MarginProbe® Helps New Mexico Breast Cancer Surgeon Ensure Clear Margins for IORT

Medical Device Manufacturer Dilon Medical Technologies, Inc

Calvin Ridgeway, M.D. Image courtesy of Lovelace Medical Group

Calvin Ridgeway, M.D., is a surgical oncologist specializing in breast cancer care. He began his career as a surgical oncologist for the United States Air force at Kirtland Air Force Base in Albuquerque and in 2008 joined Lovelace Women’s Hospital to start their breast care center – the first accredited in New Mexico. After treating breast cancer for 20 years, Dr. Ridgeway admits there have been many changes in breast cancer treatment. One of the latest shifts in the industry is the introduction of intraoperative radiation therapy.

Traditionally, after undergoing a breast conserving procedure, women are required to return  every day for several weeks to receive external beam radiation (EBRT) to her entire breast “This can be very difficult for patients living in rural areas who travel to receive their surgery.” says Dr. Ridgeway. “It is not only an inconvenience, but also a stressor for these women. That is why I have chosen to offer  intraoperative radiation therapy. A few minutes of added time in the OR replaces weeks of follow up therapy.” Dr. Ridgeway explains that Intraoperative Radiation Therapy (IORT) is a relatively new way to administer radiation therapy at the time of surgery.

Dr. Ridgeway began to offer IORT following the release of the TARGIT-A trial data in 2013. This study compared the long term effects and rate of recurrence between single-dose IORT and fractionated EBRT for breast cancer. 1721 patients were randomized to IORT and 1730 to EBRT. The 5-year risk for local recurrence in the conserved breast was 3.3% (95% CI 2.1–5.1) for IORT versus 1.3% (0.7–2.5) for EBRT. The results showed that lumpectomy followed by IORT should be considered as an option for eligible patients (tumor sized 2 cm or less) as an alternative to postoperative EBRT.

Achieving clear margins is crucial for IORT

Positive margins following lumpectomy with IORT leads not only to a second surgery, but also reverts the patient back to whole breast radiation. Therefore, for patients undergoing IORT, the utmost attention should be given to achieve clear margins during the initial procedure. “Achieving clear margins is an important aspect of every breast conserving therapy, but for patients undergoing intraoperative radiation therapy (IORT), clear margins are  even more important,” says Dr. Ridgeway. “If a surgeon wants to offer IORT, they need to ensure they get all of the cancer in the first surgery.”

Since April 2014, Dr. Ridgeway has had the chance to work with MarginProbe®, the latest tool to help ensure clean margins in breast conserving surgery. With MarginProbe, surgeons can identify positive margins on the lumpectomy specimen in real-time, enabling them to immediately take additional tissue in the operating room. “Before MarginProbe, there was not a way for me to confidently know I was getting all of the cancer during the first surgery. My reexcision rate was 9% – which was still good compared to the national average of 20-30%,” states  Dr. Ridgeway. “However, since using MarginProbe, my rate of re-excision has dropped to 4%.”

MarginProbe improves not only reexcision rate but also the amount of tissue excised

Dr. Ridgeway conducted  a clinical study with MarginProbe and compared the amount of breast tissue he was excising before and after utilizing the device. His data showed that using MarginProbe to provide assessment of lumpectomy margins resulted in fewer positive margins and led to significantly smaller lumpectomy cavities.

“Achieving negative margins while simultaneously creating a small lumpectomy cavity is critical to the success of intraoperative radiotherapy for breast cancer,” says Dr. Calvin Ridegeway. “In the 111 lumpectomies performed where the MarginProbe was used, the margins were inadequate in 5 (4.5%). In the historical control group of 87 lumpectomies, 9 (10.3%) were inadequate.”

“Because the applicator that doses the radiation during IORT is 5mm, it is important to have a smaller cavity so that you know the radiation will be administered successfully. While using MarginProbe I have seen a decrease in the amount of tissue I am excising.”

During this study, the mean specimen size in the control group was 132 +/- 19 cubic centimeters (95% CI) compared to 81+/- 13 cubic centimeters (95% CI) in the MarginProbe group. Dr. Ridgeway also observed a steady decrease in volume as he continued to use the MarginProbe. In the last 10 surgeries, the mean volume of the specimens was 51 cc.

“Using MarginProbe to provide objective assessment of lumpectomy margins has resulted in fewer positive margins and has led to significantly smaller lumpectomy cavities,” says Dr. Ridgeway. “MarginProbe improves the suitability of the lumpectomy cavity for intraoperative radiotherapy.”

MarginProbe Results

“With MarginProbe I am taking less tissue and ensuring my patients do not need to come back to our facility- for a second surgery or for their radiation therapy,” says Dr. Ridgeway. “In the future, I think that IORT will be the standard of care for breast conserving surgery for patients who are eligible. Furthermore, I think that all surgeons who choose to offer  IORT should use the MarginProbe to ensure the margins are clear and the cavity is an appropriate size.”

Dr. Calvin Ridgeway MD

  • Fellow American College of Surgeons (FACS)
  • Practicing breast surgery since 1992
  • He received his medical degree from Tulane University School of Medicine in 1987

Lovelace Health System

  • Comprised of Lovelace Medical Center, Heart Hospital of New Mexico at Lovelace Medical Center, Lovelace UNM Rehabilitation Hospital, Lovelace Women’s Hospital, Lovelace Westside Hospital, Lovelace Regional Hospital-Roswell and Lovelace Medical Group/Southwest Medical Associates.
  • First nationally accredited breast center in New Mexico
  • Women’s Choice Award Winner for breast care from 2015-2017


Disclaimer: The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of Dilon.