Hepatocellular Carcinoma (HCC)

  •           Gross appearance of HCC:
  • – Nodular/Multifocal: Usually co-exist with cirrhosis
  • – Massive/Diffuse: Multiple, small foci scattered diffusely throughout the liver
  • – Solitary mass

  How to differentiate High grade dysplastic nodule from Early HCC?

  • – It can be done by immunohistochemistry
  •   HCC is positive for:
  •           • Glypican-3 (GPC-3)
  •           • Haet shock protein (HSP 70)
  •           • Gluatmin synthase
  •           • BIRC 5

  

                                     Imaging study of HCC

 

                                                   USG:

  • – Variable
  • – For tumor < 5 cm:
  •             • Hypoechopoic and thin peripheral capsule
  •             • It can also be hyperechoic or variable echogenicity
  • – Doppler USG should be done to assess the patency of portal vein/ inferior vena cava

                                             

                                                                    CT scan

                         BASICS OF CONTRAST- ENHANCED DYNAMIC CT SCANNING:

  •                                          Purpose of contrast-enhanced CT (CECT) :
  • – To find pathology by enhancing the contrast between a lesion and the normal surrounding structures
  • – Sometimes a lesion is hypovascular compared to the normal tissue and in some cases a lesion is hypervascular compared to the surrounding tissue in a certain phase of enhancement.
    So it is important to know in which phase a CT should be performed depending on the pathology that you are looking for

 

 

                                                Phases of Dynamic CT scanning:

 

  1. Non-enhanced CT (NECT)
  2. Early arterial phase
  3. Late arterial phase
  4. Hepatic or late Portal phase

 

  •                                              Non-enhanced CT (NECT):
    – Helpful in detecting calcifications, fat in tumors, fat-stranding as seen in inflammation like appendicitis, diverticulitis, omental infarction etc.
  •              
  •                Early arterial phase:
  • – 15-20 sec p.i. or immediately after bolustracking
  • – This is the phase when the contrast is still in the arteries and has not enhanced the organs and other soft tissues

 

  •                        
  •                      Late arterial phase:
  • – 35-40 sec p.i. or 15-20 sec. after bolus tracking
  • – Sometimes also called “arterial phase” or “early venous portal phase”, because some enhancement of the portal vein can be seen
  • – All structures that get their blood supply from the arteries will show optimal enhancement

 

  •                                     Figure Showing the following findings:
    • ♦ The CT-images are of a patient who underwent 2 phases of arterial imaging at 18 and 35 seconds
    • ♦ In the early arterial phase arteries are seen nicely but only see some irregular enhancement within the liver is seen
    • ♦ In the late arterial phase multiple tumor masses are seen clearly
  •                                
  •                               Hepatic or late portal phase:
    • – 70-80 sec p.i. or 50-60 sec after bolus tracking
    • – Although hepatic phase is the most accurate term, most people use the term “late portal phase”
    • – In this phase the liver parenchyma enhances through blood supply by the portal vein and you    should see already some enhancement of the hepatic veins
    •                                        
    •                                       Delayed phase:
      • – 6-10 minutes p.i. or 6-10 minutes after bolustracking
      • – Sometimes called “wash out phase” or “equilibrium phase”
      • – There is wash out of contrast in all abdominal structures except for fibrotic tissue, because fibrotic tissue has a poor late wash out and will become relatively dense compared to normal tissue. This is comparable to late enhancement of infarcted scar tissue in cardiac MRI

 

  •                      
  •                            
  •                                Peculiarities of Liver lesion imaging:
    • – 80% of normal liver parenchyma is supplied by the portal vein
    • – Rest of the 20% is supplied by the hepatic artery
    • – So the normal parenchyma will enhance maximally in the hepatic phase at 70-80 sec p.i. and only a little bit in the late arterial phase at 35-40 sec p.i.
    • – On the other hand, All liver tumors get 100% of their blood supply from the hepatic artery
    • – So a hypervascular tumor is best seen in the late arterial phase
    • – A hypovascular liver tumor however is poorly enhance in the late arterial phase, because it is hypovascular and the surrounding liver does also enhance poorly in that phase.
      This tumor is best seen when the surrounding tissue enhances, i.e. in the late portal (or hepatic) phase at 75-80 sec p.i.
  •                                        
  • On a non-enhanced CT-scan (NECT) liver tumors are not visible, because the inherent contrast between tumor tissue and the surrounding liver parenchyma is too low
  •                                        HCC on MRI
    • – HCC on T1 image may be iso-intense, Hypo-intense, Hyper-intense
    • – T2 Image: usually hyper-intense
    • – Gadolinium enhanced MRI: typically enhanced

