Microwave ablation of liver metastases guided by contrast-enhanced ultrasound: experience with 125 metastases in 39 patients.
OBJECTIVE
The aim of our study was to evaluate the efficacy of microwave (MW) ablation of liver metastases guided by B-mode ultrasound (US) and contrast-enhanced US (CEUS).


METHODS
39 patients (17 women and 22 men) with a total of 125 liver metastases were treated with percutaneous or intraoperative CEUS-guided MW ablation. The primary tumor was colorectal cancer (n = 31), breast cancer (n = 6), carcinoid tumor (n = 1), and gastrointestinal stromal tumor (GIST) (n = 1). The median number of metastases ablated in the 45 treatment sessions was 2 (range 1 - 11). The median size (maximum diameter) of the 125 metastases was 1.5 cm (range, 0.6 - 4.0 cm). Nineteen (15 %) of the 125 metastases were bigger than 2 cm. Metastases smaller than 2 cm were treated with a single needle, metastases bigger than 2 cm were treated with 2 or 3 parallel needles.


RESULTS
The 45 MW ablation sessions were performed percutaneously (n = 30), during laparotomy (n = 3), or during laparotomy combined with liver resection (n = 12). The 39 patients were followed up for at least 4 months with a median duration of 11 months (range, 4 - 20 months). The technical success rate was 100 %. The clinical effectiveness was 100 % with complete coverage of the metastasis by the avascular coagulation zone evaluated on immediate post-ablation CEUS. Local tumor progression (local recurrence) was seen in 12 (9.6 %) of the 125 treated metastases, and affected 10 (26 %) of the 39 patients. One major complication was observed in the form of a liver abscess that easily resolved after percutaneous drainage. Four minor complications were observed: Three cases of pain located at the puncture site and one case of ascites. CEUS was valuable in all phases of ablation including pre-ablation staging and procedure planning, placement of MW needles in the tumor, immediate post-ablation control of coagulation size, and finally in the long term follow-up regime.


CONCLUSIONS
CEUS-guided MW ablation of liver metastases is an efficient and safe ablation technique with several advantages compared to other ablation modalities.
Department of Gastric Surgery, Herlev Hospital, University of Copenhagen. tlo@dadlnet.dk
T
T
Lorentzen
B O
BO
Skjoldbye
C P
CP
Nolsoe
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D003131:Combined Modality Therapy; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D008297:Male; D008872:Microwaves / Q000627:therapeutic use*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D010743:Phospholipids; D012189:Retrospective Studies; D013459:Sulfur Hexafluoride; D016896:Treatment Outcome; D047368:Tumor Burden; D018084:Ultrasonography, Interventional / Q000379:methods*
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride