Cryotherapy is an experimental treatment for breast cancer. Cryotherapy freezes and kills the cancer cells that make up the tumor. The very small study reviewed here suggests that cryotherapy may be a safe and effective alternative to surgery to remove breast cancer.
All cells, including cancer cells, contain water. When cryotherapy freezes the cells, the water turns to ice crystals. These ice crystals, along with the cold itself, destroy the cancer cells.
Right now, cryotherapy is used regularly to treat certain cancers and other lesions. For example, dermatologists apply liquid nitrogen directly to the skin to kill certain early-stage skin cancers and other skin lesions that could potentially turn into cancer (called pre-cancerous lesions). Cryotherapy also is used to treat some forms of cervical, prostate, and bone cancer. Still, using cryosurgery to treat other types of cancer, including breast cancer, is experimental.
When cryotherapy is used to treat breast cancer, one or more small tubes -- called cryoprobes -- deliver either liquid nitrogen or argon gas directly to the cancer tissue. Ultrasound, computerized tomography (CT), or magnetic resonance imaging (MRI) is used to put the cryoprobes in exactly the right place. Cryotherapy is less invasive than lumpectomy or mastectomy and preserves more of the breast than lumpectomy.
In this small study, 27 breast cancer tumors in 14 women were treated with cryotherapy that used several cryoprobes to deliver the liquid nitrogen or argon gas and freeze the tumors. The women got local anesthesia and a mild sedative before the cryotherapy. After treatment, the researchers biopsied the tissue around the frozen tumor (this tissue is called as "the margins") to be sure there were no cancer cells in the margins. Most of the women have been followed for about 18 months after the cryotherapy and one woman has been followed for 6 years.
Much more research is needed before doctors know if cryotherapy is a good alternative to breast cancer surgery and when it's best used.
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TAMPA (MedPage Today) -- Multiprobe cryotherapy was safe and effective in breast cancer patients and didn't require subsequent surgery to ensure that all tumor cells were killed, researchers reported here.
In a small study, there were no cases of localized recurrence and only one case of regional recurrence over a mean follow-up of 18 months, Peter J. Littrup, MD, of Karmanos Cancer Institute in Detroit, and colleagues reported here at the Society of Interventional Radiology meeting.
"It is not only locally curative in that unusual group of patients who refuse surgery, but it is also an excellent control for those with bulky disease," Littrup said.
Some of the controversy regarding the technology stems from the knowledge that there are already several good treatments for breast cancer, including surgery and chemotherapy. Yet these are more invasive and often don't preserve the breast, Littrup said.
However, among all research dollars spent on breast cancer, he said breast conservation is now a primary focus.
There has also been a lack of long-term data, so interventional treatments such as cryotherapy, radiofrequency ablation, or laser therapy are reserved for women who can't have surgery or have refused it.
Others argue that singular cryotherapy probes don't work for tumors larger than 1.5 centimeters. However, multiple probes can take care of that, Littrup said. In prostate cancer, for example, a 5-cm tumor can be taken down with more than six probes.
The researchers wanted to assess that approach in breast cancer, so they treated 14 patients for a total of 27 breast cancer tumors.
All patients had local anesthesia and were only mildly sedated.
The 2.4-mm cryoprobes reached temperatures near -30 degrees Celsius. Saline injections protectedthe skin and chest wall from the cold.
Seven patients had only ultrasound guidance for probe delivery and ice margin definition, while another seven used ultrasound and computed tomography (CT). Magnetic resonance (MR) helped define multifocal recurrences and initial tumors.
Littrup said the study is now in its sixth year and still has not seen any local recurrence; there was only one regional recurrence.
There have been no significant complications, and patients reported minimal discomfort, he added.
Biopsies at the margin of the cryotherapy site and immediately after the procedure were all negative, negating the need for surgery to assure cancer cells had been destroyed.
Littrup said ultrasound produced sufficient ice visualization for small tumors, while CT confirmed posterior margins and overall ice extent for larger regions requiring more than three probes or deep lesions.
"MR planning and follow-up is crucial to have a road map and know where all these [tumors and treated areas] are," he said. "Ultrasound and CT are a crucial combo as well, when dealing with deeper and or more bulky tumors."
He concluded that using multiple probes "ensures thorough coverage, minimal discomfort, and excellent cosmetic satisfaction for breast conservation."
With regard to the future, Littrup also noted that the FDA convened a meeting last fall that "raised the question if ablation is so good, why isn't more being done for breast cancer?"
Brian F. Stainken, MD, president of SIR, said these data are "potentially game changing," but questioned whether it was ready for broad dissemination.
"It's continuing proof of concept, and may find broad application," Stainken said. "We'll need to keep a close watch on it for the next two years."
Littrup reported disclosures relevant to developments in cryotherapy.
Primary source: Society of Interventional Radiology Source reference: Littrup PJ, et al "Cryotherapy for a spectrum of breast cancer: US and CT guidance" SIR 2010; Abstract 158.
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