KW seminar: Interventional Oncology

Question 1

In the lecture is discussed that when a patient that has been treated for rectal cancer has metastasis to the liver, that first the board discusses the options of surgery. What is something to take into consideration?

Answer 1

The location of the metastasis. If it’s on the edge of the liver, a small part of the liver can be resected. But if the metastasis is located deeper in the liver, a whole piece of the liver needs to be resected and if this is the case you also need to look at the fact if the tumor also comprises blood vessels etc. (invasion). So then other options are possible as well.

Question 2

In the lecture is discussed that when a patient that has been treated for rectal cancer has metastasis to the liver, that first the board discusses the options of radiotherapy. What is something to take into consideration?

Answer 2

That with radiotherapy a large part of the liver needs to be irradiated. But also surrounding organs can be irradiated as a consequence. So radiotherapy is an option, but there are risk to this.

Question 3

In the lecture is discussed that when a patient that has been treated for rectal cancer has metastasis to the liver, that first the board discusses the options of chemotherapy. What is something to take into consideration?

Answer 3

Chemotherapy works best if there are multiple lesions in the body. But treating a single metastasis with systemic chemotherapy…

Question 4

Doctors distinguish patients that still have a full care possible and patients that need palliative care. Here the old situation was that if a patient had full cure possible, the cancer could be resected. If the cancer had spread, then radiotherapy was needed. And when these metastasizing lesions are invasive, chemotherapy is offered. What has changed in the new situation?

Answer 4

See picture.

Question 5

Name two types of treatments that belong in the category interventional oncology.

Answer 5

Needle-guided ablation and catheter-guided ablation.

Question 6

What (in short) is needle-guided ablation?

Answer 6

Use of radiology imaging techniques to guide a needle with a probe into the tumor, the tumor can then be destroyed by several techniques (percutaneous ethanl injection, radiofrequence ablation, cryoablation etc.)

Question 7

What (in short) is cathether-guided ablation?

Answer 7

Via the arm or via the groin you go into blood vessels and into the blood vessels within the liver (or other organ that has a tumor). Here, the cathether is placed into the vessel that supplies the tumor with nutrients and oxygen and beads are then injected into this vessel. These beads are either radioactive or loaded with chemotherapy.

Question 8

Explain in short the general mechanism, indications (for what tumor) and complications for cryoablation?

Answer 8

• General: Cryoablation means freezing the tumor so that there’s irreversible damage of cancer cells.
• Indications: kidney, prostate, bone, liver (liver is fairly dangerous due to freezing/cracking of healthy parts)
• Complications: hemmorrhage due to rupture, liver abscess due to biliary injury and with large tumors there’s a risk for cryoshock syndrome.

Question 9

What is radiofrequency ablation (RFA)?

Answer 9

Electrodes are placed within a tumor. The electrodes are connected to a machine, there are also grounding pads on thighs to complete the circle. The alternating current creates friction between ions, which creates heat. If the temperature rises between 50-100 degrees, tumor coagulation occurs.

Question 10

For radiofrequency ablation (FRA) electrodes are used that either are non-expandable or expandable. The type of electrodes affects the shape of the ablation zone. How?

Answer 10

Non-expandable electrodes have an oval ablation zone. Expandable electrodes (umbrella) have a spherical ablation zone. (Note that the non-expandable electrodes are not very practical, since the shape of the ablation one is much smaller compared to the expandable electrodes).

Question 11

What two ways are their to apply electrodes?

Answer 11

Electrodes can be placed on the tumor during surgery, it can be done laparoscopically or placed percutaneous where it is ultrasound guided.

Question 12

What is the heat sink effect in radiofrequency ablation?

Answer 12

So radiofrequence ablation therapy works through a needle that heats up the tumor which results in tumor coagulation. The heat sink effect occurs when a tumor coagulates through the use of electrodes and heat. But if a blood vessel is near the tumor, the temperature of the blood (37 degrees) will slow and cool down the process of coagulation near the area of the blood vessel. So the heat sink effect reshapes the ablation zone.

Question 13

What factors influence the recurrence rate?

Answer 13

• Regional or distant tumor
• Size of tumor
• Approach (open, laparoscopic, percutaneous)
• Proximity of vessels (heat sink effect)

Question 14

What is microwave ablation (MWA)?

Answer 14

Probe/electrode is placed on tumor, microwaves are generated that travel through this electrode and can coagulate a tumor of <5 cm within minutes.

Question 15

Why is microwave ablation more effective than radiofrequency ablation?

Answer 15

Microwave ablation generates active heat and therefore is more specific (blood vessels don’t affect the heat but blood vessels van be affected by the high heat (>100 degrees))

Question 16

When is microwave ablation not used?

Answer 16

When a biliary duct is close to the tumor

Question 17

What is Laser Induced Thermotherapy used for mostly and why at the same time is this therapy not used frequently anymore?

Answer 17

It is mostly used for superficial cancer in e.g. head and neck area. But since you need to use a lot of electrodes and the ablation zone is still small, it isn’t used very frequently anymore.

