Ultrasound cryoablation showed promise for treating early, low-risk breast cancer, researchers reported here.
In 190 cases to date, including follow-up out to 3 years, just two recurrences were observed, and both occurred in women whose cancers were outside the parameters of the study protocol, reported Kenneth Tomkovich, MD, of the CentraState Medical Center in Freehold, New Jersey, and colleagues.
Additionally, the procedure was successfully completed in all patients and there were no serious adverse events reported, they said in a presentation at the Radiological Society of North America annual meeting.
In terms of the recurrences, one was in a patient whose tumor was >1.5 cm (the study limit was ≤1.5 cm), while the other was in a patient who had extensive ductal carcinoma in situ.
“If the positive preliminary findings are maintained as the patients enrolled in the study continue to be monitored, that will serve as a strong indication of the promise of cryotherapy as an alternative treatment for a specific group of breast cancer patients,” Tomkovich told MedPage Today. “However, these women [with recurrences] were included in the trial and… are part of the intention-to-treat protocol.”
Alice Police, MD, of the Northwell Health Cancer Institute in Sleepy Hollow, New York, expressed caution about the results. “Cryoablation has been around for a while, with some early reports that are promising,” she said. “My problem with this study… is that its claims of low recurrence rates are premature with only 24 patients having a follow-up of more than 36 months.”
“The average time of a local recurrence is 2.5 to 3 years, so with only 24 patients in that category, conclusions cannot be drawn,” Police, who were not involved in the study, told MedPage Today.
As part of the ongoing Ice 3 trial, Tomkovich’s group enrolled patients at 18 centers across the U.S. to assess ultrasound-guided cryoablation (IceSense 3, IceCure Medical) as a primary treatment for breast cancer without surgical lumpectomy. Starting in 2014, the researchers began performing cryoablation on women, ages ≥60, with biopsy-proven, low-risk breast cancer. Patients had to have estrogen receptor-positive (ER)/progesterone receptor-positive (PR) disease, or ER+/PR- and HER2-negative disease.
After local anesthesia, patients underwent a freeze, thaw, freeze-cycle of cryoablation with the goal of a visible ice ball producing at least a 10-mm margin of ice around the tumor, the authors explained. Tomkovich added that the procedure in the study takes <1 hour, and patients are generally able to resume their normal activities of daily living shortly after leaving the clinic.
Post-procedure, patients were followed for recurrence with mammography at 6 and 12 months. Patients will be followed annually for 5 years. Common post-procedure imaging showed some cases of fat necrosis, scarring, and a mammographic “halo” effect.
The authors reported that 78 patients had at least 24 months of follow-up, while 24 patients had at least 36 months of follow-up. “There has been no recurrence in 156/157 patients with at least 6-months of follow-up (99.4% success rate),” they noted.
“We’re finding smaller and smaller breast cancers, but we’re still treating them the same way we did 30 years ago,” Tomkovich said. “Lumpectomy is 90-95% effective at removing cancer. We were going for something close to that [with ultrasound-guided cryoablation], but our preliminary results have been even better. We’re getting the same results at 18 centers around the country.”
“If it’s proven that cryoablation works, then some women might be more inclined to opt-in for it over surgery,” he added.
Police pointed out other issues that need to be addressed with breast cryoablation, such as the assessment of margin status; how to handle genetic testing if the treatment does not allow for the collection of tissue; and how sentinel node testing would be performed because the surgery and anesthesia required for that procedure could negate the advantages of cryoablation.
Tomkovich disclosed relevant relationships with Scion Medical Technologies and IceCure Medical.
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Radiological Society of North America
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