Lymph Node Dissection Rates High for Some Women With DCIS

Alexander M. Castellino, PhD

April 09, 2015

There has been an increase in the incidence of ductal carcinoma in situ (DCIS) on screening mammography. However, some women undergoing mastectomy or breast conservation surgery (BCS) following a DCIS diagnosis also undergo axillary lymph node evaluation — against National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) guidelines.

In an article published online April 9 in JAMA Oncology, researchers from the Columbia University Medical Center, in New York City, report on the prevalence of axillary lymph node evaluation in women with a biopsy-proven diagnosis of DCIS.

They report that 29.2% of 35,591 women with DCIS undergo an axillary evaluation — sentinel lymph node biopsy (SLNB) or full axillary lymph node dissection (ALND).

"This was an eye-opener," corresponding author Dawn L. Hershman, MD, of the Herbert Irving Comprehensive Cancer Center at Columbia University, told Medscape Medical News. "Almost 1 in every 5 women undergoing BCS received axillary evaluation despite recommendations against this practice by both NCCN and ASCO."

"We need a better understanding of who needs these procedures," she added.

Although axillary lymph node evaluation is the standard of care in the surgical management of invasive breast cancer, a benefit has not been demonstrated in DCIS, Dr Hershman and colleagues indicate in their report.

In an accompanying commentary, Kimberly J. Van Zee, MD, from the Evelyn Lauder Breast Center of Memorial Sloan Kettering Cancer Center, New York City, comments that "the proportions undergoing nodal evaluation are not consistent with current guidelines."

Dr Van Zee told Medscape Medical News: "The women in the study may not represent the general population of women in the United States undergoing DCIS procedures."

She also emphasized that only 4.7% of DCIS procedures in this patient population were performed by surgical oncologists; most of the procedures were performed by general surgeons.

"The management of breast cancer has undergone a radical transformation over the past few decades, and its evolution is continuing. Axillary surgery has become markedly less aggressive and morbid over the past 20 years. [Dr Hershman] and colleagues have shed some light on how the changes in recommended practice have been adopted in a broad sample of hundreds of predominantly small, urban, nonteaching hospitals across the country and by general surgeons who infrequently treat women with DCIS," Dr Van Zee concludes in her commentary.

An Analysis of 35,591 Women With DCIS

Dr Hershman and colleagues accessed the Perspective database, which is an all-payer database and captures approximately 15% of outpatient and inpatient hospitalizations and includes data from more than 600 acute-care hospitals.

Data for excisional breast procedures were accessed for women aged 18 to 90 years from January 2006 through December 2012 — a period following the publishing of recommendations by ASCO and NCCN against axillary evaluation in women undergoing BCS.

Of 35,591 women with a DCIS diagnosis who underwent mastectomy or BCS, 29.2% had axillary evaluation ― 84.2% had SLNB and 15.8% had a full ALND.

Axillary evaluation was reported in 63% of women undergoing mastectomy ― full ALND in 15.2% women and SLNB in 47.8% women. Patients undergoing BCS had a lower rate of axillary evaluation — 17.7%.

For the approximately 18% of women undergoing BCS and axillary evaluation, Dr Van Zee indicated that, barring a few exceptions, nodal evaluation is generally not recommended.

Dr Hershman and colleagues reported that "surgeon volume was the most significant predictor of axillary evaluation with BCS, with high-volume surgeons less likely to perform lymph node dissections than low-volume surgeons."

However, Dr Van Zee told Medscape Medical News that the category of high-volume surgeons was defined on the basis of a median of >2.67 surgeries per year (range, 1 - 23.8). Most surgical oncologists and breast cancer surgery specialists perform significantly more than 2.67 surgeries per year, she told Medscape Medical News.

For women undergoing mastectomy, axillary evaluation increased from 56.6% in 2006 to 67.4% in 2012; ALND decreased from 20.0% in 2006 to 10.7% in 2012. Axillary evaluation was relatively stable for women undergoing BCS — 18.5% in 2006 to 16.2% in 2012.

Dr Van Zee noted: "[T]he use of ALND decreased over time, consistent with the shift from ALND to SLNB as the standard axillary staging procedure. However, it is surprising that even as late as 2012, 11% of women underwent ALND."

Dr Van Zee told Medscape Medical News that general surgeons do not have the training it takes to do SLNB. As she stated in her commentary: "The technique of SLNB requires training and experience and also requires some institutional support if radioactive tracer is used. These low- and mid-volume surgeons slowly did decrease their use of ALND and increase their use of SLNB, such that by 2012, most women undergoing mastectomy (57%) had SLNB."

This falls far short of the general recommendation that women undergoing mastectomy for DCIS have an SLNB, she added.

Additional Analysis

The observations from the study may not be representative of the entire population of women diagnosed with DCIS, Dr Van Zee suggested.

First, the database used for this study captured only 15% of the entire US population diagnosed with DCIS during the study period.

Second, the patients in the population analyzed in the study were generally treated in small, urban, nonteaching hospitals in the South, with surgical procedures performed by general surgeons:

  • 54% of surgeries were undertaken in hospitals with a bed count <400

  • 89% of hospitals were in the urban setting

  • 61% were done in nonteaching hospitals

  • 44% of surgical procedures were done in the South

  • 95% were performed by general surgeons — only ~5% of surgeries were undertaken by surgical oncologists

Dr Hershman and colleagues concede that limitations of the study included use of a database with a relatively higher proportion of women treated at small to midsize hospitals; the facilities are in urban settings and are mainly nonteaching.

For Dr Van Zee, the combination of ALND and SLNB for the analysis was also a limitation. "This makes interpretation difficult, since SNLB is recommended for those undergoing mastectomy, whereas ALND is not, and SLNB may be appropriate in some cases of BCS, whereas ALND is not," she writes.

She told Medscape Medical News: "The standard of care for women undergoing mastectomy is SLNB; for women undergoing lumpectomy, it is doing nothing, except in certain situations."

Dr Hershman indicated to Medscape Medical News that a more personal approach must be undertaken in women with DCIS to identify those who will benefit most from axillary nodal evaluation.

She suggested that a prospective study may be able to identify whether there is a clinical benefit to axillary evaluation on women with DCIS. Dr Hershman also proposed placing a marker such as a dye in the node rather than removing it; "it can be excised at a second operation should invasive cancer be identified on final pathology," she said.

The authors and the editorialist have disclosed no relevant financial relationships.

JAMA Oncology. Published online April 9, 2015. Abstract, Commentary

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