Role of interventional radiologoly in hepatic lesions.pptx

Role of interventional radiologoly in management of hepatic lesions

1. Role of intervention radiology in management of hepatic lesions

2. INTRODUCTION Liver is among the most common sites for primary and secondary tumors. Hepatocellular carcinoma (HCC) represents more than 90% of the primary liver tumors and is the second important cause of cancer related death. Metastatic liver tumors are even more common in colorectal carcinoma Surgery remains the first line of therapy for these patients and the options of resection or liver transplant provide best outcomes of 5-year survival ranging from 60% to 80%. However, the vast majority of these patients are unsuitable for surgery due to the advanced disease at diagnosis, poor liver reserve and performance status. Furthermore, limited infrastructure, organ shortage and long waiting period denies timely liver transplantation in many.

3. Over the last two decades, many radiological interventions consisting of ablative techniques or angiographic procedures have evolved, effectively prolonging survival. Being widely available, safe, and efficacious, these minimally invasive techniques have become widely popular and have emerged as the alternative therapeutic options to surgery for both primary and secondary liver malignancies.

4. Percutaneous ablative techniques A) Chemical ablation: Ethanol • Acetic acid. B)Thermal ablation: • Radiofrequency ablation • Microwave ablation • Laser ablation • Cryoablation • High intensity focused ultrasound ablation. C) Nonthermal ablation: • Irreversible electroporation (IRE) or nano knife

5. Intra-arterial procedures • Trans arterial embolization • Trans arterial chemoembolization (TACE) • Trans arterial chemotherapy (TAC) • Trans arterial rhenium/Yttrium therapy (TART) Portal vein embolization

6. Pretreatment Assessment for Locoregional Therapy The evaluation includes : Laboratory studies include complete blood count, liver function tests, coagulation profile and AFP levels. Cross-sectional imaging by either multiphasic computed tomography (MPCT) or MRI is essential for staging of the disease. Treatment planning is done by careful appraisal of the imaging for the size, number, and location of the tumors, presence of macrovascular (portal vein) invasion, and extrahepatic disease. Holistic treatment needs to be done, which involves treating the tumor, the underlying tumor etiology (invariably viral hepatitis) and the associated deranged liver function.

7. Percutaneous Ablative Therapy Unresectable early HCC. It aims at destroying the viable tumor tissue and creating a safety margin of 0.5–1 cm around. It is safe, easy to perform, and well tolerated with very low major and minor complication rates. The best outcome of complete response following ablation varies and is related to the size of the tumor (90–100% in tumors of 2 cm, 50% in the tumors of 5 cm). Hence, the real benefit of therapy lies in treating early, small tumors.

8. Selection Criteria: Child-Pugh class A/B cirrhosis. Performance status of 0–1, Tumor size smaller than 5 cm (ideal < 3 cm), Well-defined intrahepatic with hepatic parenchyma all around, solitary or multiple (not more than 3 in number) with the absence of vascular invasion and extrahepatic disease.

9. Absolute contraindications Intravascular invasion, Tumor located less than 1 cm from the main biliary duct,Intrahepatic biliary dilatation, exophytic tumor or uncorrectable coagulopathy. Relative contraindications Extrahepatic metastases, bilioenteric anastomosis, superficial lesions, lesions close to gall bladder or any part of the gastrointestinal tract, ascites, low platelet count (<50,000/mm3) , pacemaker/defibrillator, hepatic failure.

10. Chemical ablation Chemical ablation involves the use of percutaneous ethanol/ acetic acid injection (PEI) into the tumor. It is inexpensive and can be readily performed with imaging guidance without the use of any special equipment. Mechanism of ethanol/acetic acid ablation: Ethanol distributes through the tumor interstitium , its cytotoxic mechanisms - cytoplasmic dehydration, denaturation of cellular proteins, and small vessel thrombosis. These effects result in coagulative necrosis . Cytotoxic mechanisms of acetic acid - protein denaturation, dissolution of cellular basement membranes, and destruction of interstitial collagen.

