New ASCO Guideline Expands Recommendation for SLN Biopsy Use in Early Stage Breast Cancer

An updated guideline from ASCO regarding the use of sentinel lymph node (SLN) biopsy in early stage breast cancer supports the use of the procedure over axillary lymph node dissection (ALND) in a larger group of patients than previously recommended.¹

The new guideline, which was authored by a multidisciplinary panel of experts, updates recommendations initially released in 2005² and is based on data from nine randomized controlled trials and 13 cohort studies.

The 2005 SLN biopsy recommendation, which was based on limited available data, stated, “[Sentinel node biopsy] is an appropriate initial alternative to routine staging ALND for patients with early-stage breast cancer with clinically negative axillary nodes. Completion ALND remains standard treatment for patients with axillary metastases identified on [sentinel node biopsy].”

The updated review yielded three recommendations based on data from randomized controlled trials:

Women without sentinel lymph node metastases should not undergo ALND

According to the updated guideline, the benefits of not performing an ALND in women without sentinel lymph node (SLN) metastases outweigh the risks. The quality of evidence was strong and strength of recommendation was high, the committee wrote.

Seven randomized clinical trials investigated whether ALND could be avoided in this subgroup. These trials reported on survival, disease-free survival (DFS)/event-free survival, recurrence, adverse events (AEs), performance, and quality of life (QoL).

Women with one to two SLN metastases who will undergo breast-conserving surgery with whole-breast radiotherapy should not receive ALND

The guideline states that, as benefits outweigh harms, physicians should not recommend ALND for patients who have one to two SLN metastases and plan to undergo breast-conserving surgery with conventionally fractionated whole-breast radiotherapy.

This recommendation was based on data from the ACOSOG Z0011 and IBCSG 23-01 trials, which reported on survival, DFS, recurrence, and AEs. The update committee noted that this recommendation does not apply to patients whose axillary nodal positivity is confirmed by fine-needle aspiration, as these patients may have a higher tumor burden compared with those confirmed by dissection of an SLN.

The committee also noted that this recommendation should be carefully considered in patients who have large/bulky SLN metastases and/or gross extra nodal extension of the tumor, as these were exclusion criteria in the Z0011 trial.

Women with SLN metastases who plan to undergo mastectomy may be offered ALND

ALND may be an appropriate treatment for women with SLN metastases who will have mastectomy, the guideline states.

This recommendation was based on a subgroup analysis of the IBCSG 23-01 trial, in which 9% of patients in each arm underwent mastectomy. There was a lower risk of events in the no-ALND and breast-conserving surgery (with or without radiation therapy) arm. AEs, QoL, and performance were not reported in the analysis.

As this recommendation was based on one subgroup analysis of one study, the committee wrote that evidence quality was low and the strength of the recommendation was weak. The committee noted that future research could support or reject this recommendation.

Based on its review of cohort studies and informal consensus, the ASCO panel also made two additional recommendations. According to the first, women with DCIS receiving mastectomy, with resectable cancer and multicentric tumors, who had prior breast and/or axillary surgery, and/or who had neoadjuvent systemic treatment may be offered SLN biopsy. In the second recommendation, the committee states that SLN biopsy should not be offered to women with DCIS receiving breast-conserving surgery, with large or locally advanced T3 or T4 breast cancer, with inflammatory breast cancer, or who are pregnant.

Though the updated guideline answers important clinical questions regarding sentinel lymph node biopsy in early stage breast cancer, Gary Lyman, MD, MPH, FASCO, co-chair of the ASCO expert panel, said that dialogue between patient and physician is still crucial.

“We strongly encourage patients to talk with their surgeon and other members of their multidisciplinary team to understand their options and make sure everybody’s on the same page,” Lyman said in a statement. “The most critical determinant of breast cancer prognosis is still the presence and extent of lymph node involvement and, therefore, the lymph nodes need to be evaluated so we can understand the extent of the disease.”

References

1. Lyman GH, Temin S, Edge, SB, et al. Sentinel Lymph Node Biopsy for Patients With Early-Stage Breast Cancer: American Society of Clinical Oncology Clinical Practice Guideline Update [published online March 24, 2014]. J Clin Oncol. doi:10.1200/JCO.2013.54.1177
2. Lyman GH, Giuliano AE, Somerfield MR, et al. American Society of Clinical Oncology guideline recommendations for sentinel lymph node biopsy in early-stage breast cancer. J Clin Oncol. 2005;23(30):7703-7720.