| Freezing out breast cancer
Clinical promise and clues to patient selection seen in initial clinical trials
A technique already used to freeze and kill benign breast masses also appears to kill small malignant breast cancers, new research from a clinical trial at the University of Michigan Comprehensive Cancer Center shows.
And while the number of patients studied to date is small, the vast majority – seven of nine – had no cancer left after their invasive tumors were frozen. The minimally invasive, ultrasound-guided procedure used in the study is called cryoablation. In addition to the seven patients whose breast cancer was completely killed, two others had nearly complete cancer elimination, with one experiencing total death of the invasive portion of her cancer and the other showing a small portion of invasive tumor remaining.
The initial results yield important clues about which patients might be the best candidates for the procedure in the future, based on their tumors’ size and appearance on ultrasound images. And the results confirmed that the procedure caused no cosmetic changes to the breast’s appearance.
"While this is an early result, it is encouraging, and it will guide future research on this technique for patients with malignant disease," says Marilyn Roubidoux, M.D, an associate professor of radiology at the U-M Medical School. "For instance, the experience with these first nine patients gives us clues to patient selection. We hope that if further investigation continues to yield good results, this technique may become a viable option for women with early-stage breast cancer."
The technique is already in use in many states as an office-based, non-surgical means of treating benign breast disease, via a thin probe inserted into the center of the tumor under local anesthesia and with real-time guidance from ultrasound imaging.
The study of nine U-M patients is part of a recently completed multicenter clinical trial of cryoablation for malignant breast cancer, led by U-M surgical oncologist Michael S. Sabel, M.D. A new clinical trial is currently being planned; no patients are being recruited right now.
Analysis showed that seven of the nine patients had complete necrosis — death — of their tumors. Their tumors ranged in size from 8 millimeters to 17 millimeters, and most were classified on biopsy as invasive ductal carcinoma. There were no complications during the six-week follow-up period, no pain, and none of the patients needed to be sedated. The procedures took about 30 minutes and were conducted via a tiny incision in the breast that was closed by a small bandage.
Roubidoux notes that the initial success of the technique in malignant cancer does not mean that cryoablation should be seen as a final treatment yet. Patients in the trial, and those in future trials, need additional breast surgery to assess the effectiveness of the cryoablation. In addition, as with conventional surgical treatment, radiation and/or chemotherapy may be needed.
The current trial was funded in part by Sanarus Medical, Inc., which has U.S. Food and Drug Administration approval for its Visica cryoablation system as a means of freezing benign breast masses called fibroadenomas.
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