1.What is radiofrequency ablation for liver cancer? What is its principle?
Radiofrequency ablation is essentially a physical treatment method mainly using radiofrequency waves as the medium, and it is one of the most advanced physical treatment methods in liver cancer treatment at present.
The main working principle of radiofrequency ablation is that the radiofrequency waves generated by the radiofrequency generator are guided to the area to be treated by electrical conduction and professional key guiding electrodes, and the rapid increase of temperature causes the evaporation, drying and solidification of water inside and outside the cells, resulting in sterile necrosis of local cells. In the effective range, the local cells will be completely inactive, which is equivalent to the “excision” of the local lesion.
Radiofrequency ablation is a good choice for patients with recurrence of tumor due to its advantages of high efficacy, low trauma, fast recovery and less surgical complications, which can control the condition of recurrence of tumor after surgery and bring hope of survival to patients with liver cancer.
2. Current treatment methods of common liver tumors.
At present, the mainstream treatment methods for liver tumors mainly include open surgery, interventional therapy and radiofrequency ablation. In essence, surgery and radiofrequency ablation belong to the category of physical therapy, while TACE has both physical therapy and chemotherapy, and in terms of effect, it is more inclined to chemotherapy. The differences between the two treatment methods are as follows
Physical therapy: Physical therapy methods are the most thorough treatment measures, and properly applied, they are the effect of total annihilation of tumor cells. The specific surgical methods include: one, of course, is the surgical method to move the tumor tissues out of the body, which is also equivalent to a more complete annihilation war; the other is the method to increase the local temperature to achieve the purpose of tumor elimination. There are many methods to raise the temperature locally, radiofrequency ablation is one of them, which can also achieve the result of complete elimination of tumor tissues.
Chemotherapy: If patients are not suitable to use physical methods, they can choose chemical methods. Most of the chemotherapy methods can not completely eradicate the tumor cells, but can have a certain effect on the cell growth, but cannot achieve “annihilation”. The common and familiar one is chemotherapy. By interfering with the metabolic process of cells and affecting their growth, various drugs are used to slow down their development.
The treatment of liver cancer should be combined with the improvement of autoimmune system. The purpose of physical or chemical treatments is mainly to directly destroy tumor cells, but in fact, the body itself has certain ability to remove or inhibit the growth of tumor cells, so it is also important to make good use of the body’s own ability and strengthen its own immunity. These measures, mainly are some immune modulation measures. Including should ensure the nutritional intake of patients, don’t limit the kind of food eaten, ensure the supply of protein (meat, etc.), the maintenance of nutritional status is the basic guarantee of immunity; secondly, reasonable application of immunomodulatory drugs, such as thymidine, etc., for active immune regulation; in addition, traditional Chinese medicine, etc., has an important role in increasing immunity, and under the premise of not affecting the food eaten, it can be taken appropriately, which has a certain effect against tumor. In addition, traditional Chinese medicine, which plays an important role in increasing immunity, can have a certain effect on anti-tumor if taken properly without affecting food.
3.What kind of liver cancer should be treated by radiofrequency ablation first?
As a new treatment method for liver cancer, radiofrequency ablation has its technical advancement such as less invasive and complete elimination of lesions, but not all liver cancer treatments can choose radiofrequency ablation.
Firstly, it is judged by the size of the tumor. The main mechanism of radiofrequency ablation is to achieve tumor cell inactivation by local heat energy. Since the main medium of heat energy generation is the RF ablation needle, the main mechanism of RF ablation is the inactivation of tumor cells. From the technical aspect, the effective action diameter of commercialized RF ablation needles generally does not exceed 5 cm, and the most reliable action range is within 3 cm. This imposes specific requirements on the size of the tumor. Indications for radiofrequency ablation: The maximum diameter of the tumor should preferably not exceed 3 cm. For tumors with a maximum diameter of 5 cm or less, the use of special ablation needles, or multi-point deployment of needles, will also have a better treatment effect in some patients.
Secondly, the location of the tumor is important. Because the main mechanism of radiofrequency ablation is local thermal effect, which has a killing effect on tumor cells, but it can also damage normal tissues. Therefore, whether the damage to normal tissues and structures can be avoided in the treatment process is one of the bases to judge whether RF ablation is applicable. Tumors in certain areas are not suitable for radiofrequency ablation. For example, if the tumor is located at the edge of liver, closely related to intestinal canal, or at the edge of gallbladder, or adjacent to diaphragm, local hyperthermia may cause damage to adjacent organs and even lead to serious complications such as intestinal perforation, and so on.