11. Technique of chemical ablation Realtime ultrasound (US) guidance and local anesthesia. A 20–22 gauge end-hole or conical tip multi–side-hole needle. Infusion is performed slowly in 0.1– 0.2 mL aliquots with continuous US monitoring. When the tumor becomes echogenic, the needle is withdrawn while injecting local anesthetic agent for local pain relief. Volume of ethanol and acetic acid injection: 95% ethanol or 50% acetic acid. Volume estimation - Volume of the tumor and a “surgical margin” of 1 cm beyond the periphery of the lesion. V= 4/3 π ( r + 0.5).

12. For PAI, the maximum total volume of acetic acid required to ablate the tumor is three times the maximum diameter of the tumor. This total dose is injected over multiple sessions (1–2 mL of acetic acid per tumor per session per week) under US guidance. Advantage of PAI over PEI: Both PAI and PEI are effective in <3 cm(small HCC). PAI has high diffusion capacity, and requires smaller volume of acetic acid and fewer treatment sessions. PAI has an advantage of infiltrating the tumor septae and capsule of tumors, whereas ethanol is unable to do so. Due to this limitation, PEI is unable to ablate the small satellite nodules and create a safety margin. The local recurrence rate of the tumor is therefore higher in PEI than PAI [37% and 8%, respectively (P < 0.001)].

13. Complications: Minor complications - transient pain, fever, transient renal failure (with acetic acid). Major complications (rare ) - Hemorrhage, liver necrosis and abscess formation.

14. Thermal ablation Radiofrequency ablation(M/c), microwave ablation, Cryoablation Laser ablation HIFU

15. Radiofrequency ablation Principle of RFA: Induce thermal injury to the tumor tissue by electromagnetic energy deposition. Types of RFA electrodes : Electrodes which have either monopolar or bipolar technology. RFA electrode designs. (A) Monopolar single electrode; (B) Clustered electrode; (C) Tined electrode; (D) Multitined ; (E) Saline perfused; (F) Bipolar single electrode. Note: The area marked around each electrode represents the shape of ablating zone

16. A.Prongs protrude in “Christmas tree” configuration from tip of needle .B, Ten prongs protrude in umbrella configuration from tip of needle C, Single (solid arrow ) and clustered (open arrow ) cooled-tip needles.

17. Patient selection Contraindication <3 cm size lesions. Up to 5 cm diameter – chances of complete ablation diminish with an increase in tumor diameter. The technique can also be used to treat multiple lesions and up to three lesions can be safely treated in single or multiple sittings. “heat sink effect”. Lesions not < 1cm normal liver parenchyma separating it from the liver capsule, gallbladder, porta hepatis or major vessels. Extrahepatic metastatic disease, tumor volume > 30% TLV , sepsis, severe debilitation, and uncorrectable coagulopathies.

18. Technique of RFA US/CT guidance, under intravenous sedation and standard cardiac, pressure, and oxygen monitoring. To perform a typical ablation with monopolar RFA system, two grounding pads are placed on the patient's thighs to begin with. The electrode is inserted into the lesion under either US or CT guidance. A pulsed RF energy is applied for 15–30 minutes, @ 80°C to 110°C.

19. Post-RFA evaluation Contrast-enhanced sonography is useful for ascertaining the completeness of ablation. In residual disease, reapplication in the untreated area in the same sitting for complete response. Multiphasic CT - evaluating any associated complications.

20. Complications Limitations of RFA Pain or fever. Peritoneal hemorrhage, bile duct injury, hepatic abscess, intestinal perforation. Difficult >5 cm tumor . Tumors adjacent to large blood vessels are difficult to treat due to the “heat-sink effect”—a perfusion mediated tissue cooling reducing the extent of coagulation necrosis produced by thermal ablation.

21. Microwave ablation: Microwave ablation (MWA) uses electromagnetic waves generated from one or more thin microwave antennas that are applied directly to the tumor to create heat and friction that destroys the tumor. The benefit of MWA over radiofrequency ablation (RFA) is the ability to do multiple ablations at the same time. MWA has the potential to destroy larger sized tumors faster and with less pain.

