The 12-month results of the study, presented at CIRSE 2014, demonstrated that new microwave technology can achieve a substantial rate of complete necrosis of liver metastases, even in a short-term treatment with few major complications.
The study was based on the premise that the latest microwave technology is expected to obtain larger volumes and faster area of ablation than radiofrequency. Guido Poggi, Istituto Clinico Città di Pavia, Pavia, Italy, presented the results.
The researchers collected data from 14 Italian centres. They treated 312 tumours that were unresectable liver metastases from colorectal cancer in 178 patients. There were 116 patients who had a single lesion; 15 of these developed another single metachronous lesion. Forty patients presented with two lesions; 18 presented with three lesions, and 19 presented with more than three lesions. The mean diameter was 2.7cm. Of these, 30% were deep lesions and 70% were superficial, and 30% of the lesions were close to the vessels, Poggi, said.
The researchers observed a complete response in 268 lesions (86%). Complete response was obtained in 97.5% lesions
Poggi told Interventional News: “Taking into account the limitations of a retrospective, multicentre study, the results that we have observed are very encouraging, particularly with regard to the high rate of complete ablation obtained in lesions up to 4cm in diameter. These results confirm that the latest microwave technology is a promising technique for the treatment of patients with colorectal liver metastases.
We used a microwave 2.45MHz generator (Amica-Gen) delivering energy of 40–100W through a 14 or 16 gauge internally cooled coaxial antenna (Amica-probe), featuring a miniaturised quarter wave impedance transformer (“mini-choke”) for reflected wave confinement. An automatic peristaltic pump was used for applicator cooling to avoid the probe overheating.”