Percutaneous tumor ablation: increased coagulation by combining radio-frequency ablation and ethanol instillation in a rat breast tumor model.
OBJECTIVE
To determine if percutaneously applied radio frequency (RF) combined with percutaneous ethanol instillation (PEI) can increase the extent of ablation in rat breast tumors.


METHODS
R3230 mammary adenocarcinoma was implanted bilaterally in the mammary fat pads of 18 female rats. The tumor nodules measured 1. 2-1.5 cm. Eight tumors each were treated with (a) conventional, monopolar RF (96 mA +/- 28; 70 degrees C for 5 minutes); (b) PEI (250 microL of ethanol infused over 1 minute); (c) combined therapy of PEI immediately followed by RF ablation; or (d) combined therapy of RF ablation immediately followed by PEI. Four tumors were not treated and served as controls. Histopathologic examination included staining for mitochondrial enzyme activity. Resultant coagulation necrosis was compared between treatment groups.


RESULTS
Coagulation necrosis was observed only within treated tumors. Tumors treated with RF alone had 6.7 mm +/- 0.6 of coagulation surrounding the electrode, and those treated with PEI alone had 6.4 mm +/- 0.6 of coagulation around the instillation needle (not significant). Significantly increased coagulation of 10.1 mm +/- 0.9 (P: <.001) was observed with the combined therapy of PEI followed by RF. RF followed by PEI did not increase coagulation (6.4 mm +/- 0.8 around the needle; not significant).


CONCLUSIONS
PEI followed by RF ablation therapy increases the extent of induced coagulation necrosis in rat breast tumors, as compared with either therapy alone.
Goldberg
S N
SN
Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA. sgoldber@caregroup.harvard.edu
Kruskal
J B
JB
Oliver
B S
BS
Clouse
M E
ME
Gazelle
G S
GS
D000279:Administration, Cutaneous; D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D003131:Combined Modality Therapy; D000431:Ethanol / Q000627:therapeutic use*; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000601:surgery*; D051381:Rats
D000431:Ethanol