On June 22, 2012, a U.S. Food and Drug Administration (FDA) expert panel voted 10 to 1 to approve the MarginProbe system -- a device that helps surgeons decide if all the cancer tissue has been removed during lumpectomy.
Lumpectomy followed by radiation therapy is considered to be as good as mastectomy for women diagnosed with early-stage breast cancer with an average risk of the cancer coming back (recurrence). Research has shown that recurrence risk is about the same with either type of surgery.
During lumpectomy, the surgeon removes the cancer tumor and some of the normal tissue (called the margin) that surrounds it. After lumpectomy, a pathologist carefully examines the tissue that was removed to see if cancer cells are present in the margins. Margins that are free of cancer are called "negative" or "clean." Margins that have cancer cells in them are called "positive."
Ideally, the surgeon would learn the status of the margins before the lumpectomy is finished, so tissue can be removed until the margins are clean. Unfortunately, analyzing the removed tissue takes about a week. Sometimes after the pathology report is done, the margins are found to contain cancer cells and more surgery is needed. This additional surgery is called a re-excision lumpectomy, or just reoperation.
Because all the breast tissue is removed during mastectomy, the need for more surgery isn't as much of an issue with mastectomy.
The MarginProbe system uses electromagnetic waves to identify possibly cancerous tissue. It was developed to help surgeons better judge how much tissue needs to be removed during lumpectomy, making it less likely that a woman will need more surgery after lumpectomy.
The MarginProbe system detects subtle electromagnetic differences between breast cancer cells and normal breast tissue. In minutes, a surgeon can test the margins and decide if more tissue needs to be removed. MarginProbe can be used during lumpectomy for both DCIS (ductal carcinoma in situ) and invasive breast cancer.
The FDA expert panel voted based on research looking at the benefits of the MarginProbe system: women whose surgeons used MarginProbe during lumpectomy were 56% less likely to need more surgery compared to women whose surgeons didn’t use MarginProbe. The results suggest that the MarginProbe system could help surgeons be more confident that no cancer has been left behind after lumpectomy.
The FDA doesn’t have to follow the recommendations of its expert panels, but it usually does. It’s likely that the FDA will approve the MarginProbe system soon.
If you've been diagnosed with early-stage breast cancer and are planning treatment, you and your doctor will consider which type of surgery makes sense for you based on your unique situation. For many women, lumpectomy followed by radiation therapy is a good option and more attractive than mastectomy, both physically and emotionally.
Still, choosing lumpectomy means possible repeat surgery after the tissue removed during lumpectomy is analyzed. Talk to your doctor about any concerns you have about this possibility and how your concerns might influence the type of surgery you choose. If you choose lumpectomy, ask your surgeon how she or he will decide how wide the lumpectomy margins should be and how that might be influenced by your concerns about the possible need for more surgery. Together, you and your doctor can decide on a surgical plan that is right for YOU.
Stay tuned to Breastcancer.org Research News for updates on the FDA’s decision on the MarginProbe system.
Editor's Note: To help standardize the definition of negative margins, the American Society for Radiation Oncology and the Society of Surgical Oncology issued new guidelines in February 2014 saying that clear margins, no matter how small as long as there was no ink on the cancer tumor, should be the standard for lumpectomy surgery.