New Guideline on Lumpectomy Margins Should Reduce Re-excision

Zosia Chustecka

February 11, 2014

A new guideline on margins in breast cancer surgery is likely to reduce the re-excision rate for women with early-stage breast cancer who undergo lumpectomy. At present, this re-excision rate is around 20% to 25%, and is considered unacceptably high by experts.

The new guideline was developed by the Society of Surgical Oncology (SSO), in conjunction with the American Society of Radiation Oncology, and has been endorsed by the American Society of Clinical Oncology and the American Society of Breast Surgeons.

It is available online at www.redjournal.org, www.annsugoncol.org, and jco.ascopubs.org, and will be published in the March print issues of the International Journal of Radiation Oncology * Biology * Physics, the Annals of Surgical Oncology, and the Journal of Clinical Oncology.

The document establishes "the use of no ink on tumor as the standard for an adequate margin in invasive cancer in the era of multimodality therapy," and adds that the "routine practice of obtaining wider negative margins than no ink on tumor is not indicated."

"The definition of an adequate margin has been a major controversy. Therefore, it was only natural that we decided to create a definitive guideline that helps to minimize unnecessary surgery while maintaining the excellent outcomes seen with lumpectomy and radiation therapy," said Monica Morrow, MD, chief of breast surgery at the Memorial Sloan-Kettering Cancer Center in New York City, in a statement. Dr. Morrow is also immediate past president of the SSO and cochair of the guidelines consensus panel.

Dr. Meena Moran

"Our hope is that this guideline will ultimately lead to significant reductions in the high re-excision rate for women with early-stage breast cancer undergoing breast-conserving surgery," said cochair Meena Moran, MD, associate professor of therapeutic radiology at the Yale School of Medicine and the Yale Cancer Center in New Haven, Connecticut.

"The vast majority of re-excisions are unnecessary because disease control in the breast is excellent for women with early-stage disease when radiation and hormonal therapy and/or chemotherapy are added to a woman's treatment plan," she said in a statement.

In an interview with Medscape Medical News, Dr. Moran said it was studies that reported re-excision rates of approximately 20% to 25% that had made headlines over the last few years that prompted work on the guideline. In hindsight, it was highly likely that many of those women had undergone the re-excision unnecessarily.

Dr. Moran commented that re-excision is another separate operation, which often takes place weeks after the initial lumpectomy, when the woman has already begun to heal. It can be several weeks later, because the tissue sample removed during the lumpectomy has to be prepared and examined by the pathologist, who reports the pathology back to the surgeon, which then needs to be discussed with the patient to make the decision about re-excision. Often, the patients' cases are reviewed at a tumor board. Obviously, the re-excision surgery delays additional treatment (such as chemotherapy or radiation), and there are many detriments to the patient (such as psychological stress, added discomfort/pain, costs).

"The big question is, have we left behind a significant burden of tumor cells that will not be irradiated by chemotherapy, radiation, or hormone therapy," she said. This could lead to recurrence, and it is this concern of local recurrence that drives the re-excision procedures, but at the same time there have been questions over whether they are really necessary.

The new guideline is a consensus from a panel of breast experts and provides evidence-based information on which to make these decisions, she commented. "While this guideline still needs to be applied in the context of each individual patient, it should give many physicians and patients the confidence to forgo a re-excision in specific situations so that that patients are not overtreated " she added.

Dr. Moran felt that the consensus was welcomed by many experts in the field, noting that it was reviewed and endorsed by several prominent professional bodies.

"Timely and Excellent"

Approached for comment, Quyen Chu, MD, MBA, professor of surgery and director of surgical oncology at the Feist-Weiller Cancer Center at Louisiana State University Health Sciences Center in Shreveport, told Medscape Medical News: "This is a timely and excellent guideline."

"The issue of what constitutes optimal margin width has probably been discussed at great lengths at multiple tumor board sessions across the nation," he said, and "a number of us have probably been asked by our international colleagues to comment on what we think should be the 'ideal margin' width."

