The local ablation therapy is a type of treatment that uses physical or chemical methods to directly kill the tumor tissue by targeting the tumor with the guidance of medical imaging technology. It mainly includes radiofrequency ablation (RFA), microwave ablation (MWA), cryoablation, high power focused ultrasound ablation (HIFU) and anhydrous ethanol injection (PEI), which are minimally invasive, safe, simple and easy to perform multiple times. The imaging-guided techniques include US, CT and MRI, while the treatment routes are percutaneous, trans-laparoscopic surgery and trans-open surgery.
1, indications and contraindications.
(1) Indications: Usually applicable to single tumor with maximum diameter ≤5cm; or tumor number ≤3 and maximum diameter ≤3cm. Liver function is graded as Child-Pugh A or B, or the standard is achieved with medical liver care. Sometimes, for single tumors >5cm in diameter that cannot be surgically resected, or multiple tumors with a maximum diameter >3cm, local ablation can be used as part of palliative comprehensive treatment, but it needs to be strictly controlled.
(2) Contraindications.
(i) Huge tumor or diffuse hepatocellular carcinoma.
(② Combination of portal trunk to secondary branch carcinoma thrombosis or hepatic vein carcinoma thrombosis, adjacent organ invasion or distant metastasis.
③Tumors located on the visceral surface of the liver, more than 1/3 of which are exposed.
④ those with a liver function classification of Child-Pugh grade C, which cannot be improved by liver protection treatment.
⑤ ruptured esophagogastric fundic variceal bleeding within 1 month prior to treatment.
(vi) Those with uncorrectable coagulation dysfunction and obvious blood abnormalities with a significant bleeding tendency.
(vii) Intractable massive ascites with malignant fluid.
(viii) Combined active infection, especially inflammation of the bile duct system, etc.
(⑨) Failure of vital organs such as liver, kidney, heart, lung and brain.
⑩Patients with impaired consciousness or unable to cooperate with treatment.
Meanwhile, tumor in the first hilar region should be a relative contraindication; tumor close to the gallbladder, gastrointestinal, diaphragm or protruding from the hepatic peritoneum is a relative contraindication to percutaneous puncture route; intrahepatic lesions with extrahepatic metastases should not be regarded as absolute contraindication, and sometimes local ablation therapy can still be considered to control the development of local lesions.
The ablation methods that can be carried out in our department are
(1) Radiofrequency ablation (RFA): It is the representative treatment mode of minimally invasive treatment for liver cancer and the most widely used thermal ablation method; its advantages are convenient operation, avoidance of open surgery, short hospitalization time, precise efficacy and relatively low cost. For patients with small hepatocellular carcinoma, the long-term efficacy of RFA is similar to that of liver transplantation and hepatectomy, and is superior to TAE/TACE treatment alone. Compared with anhydrous ethanol injection, RFA has significant advantages of high radical rate, less number of treatments required and high long-term survival rate for 3-5 cm tumors.
The essence of RFA treatment is the precise inactivation of the tumor as a whole and minimization of normal liver tissue damage, which presupposes the confirmation of the extent of tumor infiltration and satellite foci. Therefore, precise imaging prior to treatment is highly emphasized, and ultrasound is the preferred method to guide RFA treatment. In recent years, ultrasonography (CEUS) has played an important role; CEUS helps to confirm the actual size and shape of the tumor, define the extent of tumor infiltration, detect microscopic hepatocellular carcinoma and satellite foci, and provide a reliable reference basis for developing ablation protocols to inactivate the tumor. The tumors in the peripheral areas such as cardiodiaphragmatic surface, gastrointestinal area, gallbladder and hepatic hilum are not safe enough and prone to complications. For tumors >5cm, RFA treatment is difficult to obtain radical efficacy; it is easy to miss small satellite foci, resulting in a high recurrence rate; RFA is difficult to control metastasis, and there are problems such as needle tract metastasis, puncture-induced damage to surrounding organs and induced rupture of liver cancer.
(2) ercutaneous ethanol injection (PEI): It is suitable for the treatment of small hepatocellular carcinoma with diameter ≤3 cm and recurrent small hepatocellular carcinoma. For hepatocellular carcinoma >3 cm or recurrent foci not suitable for surgery, it can also play the role of palliative treatment. Clinically, some cancer foci are close to the hepatoportal, gallbladder and gastrointestinal tract tissues, and thermal ablation treatment (RFA and MWA) may easily cause damage; in this case, PEI or PEI combined with thermal ablation can be considered to prevent complications.
(3) Ar-He knife: using freezing to treat tumors.
RFA and MWA both cause local tumor cell necrosis through thermal effect, but the energy introduced by MWA may be higher and the ablation range is relatively larger, but there is no significant difference between them in terms of local efficacy, complications, and survival rate. The necrosis of the lesion should be regularly observed after ablation treatment, and if any lesion remains, it should be actively treated to improve the efficacy of ablation treatment.
Currently, there is a clinical controversy as to whether surgery or percutaneous ablation should be preferred for hepatocellular carcinoma ≤5 cm. The results of several prospective randomized controlled and retrospective comparative studies have shown that local ablation therapy (mainly RFA and MWA) can achieve similar long-term survival outcomes as surgical resection for small hepatocellular carcinoma; however, compared with both, surgical resection has the advantages of accumulated experience, high prevalence and low recurrence rate, and can remove multiple lesions, microscopic foci and cancer thrombi in the same anatomical region; while percutaneous local ablation is characterized by low complication rate, rapid recovery and short hospital stay. Two randomized controlled studies have shown no significant difference in survival between ablation and surgical resection, but surgery has an advantage in terms of tumor-free survival (DFS) and recurrence rate.
In clinical practice, the appropriate initial treatment should be selected after thorough consideration of the patient’s physical condition and liver function, the size, number, and location of the tumor, the technical strength of the unit, and the patient’s wishes.
It is usually considered that if the patient can tolerate anatomical liver resection, surgical resection should be preferred, which can simultaneously remove micro-metastases in the corresponding liver segment or lobe and effectively prevent postoperative recurrence. Therefore, surgical treatment is still the first choice for hepatocellular carcinoma ≤5 cm. For hepatocellular carcinoma ≤5 cm that meets the indications of both local surgical treatment and ablation treatment, surgical treatment should be performed when available, while local ablation can be another treatment option in addition to surgical resection. For those with 2-3 cancer foci located in different areas and poor liver function that cannot be resected, including those with liver function Child-Pugh grade B or up to grade B after hepatoprotective therapy, local ablation therapy can be considered. For hepatocellular carcinoma of deep or central type ≤3 cm, local ablation can achieve the efficacy of surgical resection and obtain radical ablation under minimally invasive treatment, which can be preferred. For hepatocellular carcinoma of 3-5 cm, the therapeutic effect can be improved by selecting appropriate instrumentation needle, mastering reasonable ablation technique and accumulating certain treatment experience. It is generally believed that most patients also need comprehensive adjuvant therapy after local ablation.