Vacuum-assisted resection of malignant tumors with and without subsequent radiofrequency ablation: Feasibility of complete tumor treatment tested in an animal model

Purpose: To evaluate the feasibility of vacuum-assisted tumor excision with and without RF ablation for the minimally invasive treatment of small tumors. Materials and methods: Twenty VX2 tumors were implanted bilaterally into the spine muscle of 10 rabbits. Tumor excision was performed after tumor sizes reached 10 mm (12-27 d incubation) with use of a vacuum-assisted biopsy device. Three or four directed vacuum-assisted biopsies were performed in angle steps of 30 degrees. In 10 tumors, ultrasound (US)-guided radiofrequency (RF) ablation (8 min, 60 W) was subsequently performed with use of a cooled-tip electrode system. Follow-up US was performed at 3-4-day intervals for as long as 3 weeks after excision/RF ablation. Autopsy and histopathologic analysis were performed. Results: The duration of vacuum excision ranged from 12 to 45 minutes (25 min +/- 7). Histologically tumor-free margins in the outer round of the core biopsy specimens were found in only four of 20 cases (20%). Maximum lesion sizes during RF ablation ranged from 18 to 25 mm (20 mm +/- 2.6). Histologic examination of the excision specimens documented tumor-free margins in only three tumors (30%) among the excision-only group and only one (10%) among the combined excision/ablation group. Local recurrences occurred in eight of 10 cases (80%) after vacuum excision alone, whereas recurrence after combined excision and RF ablation occurred only in two of 10 cases (20%; P<.05). Conclusions: Local tumor resection with use of vacuum-assisted biopsy is feasible and promising as a minimally invasive therapy for the treatment of small focal breast neoplasms. Combined excision and RF ablation techniques may reduce the rate of local recurrence considerably.