Thirdly, the treatment effect cannot be guaranteed. In order to ensure the effective thermal killing of tumor, the treatment process must ensure that the temperature reaches the target temperature, otherwise the tumor cells will have residual and increase the recurrence rate. Therefore, it is also necessary to exclude the situation where the local temperature cannot reach the target value due to the possible loss of thermal energy in the treatment over kind. For example, for tumors located in large blood vessels, such as around the hepatic veins, the continuous flow of blood will cause a continuous loss of thermal energy during the treatment process, and the local temperature will not reach the target value, thus failing to achieve the treatment goal. Tumors in similar locations are relative contraindications to radiofrequency ablation treatment, and radiofrequency ablation will not be chosen when a better option is available.
Fourth, the complication of bleeding from the puncture tract. Even if a patient is suitable for radiofrequency ablation, there is a risk of complications. Since the ablation needle must pass through part of the liver to reach the target lesion, bleeding from the puncture tract is one of the most likely complications of radiofrequency ablation. To ensure safe puncture, the patient’s coagulation must be relatively normal or can be corrected by medication. In practice, complications such as bleeding from the puncture tract are also greatly increased if the volume of abdominal water is enormous and the distance between the liver and the abdominal wall is increased, to name a few.
However, the patient’s condition is not static, and neither are the treatment options. Experienced doctors will choose to apply the treatment plan according to the patient’s physical condition and lesion, and radiofrequency ablation can be used accordingly in the early, middle or late stages of treatment, combined with other treatment methods to achieve optimal results.
4. Tumors larger than 3-5 cm can also undergo radiofrequency ablation and improve the efficacy after reducing the tumor volume through therapeutic measures.
Theoretically, the effect of radiofrequency ablation is mainly related to the tumor volume. For non-indicated tumors (those with larger volume, especially those larger than 5 cm), radiofrequency ablation may still be performed as long as its volume can be effectively reduced.
According to the nature of tumors, they are mainly divided into primary tumors (e.g. liver cancer) and secondary tumors (e.g. liver metastases from colon cancer), and different measures can be taken respectively.
For primary tumors, some chemical approaches have significant effects on shrinking the tumor. Among them, interventional embolization is preferred. after TACE treatment, by reducing the blood supply of tumor arteries and local chemotherapy, the growth of tumor is inhibited, and necrosis can occur in the core part of tumor in sensitive cases, so that the tumor volume is reduced. After 1 cycle or 2-3 cycles of treatment, if the tumor is monitored to have shrunk to within the effective range of radiofrequency ablation, radiofrequency ablation can be performed. Combining the two for sequential treatment, fully combining the advantages of both methods, can reduce the number of treatments and improve the treatment effect. Secondly, ultrasound-guided anhydrous alcohol injection, etc., can also be applied to certain tumors, especially those with poor arterial blood supply, to reduce the tumor volume through local chemical killing, followed by radiofrequency ablation.
Secondary tumors, mainly metastases, most of them require systemic or local chemotherapy to control tumor growth, unless some special types are involved. For those who are sensitive, the tumor volume can be reduced and enter the effective range of radiofrequency ablation, then radiofrequency ablation can be performed.
5.Advantages of radiofrequency ablation for hepatocellular carcinoma, common treatment paths and options.
Radiofrequency ablation of hepatocellular carcinoma essentially belongs to the category of interventional treatment, and also has the advantages of minimally invasive interventional treatment. Generally speaking, most of the liver cancer radiofrequency ablation treatments are performed under local anesthesia through the skin, and certain amount of pain-relieving and sedative drugs will be given to reduce the discomfort during the treatment. In terms of invasiveness, for a single lesion, the skin only needs a pinhole-sized wound to complete the procedure.
Therefore, the ability to complete the procedure with such minimal trauma is due to two factors.
(1) Strict grasp of indications, not suitable for radiofrequency ablation is firmly not forced to carry out.
(2) the help of advanced imaging and navigation equipment.
At present, the treatment is usually performed under CT guidance, partly under ultrasound guidance, or under DSA equipment guidance. The rapid development of imaging equipment technology ensures precise navigation of the RF ablation needle puncture process and guarantees the treatment effect.
In special cases, the treatment can also be performed transabdominally, either open or under laparoscopic guidance. Some tumors in special sites may not be treated with RF ablation by the percutaneous route, but can be treated by the transabdominal route. For example, tumors in the margins of the liver. The transabdominal route undeniably broadens the indications for RF ablation, but the transabdominal route is far more invasive than the transcutaneous route and also requires general anesthesia. There are higher demands on the patient’s general condition to ensure the safety of the procedure.
In conclusion, there is no best method for the patient, only the most appropriate one. Strictly grasp the indications in order to achieve the most desirable treatment results with the least and most reasonable trauma.