Cryoablation – the destruction of cancer cells through freezing – shows early signs of efficacy in treating women at low risk of breast cancer, according to research presented today at the Annual Meeting of the Radiological Society of North America (RSNA). Researchers said that over four years of the study, only one case of cancer recurrence occurred in 180 patients.
"If positive preliminary findings are maintained while patients enrolled in the study will continue to be monitored, it will serve as a strong indication of the promise of cryotherapy as an alternative treatment for a particular group of breast cancer patients," said MUDr. Kenneth R. Tomkovich, radiologist from Princeton radiology and director of breast examination and surgery at the CentraState Medical Center in Freehold, NJ
Cryoablation, also known as cryotherapy, has been used to treat cancer in other organs in the body, including the kidneys and lungs, but has so far become a treatment for breast cancer. Dr. Tomkovich started studying for this indication more than a decade ago, as imaging progresses in mammography and ultrasound, and the development of tomosynthesis has made detection of more risky tumors possible. These small initial cancers have the potential to be invasive without treatment and life threatening. But treatment options do not keep pace with progress in imaging.
"We find smaller and smaller breast cancer, but they are still treated just like thirty years ago," said Dr. Tomkovich.
Cryoablation is a potential new weapon in the arsenal against breast cancer. The procedure begins by inserting the probe into the tumor through incision of bone size in the skin while the patient is under local anesthesia. The probe is conducted with high-resolution ultrasound in conjunction with mammography images. Once the probe is in place, liquid nitrogen is introduced into it. During the initial, eight-minute freeze cycle, an ice ball develops around the tumor and kills cancer. After the defrost cycle, an additional 8-minute freeze cycle is used to ensure complete destruction of the cancer cells. The procedure takes less than an hour, and patients may soon return to normal activity.
In the study of Ice 3, Dr. Tomkovich and colleagues from 18 US Centers studied cryoablation as the primary treatment for breast cancer without surgical lumpectomy. Beginning in 2014, researchers began cryoablation in women aged 60 and older with biopsies of proven, low-risk breast cancer. Patients undergo this procedure and then repeat with mammography at six and twelve months and then every year for five years.
Meanwhile, scientists have three-year follow-up data of approximately 20 patients and two-year follow-up data in over 75 patients. The preliminary results were very promising. The procedure was successfully completed in all patients and no serious adverse events were reported. Only one patient experienced a relapse, the procedure achieving a 99.4 percent success rate.
"Lumpectomy is 90 to 95 percent effective in removing cancer," Dr. Tomkovich. "We were moving closer to that, but our preliminary results were even better, and we are getting the same results in 18 resorts across the country."
Cryoablation takes precedence over ablation techniques that use heat to destroy tumors. In one, the tissue retains its appearance when it is frozen, whereas warming tends to distort it, rendering imaging less reliable. Dr. Tomkovich reminds how bacon keeps its shape when it's frozen, but it's circling and shrinking during cooking. Additionally, there is preliminary evidence from studies in mice that cryoablation can stimulate the response of the immune system against cancer cells in the body.
The final results of the study will be published if all data on the monitored data are available for all women who have been treated.
"If it is proven that cryoablation works, then some women may be more inclined to opt for surgery," Dr. Tomkovich.