Margin Call: Expert Supports Greater Margin Width in Lumpectomy for Some Patients With DCIS

Jason M. Broderick @jasoncology
Published: Friday, Mar 07, 2014

Melvin J. Silverstein, MD,
FACS, from Keck School of Medicine
University of Southern
California

Melvin J. Silverstein, MD, FACS

Over the past few decades, the optimal margin width for minimizing recurrence after breast-conserving surgery (BCS; lumpectomy) has been a topic of much debate.

To provide some clarity to practitioners, the Society of Surgical Oncology and the American Society for Radiation Oncology recently released a consensus guideline on margins in BCS for invasive breast cancer (Table 1). Their definition of a clear margin is no ink on tumor, and the guidelines are meant for patients with invasive breast cancer who receive postexcisional radiation therapy.

These guidelines, however, do not address patients with noninvasive disease (ductal carcinoma in situ [DCIS]). At the 31st Annual MBCC, Melvin J. Silverstein, MD, FACS, a breast cancer expert and surgeon at Hoag Memorial Hospital Presbyterian in Newport Beach, California, discussed his research on optimal margin width in lumpectomy for patients with DCIS.

Silverstein, who is also a professor at the Keck School of Medicine of the University of Southern California, said that wider margins are important for patients with DCIS who are treated with excision alone; however, he stressed that margins alone are not the answer for determining optimal patient treatment.

A controversial meta-analysis published in the Journal of the National Cancer Institute in 2012 suggested that wide margins (≥10 mm) are optimal for lowering the risk of ipsilateral recurrence for all cases of DCIS treated with lumpectomy, regardless of radiotherapy use.1

Table 1. Summary of SSO/ASTRO Consensus Guideline on Margins for Breast-Conserving Surgery With WBRT for Invasive Cancer

Category Recommendation
Positive Margins At least a two-fold increase in the risk of IBTR is associated with a positive margin (ink on invasive tumor or DCIS). A radiation boost, sytemic therapy, or favorable biology do not offset this risk.
Negative Margins The risk of IBTR is minimized by negative margins, defined as no ink on the tumor; however, this risk is not significantly decreased with wider margins. Obtaining negative margin widths wider than no ink on tumor as standard practice is not indicated.
Systemic Therapy Systemic therapy decreases IBTR rates. In the infrequent cases when adjuvant systemic therapy is not used, the data do not support the need for margins wider than no ink on tumor.
Systemic Therapy Systemic therapy decreases IBTR rates. In the infrequent cases when adjuvant systemic therapy is not used, the data do not support the need for margins wider than no ink on tumor.
Biologic Subtypes The data do not support the use of margins wider than no ink based solely on biologic subtype, such as triple-negative breast cancer.
Radiation Therapy Delivery Margin width should not impact the selection of WBRT delivery technique, fractionation, and boost dose.
Invasive Lobular Carcinoma and LCIS For patients with invasive lobular carcinoma, negative margins wider than no ink are not indicated. The presence of classic LCIS at the margin is not an indication for re-excision. It remains unclear what the significance is of pleomorphic LCIS at the margin.
Young Age Women ≤40 years old have an increased risk of IBTR following BCT and postmastectomy local relapse on the chest wall. Young age is also more commonly linked with adverse pathologic and biologic characteristics. The data do not suggest that the higher risk of IBTR in these patients can be offset by wider margins.
Extensive Intraductal Component An extensive intraductal component identifies patients who may have a large residual DCIS burden following lumpectomy. With negative margins, the data do not show a link between an extensive intraductal component and a higher risk of IBTR.

The guideline is based on a meta-analysis of 33 studies conducted by a multidisciplinary consensus panel. The studies included 28,162 patients with early-stage invasive breast cancer (stages I and II), all of whom had received BCT and adjuvant WBRT.
ASTRO indicates American Society for Radiation Oncology; BCT, breast-conserving therapy; DCIS, ductal carcinoma in situ; IBTR, ipsilateral breast tumor recurrence; LCIS, lobular carcinoma in situ; SSO, Society of Surgical Oncology; WBRT, whole-breast radiation therapy.
Source: Moran MS, Schnitt SJ, Giuliano AE, et al. Society of Surgical Oncology–American Society for Radiation Oncology consensus guideline on margins for breast-conserving surgery with whole-breast irradiation in stages I and II invasive breast cancer [published online February 10, 2014]. J Clin Oncol. doi:10.1200/JCO.2013.53.3935.

The results of the meta-analysis have been disputed since publication, and have not been adopted as the standard surgical approach in DCIS. One major critique was that the cases of margins ≥10 mm came from more recent studies than those with narrower excisions. Thus, the development of better diagnostic and treatment techniques, not margin width, might explain the better prognoses.


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