corlette classification describes how far a perihilar bile duct cancer has grown up into the bile ducts where they join below the liver. It sorts the tumour into types I to IV, and surgeons use it to plan which part of the liver and duct would need to come out. It is a map for surgery. It is not the stage of the cancer, and it does not say whether the cancer has spread.
Why perihilar tumours need their own map
Perihilar cholangiocarcinoma, also called a Klatskin tumour, grows at the hilum, the point just below the liver where the right and left bile ducts meet to form one main duct. Blood vessels for the liver run right beside it. A tumour a few millimetres higher or lower can change the operation completely, so doctors need a precise way to say where it sits. Our page on perihilar cholangiocarcinoma explains the disease itself.
The two questions staging answers
Your team asks two separate things. First, where exactly is the tumour along the ducts, and which blood vessels does it touch? Bismuth-Corlette and scans of the vessels answer that. Second, how far has it spread beyond the duct, to lymph nodes or other organs? The TNM stage answers that. You need both to understand a plan.
The five types
What do Bismuth types I, II, IIIa, IIIb and IV mean?
Each type describes how high up the duct tree the tumour reaches. Higher usually means a bigger operation, though every case is judged on its own scans.
Type I
The tumour sits in the main duct below the point where the right and left ducts join. The join itself is clear.
Type II
The tumour reaches the join and involves it, but does not climb further into either the right or the left duct.
Type IIIa and IIIb
The tumour has grown up into one side. IIIa means the right duct, IIIb means the left. Surgery, if possible, usually removes that side of the liver along with the ducts.
Type IV
The tumour reaches up into both the right and left ducts, or appears in more than one place along them. This was once thought to rule out surgery. Some type IV tumours can now be removed by specialist liver surgeons, so the type alone does not decide.
What the type does not tell you
- Whether lymph nodes are involved
- Whether the cancer has spread elsewhere
- Whether key blood vessels are involved
Not sure whether this applies to you?
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How is Bismuth-Corlette different from the TNM stage?
Bismuth-Corlette
TNM stage
Describes where the tumour runs along the ducts
Describes how deep it has grown and how far it has spread
Read from MRCP or CT before treatment
Partly from scans, confirmed after surgery from the removed tissue
Guides which part of the liver a surgeon plans to remove
Guides the overall treatment plan and follow-up
Says nothing about lymph nodes or distant spread
Includes lymph nodes (N) and distant spread (M)
Types I to IV
Stages 0 to IV, with sub-groups
How it is worked out
Which tests are used to stage a perihilar tumour?
Scans before any stent, where possible
An MRI of the bile ducts, called MRCP, and a contrast CT show the ducts and the blood vessels most clearly before a stent is placed. A stent can blur the picture, so teams prefer the scans first when the patient is well enough to wait.
Relieving the jaundice
Most people need bile drained with a stent or a tube before any treatment. Our page on why a stent comes first explains the reasons. Brushings or a biopsy are often taken at the same time.
Checking for spread
A CT of the chest and sometimes a PET-CT look for spread to lymph nodes, the lining of the abdomen or other organs. Some surgeons also look inside with a camera before a big operation.
The tumour board
Surgeons, oncologists and radiologists review every scan together and agree the type, the vessels involved and how much healthy liver would remain. CION arranges the scans and procedures through accredited partner hospitals and brings the results to its tumour board.
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Commonly believed
What do families often misread in a staging report?
"Type IV means stage four, so nothing can be done."
Bismuth type IV and TNM stage IV are different scales. Type IV describes how high the tumour climbs up the ducts. It does not mean the cancer has spread to other organs, and treatment is still planned.
"Type I is small, so it must be early."
A type I tumour can still have reached lymph nodes or a blood vessel. The full TNM stage and the vessel scans matter as much as the type.
"If they put in a stent, the cancer is being treated."
A stent drains bile and clears the jaundice. It does not treat the tumour. It is usually the first step that makes later treatment safe.
"The staging is done, so the plan is fixed."