Question 18

What is High-Intensity Focused Ultrasound (HIFU)?

Answer 18

Patients goes into a MRI. Here, a transducer in the MRI produces converging ultrasound-bundles which heat up focal spot (ablation zone).

Question 19

For what cancers is High-Intensity Focused Ultrasound (HIFU) mostly used? And for what cancer can it not be used for?

Answer 19

It is mostly used for prostate cancer, tumors in the pelvic area and deep seeded tumors in the liver. It doesn’t work in the lungs, due to the air in the lungs (air blocks the incoming bundles of heat that are ultrasound led).

Question 20

What is Percutaneous Alcoholablation (PEI)?

Answer 20

A side hole needle is percutaneous ultrasound or CT-guided into the tumor. Here, 95-100% of ethyl-alcohol is injected into the tumor.

Question 21

(For illustration): Radiofrequency Ablation (RFA) has a better cure rate than Percutaneous Alcoholablation (PEI). Why is Percutaneous Alcoholablation still used more in developing countries?

Answer 21

There are many people in developing countries with hepatitis A/B who develop tumors in the liver. It is known that RFA works better, but PEI is cheaper.

Question 22

What is Irreversible Electroporation (IRE) (also called nano knife)?

Answer 22

With electrical pulses small (nano) holes are created in the cellular membranes of the tumor which destroys the cancer cells without any additional damage to surrounding tissues (which is the case for many therapies that include heat).

Question 23

What is reversible electroporation?

Answer 23

Highly intense electric pulses create small pores in membranes. Because of this, DNA/medicine and other stuff can be transported from the extracellular compartment to the intracellular compartment.

Question 24

When does reversible electroporation result in irreversible electroporation?

Answer 24

When the intensity of the electric pulses is increased (up to 3.000 V), the membranes is irreversibly damaged. This causes cells to go into apoptosis (not coagulation necrosis).

Question 25

What are (theoretical) advantages of irreversible electroporation (IRE)?

Answer 25

All cells die, but the extracellular matrix remains intact. Therefore less complications such as blood vessel injury, biliary tract injury, intestinal injury and nerve damage (which makes treatments of tumor near these sides possible).

Question 26

What cancers can be treated with irreversible electroporation (IRE)?

Answer 26

Central located liver tumors, pancreatic cancer, central renal cancers, deep seeded tumors next to nerves, prostate cancer.

Question 27

The liver has a double blood supply. 75% of all blood is supplied by the vena portae and the rest is supplied by the a. hepatica. Why is cathether-guided ablation useful in liver cancer?

Answer 27

Because tumors in the liver receive their blood through the a. hepatica which is only 25% of normal blood supply. With cathether-guided ablation you can very easily ablate the a. hepatica, leaving enough blood for the healthy liver.

Question 28

Why is their a revival in survival of liver cancer through the use of catheter-guided ablation?

Answer 28

Because a tool has been added to this treatment where you implant a pump into the body that can continuously secrete chemotherapy into the tumor.

Question 29

So depending on the tumor for hepatocellular carcinoma we tend to use beads that we have loaded with chemotherapy. How is this type of cathether-guided ablation called?

Answer 29

Trans-Arterial Chemo-Embolisation (TACE).

Question 30

What is (trans-arterial) radio-embolisation (SIRT)?

Answer 30

Cathether-guided ablation where beads are used that are irradiated.

Question 31

Why is radio-embolisation superior over chemo-embolisation?

Answer 31

Because you only need a small amount of beads compared to the amount of beads used in chemo-embolisation.

Question 32

What is portal vein embolisation?

Answer 32

If there’s a large tumor in the right liver lobe, a cathether is placed into the right portal vein. This portal vein is then occluded, which causes the left liver lobe to grow (future liver remnant). Note: if future liver remnant >30%, then the surgeon can safely resect the other part of the liver.

Question 33

Just have a look to give yourself an idea if and when interventional oncology is used.

Answer 33

Ok

Question 34

What is the CLOCC trial?

Answer 34

A trial where chemotherapy is compared with chemotherapy + radiofrequency ablation.

Question 35

Radiofrequency should be favored when it comes to complication rate but when it comes to overall survival surgery is still the standard. But several studies point to different results (so no significant difference). To what did this lead?

Answer 35

To the collision trial about colorectal liver metastases (surgery vs thermal ablation)

Question 36

When are cryoablation and radiofrequency ablation used?

Answer 36

• Tumors < 4 cm
• If partial nefrectomy is not possible
• If nessecary to spare the kidneys
• If there’s co-morbidity

Question 37

What therapy is used in a patient with treated rectal cancer and liver metastasis?

Answer 37

Small tumor located deep in the liver, thus microwave ablation.

Question 38

What therapy is used in a patient with a huge liver tumor?

Answer 38

A mix of therapies. First Trans-Arterial Chemo-Embolisation (TACE), then radiofrequency ablation (not really suited due to heat sink effect) and at last microwave ablation.

Question 39

What therapy is used in a patient with a solid left kidney mass (in the only kidney left)?

Answer 39

Microwave ablation