The most recent recommendations from the American Society of Clinical Oncology (ASCO) on the approach to sentinel lymph node biopsy in patients with early-stage breast cancer echo 2014 ASCO guidelines for a conservative approach. The “less is more” approach that is recommended in the clinical practice update advises against routine axillary lymph node dissection (ALND) in the presence of cancer in a sentinel node.
Despite this guidance, surgeons still routinely perform full lymph node dissection, according to the lead author of the update, Gary H. Lyman, MD, MPH, Codirector, Hutchinson Institute for Cancer Research Outcomes, University of Washington, Seattle.
The update was issued after a review of 8 randomized controlled trials, systematic reviews, meta-analyses, and clinical practice guidelines released from 2012 through July 2016, discovered through a search of PubMed and the Cochrane Library.
Similar to the 2014 guidance, “the Update Committee advises that axillary lymph node dissection can be avoided in patients with one or two positive sentinel nodes only when conventionally fractionated whole-breast radiation therapy is planned,” the authors of the report wrote. “Clinicians should also consider this recommendation with caution in patients with large primary tumors (>5 cm), those with large or bulky metastatic axillary sentinel lymph nodes, and/or those with gross extranodal extension of the tumor.”
Of the 8 publications reviewed, “none prompted a change in the 2014 recommendations, which are reaffirmed by the updated literature review,” according to the Update Committee.
The recommendations are as follows:
- Clinicians should not recommend ALND for women with early-stage breast cancer who do not have nodal metastases (evidence quality: high; strength of recommendation: strong)
- Clinicians may offer ALND for women with early-stage breast cancer with nodal metastases found in sentinel node biopsy specimens who will receive mastectomy (evidence quality: low; strength of recommendation: weak)
- Clinicians may offer sentinel node biopsy for women who have operable breast cancer and who have multicentric tumors (evidence quality: intermediate; strength of recommendation: moderate), ductal carcinoma in situ (DCIS) when mastectomy is performed (evidence quality: insufficient; strength of recommendation: weak), prior breast and/or axillary surgery (evidence quality: intermediate; strength of recommendation: strong), or who have received preoperative/neoadjuvant therapy (evidence quality: intermediate; strength of recommendation: moderate)
- Data are insufficient to change the 2005 recommendation that clinicians should not perform sentinel node biopsy in women who have early-stage breast cancer and have large or locally advanced breast cancers (T3/T4), inflammatory breast cancer, DCIS when breast-conserving therapy is planned, or who are pregnant.
These practices seem to have been embraced within academic centers and larger hospitals and cancer centers, “but compliance is still quite variable elsewhere,” Dr Lyman said in a statement prepared by Fred Hutchinson Cancer Research Center. “In smaller hospitals, particularly in rural areas, many women are still being told they need a full axillary dissection. There are economic issues, geographic issues, and education issues for both clinicians and patients.”
The guidance reflects results from the ACOSOG Z0011 randomized clinical trial. This study demonstrated that sentinel lymph node dissection alone did not compromise local-regional control, disease-free survival, and overall survival compared with ALND in women with clinically node-negative, T1/T2 breast cancer who were treated with breast-conserving therapy and were found to have metastases in 1 or 2 sentinel lymph nodes.
At the 2017 Miami Breast Cancer Conference, Elizabeth A. Mittendorf, MD, PhD, Associate Professor, Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, who was not part of the Update Committee, expressed concern that surgeons may be extrapolating the recommendations to populations that did not meet the ACOSOG Z0011 trial eligibility criteria or who did not undergo study-specific treatment.
“Specifically, experts generally agree that the data should not be applied to patients undergoing mastectomy, particularly because many patients who receive mastectomy do not receive radiation, which might have contributed to the favorable outcomes in the ACOSOG Z0011 study,” said Dr Mittendorf. “Despite this, a report from the National Cancer Database showed that 22.3% of patients undergoing mastectomy and found to have 1 to 2 positive sentinel lymph nodes did not undergo ALND, suggesting that surgeons have extrapolated the results from the ACOSOG Z0011 trial to a broader population of patients.”