The final stage is often only confirmed after surgery, when the removed tissue is examined. Plans can change once that report is back.
Being straight with you
What can this page not tell you?
It cannot tell you whether your tumour can be removed. That depends on the Bismuth type, on which arteries and veins are involved, on how much healthy liver would remain, and on your overall fitness. Our page on surgery for perihilar cancer explains how surgeons weigh those things. Nor can it give you an outlook. Staging describes the tumour. It does not predict one person's course.
Who this page does not apply to
Bismuth-Corlette is used only for perihilar tumours. Cancer inside the liver, called intrahepatic cholangiocarcinoma, is staged differently, as our page on staging intrahepatic cholangiocarcinoma explains. Tumours lower down the duct near the pancreas, and gallbladder cancer, also have their own systems.
Ask about testing the tumour's DNA
Bile duct cancers should have their DNA tested, called molecular profiling, because some carry changes that a targeted medicine can act on. Not every tumour has one. Ask whether there is enough tissue for it.
Bring every scan, the stent report and any biopsy result when you ask for a second opinion. The tumour board needs the images, not just the reports.Questions we are asked
Common questions about staging perihilar bile duct cancer
Is a Klatskin tumour the same as perihilar cholangiocarcinoma?
Yes. Klatskin tumour is an older name for a bile duct cancer at the hilum, where the right and left ducts join just below the liver. Reports may use either name. The Bismuth-Corlette type applies to both, because they describe the same tumour.
Does a higher Bismuth type mean a worse cancer?
Not exactly. A higher type usually means a bigger or more complex operation, because more of the duct tree is involved. It says nothing about spread to lymph nodes or other organs. Your team reads the type together with the TNM stage and the vessel scans before drawing any conclusion.
Can the Bismuth type change?
It can be revised. Scans before a stent are clearer, and findings during surgery sometimes show the tumour reaches further than expected. If the tumour grows over time, a later scan can also show a higher type. Always ask which scan the type was based on.
Why does my report also mention the portal vein and hepatic artery?
These vessels run right beside the hilum and carry blood into the liver. Whether the tumour touches them, and on which side, is often as important to the surgeon as the Bismuth type. Some systems used by liver surgeons combine both into one assessment.
Is a biopsy needed before staging?
Not always. Getting tissue from the hilum is hard, and brushings can miss the cancer. Some people go to surgery on the strength of the scans alone, after a full tumour board review. The tissue then confirms the diagnosis and the final stage.
What if the tumour cannot be removed?
Treatment continues. Keeping the bile draining, medicines such as chemotherapy and immunotherapy, and sometimes radiation are all used. Our page on treatment when bile duct cancer cannot be removed explains the options and how they are chosen.
Does staging tell us how long someone has?
No. Stage groups describe large numbers of people, not one person, and individual courses vary widely. Your oncologist can talk about what the stage means for treatment choices. Be wary of any website, or any person, who offers a precise figure for one patient.
How do I get the staging reviewed?
Collect the scan images on a disc or a link, the reports, the stent or ERCP notes and any biopsy result. Call the CION helpline. The tumour board can review them and tell you whether the type and stage are clear or need another test.
Your Specialists
Meet CION's liver cancer specialists. Bring your scan reports and liver blood tests.
Our medical and surgical oncologists plan liver cancer care together, weighing the tumour and how well your liver works before choosing surgery, a liver-directed procedure or medicines.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
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Sources
- American Cancer Society — Stages of Bile Duct Cancer
- National Cancer Institute — Bile Duct Cancer Treatment
- American Cancer Society — Bile Duct Cancer Surgery
- Cancer Research UK — Bile duct cancer (Cholangiocarcinoma)
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Perihilar cholangiocarcinoma and the Klatskin tumourWhat this cancer is, before the stagingSurgery for perihilar bile duct cancerHow the type and the vessels shape the operationWhy a stent comes before any cancer treatmentThe step most people have firstTreatment when bile duct cancer cannot be removedThe options if surgery is not possible
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