Ali Golshan MD, Abstract Co-Author: Nothing to Disclose

Robert Daniel Suh MD, Abstract Co-Author: Consultant, Covidien AG

Robert Cameron MD, Abstract Co-Author: Nothing to Disclose

Fereidoun G. Abtin MD, Presenter: Research Consultant, MedQIA Imaging Core

To investigate the feasibility of percutaneous CT (PCT) guided cryoablation for chest wall and pleural tumors, as an alternative to other thermal ablation techniques, the complications observed and follow up response.

Since July 2007, 35 lesions have been ablated in 21 patients, indicated as a palliative to avoid invasion into a vital structure, decrease tumor burden or for local pain control. These lesions include 12 mesotheliomas and 23 other tumor types (i.e. thymoma). Clinical and imaging data were evaluated for baseline lesion size, duration of ablation, complications and post ablation tumor response.

14 lesions were treated for pain palliation and all had positive response. Tumors ranged in size from: 6 x 6 mm to 57 x 42 mm with an average diameter of 33 mm. Minor complications (no intervention needed) included: 2 pneumothorax, 1 pleural effusion, 2 erythema and 1 swelling. Major complications included: 1 hemothorax requiring a chest tube, 1 hemopneumothorax requiring a chest tube, 1 pneumothorax requiring a chest tube and 1 reactive pleural effusion treated with thoracocentesis. Of the 35 lesions (12 mesotheliomas), 26 had one follow up (7 mesotheliomas) 1 to 6 months after ablation and 10 (1 mesothelioma) had a second follow up. On the 1st follow up 18 lesions decreased in size, 2 were stable and 6 increased in size. On the 2nd follow up 9 showed decrease in size. In follow-up group one average tumor diameter decreased 4.5 mm; which was statistically significant (p-value = .033, paired sample t test). Dividing the data into mesothelioma and other tumor type subgroups: the average decrease in tumor size was 7.0 mm for mesotheliomas (p=0.03) and 4 mm for other (p=0.175). 71.4% of the mesotheliomas and 47.4% of the other tumor types decreased in size more than the sample mean on the first follow up, yielding an odds ratio of 2.77. 8 out of 10 patients with PET CT follow up showed no or decreased activity after cryoablation.

There is a statistically significant decrease in tumor size status post cryoablation for all comers and the mesothelioma sub-group. A mesothelioma lesion is 2.77 times more likely, than other tumor types, to decrease in size more than 4.5 mm (sample mean decrease in tumor size).

Cryoablation appears to be an effective alternative method for local control of pleural and chest wall lesions, with minimal complications.

Golshan, A, Suh, R, Cameron, R, Abtin, F, CT-guided Percutaneous Cryoablation of Mesotheliomas and Other Chest Wall Tumors: A Retrospective Assessment of 35 Cryoablated Tumors.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8012287.html