Interventional radiological methods are applications that are little known, but their importance is increasing in cancer treatment. The rate of cancers diagnosed in the early stages is increasing day by day, which distracts us from classical surgeries. These methods are applied by expert interventional radiologists.
Surgery in cancer treatment is one of the main treatment methods that has been indispensable for centuries. Especially in the last 20-30 years, there have been important developments in technology and in the medical treatment of cancer. As a result of the detection of a group of cancers being sensitive to chemotherapy and radiotherapy, surgery is performed in these tumors or only in selected patients. An example of these cancer types is nasopharyngeal cancer, which is called upper pharyngeal cancer. In the early and advanced stages of laryngeal cancer, surgery has been replaced by radiotherapy and radio-chemotherapy. With the increase in the importance of radiotherapy in cancer treatment and the technological revolution in this field, radiotherapy has been used in many types of cancer. Over time, this success has led to the use of stereotactically applied radiotherapy method as SRS (radiosurgery), that is, radiosurgery. Today, radiosurgery has become extremely popular applications in brain tumors, many cancer types that have been regenerated in limited areas and sizes, early stage lung cancer and prostate cancer.
Currently, 3 groups of methods are used for percutaneous ablation in cancer:
It is the destruction of the tumor by injecting chemicals such as alcohol and acetic acid into it. It is an effective and safe method that has been used all over the world for more than 20 years. The most important advantages are low cost and less side effects. However, sometimes multiple attempts are required to completely kill the tumor.
It is mostly used in liver tumors, especially in the primary tumor of the liver (hepatocellular carcinoma). Apart from this, it is also used in thyroid tumors and lymph node metastases.
It is based on the destruction of the tumor by heating or freezing it by means of an electrode placed in its center. These methods;
The most popular of these is radiofrequency ablation (RFA), the second most common being microwave. In radiofrequency, alternating electric current is applied to the tissue and the ions in the tissue are activated. The friction that occurs as a result of this movement turns into heat and the tissue is destroyed. In the microwave, on the other hand, heat is produced by activating the water molecules in the tissue with high frequency electromagnetic waves. The main difference between the two methods is the use of electric current in radiofrequency and electromagnetic waves in microwave to generate heat. Both methods are effective in conductive areas such as the liver and soft tissue, but the experience with radiofrequency is much greater.
After it is placed in the tumor, alternating current is given to the tumor tissue through the needles opened in the shape of an umbrella. This current moves the (+) and (-) charged ions back and forth in cancer cells, creating an average of 80-100 degrees heat around the needle. The heat generated causes tissue death in an area of approximately 3-5 cm in diameter around the needle. The size of the destroyed area may vary depending on the type and number of needles used.
Radiofrequency ablation has been used in the field of cancer for more than 25 years. It was first used in liver cancers and metastases, and then it was widely used in lung, kidney, thyroid and bone tumors.
The development of microwave ablation has shown a parallel development with the microwave heaters we use in the kitchen in daily life. These waves, created by needles (antennas), move the water molecules in the tissue in the form of waves (oscillation), and heat between 80-100 degrees is generated in the tumor tissue by the friction of these molecules. The heat generated causes the death of the cancerous tissue in an area of approximately 3 cm in diameter around the needle. This area may increase or decrease slightly depending on the duration of the ablation, the type and number of needles used. In microwave ablation, electromagnetic waves are sent to the tissue instead of electricity.
Cryoablation is an ablation method that freezes and destroys cancerous tissue. During the procedure, high-pressure Argon gas is passed through the needles placed inside the tumor and released at the very tip of the needle. The sudden decrease in the pressure of the Argon creates a cooling effect, that is, freezing, in the tissue up to minus 40-80 degrees. In this phenomenon, called the Joule-Thompson effect, an iceball forms around the cryoablation needle. This ice ball leads to widespread tissue death as a result of the formation of ice crystals in the tumor, occlusion of the vessels and self-death of cells (apoptosis).