The cancer-killing freeze is achieved by delivering a very low temperature gas to the tumor using needle-like probes.
Littrup tells WebMD that a single-probe freezing approach has been used for several years to treat breast cancer, but it is widely considered to be unsuitable for tumors larger than 1.5 centimeters.
"We've been using multiple probes for many years to treat prostate cancer with a minimum of five probes," he says. "So it just made sense to me to try multiple probes for breast cancer."
He adds that recent technological advances resulting in smaller and easier-to-manage probes and better ways to guide them to the tumor have made nonsurgical cryotherapy an attractive option for breast cancer.
The 13 patients included in the study had a total of 25 tumors, ranging in size from 0.5 centimeters to 5.8 centimeters. The average tumor size was 1.7 centimeters.
Using local anesthesia with mild sedation, an average of three probes per tumor were guided to the tumor site using either ultrasound alone or ultrasound with computed tomography (CT) imaging. The probes produced "ice balls" ranging in size from 2 centimeters to 10 centimeters, depending on the size of the targeted tumor.