A very small, preliminary study shows that a new device is good at determining whether the outer edges (called margins) of the mass of tissue removed during lumpectomy are healthy or contain breast cancer. The device can be used during surgery and offers results in 5 minutes, compared to standard methods which take about a week.
In lumpectomy, a surgeon removes the cancer tumor and some of the normal tissue (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 completed, so as much tissue as needed could be removed until the margins were clean. Unfortunately, analyzing the tissue using currently available methods takes about a week. So in about 40% of lumpectomies, the margins are later found to contain cancer cells and more surgery is needed. This additional surgery is called a re-excision lumpectomy.
In this study, researchers used a new imaging device to analyze the margins of 55 tissue samples removed during lumpectomy. Most of the samples were from women diagnosed with early-stage, invasive breast cancer. Nine of the samples were from women diagnosed with DCIS (ductal carcinoma in situ). The researchers compared the results from the experimental device to the pathologists' reports on the margins.
In looking at the invasive breast cancer tissue samples:
- Margins classified as positive by the pathologist were correctly classified by the device 80% of the time.
- 20% of the positive margins were incorrectly classified as negative/clean by the device.
- Margins classified as negative/clean by the pathologist were correctly classified by the device 67% of the time.
- 33% of the negative/clean margins were incorrectly classified as positive by the device.
In looking at non-invasive DCIS:
- Margins classified as positive by the pathologist were correctly identified by the device nearly 90% of the time.
This experimental imaging device has tremendous potential. It could possibly eliminate the need for more surgery after lumpectomy because surgeons would know before they completed the procedure whether or not the margins were clean. Still, the device is experimental. While it looks promising, the accuracy is not yet reliable enough for doctors to use it with complete confidence. Improving the technology and more research will some day offer doctors a better, more immediate way to know whether margins are clean during lumpectomy.
Stay tuned to Breastcancer.org for the latest news on research that may lead to better ways to prevent, diagnose, and treat breast cancer.