A novel device employed during breast surgery reduces the need for re-excision due to positive margins. This lessens patient anxiety, lowers treatment costs, and helps preserve the cosmetic appearance of the breast, according to a large prospective study reported at the 2012 Breast Cancer Symposium.1
Intraoperative Identification
The MarginProbe (Dune Medical Devices, Inc) provides surgeons with real-time, immediate intraoperative detection of cancerous tissue at the margin of the excised specimen. An FDA advisory panel recently recommended its approval.
“In breast-conserving surgery, which is performed in 60% to 75% of patients with early breast cancer, it is incredibly important to obtain clear margins,” said senior investigator Susan K. Boolbol, MD, of Beth Israel Medical Center, New York. “Intraoperative identification of residual disease at the margins of the excised specimen relies upon visual examination and palpation. Numerous techniques have been tried to improve intraoperative identification, but no significant improvements have been seen in 25 years.”
The pathology report, therefore, provides the margin status 1 or 2 weeks postsurgery. In 20% to 40% of cases, it indicates the presence of positive margins and the patient must undergo a second excision, she said.
The MarginProbe utilizes radiofrequency electrical fields to identify cancer on the surface of excised tissue specimens, which has a different electrical property from normal tissue.
Study Details
The study involved 495 patients with pure ductal carcinoma in situ (DCIS) or invasive cancer with a DCIS component enrolled at 21 sites. Patients underwent lumpectomy; excised tissue was inspected and palpated, with further excision if the surgeon deemed it necessary. At this point, patients were randomly assigned to having tissue evaluated intraoperatively or not with the probe, as an adjunct to standard of care.
“The probe was able to identify positive margins that required re-excision intraoperatively, and the intraoperative evaluation for positive margins usually minimized the total tissue that had to be resected,” Dr. Boolbol reported. “By using the probe both in the pure DCIS population and in the invasive cancer–plus-DCIS group, we reduced the number of times we needed to go back to the operating room.”
The intraoperative assessment essentially cut the need for re-excision by half. In the pure DCIS subgroup, repeat surgery was necessary in 37% of the control arm vs 13% of the device arm. In the invasive/DCIS subset, repeat procedures fell from 33% to 17%. The one-stop procedure was no different from the standard approach in the amount of total tissue volume removed, which averaged 85 cc in the device arm and 76 cc in the control arm among the pure DCIS group and 94 cc and 90 cc, respectively, in the invasive/DCIS subset, showing statistical noninferiority of the novel approach in preserving tissue volume.
“These are very impressive results,” Dr. Boolbol commented at a press briefing. “Further clinical studies are needed, but this appears to be a novel device that can potentially affect the way we perform lumpectomies.”
Bigger Issue
Andrew D. Seidman, MD, of Memorial Sloan-Kettering Cancer Center, New York, agreed that the interval between surgery and receipt of the pathology report is a stressful time for patients, and said, “any device that can reduce anxiety, cost, time, expense, and effort for patients by getting it right the first time is welcome news.”
Monica Morrow, MD, the Anne Burnett Windfohr Chair of Clinical Oncology at Memorial Sloan-Kettering Cancer Center, however, noted, “The margin issue is much more complicated.”
Dr. Morrow, a breast surgeon, told The ASCO Post, “The reoperation rate is completely dependent on how an ‘inadequate margin’ is defined, and there is no consensus on this. If your definition is ‘tumor not touching ink,’ then it appears this probe will help to reduce the reoperation rate. If your definition is 5 mm, then it may or may not. It depends on what your baseline positive margin rate is.”
Dr. Morrow further pointed out that the manner in which the specimen is processed also affects the positive margin rate. “At Memorial we have processed them in three different ways over the past 10 years. Our positive margin rate was 50% with one approach, 18% with another, and with the way we do it now—which is to take separate margin specimens from around the cavity—it has dropped to 6%,” she said.
“The single most important thing to reducing positive margin rates is to come to a national consensus on the definition of an adequate margin,” she emphasized. A consensus conference will tackle this issue later this year. ■
Disclosure: Dr. Boolbol was an investigator in the clinical trial and served as a consultant for Dune Medical during the FDA approval hearing. Drs. Seidman and Morrow reported no potential conflicts of interest.
Reference
1. Freedman BC, Boolbol SK, Cocilovo C, et al: Reduced re-excisions while conserving tissue volume resected in DCIS patients. 2012 Breast Cancer Symposium. Abstract 144. Presented September 13, 2012.
