Cryotherapy gains muscle in tumor ablation

Cryotherapy is often portrayed as radiofrequency ablation's little brother. But the thermal ablation technique is muscling in on malignancies in several organ systems, according to studies presented Tuesday at the RSNA meeting.

Dr. Hussein D. Aoun, a radiologist at Wayne State University Medical Center in Detroit, presented two studies assessing the ability to use cryotherapy to ablate liver and lung tumors. The first one evaluated CT-guided treatment of 70 masses with 58 procedures in 47 patients.

Aoun and colleagues found cryotherapy provides a visually reliable and effective treatment alternative to its heat-based brethren. The team successfully treated lesions 3.4 cm in average size, including large masses near blood vessels, with a recurrence rate of 9.7% at two-year follow-up.

The technique is virtually painless and allows use of auxiliary devices unsuitable for RFA, such as balloons, to protect tumor-adjacent organs. It thus proves particularly amenable to patients with anesthesia-related risks and tumors near painful sites, such as the diaphragm or the chest wall, Aoun said.

The second study released data for CT-guided treatment of 56 primary and metastatic lung tumors with 51 procedures in 36 patients. Cryotherapy successfully ablated tumors 3.1 cm in average size, with a two-year recurrence rate of 16.1% for masses. Twenty-two percent of these tumors were located near important vasculature, such as the aorta or pulmonary vein/artery.

"Cryotherapy doesn't seem to be as far sensitive to tumor size or vessel proximity, because we can actually sculpt the isotherm freezing directly into central structures of almost any area. We learned all this from years of work in the prostate. This is all well-defined science," said coauthor Dr. Peter J. Littrup, a professor of radiology, urology, and radiation oncology at Wayne State University.

In a different study, Dr. Thomas Atwell presented results on successful percutaneous cryoablation of 59 renal tumors in 58 patients treated from March 2003 to date.