| Background and Objective Hepatocellular carcinoma(HCC)is one of the most common malignant tumors in the world, and the second most common one in our country, and it is very difficult to treat. Although surgical resection is thought as the most effective management for small HCCs, it is often limited due to the special location of the tumor or poor hepatic functional reserve. It has also been observed that the recurrent rate remains high in small HCCs after surgery. So, various methods for tumor ablation have emerged as the times require. Percutaneous ethanol injection (PEI) has gained a wide popularity because of its high antitumoral effecacy as well as its relatively simple and inexpensive application. However, a large amount of ethanol and multiple treatment location are required for PEI because of the limited osmosis of ethanol. For the first time in 1994, Ohnishi reported percutaneous acetic acid injection (PAI) in the treatment of small HCCs. It was confirmed that PAI caused more tumor ablation and fewer side-effects than PEI did, and that PAI might take the place of PEI in the treatment for small HCC. As the use of PAI is explorative and developmental, there are many questions to be answered, such as the principle ,the optimal dose and concentration of acetic acid for tumor ablation. That's the purpose of this study.Materials and Methods New Zealand rabbits were implanted VX2 tumor tissue into their livers to establish tumoral models in the comparativeexperiment for different concentrations of acetic acid. 20 single-lesion models were divided into 4 groups randomly and 5 rabbits in each group. The model of the group A received 1.0ml normal saline injection in tumor foci. The tumor foci in the rest three groups(group B, group C, group D) were performed PAI with 25%, 50%, 75% acetic acid (dose: 1.0ml) respectively. The changes of the reaction and the functions of liver and kidney were observed after PAI in different periods. The changes of tumor size and pathology were observed in 14 days after PAI.In control experiment for PAI and PEI, 8 three-lesion models were used for this study. Three lesions of each received respectively normal saline, 50% acetic acid and absolute ethanol injection. One rabbit was killed respectively in 1 hour, 1 day, 3 days after operation. The remained rabbits were killed 14 days after operation. The pathological changes of each lesion were observed in light microscope and electron microscope.Results The implantation success rate for VXz tumor tissue in liver was 96.2%. There were found implantation out liver in 15.6% animals, ascites in 9.4% animals and incision infection in 12.5%. 14 days after implantation, the lesions in livers were 0.90 ?0.25cm in diameter. They were demonstrated rich blood supply on ultrasound and inhanced CT and fed mainly by hepatic artery. They had no capsule with an outline of white nodule, looking like fish meal. Early metastasis was discovered mostly in lung, liver and lymph nodes of abdomen.In the comparative experiment for different concentrations of acetic acid, intoxation was found in all treated animals within 1 day after PAI, but obviously in group D. It relieved gradually after 3 days in most of the animals. Hepatic function was obvious damaged in group B and group C 1 day after PAI, and recovered 7 days later. However, both hepatic and renal function damage occurred in group D 1 day after PAI, and only renal function recovered 7 days later. There was no significant difference in tumor growth rates between the treatment groups after 14 days, but significant differences were found between treatment groups and control group. Compared with group A and B, group C and D had significant higher tumor necrotic rates, and no significant difference was found between group C and D. Therefore, the results in this study showed that 50% acetic acid would besuitable for PAI.In the control experiment for PAI and PEI, the dosage of normal saline, 50% acetic acid and absolute ethanol injected into the tumors had no significant diffe... |
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