22. Cryoablation: Which the tumor is frozen and this results in cell death. The technique involves creation of an ice ball with subzero temperatures by circulating liquid nitrogen in a probe that is directly inserted into the tumor. Cryoablation is more widely used in kidney, prostate, lung and bone than in liver tumors.

23. High-intensity focused ultrasound ablation: Noninvasive modality producing thermal ablation. The high frequency ultrasound beam is generated by ultrasound transducer which is arranged into a spherical form by an acoustic lens to create a focal point. The beam on reaching the focal point, delivers high temperature focused acoustic energy to the liver tumor producing tumor destruction at a temperature of 60 ‘C. HIFU is effective in tumors close to major vessels like inferior vena cava, portal or hepatic veins. Complete response can be achieved in 91% of tumors of <3 cm and the 1 and 3 years survival rates are 87.7% and 62.4%, respectively.

24. Intra-arterial Procedures • Trans arterial embolization • Trans arterial chemoembolization (TACE) • Trans arterial chemotherapy (TAC) • Trans arterial rhenium/Yttrium therapy (TART)

25. Trans arterial Chemoembolization (Conventional) Intraraterial delivery of chemotherapy agents , emulsion in an oily medium, combined with embolic material. Rationale : HCC supplied by HA, Liver by PV. Advantages: Greater concentrations. Prolonged periods of time. Minimize systemic toxicity. Preserve as much functional liver tissue as possible.

26. Indications Contraindications BCLC-B Nodular encapsulated HCC. Multinodular HCC. Portal vein should be patent. OTHERS: Metastasis from colorectal CA/Neuroendocrine tumors . Child C Occlusion main portal vein Macroscopic vascular invasion / extrahepatic spread /Metastasis. Impaired liver/kidney function. Tumor burden >70%. Decompensated portal hypertension.

27. Procedure Intra- arteral injection of chemotherapeutic drugs followed by embolization of the feeding supply to the tumor. Mixing the chemotherapeutic drugs with lipiodol and the subsequent embolization is performed by either gelfoam pledgets or PVA particles. This results in extensive necrosis of the hypervascular HCC .

28. TACE is two steps : 1)intra- artenal injection of chemotherapeutic drugs 2)Embolization of the feeding supply to the tumor. Chemotherapeutic drug emulsion: Chemotherapeutic drugs + lipiodol Embolization is performed by either gelfoam pledgets or PVA particles This result in extensive necrosis of the hypervascular HCC .

29. Agents used: Doxorubicin, epirubicin . Combination with cisplatin are the commonly used chemotherapeutic agents. Lipiodol, mixed with chemotherapeutic drugs to prepare emulsion, is used as a drug carrier. This drug emulsion is selectively retained within the tumor cells resulting in increased exposure of the neoplastic cells to the chemotherapeutic agents and also enhances the visibility of the emulsion on fluoroscopy.

30. Technique Chemoembolization is performed in the angiography suite, under aseptic precautions with the patient under conscious sedation and through the percutaneous route. Initially diagnostic mesenteric and celiac arteriograms are performed.By using various polyurethane catheter (4 or 5F) with the digital subtraction technique to determine the vascular anatomy, feeding tumor supply and the portal blood flow. The placement of the catheter tip in the feeding artery, as close to the tumor as possible, After advancement of the microcatheter system to the appropriate segmental or subsegmental vessel supplying the tumor, the chemotherapeutic mixture is injected slowly at the rate of 1 mL/minute under continuous fluoroscopic observation avoiding reflux of chemotherapeutic agent into nontarget areas. There are no recommendations regarding the volume of emulsion to be injected with reference to the tumor size.

