Study Of Clinical Application Of RFA In Treatment Of Primary Carcinoma Of Liver

In China, liver cancer is one of the theriomas with a highest attack rate, about 110,000 Chinese died of it every year, which occupies 45% the whole who died of liver cancer around the world. At present, surgical carcinectomy is still the preferred remedy. However, liver cancer attack is secret, it has no specific symptom and has low detection rate and at its early stage. so, once there are symptoms appearing, its already in its medium and advanced stage. Furthermore, owing to economic, age factors and low operable rate, the survival time of liver cancer patients is greatly decreased.Among nonsurgical therapies, the effect of total body chemotherapy and radiation therapy proves to be poor. With the improvement of modern medical technology, many topical therapies have emerged as the times require, including cry therapy, therapy with high-frequency ultrasound knife, percutaneous intratumor absolute alcohol injection, microwave therapy and radio frequency Ablation. RFA rose in 1990's, which is regarded as the most advanced interstitial therapies in the world. RFA can kill more tumors and its hurt to organs is less.RFA is originally applied in neurosurgical operation to treat tumor or functional neural disorder, and also applied in the ablation of heart abnormal conducting route standard heart rate. The research and application of RFA used in treating liver tumor originate from 1790's. At first, RFA is first applied to those patients who have lost operation chances. Then as the technique matures, the indications of RFA become more and more. Now RFA is used as an intermediate therapy toward liver transplantation operation, and even can take the place of hepatectomization.The theory of RFA is to treat tumor through an electrode set in the center of the tumor, which can cause wagulative necrosis through high-frequency alternating curreut. Guided by ultra-sound, electrode needle with insulated body and naked point will. The radio-frequency wave (450～550KHZ) generated by radio-frequency generator will send off RF current through the electrode needle, and will form a loop with auxiliary electrode, which will generate heat through molecule friction and ion dissipation in peripheral tissues. To pical temperature will reach 90～100,which will cause the dissolution of bilayer lipid film of normal tissue cells, denaturalization of protein in cells, The inreversible change of mitochondrial and lysosomal membrane, the loss of moisture in cells and thus the coagulative necrosis of tissues. Meanwhile, the heat will coagulate the vascular tissues around the tumor, which will from a reaction cone so as not to apply blood to tumor and to stop the diadexis of the tumor. The heat source is not the electrode itself, but mainly the tissues around the electrode. Tumor cells have poor endurance capacity for heat, and are more sensitive to heat than normal cells since blood circulation in tumor is less, and the vasodilatation of vascular bed is poor.Rossi et al are the first to prove that RF heat will cause thermal damage in deep liver tissues, but will not hurt the normal liver tissue around. They reported the therapy of RFA guided by ultra-sound to ablate deep tumors. Afterwards, various animal tests and clinical trials all prove that RFA has evident effect in treating liver cancer, and has already applied in clinical care.There are three kinds of RFA therapy: (1) percutaneous RFA guided by ultra-sound /CT, (2) RFA under a celioscope, (3) RFA during the operation.Ultrasonic examination is currently the most widely used RFA radiological examination, which has many advantages, such as real-time display, short application time, convenience, smaller trauma and fast recovery. If the diameter of the tumor is smaller than 5cm and not adjacent to import ant viscera's of stomach, bowel, kidney and musculus diaphragm, and there is an appropriate penetrating route, a percutaneous therapy can be adopted. If the tumor is big and there is difficulty in finding an appropriate penetrating route or it's adjacent to important viscera's, which will hurt the above viscera's, it's not appropriate to adopt the therapy guided by ultra-sonic examination.Indications of liver cancer RFA have changed with the innovation of technology and the accumulation of experiences, and the following opinions are generally acknowledged.1. The general conditions of the patient(1)The general conditions are good, there is no evident diseases in important viscera's, whose functional conditions are good or only have light damage.(2)Liver function is normal or only has light damage with its classification of A or B.1. topical conditions(1) Single tumor, or tumors are less than 5, whose diameter is less than 3cm, accompanied by severe hepatocirrhosis and liver volume evidently reduced(2) With the recent recrudescence of liver cancer after hepatectomization, the patient is not fit for or not willing to receive a second operation.(3)There is great difficulty in operation: the tumor is in the porta or near the second porta, multiple-electrodes can be applied to reach the tumor without damaging important veins and bilee duct.(4)The patient can't endure chemotherapy or radiation therapy, and are undergoing palliative treatment of huge liver tumorsThe most ideal target of RFA is the tumor with the diameter of less than 3cm and not in the area of porta, completely surrounded by parenchyma liver cells, located beneath. The liver capsule 1cm or deeper, and away from big liver veins, portal vein and bile duct 2cm or further. The focus number of metastatic liver cancer should be less than 3, the primary focus has been removed and there no other metastatic focus outside of liver.A retrospective analysis is conducted in this study concerning the clinical data of 36 patients of primary hepatic carcinoma treated with radiofrequency abiation (RFA), and the results are assessed according to the alleviation of symptoms, the minification of diseased region and the changes of MRI signals. A MRI examination 3 months after the treatment shows that liquefactive necrosis appears in the treated region, heterogeneously intensified after reinforcement, and the signal presents a circular pattern. A follow up study conducted within 1 to 5 months after the FRA treatment shows that symptoms disappear in 30 cases (83.33%), and are alleviated to different degrees in the rest 16 cases (44.44%). No new nidus is found in 30 cases out of the 32 cases of primary tumor, and no major complications or deaths relevant to RFA result from the treatment. The total necrosis rate of various tumors is 69.04%, among which the total necrosis rate of tumors equal or less than 3.0cm in diameter is 80.76%.Rossi et al reported the treating results and experiments of 50 patients with primary and secondary carcinoma of liver cancer through single or double electrodes RFA during the recent 7 years. Their results show that 16 patients (41%) recurred, 2 patients (5%) recurred partially, and 14 patients (36%) have new focus during regular visits of 22.6 months. It's effective in ablating the recrudes cence of the tumor. The cumulative survival rate shows that the survival time of patients of liver cell cancer is 44 months. One year, two year, 3 years and 5years survival rate can reach 94%, 86%, 68%,and 44%.After the hepatic atomization of primary liver cancer, but the recrudesce rate of metastasis liver cancer can reach 50%,only 1 patient survived without tumor. Then the results of 37 cases of subclinical carcinoma of liver iateria with the application of electrode needles with retractable hamulus are reported and CT examination is conducted in order to assess the condition of thanatosis, and 44 out of 45 nidi show no signs of depravation. Among 11 liver metastasis patients, only 2 have tumor necrosis. The treatment effectiveness of this iateria shows no obvious difference from other types of iateria with electrode needles, and no major complications appear in any case.Conclusion: RFA is a safe and minimally invasive technique to treat liver malignant tumor with reliable treatment effect, the result is satisfactory especially for primary hepatic carcinoma with diameter less than 3cm and insufficient blood supply.