Toshiyuki Matsuoka MD, Presenter: Nothing to Disclose

Masami Toyoshima MD, Abstract Co-Author: Nothing to Disclose

Akira Yamamoto MD, Abstract Co-Author: Nothing to Disclose

Kenji Nakamura MD, Abstract Co-Author: Nothing to Disclose

Ryusaku Yamada, Abstract Co-Author: Nothing to Disclose

Yuichi Inoue MD, Abstract Co-Author: Nothing to Disclose

To evaluate efficacy and complications of radiofrequency ablation (RFA) as local treatment for inoperable lung metastases of less than 3 cm.

Thirty lung metastases in 16 patients (from lung 7,others 9) were treated to obtain local control by RFA using LeVeen Needle with CT guidance and were assessed at a minimum of 6 months after the procedure. Nodule size was 8-29mm(mean 19.0mm). The procedure was started at output 10-30 watt by gradually increasing output until roll off (sudden elevation of impedance meaning coagulative necrosis of tissue) being achieved or 15 minutes and was underwent with safety margin of 5mm as possible. CT was performed 1 month, 3 months, and then every 2 or 3 months after RFA and the largest diameter (LD) of ablated area that consisted of the lesion and surrounding lung tissue was measured. LD was compared with pretreatment diameter of the nodule and response was assessed by RECIST (the Response Evaluation Criteria in Solid Tumors). Complications were recorded during and after the procedure.

All procedures were technically successful. 19 of 30 nodules were ablated at several stations to cover the whole lesion. Average duration of energy application per a nodule was approximately 40 minutes. Observation periods were 6- 41 months (mean 15.4 months). Of the 30 nodules, 15 were judged to be CR, 3 PR, 3 SD and 9 PD. For 23 nodules in which roll off occurred at all stations, 14 CR, 3 PR, 2 SD and 4 PD. On the other hand, the corresponding values were 1,0,1 and 5 respectively for the 7 nodules in which roll off did not occur because of insufficient output due to severe pain in 4 or unknown reason in 3. Roll off group had a significantly higher effective rate (including CR, PR and SD,19 of 23, 82.6%,P=0.023) than non roll off group (2 of 7, 28.6%). There was not significant difference for nodule size and a primary organ. Pain or heat sensation was observed in 67%. Pneumothorax occurred in 37%. There was no serious complication to need surgical management.

RFA has the potential to become an effective and minimally invasive therapy for small lung metastases. It is important to achieve roll off to get good therapeutic results.

Matsuoka, T, Toyoshima, M, Yamamoto, A, Nakamura, K, Yamada, R, Inoue, Y, Inoperable Small Lung Metastases: Minimally Invasive Local Treatment by Radiofrequency Ablation.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4409270.html