Minimally Invasive Interventional Treatments in Oncology

1.05.2020 00:39:29

Interventional Radiology is one of the most frequently used areas in cancer treatments besides cancer diagnosis and staging. In parallel with the technological advancements, the place of the interventional methods in cancer treatment is gaining importance each year. The most significant advantages of these methods are as follows: they can be carried out without pain through a needle hole with local anesthesia, their tumour killing effect is high, they can be administered together with other treatments and the patients can return to their normal lives in a short time after the treatment. The interventional treatment methods for cancer can be examined in 2 groups and these are percutaneous ablations and arterial treatments.

PERCUTANEOUS ABLATIONS

It is the direct destruction of the tumour with special needles placed in it. The most frequently practiced ablation methods are cryoablation, NanoKnife and radiofrequency.

CRYOABLATION

Recently, the diagnosis and treatment methods that play an important role in the struggle against cancer have prioritized the comfort of the patients with the technologic advancements. With cryoablation i.e. tumour freezing technique via needle, one of the most important innovations in this area in the world and which is known as “iceball”, the harmful tissues or tumours in the body are destructed by freezing, and targeting the cancer cell is done with precision.

It is also used in very big masses

In the procedure performed by the insertion of special needles in the body, a tissue or tumour in the body is destructed by freezing. First, appropriate number of needles is placed in the mass with the information obtained from imaging methods such as CT or MRI scan. Whereas a single needle is enough for a mass with a diameter of 1cm, the number of needles increases with the increasing tumour diameter. In the current cryoablation devices, 20-25 needles can be inserted in the body. These can work simultaneously and therefore considerably big masses can be destructed by applying extreme cold.  

Cold down to -80 degrees can be applied to the tumour

In cryoablation technique, argon gas is circulated through the needles and this causes a coldness that varies between -20 and -80 degrees in the tip of the needle. This coldness kills the tumour or pathologic tissue by destroying it. In our country, ablation methods which are usually similar to each other such as radiofrequency, microwave and laser are used most frequently. However, cryoablation is a technique that works with a completely different mechanism and that has may specific properties and advantages. Since cryoablation and the other ablation methods destroy only the tumour with pin-point shots and do not cause damage in the tissues, they can be repeated many times.

 

High rate of success can be obtained in most dangerous cancer types

Cryoablation can be used successfully in the frequently encountered and risky cancer types such as prostate, kidney, lung, liver and soft tissue tumours. While it is used as a standalone procedure in some cases, it is a method that can be used simultaneously with chemotherapy and radiotherapy in other cases. However, there are cases for which cryoablation cannot be used. Since the freezing procedure damages the nerve tissue, it is either not used in the brain, in the spine or in the regions where there are important nerves or it is applied by protecting the nerve tissue with special techniques. It cannot be used in gastric, intestinal or gallbladder tumours and it should be applied with caution in the tumours near these organs. In such cases, entry is made via a needle under ultrasound or CT guidance and gas or fluid is given between these structures and the tumour to move the critical organs away and so the procedure can be performed safely.  

The procedure takes 30 minutes in average

In the cryoablation procedure, the cancerous tumour is transformed into an iceball. When this ice ball melts, the cancerous tumour disappears. This procedure takes 30 minutes in average. Local anesthesia is sufficient for cryoablation, which is a painless method. The patient is discharged on the same day after the procedure. Whereas with other methods, it cannot be understood which part of the tumour is destroyed during the ablation, with this method, an image like an ice mass is seen in the ultrasound examination. The whole area inside of the ice mass beginning from the 0.5cm is named as the fatal region. The most important advantage of cryoablation is that it can be known exactly how much of the tumour is destroyed during this procedure.

RADIOFREQUENCY ABLATION

The most frequently used method in oncologic interventions is “tumour burning” procedure used in the treatment of tumours occurring in the tissues of the liver, lung, soft tissue and bone. Entry is done to the middle of the tumour by needle over the organ with the tumour, and the cancerous tumours are burnt. One of the most frequently used methods used is radiofrequency. Radiofrequency ablation is most frequently used in the tumours of the liver, lung, kidney and thyroid.

MICROWAVE ABLATION

Same as in radiofrequency, this is a method that destroys the tumours by burning but recently, it has become a more frequently preferred method when compared with radiofrequency. It is mostly applied on liver.

NANOKNIFE ABLATION (IRREVERSIBLE ELECTROPORATION)

In this method, with the help of imaging systems, special needles are placed in the tumour and short-term but very high electrical currents are administered under general anesthesia. This way, wide holes are opened in the cellular walls of the cancer cell and the cancer cells die while the healthy cells are not damaged. The most important feature of this procedure is that the critical structures such as the vessels, nerves and stomach-intestines are not damaged much during the ablation procedure. Thus, NanoKnife method is especially preferred in tumours neighbouring such critical organs and structures. With such features, NanoKnife is promising in tumours of the bile ducts in liver and liver tumours adjacent to major vessels and in pancreas and prostate cancers. 

ARTERIAL TREATMENTS

INTRA-ARTERIAL CHEMOTHERAPY

Intraarterial chemotherapy, which is given to patients who do not benefit from chemotherapy, is carried out by detecting the vessels feeding the tumour by angiography and by entering the vessel interventionally and administrating intensive chemotherapy. The most important advantage of the procedure for the patient is that it has little side effects while the effect of the drug on the tumour is high.

CHEMOEMBOLIZATION (TACE)

This is especially performed for liver cancers with no chance of surgery. For this, small particles impregnated with chemotherapy drug or some contrast agents mixed with chemotherapy are injected in the arteries feeding the tumours in the liver. Thus, both the vessels of the cancer cells are blocked and the loaded drug is given directly to the tumour for 1-2 weeks. While the normal liver cells are affected very little from this treatment; the cancerous tissue is very much affected.

RADIOEMBOLIZATION (Y90 TREATMENT)

In radioembolization, very small obstructive particles, which are about one tenth of a millimetre, are loaded with radioactive material and are injected directly to the artery of the liver or to the vessel feeding the tumour. This way, a very high dose of radiotherapy is given to the tumours and the healthy tissues are very little affected. The procedure is practiced both in liver and kidney tumours.

CHEMOSATURATION

This method, which is used only in liver tumours, is the administration of a very intense amount of chemotherapy directly to the cancer cell. While this procedure is being carried out, the artery and vein of the liver are isolated so that a high amount of chemotherapy drug entering the blood circulation and causing toxic effect for the patient are prevented. The procedure is performed in periods of once a month.