More than 50% of global primary liver cancer (HCC) occurs in China, which is the number two killer among cancers. In recent years, the overall level of hepatocellular carcinoma treatment has improved. In addition to the improvement of early diagnosis rate and surgical methods and techniques, the application of new treatment technologies plays an important role in the treatment of hepatocellular carcinoma. Among them, local ablation therapy represented by radiofrequency ablation (RFA) has developed rapidly and its efficacy in treating small hepatocellular carcinoma has been widely accepted.
The efficacy of RFA has been widely accepted. The 2008 edition of NCCN clinical practice guidelines for HCC in the United States has identified RFA as an important treatment tool for liver cancer as well as surgery. However, most of the patients with liver cancer in China are middle and advanced stage cancer with large tumors, and it is equally difficult and risky to perform RFA for patients with common non-surgical indications. Especially for the three major challenges of larger tumors, adjacent peripheral organ tumors and blood-rich tumors, standardized treatment and individualized treatment need to be established; and imaging-guided treatment should be emphasized.
I. Advantages of ultrasound-guided RFA treatment
Ultrasound-guided percutaneous RFA treatment can flexibly select the puncture route under the guidance of color ultrasound, and guide the needle to avoid abnormal blood vessels, large blood vessels and ligamentous structures. As a minimally invasive thermal coagulation treatment method, RFA has the advantages of no radiation, low cost and easy operation, which will play an important role in the treatment of focal liver cancer and recurrent cancer.
II. Indications
A large number of patients with non-surgical indications for hepatocellular carcinoma include those with poor liver reserve function and non-small hepatocellular carcinoma. Therefore, the indications for percutaneous RFA in Chinese patients are wider than those reported abroad. The selection of indications for percutaneous RFA is not sufficient only based on the patient’s systemic condition (Child-Pugh classification) and TNM stage of the tumor, but also requires a comprehensive analysis in combination with the presence or absence of tumor envelope, location and adjacent relationship, degree of blood supply and biological behavior. 2008 Selection of Surgical Treatment for Hepatocellular Liver Cancer – 3rd Edition), we propose the following two-grade proposal of indications and contraindications for radiofrequency ablation treatment of HCC for reference.
(i) Indications
Referring to patients who may obtain local radical efficacy by RFA treatment.
1.≤3 cancer foci with the largest foci ≤3.0 cm.
2.Single lack of blood supply liver cancer ≤5.0cm in diameter.
3.Recurrence of cancer 1 year after surgical resection, with the same tumor size characteristics as above.
4.The above tumor has envelope or clear boundary, and the periphery of the tumor has sufficient safety range for tumor extirpation.
5.The above tumor has Child-Pugh grade A or partial grade B liver function and no extra-hepatic metastasis.
(II) Relative indications
The following tumors may have better efficacy or tumor reduction by using adjuvant technology treatment strategy.
1.Tumor size and morphology and patient’s liver function and other conditions meet the indications, but the tumor location for RFA is difficult and risky, such as adjacent to the cardiodiaphragm, gastrointestinal, right adrenal gland, gallbladder, hepatic hilar, and large blood vessels.
2.Non-surgical indications, 5-6 cm tumor with poor blood supply after repeated transcatheter arterial chemoembolization (TACE).
3.For larger tumors or multiple tumors treated by combined surgical resection, or elective fractionated treatment can be performed.
4.Preoperative treatment during liver transplantation for liver cancer.
5.Short-term recurrence within 1 year after surgical resection is not suitable for re-operation.
6.Tumor combined with small carcinoma thrombus in the terminal branch portal vein
7.Part of Child-Pugh grade C has been significantly improved by liver preservation treatment, with ≤3 tumors and maximum foci ≤3.0cm.
(C) Contraindications and relative contraindications
Referring to the following patients who may cause complications or poor efficacy.
1.Tumor scope >5cm, showing multi-nodular infiltration and invading large blood vessels.
2. The number of tumors is ≥5.
3.Large tumor located on the visceral surface of the liver >4cm and more than 1/3 of the tumor protrudes from the liver surface, large tumor in the caudate lobe of the liver. 4.There is a portal trunk, primary branch or hepatic vein thrombus, severe extrahepatic metastasis.
5.Child-Pugh grade C (persistent massive ascites, jaundice, etc.) without improvement after hepatoprotective treatment.
6.Obvious vital organ failure.
7, Active infection, especially biliary co-infection.
8.History of multiple ruptured esophagogastric fundic varices is a relative contraindication and requires caution.
Treatment principles
The key to reduce recurrence and metastasis is the overall inactivation of the tumor by primary ablation. The scope of CEUS enhancement in the arterial phase is proven to define the extent of HCC infiltration, and the application of guided RFA must be emphasized. the safe scope of ablation should completely cover and exceed the cancer circumference by 0.5 cm; the border is unclear and irregular tumor increases in 56.4% range by CEUS, so the use of The RFA or ablation range under CEUS should be at least greater than or equal to 1 cm of cancer circumference. For tumors larger than 3.5 cm, 5 cm spherical ablation foci should be used for multifocal overlapping ablation. Multiple cancer foci should be treated with one to three times of TACE combined with RFA or surgical resection of the main cancer foci and RFA ablation of the daughter foci.
IV. Treatment plan
Once patients with hepatocellular carcinoma are selected for RFA treatment and meet the indications and basic conditions for RFA treatment, they should first be treated by Contrast-enhanced ultrasound (CEUS).
