Pathologic assessment of radiofrequency ablation of pulmonary metastases.
OBJECTIVE
To evaluate pathologically the effectiveness of radiofrequency (RF) ablation in the treatment of pulmonary metastases.


METHODS
Patients with multiple pulmonary metastases scheduled for surgical resection were prospectively enrolled. Patients underwent RF ablation of one percutaneously accessible tumor and within 2-4 weeks underwent surgical resection of the ablated tumor and any additional lesions. Resected tumors all were assessed by routine light microscopy, and selected tumors were assessed by immunohistochemistry with MIB1 and proliferative cell nuclear antigen (PCNA). Relationship of ablation zone to the tumor and viability of the ablated tumors were assessed.


RESULTS
Nine patients (four men and five women) 46-76 years of age were included in the study. Four patients had metastatic colorectal carcinoma, and five patients had metastases from soft tissue sarcomas. Ablated tumors ranged from 1.0-3.0 cm in diameter. Each target lesion was completely encompassed by the ablation zone. All tumor tissue within the ablation zone showed characteristic changes of coagulative necrosis with hematoxylin and eosin staining. Tumors showed preservation of MIB1 staining but loss of PCNA protein staining. RF ablation resulted in complete coagulative necrosis of all the pulmonary metastases treated in the study.


CONCLUSIONS
Although this series is small, it provides histologic support for RF ablation as an effective treatment for selected pulmonary metastases.
Jaskolka
Jeffrey D
JD
Mount Sinai Hospital, Department of Medical Imaging, Room 564, Toronto, Ontario, Canada. jjaskolka@mtsinai.on.ca
Kachura
John R
JR
Hwang
David M
DM
Tsao
Ming S
MS
Waddell
Thomas K
TK
Asch
Murray R
MR
Darling
Gail E
GE
Johnston
Michael R
MR
D000368:Aged; D002277:Carcinoma / Q000737:chemistry / Q000556:secondary / Q000601:surgery*; D017115:Catheter Ablation; D002470:Cell Survival; D015179:Colorectal Neoplasms / Q000473:pathology*; D004396:Coloring Agents; D004801:Eosine Yellowish-(YS); D005260:Female; D006416:Hematoxylin; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008175:Lung Neoplasms / Q000737:chemistry / Q000556:secondary / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009864:Ontario; D011446:Prospective Studies; D012509:Sarcoma / Q000737:chemistry / Q000556:secondary / Q000601:surgery*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D044767:Ubiquitin-Protein Ligases / Q000032:analysis
D004396:Coloring Agents; D019394:Ki-67 Antigen; C513496:MIB1 ligase, human; D044767:Ubiquitin-Protein Ligases; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin