| Objective: As the demand of human increased about beauty, minimallyinvasive techniques have gained more and more attention to cure T1stagebreast cancer. Microwave ablation (MWA), as a new type of minimallyinvasive treatment, has been used for breast cancer therapy. MWA has theadvantages of less wound, less pain, low cost and simple operation. MWA canexert an efficient influence under the propose condition. It is reported that therange of microwave ablation is similar and more than2cm between thecondition of30watts,180seconds and40watts,120seconds for normaltissue of breast. The report on the treatments for the breast cancer is fairly rareat home and abroad. In our study, microware ablation was used to treat VX2breast cancer of rabbit with the diameter below2cm and explore its feasibilityand security in early breast cancer under the condition of30w180s and40w120s respectively, providing more evidences for microwave ablation therapy.Methods：132New Zealand white rabbits were used to set up models of VX2breastcancer in rabbit by injection of tumor tissue pieces suspension subcutaneously.The tumor growth was observed macroscopically and by high-frequency colorDoppler ultrasound.2A total of28VX2breast cancer models in rabbit who were2weeksestablished with the single tumor （≤2cm）were divided into four groupsrandomly. Group A was treated by microwave ablation therapy underultrasound guidance at30watts for180seconds (7). Group B was treated bymicrowave ablation therapy under ultrasound guidance at40watts for120seconds (7). Group C was the operate group (6)Group D was the controlledgroup (6). The four groups of rabbits were observed simultaneously andresidual cancer, average survival time, living status, skin condition in the ablation areas and metastasis condition of lymph nodes were recorded.Results:1Condition of modelsThe success rate of injection of tumor tissue pieces suspension was93.75%(30/32). The tumor size was0.089±0.049cm~3at the end of the firstweek after tumor tissue pieces suspension injection and0.76±0.49cm~3.2The rate of residual cancerThe residual cancer was not found in group A. One residual cancer wasfound in group B, and the rate of residual cancer is14.29%(1/7). The residualcancer was not found in group C.There was no obvious statistical difference in the residual cancer rate ofgroup A, group B and group C.3Survival condition of group A, B and C after three months of the modelestablishmentThe survival rate of group A, B and C were100%(7/7),86%(6/7) and100%(7/7) respectively. None of the rabbit of group D was alive.3.1There were obvious statistical differences in the survival rate of group Aand group D (P=0.03<0.05), the survival rate of the rabbits under thecondition of30watts for180seconds was higher than the controlled group.3.2There were obvious statistical difference in the survival rate of group Band group D (P=0.04>0.05), and there was no obvious difference in thesurvival rate under the condition of35watts for120seconds and thecontrolled group.3.3There were obvious statistical difference in the survival rate of group Cand group D (P=0.03>0.05), and there was no obvious difference in thesurvival rate between the operate group and the controlled group.4metastasis of tumors in models of VX2breast cancer in rabbitsThe lymph nodes of group A in two of them were metastasized with therate of28.50%(2/7). The lymph nodes of group B in three of them weremetastasized with the rate of42.80%(3/7). The lymph nodes of group C infour of them were metastasized with the rate of57.20%(4/7). The metastasis rate of lymph nodes in group D was100.00%.4.1There was no obvious statistical difference in the metastasis rate of lymphnodes between group A and group D (P=0.201>0.05), and there was noobvious difference in the metastasis rate of lymph nodes under the conditionof30watts for180seconds and the controlled group.4.2There was no obvious statistical difference in the metastasis rate of lymphnodes between group B and group D (P=0.305>0.05), and there was noobvious difference in the metastasis rate of lymph nodes under the conditionof35watts for120seconds and the controlled group.4.3There was no obvious statistical difference in the metastasis rate of lymphnodes between group C and group D (P=0.410>0.05), and there was noobvious difference in the metastasis rate of lymph nodes between the operategroup and the controlled group.5The skin condition in the ablation areas of group A and group BThe incidence of skin burn in group A was14.30%(1/7). The incidence ofskin burn in group B was57.10%(4/7).The incidence of skin burn in group ofmicrowave ablation therapy at30watts for180seconds is low than in groupof microwave ablation therapy at40watts for120.Conclusion:1The models of VX2breast cancer in rabbit by injection of tumor tissuepieces suspension subcutaneously is characterized by high success rate, simpleoperation, vigorous tumor growth and short cycle of modeling, and thusprovide an ideal foundation for basic study and clinical therapy for breastcancer.2The therapeutic effect is same between the two microwave ablation therapygroup and the operate group.3Microwave ablation therapy for VX2breast cancer of rabbit under thecondition of30watts,180seconds and40watts,120seconds enhances thesurvival rate of rabbits,prolongs the lifespan of the rabbits and providesclinical evidences for early breast cancer treatment.4There was no obvious statistical difference in success rate of the metastasis rate of lymph nodes among four groups.So after microwave ablation therapy,Axillary lymph node dissection should be followed.5The incidence of skin burn in group of microwave ablation therapy at30watts for180seconds is low than in group of microwave ablation therapy at40watts for120. |
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