Freezing Out Breast Cancer
Reported March 22, 2010
(Ivanhoe Newswire) — Interventional radiologists have opened the door to an encouraging potential for treating the nearly 200,000 U.S. women who are diagnosed with breast cancer each year. The procedure is called image-guided, multiprobe cryotherapy.
“Minimally invasive cryotherapy opens the door for a potential new treatment for breast cancer and needs to be further tested, Peter J. Littrup, M.D., radiologist and director of imaging research and image-guided therapy for the Barbara Ann Karmanos Cancer Institute in Detroit, was quoted as saying. When used for local control and/or potential cure of breast cancer, it provided safe and effective breast conservation with minimal discomfort for a group of women who refused invasive surgery or had a local recurrence and needed additional management. This is the first reported study of successfully freezing breast cancer without having to undergo surgery afterward to prove that it was completely treated,” Littrup added.
In the 13-patient study, no localized treatment recurrences were seen for up to five years, no significant complications were noted and women were pleased with the cosmetic outcomes, noted Littrup, who is also a professor of radiology, urology and radiation oncology at Wayne State University in Detroit. Cryotherapy was applied according to well-established freezing principles, and biopsies at the margins of the cryotherapy site immediately after the procedure and at the cryotherapy site in follow-up were all negative — showing no cancer.
A woman has about a 13 percent lifetime risk of developing breast cancer, with women 50 years of age and older accounting for approximately 80 percent of all breast cancers. For these women, as well as the thousands of men diagnosed each year, breast cancer treatments can be highly effective but often require invasive treatment options such as surgery and chemotherapy. Surgery offers the best chance for a cure. Until long-term data are available, interventional treatments — such as cryotherapy, thermal ablation and laser therapy — are reserved for women who cannot have — or have refused — surgery.
In this study’s cryotherapy treatment, researchers used several needle-like cryoprobes that were evenly spaced and inserted through the skin to deliver extremely cold gas directly to the tumor to freeze it. This technique has been used for many years by surgeons in the operating room; however, in the last few years, the needles have become small enough to be used by interventional radiologists through a small nick in the skin, without the need for an operation.
The “ice ball” that is created around the needle grows in size and destroys the frozen tumor cells. The major benefits of cryotherapy are its superb visualization of the ice treatment zone during the procedure, its low pain profile in an outpatient setting and its excellent healing with minimal scar. Breast imaging has markedly advanced by accurate improvements in breast magnetic resonance imaging (MRI), allowing for excellent treatment planning of tumor size and extent within the breast, as well as showing zones of destruction thoroughly covering the tumor after cryotherapy, Littrup noted.
Surgeons and radiation oncologists have long tried to provide at least a 1-centimer margin of treatment surrounding all aspects of a localized breast cancer, and it was important to ensure a similar “surgical margin” of lethal temperatures beyond all tumor margins by cryotherapy in this study, said Littrup. “The well-visualized ice margin by ultrasound CT or MR is actually only the 0-degree Celsius line, or isotherm, which is not sufficiently lethal to cancer cells, but has unfortunately been confused with the actual treatment margin. We made sure that the lethal isotherm of approximately -30 degrees Celsius extended beyond all tumor margins,” said Littrup.
After breast MRI and thorough consultation, patient consents were obtained for institutional review board-approved breast cryotherapy. In 13 cryotherapy sessions, 25 breast cancer foci were treated in 13 patients using multiple 2.4-millimeter cryoprobes. Using only local anesthesia with mild sedation, ultrasound guidance alone was used in six patients; seven patients required both CT and ultrasound to better define ice margins. MR and/or clinical follow-up were available for up to 65 months after cryotherapy.
SOURCE: Presented at the Society of Interventional Radiology Annual Scientific Meeting in Tampa, FL, March 16, 2010