- Buyers Guide
Military Microwaves Supplement
Recent Advances in Radar Technology
Using Calibration to Optimize Performance in Crucial Measurements
Radiofrequency ablation of the lumpectomy site during breast cancer surgery can provide an effective alternative to post-operative external radiation therapy (XRT) and reduce repeat surgeries to achieve clear tumor margins, according to one of the first published long-term studies to examine this new treatment protocol. Researchers reported this week at the American Society of Breast Surgeons (ASBrS) Annual Meeting that utilizing radiofrequency-generated heat to create an added disease-free zone around the tumor cavity is at least as effective in preventing local tumor recurrence as XRT following surgery. In many cases, ablation also extended the disease-free zone sufficiently to eliminate the need for repeat surgery to correct inadequate disease-free tumor margins identified in post-operative pathology examination.
"Radiation has a range of difficult side effects, including shrinkage of breast tissue, loss of sensation and damage to nearby healthy tissue," comments lead study author V. Suzanne Klimberg, MD, FACS, Muriel Balsam Chair in Surgical Oncology and Professor of Surgery and Pathology at the University of Arkansas for Medical Sciences, Director of the Breast Cancer Program at the Winthrop P. Rockefeller Institute of the University of Arkansas for Medical Sciences, and President-Elect of the ASBrS. "Additionally, for patients in rural areas in the U.S. and around the world, XRT—the standard of care following lumpectomy surgery—simply isn’t an option if a therapy center is not located nearby. Today, these patients have no choice but mastectomy."
In the study, 60 patients with invasive cancer underwent tumor excision (lumpectomy surgery) followed by radiofrequency ablation (eRFA) at 100 degrees C for 15 minutes with a real-time radiofrequency probe to extend the radius of the lumpectomy cavity by 1 cm. None of the patients received adjunctive XRT.
Patients in the study were followed with a mammogram and physical exam every six months for the first two years and yearly thereafter. During the nine year study, patients have been followed for an average of 44 months post-op, (ranging from 12 to 84 months). The study reports on a subset of 60 patients treated for invasive cancer with a lumpectomy and intraoperative RFA as an alternative to XRT. None of these patients received chemotherapy.
Pathology reports following surgery found that tumor margins were cancer-free in 44 patients, focally positive in 3, close in 11 and grossly positive in 2. It had been previously determined that because of the ablation-extended margins, only patients with grossly positive margins on post-operative pathology or residual calcifications on postoperative mammography would require additional excision of the tumor bed. In the study, 14 out of 16 patients who would have returned to the operating room (OR) with similar margin findings and XRT were spared additional surgery.
Only one patient (1.7 percent) recurred with a cancer nearby the original tumor site. One patient developed a cancer at a distant location.
"The recurrence rate for lumpectomy with follow up radiation is 1 percent per year for the first five years and then about ½ percent annually thereafter," comments Misti H. Wilson, MD, Breast Fellow and Instructor in the Department of Surgery at the University of Arkansas for Medical Science, another study author. "Patients in this study did extremely well. Without the side effects of radiation, radiofrequency ablation is an extremely appealing choice. The ablated tissue remains in the breast, so less breast mass is lost than with radiation, and post-treatment tissue shrinkage is not a problem. The cosmetic results are excellent. Often, you can barely tell a patient has had surgery."
Dr. Klimberg also notes that the eRFA has a range of practical advantages compared to radiation therapy. eRFA is delivered by the breast surgeon and does not require extensive special training. Unlike radiation, it can be delivered in any OR with no equipment other than an RFA probe and does not require follow-up treatment.
RFA has been successfully used for many years to treat a range of other types of cancer by destroying the entire tumor. But its application in breast cancer has been difficult due to the characteristics of breast tissue. Only recently have surgeons begun exploring it as an alternative to XRT to extend the margins of the tumor bed.
Based on the results of this study, eRFA is now being examined in a multicenter ABLATE (Radiofrequency Ablation after Breast Lumpectomy Added to Extend Intraoperative Margins) trial. To date, the trial includes five centers (Columbia University, University of Kansas, Comprehensive Breast Care of San Diego, University of Arizona and Rockefeller Cancer Institute in Little Rock) and is actively recruiting and training additional sites (http://surgery.uams.edu.ablate).
Objectives: Clinical trials have yet to find a size or grade of invasive cancer that can be treated with lumpectomy alone due to the higher local recurrence (LR) rate without radiation (XRT). Even with advanced tumor localization techniques and our best efforts, a large percentage of patients require re-excision for positive margins, which can be costly, time-consuming, and stressful for the patients. Adjuvant radiation also adds significant cost and morbidity to the breast cancer patient treatment regimen. Excision followed by radiofrequency ablation (eRFA) is an intraoperative method that utilizes heat to create an additional tumor-free zone around the lumpectomy cavity approximating the zone treated by brachytherapy. We hypothesized that eRFA after lumpectomy for invasive breast cancer could reduce the need for re-excision by extending the margin of tumor-free zone and maintain local control without XRT.
Method: We conducted an IRB-approved Phase II trial of patients with invasive breast cancer receiving lumpectomy followed by immediate intraoperative eRFA. Patients with tumors less than or equal to 3 cm with clinically negative nodes were included. A standard lumpectomy was performed then the RFA probe was deployed 1 cm circumferentially into the walls of the lumpectomy cavity. RFA maintained at 100 degrees C for 15 min has been shown in preclinical and clinical data to extend the lumpectomy margin by 1 cm. Validated Doppler sonography was used to determine final ablation size. Cosmesis was good. Standard H&E of lumpectomy margins was performed. None of these patients received XRT. Only patients with grossly positive lumpectomy margins was performed. None of these patients received XRT. Only patients with grossly positive margins or residual calcifications on postoperative mammography were re-resected. Patients were followed every 6 months for the first 2 years and yearly thereafter with mammogram and physical exam.
Results: Sixty patients (mean age of 68.7 ± 11.4 years) with invasive cancer who had an average tumor size of 1.1 cm ± 0.61 (range, 0.2 to 2.5 cm) underwent excision followed by radiofrequency ablation. Fifty-six patients had invasive ductal carcinoma and 4 had invasive lobular carcinoma. Thirty-three patients had grade I disease, 21 had grade II, and 6 had grade III. Margins were negative in 44, focally positive in 3, close in 11, and grossly positive in 2. Fourteen of 16 (87 percent) patients with close or positive margins were spared re-excision. Thirty-three patients were treated with hormonal therapy. Overall there were 5 deaths total, none of which were related to their primary disease. After follow-up for 44 (12-84) months, only 1 patient (1.7 percent) developed an in site recurrence. There was 1 recurrence at another site. Average cosmesis rating was good to excellent.
Conclusions: Long-term follow-up suggests that eRFA could reduce the need for re-excision, as well as reduce local recurrence for invasive breast cancer treated without XRT. For selected breast cancer patients undergoing breast conservation therapy, eRFA is an attractive alternative to breast irradiation. This concept has recently initiated a multicenter register trial called ABLATE (Adjunctive Breast Lumpectomy With RF Ablation Treatment to Reduce Re-Excision & Recurrence) in patients undergoing conservative breast surgery.
Get access to premium content and e-newsletters by registering on the web site. You can also subscribe to Microwave Journal magazine.