The first step is to understand the local situation of the tumor through ultrasound (CEUS) or other imaging means (enhanced CT, MRI), such as the number and characterization of the tumor, the presence of subfoci, whether the morphological boundary is clear and neat, the scope of infiltration, among which the relationship between the tumor and large blood vessels and surrounding organs is very important, so as to confirm the target of RFA treatment and the scope of ablation. Then, the treatment plan and ablation localization procedure can be formulated, and the corresponding additional methods and strategies can be selected to carry out the standardized treatment of RFA and appropriate individualized treatment.
(I) Large tumor treatment plan
For large tumors, multifocal overlapping ablation protocols are used to effectively inactivate the largest range of tumor foci with the least number of ablation foci. The basic elements include calculation of the number of ablation foci, ablation localization pattern and reasonable ablation procedure. For example, 4 foci were ablated in the orthotetrahedral mode for the 5.3 cm range of the spheroid; for the 6.5
For the 6.5 cm range, the positive pentagonal mode was used, with 5 foci in the largest diameter section, 1 foci directly above and 1 foci directly below, and a total of 7 foci ablated, with the puncture point located 1.3-2.2 cm from the center.
cm; for 6.5-7.5
The main tumor of irregular body tumor is enlarged according to its outer cut sphere or ellipsoid, and the irregular outer convex part is supplemented by small sphere. Reference may be made to the use of anatomical structures adjacent to the point of needle placement to assist in puncture localization. Image-guided ablation of large tumors according to the protocol is easy to obtain overall conformal inactivation. For large tumors that are difficult to inactivate and difficult to remove surgically, intraoperative RFA is proven to be safe and effective, but has shortcomings such as long anesthesia time and lack of guidance monitoring means.
(2) Individualized treatment for tumors in special sites
For larger tumors located in the adjacent gallbladder, intestinal duct and diaphragm, individualized protocols are needed for treatment due to limited safety scope, high recurrence rate and many complications. By and large, multiple small focal ablations are designed for tumors in adjacent areas, while appropriate strategies such as local water injection to separate tumors, lifting and reaming to improve inactivation rates and reduce surrounding organ burns, and aggressive post-treatment countermeasures can help reduce comorbidities. Intraoperative or laparoscopic RFA facilitates proper treatment of these tumors as well as large tumors on the liver surface.
(iii) Treatment strategy for blood-rich tumors
RFA can improve the efficacy after controlling tumor blood supply by TACE 1-2 times; for refractory tumors with unsatisfactory effect of TACE and unable to adhere to treatment but still rich in blood supply, RFA also has problems such as difficult to completely inactivate and easy to recur and metastasize. When RFA is performed alone, firstly, small ball foci with high energy are used to “base and coagulate” the area where the tumor vessels are penetrated into the tumor as shown by ultrasound, and then other areas are ablated after enhancing the blocked vessels. For cases treated locally by TACE or by alcohol injection, RFA can be guided by CEUS to understand tumor necrosis or active area, which can effectively inactivate tumor and reduce damage to normal tissue.
(IV) Combination therapy for refractory tumors
For non-surgical liver cancer with unclear boundary and larger than 6 cm, it is more appropriate to combine with surgery and TACE for comprehensive treatment. Adopting ablation of tumor near liver blood supply area and safe area first, reducing tumor and then elective surgical resection can reduce recurrence and metastasis and prolong survival. It can also be used to reduce the number of TACE combined with RFA to improve the inactivation rate and reduce the damage to liver reserve function. It has been reported that intraoperative application of Pringle strategy to temporarily block the portal vein and hepatic artery can reduce the blood supply to the target tumor and adjacent liver tissues, and obtain a safer and more complete ablation effect.
V. Analysis of common complications and their causes
In recent years, with the widespread use of RFA and the increase of treatment cases, the number of complications related to RFA treatment has gradually increased, and some of them may even lead to death. Therefore, it is important to fully understand the causes of RFA complications and to master the correct treatment methods,
Therefore, a thorough understanding of the causes of RFA complications and the correct management of these complications will facilitate safer treatment, better selection of indications, reduce the occurrence of serious complications, and improve the efficacy of RF treatment.
The complications of radiofrequency treatment mainly include mechanical injury caused by interventional operations, thermal injury caused by thermal ablation treatment and infection caused by other reasons. Studies have reported that the incidence of serious complications of RF treatment for liver tumors is about 2.2%-8.9%, and the mortality rate is 0.09%-1.6%. Bleeding and intestinal perforation were reported to be more serious complications at home and abroad, which were the main causes of death, and the incidence of abdominal wall implantation metastasis was higher, which affected the promotion and application of RFA.
Prospect
RFA treatment for hepatocellular carcinoma not only prolongs the survival period of many patients, but also gives them good vital signs and quality of life because it is minimally invasive and does not damage the reserve function of the liver, and repeated treatment is feasible to enhance patients’ confidence. As the treatment technology becomes more skillful, the number of patients receiving this treatment increases, and the application in China is promising. Emphasis on standardized RFA under the guidance of imaging can improve the efficacy and expand the scope of application for non-surgical liver cancer and postoperative recurrent cancer. Clinical studies have confirmed that RFA combined with TACE, RFA to shrink the tumor in the second stage of surgical resection or block the arterial blood supply, open RFA and other treatment modes make RFA play an important role in the comprehensive treatment of hepatocellular carcinoma, and also provide an effective minimally invasive treatment means to establish a hepatocellular carcinoma treatment mode that meets the national conditions.