Radiofrequency ablation of breast cancer cells reduces need for further surgery

30 October 2005

Fremont Calif. & Little Rock, Ark. USA. A study of patients undergoing breast-conserving surgery to remove cancerous cells has found that heating the surrounding cells of the lumpectomy site by radiofrequency ablation (RFA) reduced the need for further surgery.

RITA Medical Systems and the University of Arkansas for Medical Sciences have announced that clinical investigators at the University of Arkansas Cancer Research Center reported the results of a clinical trial, Radiofrequency Ablation (RFA)-assisted Lumpectomy, in a paper session at the American College of Surgeons (ACS) 91st Annual Clinical Congress in San Francisco. The presentation reviewed the results of a multiphase clinical trial with 25 patients in which RFA-assisted lumpectomy using RITA's products was shown to reduce the need for re-excision for inadequate margins following lumpectomy by 86%.

Professor Suzanne Klimberg MD commented, "Our short-term follow-up has shown no in-site recurrence of cancer in these patients." Dr. Klimberg continued, "We believe that RFA-assisted lumpectomy is a technique that may give women who choose breast-conserving surgery added assurance that they will not need to endure a second surgical procedure to remove cancer found during pathology examination of the margins of their lumpectomy specimen post-surgery." Professor Klimberg is Professor of Surgery and Pathology at the University of Arkansas for Medical Sciences (UAMS), and the Central Arkansas Veterans Healthcare Systems, Chief of the Division of Breast Surgical Oncology at UAMS, Director of the Breast Cancer Program at UAMS' Arkansas Cancer Research Center, and corresponding author of the clinical abstract.

In the trial, 25 patients with an average tumor size of 1.8 cm underwent RFA treatment of their lumpectomy excision site in the operating room immediately following breast conserving lumpectomy surgery. The excised lumpectomy specimen was then sent for pathology analysis. Final pathology results found inadequate margins in 28% of the patients. The inadequate margins found in those patients who received RFA at the time of surgery were not re-excised because in a bench trial of 29 mastectomy samples (breast tissue donated by patients undergoing mastectomy surgery) RFA consistently demonstrated a complete zone of ablation to a thickness greater than 5 millimeters.

A finding of "inadequate margin" is made during the post-surgery pathology examination of the lumpectomy specimen when cancer cells are found close to the perimeter of the specimen, indicating that additional cancer cells may remain in the lumpectomy site. Typically, a second operation would be required several days or weeks later to re-excise the inadequate margins in order to reduce the likelihood of in-site breast cancer recurrence. A finding of "positive margin" during the pathology examination is made when cancer cells are found on the perimeter of the lumpectomy specimen. A finding of "negative margin" during the pathology examination is made when no cancer cells are found close to the perimeter of the lumpectomy specimen.

Edward M. Copeland, MD, Edward R. Woodward Professor, Department of Surgery, University of Florida College of Medicine, and a pioneer in breast conservation therapies for breast cancer commented, "Assuring that lumpectomy margins are negative is one of the keys to preventing recurrence of breast cancer following breast conservation treatment. Were radiofrequency ablation proven to be a safe and cost effective method of obtaining negative margins, it would be a positive addition to the treatment armamentarium of the oncologic surgeon."

Mr. Joseph DeVivo, President and CEO of RITA Medical, commented, "We believe that RFA-assisted lumpectomy holds great promise for women who choose breast conserving surgery. We expect Dr. Klimberg and her team to add clinical data to support the use of the RFA-assisted lumpectomy technique. As part of an ongoing pilot study that followed the clinical trial reported at the ACS meeting this week, 8 patients out of 16 treated for breast cancer were found to have inadequate surgical margins after lumpectomy. All 8 patients were spared re-excision because Dr. Klimberg used RFA at the time of lumpectomy."

Mr. DeVivo concluded, "Our goal is to create a well-defined application of RFA in the treatment of breast cancer supported by solid clinical data. As we have previously said, we believe there is a terrific market opportunity for the application of RFA in the treatment of breast cancer."

RFA-assisted lumpectomy utilizes heat with the intent to create an additional tumour-free zone around the lumpectomy cavity. During the trial reported on at ACS this week a RITA RFA probe was deployed 1cm circumferentially into the walls of the lumpectomy cavity and maintained at 100°C for 15 minutes in 25 patients. In addition to the in-vivo clinical application of RFA, 29 prophylactic mastectomy ablations were performed revealing a 5–10mm ablation zone in 72.4%(21/29), 10–20mm in 24.1%(7/29), and greater than 20mm in 3.5%(1/29). Researchers in the clinical trial reported at ACS this week that they concluded that these ex-vivo ablations reliably created a minimum 5–10 mm zone of ablation.

An abstract of the presentation at the ACS 91st Annual Clinical Congress can be found at the American College of Surgeons website, www.facs.org

Contributing authors of the presentation abstract include Julie Kepple M.D., oncology fellow, Soheila Korourian M.D., Associate Professor, Department of Pathology, Ronda S. Henry-Tillman M.D., FACS, Associate Professor of Surgery and Director of the UAMS Cancer Control Department, Aaron Margulies M.D. FACS, Instructor of Surgery and Fellow in Diseases of the Breast, Gal Shafirstein Ph.D., Assistant Professor, Department of Otolaryngology/Head and Neck Surgery, and V. Suzanne Klimberg M.D., FACS.




RITA Medical Systems, Inc.

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