By Elisabeth Geier
An Introduction to Two Techniques
Breast-conserving surgery, also called lumpectomy, is one of the primary treatments for breast cancer. Lumpectomy allows for removal of cancerous tumors while leaving as much breast tissue as possible intact (unlike mastectomy, which can require removing all of the breast tissue, underlying muscles, and lymph nodes).
When surgeons perform lumpectomies, their goal is to remove the whole tumor along with “a little bit of an edge” of normal breast tissue, explains Roshni Rao, MD, chief of the Breast Surgery Program at NYP/Columbia. That edge, or extra margin of tissue, is then sent to pathology to be analyzed. The goal is to ensure a cancer-free margin, confirming that all of the cancerous tissue has been removed.
Surgeons can use two different techniques to get clear margins: cavity shave margins (CSM) and specimen shave margins (SSM). Dr. Rao prefers to use CSM, where the surgeon removes a little extra tissue from the lumpectomy cavity edges after the tumor has been removed. Lisa Wiechmann, MD, a breast surgeon with over 10 years of experience at NYP/Columbia, prefers SSM, in which the surgeon shaves extra tissue from the removed tumor itself.
The analogy of using a melon baller is how Dr. Rao likes to illustrate the two approaches— “What I do is I take out [a scoop] and then go into that melon again and take additional edges…What Dr. Wiechmann does is that she gets out that melon baller, takes that ball, and then shaves the edges off of it,” she explains. “Both techniques have the same ultimate purpose: to provide pathology with enough tissue to double-check that the cancerous tissue has been removed, preventing recurrence and the need for additional surgeries.”
“Obviously, I feel that my way is better, and she feels that her way is better,” says Dr. Rao. “But because I'm the chief, I'm always right.”
“Of course,” says Dr. Wiechmann, both laughing. Dr. Wiechmann was initially taught to perform lumpectomies using Dr. Rao’s preferred CSM method. But over time, she realized it was easier, faster, and just as effective for her to remove shave margins from the excised tumor rather than the surgical cavity.
“The observation I made was you're never really quite sure, once you remove that first melon ball (since we're using that analogy), as to what is really superior, where does superior meet medial and lateral [within the cavity]...because it's misshapen and the cavity is not a perfect sphere,” says Dr. Wiechmann.
She also noticed when she performed lumpectomies using SSM that “if I did have a close or positive margin, the pathologist could always match and find the exact opposite side on the additional shave margin.” Meaning that made it easier to identify where to remove additional tissue if necessary. The last observation that sealed the deal on this technique for Dr. Wiechmann is simply that the SSM method was faster for her. It was a matter of surgical preference—SSM worked better for Dr. Wiechmann. But did it make a difference for patient outcomes?
There Is No One-Fits-All ‘Best’ Approach
In the fall of 2022, Dr. Rao and Dr. Wiechmann, along with breast surgeon Stacy K. Ugras MD, FACS, released the results of a two-year study that compared CSM and SSM techniques by analyzing positive rates of primary and final shaved margins, re-excision rates, and tissue volumes removed. As stated in the abstract, the study found that “between the two methods, the need to re-excise, which would be based on a positive margin or a very close margin, is the same.”
Meaning that CSM and SSM are both effective techniques for achieving low re-excision rates, and surgeons performing either “may maintain operative preferences and achieve similar results.”
In other words, Dr. Rao and Dr. Wiechmann are both right.
“There is an art to surgery, and I think certainly we all feel that our way is better,” says Dr. Rao. “But the good news is that the data shows that we can get similarly low rates of re-excision with the technique that we're most comfortable with.”
Dr. Rao and Dr. Wiechmann’s differing preferences lead to impressive results. As Dr. Ugras explains, the national average for re-excision following breast conservation surgery (BCS) is 20 percent, but the shave margin comparison study showed that Columbia’s re-excision rates are in the low single digits. That’s due in part to the surgical methods in use: “I think the methods are beneficial, and it’s been proven that taking separate margins decreases the re-excision rate for all tumors,” says Dr. Ugras.
Surgical Techniques Can’t Stand Still
One of the most important parts of a breast surgeon’s job is to remain on the cutting edge of practice across the scope of treatment, from surgical techniques to clinical trials. Dr. Rao, Dr. Wiechmann, and Dr. Ugras are constantly refining their techniques, cognizant of re-excision, and adjusting their methods to get better and better results. That refinement extends to all parts of the multidisciplinary breast cancer group. “Our pathologists are paying really close attention to how we orient the margins,” says Dr. Ugras. “Intraoperatively, we use techniques to show the pathologist what side is the relevant side, and they process the tissue in a formalized, standardized way.”
“We also have proximity to our radiology and medical oncology teams,” explains Dr. Rao. “Our radiologists are on the same floor, and we're constantly reviewing things with them, looking at the images with them. Our medical oncologists are also right across the hall.” Disagreements about specific techniques ultimately lead to more engagement too. “We’re a close enough group that we are open to and willing to learn from each other,” adds Dr. Wiechmann.
For Dr. Ugras, the proof is in the data. “We’re constantly reassessing our own techniques and putting ourselves under the microscope to make sure we're doing the right thing,” she says. “And not just doing what we think is right, but checking the evidence and the research and looking at our outcomes.”
As Dr. Rao puts it, “It's only out of some of these discussions that you can grow and improve.” More often than not, cutting edge care relies on disagreements to grow, improve, and advance. Differing opinions over surgical technique can fuel research, comparison, and refinement of techniques. It’s an important way to ensure the best possible care and outcomes for all.