     

    Treatment Options for HCC

    1. Surgical Resection
    2. Liver Transplantation
    3. Local Ablation Therapy
    •            • Per cutaneous Ethanol Injection (PEI)
    •            • Radio-Frequency Ablation Therapy (RFA)
    1. Trans-arterial Chemo embolization
    2. Chemotherapy

     

     

     

          1. Surgical Resection

     

    • – Non-cirrhotic liver or well compensated liver disease
    • – Lesion size and location amenable to surgery
    • – Tumor confined to liver
    • – No Invasion of large vessel
    • – Normal portal pressure
    • – Single lesion < 2 cm / Carcinoma in situ
    • – All tumor nodule should be removed with a negative margin of resection
    • – After resection,at least 40% liver volume should remain to survive the post-operative period
    • – Recurrence after resection – 50%
    • – Salvage LT rarely possible

 

  •                                           2. Liver Transplantation (LT)

 

  •                    

 

  •                 

 

  •            Other Criteria for LT
    • – Where resection is not possible
    • – Cirrhosis with portal hypertension
    • – Absence of extra hepatic spread
  •       Bridging therapy if waiting time for LT is expected to be 6 months or more
  •               – TACE,RFA   To prevent tumor growth beyond Milan criteria

 

    • Predictors of worse prognosis after LT :
      • – Nodules 3-5 cm
      • – MELD score 20 cm or more
      • – AFP: 455 ng/ml or high

                                       

 

                                       3. Local Ablation Therapy

  •                              – 3-5 cm tumor
  •                              – Not amenable to resection/LT
  •                              – CTP score: A
  •                              – Used as bridging therapy before LT also
  •                      Percutaneous ethanol Injection (PEI):
  •                             – Effective in lesions 2-3 cm
  •                            – Require multiple sessions
  •                            – Small tumor with preserved hepatic function
  •                            – Complications: tumor seeding along the needle track

 

  •                       Radiofrequency Ablation:
  •                            – Effective upto 5 cm
  •                            – Require fewer session than PEI
  •                           – Can be performed percutaneously / laparoscopically / open surgery
  •                           – Survival rate is similar to surgical resection
  •                           – Recurrence rate is high in comparison to Resection
  •                           – Complications are uncommon
  •                                            
  •                                        Figure: Radio Frequency Ablation (RFA) of HCC

 

  •                                                   4.Trans-arterial Chemo embolization (TACE)

 

  •                        
  •                          Figure: Delivering a high dose of Chemotherapy to the tumor and shut of the blood supply

 

  •                           – This is a palliative treatment modality
  •                         Candidates:
  •                               – Relatively intact hepatic function (CTP: A, B)
  •                               – Total Bilirubin < 3 mg/dl
  •                               – Good performance status
  •                               -Tumor, not amenable to local ablative treatment because of size, number, location
  •                              – Bridging therapy for LT/ Resection
  •                            Contraindications:
  •                               – Macroscopic vascular invasion of any type
  •                               – Extrahepatic spread
  •                               – Doxorubicin eluting beads (DCBE) are used embolic material for TACE
  •                               – Embolising particles are loaded with Doxorubicin (gradually released)
  •                              – Beads lead to lumen occlusion and ischemia
  •                              – Decreased side effects and increased response

 

 

                                          5.Chemotherapy

 

  •                         Sorafenib is the only Chemotherapy agent
  •                        Candidates:
  •                             – Intact hepatic function (CTP: A,B)
  •                            – Portal vein thrombuosis
  •                            – Extrahepatic tumor
  •                            – Failure of other therapies

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