Percutaneous cryoablation (PCA) could potentially be used as a last line of defense to halt metastatic breast cancer spread disease by freezing and destroying tumors, according to a new study.

Researchers at the Karmanos Cancer Institute (Detroit, MI, USA) performed computerized tomography (CT) and/or ultrasound (US)-guided PCA procedures on 9 tumors in 8 patients with oligometastatic disease from breast cancer who had already undergone resection of the primary cancer; tumor location was grouped according to metastatic sites in the liver, lung, and kidney. Complications were assessed according to Common Toxicity Criteria for Adverse Events (CTCAE), Version 3.0. Median survival was given from the time of stage IV diagnosis until PCA, in addition to survival time afterwards, in order to assess the adjunctive role of PCA.

The results showed that there were no major complications, and zero local recurrences occurring. Median overall survival for all patients from time of stage IV diagnosis was 46 months, with an observed five-year survival rate of 25%. Average time from stage IV diagnosis until PCA was 16 months, and average survival after treatment was 30 months. Six of the eight patients (75%) had undergone at least a single mastectomy prior to PCA treatment. The study was presented at the Society of Interventional Radiology (SIR) 37th Annual Scientific Meeting, held during March 2012 in San Francisco (CA, USA).

“Cryoablation as a targeted therapy is beneficial because it can significantly reduce discomfort and incidence of disease,” said lead author Peter Littrup, MD, director of imaging core and radiology research at the Karmanos Cancer Institute. "It's a much better option, we think, than surgery, especially since many metastatic patients are not candidates for surgery, and it may potentially lead to longer survival if it coincides with more data concerning primary metastases in other regions of the body.”

PCA involves the use of miniature probes inserted via a catheter and guided to the tumors, at which point pressurized argon gas is introduced, effectively killing the cancerous tissue. Helium gas is then pumped in to help release the needle. Medical imaging helps detect the cryoablated tissue by detecting distinct densities between the normal tissues and frozen cancer tissue, which has a lower density than the surrounding tissue. The treatment results in minimal damage to surrounding healthy tissues and the side effects and recovery time are dramatically reduced when compared to those of other therapies.

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