Percutaneous Microwave Coagulation For Eradication Of VX2Tumors Subcutaneously In Rabbits

Background: Percutaneous microwave coagulation (PMC) has been accepted as apromising modality in the treatment of tumors in well-vascularized tissues such asliver tumors and hysteromyoma. However, PMC for treatment of tumors in lowblood-flow tissues was seldom reported. The aim of this study was to determine thefeasibility and safety of PMC for the treatment of tumors in low blood-flow tissues inrabbit model.Materials and Methods: Fifteen rabbits with VX2tumors implanted subcutaneouslyunderneath the right second nipple were divided into PMC group (n=9) and controlgroup (n=6). PMC was performed with output power of40W for1-2minutes. Thetherapeutic efficacy was evaluated by magnetic resonance imaging (MRI), physicalexaminations, survival rate, and histology. The cosmetic outcome after PMC was alsoassessed.Results: In PMC group, tumor eradication was achieved in six rabbits (66.7%)without any evidence of tumor recurrence and metastasis as proven by MRI andhistological examinations. The mean greatest and short tumor diameters of these sixrabbits were1.83and1.33cm, respectively. Slight epidermal burns, which provedreversible, were found in seven rabbits (77.8%). PMC group had a significantlylonger survival than those in control group (P=0.0097). The four rabbits withcoagulated tumors survived more than three months with their tumors becomingnonpalpable and undetectable by MRI and histological examinations.Conclusion: PMC was feasible and safe in the treatment of tumors in low blood-flow tissues in rabbit model. Attention should be paid to avoid skin burns with PMC. Purpose: Percutaneous microwave coagulation (PMC) is a promising minimallyinvasive local therapy that destroys tumors in situ. Up to now, PMC has been mainlyused in the treatment of hepatic tumors and myomas in the uterus, and it wasrecognized as an effective therapy for these two types of tumors. To our knowledge,ultrasound-guided PMC in the treatment of breast cancer has not been reported. Thepurpose of this nonrandomized clinical study was to determine the feasibility ofultrasound-guided PMC for the local treatment of solitary breast cancer3cm or lessin greatest diameter.Materials and methods: Between February1,2010and August30,2011, patientsdiagnosed with breast cancer in our hospital, were recruited in this prospectivenonrandomized study with the approval of the institutional ethics committee andwritten, informed consent. In all,41patients with core-needle-biopsy-proven breastcancers3.0cm or less in diameter accessed by ultrasound were recruited. Ultrasoundguided PMC was performed under general anesthesia, followed immediately bymastectomy. Histochemical staining with alpha-nicotinamide adeninedinucleotide-diaphorase (α-NADH-diaphorase) was used to determine cell viabilityand the extent of PMC lesions.Results: The mean tumor volume was5.26±3.80cm3, ranging from0.09to14.14cm3. PMC was successfully performed in all cases with complete tumor ablation asassessed by ultrasound. The mean time to reach complete ablation was4.48minutes,ranging from3to10minutes. Under microscope,37of the41cases (90.2%,95% confidence interval (CI):76.9%-97.3%) showed complete tumor coagulation asobserved by α-NADH-diaphorase staining. Of38cases diagnosed with invasiveductal carcinoma,36cases (94.7%,95%CI:82.3%-99.4%) showed complete tumorcoagulation. Slight thermal injuries to the skin and pectoralis major muscle, whichproved reversible, were found in3cases.Conclusions: Ultrasound guided PMC of small solitary breast cancer is feasible.Nevertheless, larger-scale clinical trials are still needed to validate PMC into astandard clinical practice.