"This guideline generated from highly respected luminaries who are also leaders in their respective fields will serve as an assurance not only to us clinicians but also to our patients who can now be better informed of their disease," he added. "It is now up to the rest of us clinicians to make sure that we carefully evaluate and monitor our outcomes as we apply this guideline to our clinical practice. We should also be cautious to realize that guidelines, no matter how great they are, should not supplant sound clinical judgment."

Also asked to comment, Kandace McGuire, MD, a surgical oncologist at the Magee-Womens Hospital of the University of Pittsburgh Medical Center, said the new guidelines are "potentially practice changing."

"The question of margin width is consistently one of the most discussed topics amongst breast surgeons and other breast care specialists," Dr. McGuire told Medscape Medical News. "There is a wide variation as to what breast surgeons consider an acceptable margin. Hopefully, these guidelines will help streamline thinking and practice."

"Consensus statements are often based on little data, usually not level 1 or 2," she said. "These guidelines (in contrast to a consensus statement) are based on what appears to be a rigorous meta-analysis of multiple level 1 data and large retrospective studies."

"I do hope that we will see a fall in the national rate of re-excision," Dr. McGuire said. "It causes patient anxiety, can alter cosmetic outcome, and is costly to the patient and the health system. These guidelines should be used as a launching board for a discussion at every institution or practice as to what their current practice is with regard to margin status and whether it should be changed based on the data presented."

Lower Costs and Burden

The guideline should lead to a reduction in re-excisions, which will result in lower costs and burden, and may also improve cosmetic outcomes, says a group of radiation oncologists writing in a related editorial in the International Journal of Radiation Oncology * Biology * Physics.

Reshma Jagsi, MD, DPhil, from the University of Michigan in Ann Arbor, and colleagues say they agree with "the general idea that routine re-excisions of close margins (beyond no ink on tumor) is not necessary," although they also emphasize the need for shared decision making, and note that some physicians and patients may wish to pursue a wider resection.

The new guideline is likely to "have a substantial impact on the community of practicing surgeons," they write.

As a result, radiation oncologists should be prepared to encounter an increasing number of patients with microscopically close margins who, in previous years, might have undergone re-excision.

Based on Meta-analysis

The guideline is based on the results of a meta-analysis of margin width and ipsilateral breast tumor recurrence (IBTR) from 33 studies involving 28,162 patients. These patients had stage I or II invasive breast cancer and were treated with whole-breast irradiation, with a minimum median follow-up time of 4 years.

Patients treated with neoadjuvant chemotherapy or patients with pure ductal carcinoma in situ (DCIS) were not included in the research for the guideline.

The consensus guideline includes 8 clinical practice recommendations:

Positive margins, defined as ink on invasive cancer or DCIS, are associated with at least a 2-fold increase in IBTR. This increased risk is not nullified by delivery of a boost, delivery of systemic therapy, or favorable biology.
Negative margins (no ink on tumor) optimize IBTR. Wider margin widths do not significantly lower this risk.
The rates of IBTR are reduced with the use of systemic therapy. In the event that a patient does not receive adjuvant systemic therapy, there is no evidence suggesting that margins wider than no ink on tumor are needed.
Margins wider than no ink on tumor are not indicated based on biologic subtype.
The choice of whole-breast irradiation delivery technique, fractionation, and boost dose should not be dependent on margin width.
Wider negative margins than no ink on tumor are not indicated for invasive lobular cancer. Classic lobular carcinoma in situ (LCIS) at the margin is not an indication for re-excision. The significance of pleomorphic LCIS at the margin is uncertain.
Young age (≤40 years) is associated with both an increased risk for IBTR after breast-conserving therapy and an increased risk for local relapse on the chest wall after mastectomy, and is more frequently associated with adverse biologic and pathologic features. There is no evidence that increased margin width nullifies the increased risk for IBTR in young patients.
An extensive intraductal component (EIC) identifies patients who may have a large residual DCIS burden after lumpectomy. There is no evidence of an association between increased risk for IBTR and EIC when margins are negative.

The consensus guideline was funded by a research grant from Susan G. Komen.

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