At the annual San Antonio Breast Cancer Symposium in December 2013, Monica Morrow, Chief of our Breast Surgical Service, was honored with the William L. McGuire Memorial Lecture Award. In her address, Dr. Morrow discussed how surgery for breast cancer is evolving in the modern era of more-effective drug therapy. We asked Dr. Morrow to give us an overview of her lecture and to speak generally about the future of breast cancer surgery.
How is surgery used to treat breast cancer?
Surgery is usually the first treatment for breast cancer and is used to reduce the amount of cancer in the breast, known as the tumor burden, to the lowest possible level. Studies show that 75 to 80 percent of patients with small breast cancers that do not involve the lymph nodes will survive 20 years if treated with surgery alone. But surgery is not our only defense.
The last 30 years have given us a multitude of new medications — like hormone therapies and targeted drugs — that not only reduce the likelihood that cancer will return or spread to other parts of the body but also improve surgical outcomes by reducing local recurrence in the breast. In fact, the advent of effective systemic therapy has cut the likelihood of a local recurrence in half.
How is surgery for breast cancer evolving?
The combination of surgery plus systemic therapy has been very successful in reducing tumor burden, and it’s unlikely that efforts to surgically reduce tumor burden even more will improve outcomes. For example, several studies have shown that the use of MRI before surgery does not improve outcomes or reduce local recurrence, even though the expectation had been that MRI’s higher sensitivity for detecting tumors would lead to better selection of women for breast-conserving surgery. What MRI does do is increase the chances a patient will have a mastectomy, a much more burdensome operation than breast-conserving surgery but with similar outcomes.
What we need to ask now is, How can we take advantage of the benefits of drug therapy to improve our approach to breast surgery? Can we do less surgery on the breast or the underarm (axillary) lymph nodes to reduce the burden of treatment for patients while still maintaining good outcomes?
What can be done to lessen the burden of breast cancer surgery for patients?
First, there needs to be consensus on what constitutes an adequate margin [around the tumor]. Approximately 25 percent of women who undergo breast-conserving surgery return to the operating room for a reexcision because the margins around the tumor are considered too small. Repeat surgeries not only can be burdensome for patients and their families, but also can increase health risks and costs and produce worse cosmetic outcomes. Given what we now know about the use of systemic therapy and its ability to minimize the incidence of local recurrence, we need to develop guidelines on just how much breast tissue needs to be removed during breast-conserving surgery.
Earlier this week, a consensus statement jointly put together by the Society of Surgical Oncology and the American Society for Radiation Oncology stated that an adequate margin should be defined as no cancer cells touching the edge of the tissue removed; there is no clinical benefit to removing more tissue than that, and therefore no need to perform additional surgeries to obtain more widely clear margins. I hope that this statement, based on a meta-analysis of more than 30 studies, will lead to widespread adoption of this definition of a standard margin so patients can be spared the trauma of a second surgery.
Second, when possible we need to avoid axillary dissection [the removal of most of the underarm lymph nodes], which causes lymphedema, a sometimes-severe swelling of the arm. Newer research indicates that for women who undergo lumpectomy plus radiation and have only one or two positive sentinel nodes, axillary dissection offers no benefit. Many in the surgical community have questioned these results, but we accept that chemotherapy given before surgery can reduce axillary metastases, so why should the results be any different if chemotherapy is given postoperatively? At Memorial Sloan Kettering, we have verified these findings in our own prospective study and have adopted guidelines to include the selective use of axillary dissection in our clinical practice. This guideline spares approximately 85 percent of women who have a lumpectomy and whole-breast radiation from complete lymph node removal.
How do you see breast cancer surgery fitting into patients’ treatment plans in the future?
We are moving toward a more multimodality approach to treating breast cancer where local therapy, meaning surgery and radiation, and systemic therapy are considered together, rather than as three separate phases of treatment. We are also learning more about the biology of breast cancer, and future studies will need to address not only whether improvements in drug therapy will allow us to safely decrease the extent of surgery and radiation, but also how an individual patient’s biology should guide treatment decisions.