The American Society of Clinical Oncology has published an updated guideline for the use of sentinel lymph node biopsy (SLNB) in patients with early-stage breast cancer, which now recommends use of the less-invasive diagnostic procedure for a larger group of patients.
The update is based on new clinical trials evidence published since the original guideline was written in 2005, and is now available online ahead of print in the Journal of Clinical Oncology (DOI: 10.1200/JCO.2013.54.1177).
“Several additional studies have been completed and published since the guidelines were first issued—studies thought to be potentially practice changing that address some of the major questions concerning the role of sentinel lymph node biopsy for the evaluation of women with early-stage breast cancer,” explained Gary Lyman, MD, MPH, FASCO, Co-chair of the guideline's expert panel.
Lyman, Co-Director of the Hutchinson Institute for Cancer Outcomes Research and a member of the Public Health Sciences Division of Fred Hutchinson Cancer Research Center, said via email that full axillary dissection, which may result in considerably more complications, is not appropriate in patients with negative SLNB findings.
“It is also felt safe for most patients with only one to two lymph nodes involved on SLNB to avoid complete lymph node biopsy if they will undergo breast-conserving surgery followed by locoregional radiation therapy,” he said.
The updated recommendations in the guideline are:
* Clinicians should not recommend axillary lymph node dissection (ALND) for women with early-stage breast cancer who do not have nodal metastases;
* Clinicians should not recommend ALND for women with early-stage breast cancer who have one or two sentinel lymph node metastases and who will receive breast-conserving surgery with conventionally fractionated whole-breast radiotherapy;
* Clinicians may offer ALND for women with early-stage breast cancer with nodal metastases found on SLNB who will undergo mastectomy; and
* Clinicians may offer SLNB for women who have operable breast cancer and the following circumstances: multicentric tumors, ductal carcinoma in situ (DCIS) (when mastectomy is performed) [the guideline notes this recommendation for DCIS was based on informal consensus], prior breast and/or axillary surgery, and preoperative/neoadjuvant systemic therapy.
Additionally, the guideline notes that there are insufficient data to change the original 2005 recommendation that clinicians should not perform SLNB in women who have early-stage breast cancer and have any of the following: large or locally advanced invasive breast cancer, inflammatory breast cancer, DCIS (when breast-conserving surgery is planned), and pregnancy.
The guideline defines SLNB as the recommended surgical procedure for evaluation of clinically tumor-free regional nodes in patients with breast cancer, barring other exclusions.
The document also notes that clinicians, pathologists, and patients should be aware of the significance of identifying metastases in lymph nodes (even single cancer cells)—as well as the reality that small metastases will be missed, being that the presence or absence of nodal metastases is the basis for making treatment decisions—and that pathologists, as part of their standard analysis, should quantify the nodal tumor burden.
Regarding the priorities for additional research, Lyman said that important questions remain about the use of SLNB, particularly in special populations such as pregnant women. “The role of SLNB in patients receiving neoadjuvant chemotherapy remains controversial. And, the critical size of the primary tumor where SLNB is no longer adequate even when negative remains somewhat uncertain.”
The updated recommendations are based on nine randomized controlled trials and 13 cohort studies, all of which the ASCO-convened Update Committee deemed eligible for inclusion in the systematic review of the evidence.
“Quality-of-life considerations were a major reason for the recommendation to avoid full lymph node dissection when it is not necessary. The major problems are the potential for lymphedema, infections, and sometimes pain, weakness, or numbness,” Lyman added.
The Update Committee included a panel of experts in medical oncology, pathology, radiation oncology, surgical oncology, guideline implementation, and advocacy who conducted a systematic review of evidence published from February 2004 to January 2013 to develop the latest recommendations to update the guideline.