31. In case of multiple vascular feeders, the emulsion is injected into all the feeders superselectively in divided fractions. In case of significant arterioportal or arteriovenous shunting, a small amount of gelfoam is injected to block the shunt prior to the injection of chemotherapeutic emulsion. Subsequently, the feeding vessels are embolized by gelfoam pledgets to reduce the blood flow and also the wash out of chemotherapeutic agents into the systemic circulation. If the tumor is very large in size, repeated sessions of TACE may be required to achieve complete response . It is also important to search for any extrahepatic supply to the tumor in such cases

32. Complications of TACE: Postembolization syndrome Major complications include hepatic insufficiency, liver abscess, ischemic complications (cholecystitis, bile duct necrosis, perforation of the alimentary tract), and renal dysfunction.

33. TACE using drug eluding beads (DEB-TACE): The main target : Reduce systemic toxicity, Increase the therapeutic efficacy Provide a sustained release of chemotherapy over time without damaging the healthy surrounding hepatic parenchyma. Thus significantly increasing the local concentration of the drug and achieving better tumor response rates.

34. Transarterial radionuclide therapy (TART) Hemodynamic principles and techniques of TART are similar to TACE. Internal radiotherapy by injection of isotopes like 131Iodine+lipiodol, 188 Rhenium + lipiodol and 90 Yttrium (90Y) into the hepatic artery has shown improvement in survival. 90Y radioembolization can deliver extremely high levels of radiation (up to 150 Gy ), with tolerable exposure to normal parenchyma.

35. TART is a safe, effective and promising therapeutic option in patients with inoperable HCC .The best candidate for TART is BCLC-Advanced stage C, i.e. HCC with portal vein tumor thrombosis (PVT).

36. Combination Treatment Increased tumor burden or larger sized tumors, multimodality approach is being considered. Better results than single therapy. Ablative therapies of PEI or RFA are performed after the procedure of TACE in cases of small residual disease, TACE followed by oral chemotherapy is used for advanced HCC and in patients with postresection recurrence (s), RFA or TACE is undertaken frequently.

37. Post procedural care Daily monitoring of liver and renal function. Followup imaging @ 3- 16 weeks. Patient‘s groin site where the arterial sheath was placed should be inspected for psuedoanerysm .

38. Transcatheter arterial embolization (TAE): In this, tumor is embolized with intra-arterial temporary or permanent embolizing materials in single or multiple sessions. It has been proved to be a less effective palliative treatment especially for large and peripherally located HCC due to development of collateral circulation. Transcatheter arterial embolization of the tumor may be done as an emergency procedure to reduce gastrointestinal hemorrhage in selected patients.

39. Gastrointestinal hemorrhage from hepatocellular carcinoma (HCC) is unusual. The causes - varices or due to direct invasion of duodenum, transverse colon and stomach by the tumor. The variceal bleeding may be consequent to portal hypertension secondary to intra-tumoral arterioportal shunts . These patients may respond well to TAE. Some studies have shown that TAE is an effective method for palliative treatment in such patients.

40. Portal Vein Embolization Percutaneous portal vein embolization has become an important preoperative treatment in patients who undergo extensive liver resection due to hepatic malignancy. It is done when future liver remnant volume is less than 25% in case of normal back ground liver (less than 40% in case of cirrhotic patients). The aim is to occlude right portal vein either through ipsilateral or contralateral approach using various embolizing agents such as glue, PVA particles and coils.

41. This results in compensatory hypertrophy of the future liver remnant and hence subsequent increase in the functional reserve of the liver and reduces postoperative hepatic failure. The procedure is done percutaneously using both ultrasound and angiography guidance. In normal livers, sufficient hypertrophy typically occurs within 2–4 weeks, whereas regeneration in patients with cirrhosis can take ≥4 weeks. This technique is mainly useful in noncirrhotic livers with malignant tumor confined to segments of one lobe.

42. THANK YOU References : AIIMS MAMC PGI Comprehensive textbook of diagnostic radiology. Chemoembolization of Hepatocellular Carcinoma with Extrahepatic Collaterals. Imaging at Percutaneous Radiofrequency Ablation of Hepatic Tumors interventional oncological treatment of hepatocellular carcinoma .