SAN ANTONIO — Cryoablation is an attractive alternative to surgery as primary definitive therapy for breast fibroadenomas, Sheldon Feldman, M.D., said at a breast cancer symposium sponsored by the Cancer Therapy and Research Center.
Interim results from the multicenter FibroAdenoma Cryoablation Treatment (FACT) Registry demonstrate that cryoablation is a safe, well-tolerated, minimally invasive procedure that conserves breast tissue.
Cosmesis is excellent, with little or no scarring. And unlike conventional open surgical excision of breast fibroadenomas, which typically is performed in an operating room and requires sutures, cryoablation is an office-based procedure performed through a 3-mm incision site using local anesthesia only, added Dr. Feldman, chief of the division of breast surgery at Beth Israel Medical Center, New York.
He reported on 439 FACT procedures in patients who underwent cryoablation at 55 U.S. sites. The mean baseline diameter of their fibroadenomas was 1.8 cm. A total of 79% were palpable at baseline, declining over time to 52% at 6 months after treatment and 33% at 1 year. Nearly all women who reported residual palpability described the treated area as softer and less prominent than pretreatment.
Fibroadenomas treated with cryoablation could be visualized using ultrasound in only 31% of cases at 6 months and 23% at 1 year.
The complication rate was low: a 0.8% infection rate and a 2.9% incidence of hematoma. Transient ecchymosis was observed in a total of 41% of the patients at short-term follow-up.
Physician ratings of cosmesis in the cryoablated area averaged a score of 4.8 at 6 months and a score of 4.9 at 12 months on a 5-point scale. No volume deficits were observed, unlike the case with open surgical excision, where permanent volume deficits are common, the surgeon continued.
At 6 months' follow-up, 85% of the patients treated with cryoablation indicated they would recommend the procedure to a friend, as did 82% at 12 months.
Cryoablation was performed in this series using the Food and Drug Administration-approved Visica treatment system marketed by Sanarus Medical Inc.
The procedure, which takes about 30 minutes to perform, entails ultrasound-guided insertion of the cryoablation probe into the fibroadenoma, followed by the creation of an ice ball that engulfs the benign tumor, destroying the tumor cells. The body resorbs the dead tissue and ablated debris over the subsequent months.
The Visica cryoablation system is undergoing evaluation for the in situ ablation of small breast cancers.
In a separate presentation at the San Antonio meeting, Michael S. Sabel, M.D., said that the cryoablation technique offers unique immunologic advantages over both lumpectomy and hyperthermic techniques such as radiofrequency, microwave, laser, and high-intensity ultrasound ablation.
Unlike other methods, cryoablation leaves behind intact tumor proteins and tumor-associated antigens. In an inflammatory microenvironment, these antigens have the capability of inducing a tumor-specific immune response, said Dr. Sabel, a surgical oncologist at the University of Michigan Comprehensive Cancer Center, Ann Arbor.
In a mouse study, Dr. Sabel demonstrated the induction of just such an augmented cryoimmunologic response as reflected in increased natural killer cell function, an increase in Th1- but not Th2-type cytokines, and an increase in tumor-specific T cells in tumor-draining lymph nodes.
This mechanistic investigation follows Dr. Sabel's recent report of a pilot safety study involving cryoablation in the treatment of 29 patients with primary invasive breast cancers not greater than 2 cm. Follow-up standard surgical resection showed that the freeze method successfully destroyed all cancers less than 1 cm, as well as invasive ductal carcinomas of 1–1.5 cm lacking a significant in situ component (Ann. Surg. Oncol. 2004;11:542–9).
Dr. Feldman disclosed that he receives compensation from Sanarus Medical Inc. for submitted data.