How are you implementing the new evidence supporting de-escalating sentinel lymph node biopsy in patients with early-stage breast cancer?

Highlights

• De-escalation is oncologically safe for older patients with small, clinically node-negative, hormone receptor-positive, HER2-negative tumors who will receive radiation.
• This approach is inappropriate for patients with triple-negative or HER2-positive tumors, where nodal status is crucial for chemotherapy decisions.
• Omitting sentinel lymph node biopsy can complicate decisions about systemic therapy, requiring close multidisciplinary collaboration before any surgery.
• Surgeons must counsel patients on the small possibility of needing a second operation if final pathology reveals higher-risk features.
• Patient selection should consider age, comorbidities, and functional status, as de-escalation is most reasonable for those unlikely to need chemotherapy.

Expert Insights

Defining the Candidate for Axillary De-escalation

Recent clinical trials, including SOUND and INSEMA, have built upon foundational studies like CALGB 9343 and PRIME 2 to demonstrate the oncologic safety of omitting axillary staging in select patients with early-stage breast cancer. Experts agree that the ideal candidate for this de-escalated approach is highly specific. Dr. Sarah Blair, a breast surgical oncologist, states she is comfortable discussing the omission of sentinel lymph node biopsy (SLNB) in postmenopausal women in their sixties or older with clinical T1N0, strongly ER/PR-positive, HER2-negative tumors. This is echoed by medical oncologist Dr. Anastasia Martynova, who suggests an age of 65 or older as a reasonable threshold for women at low risk of needing chemotherapy, while noting that comorbidities and functional status must be considered.

The nuances of the trial data are critical for appropriate patient selection. Breast surgical oncologist Dr. Karen Goodwin emphasizes the "SOUND criteria," which focused on women with small tumors (less than 1.5 cm), who were hormone receptor-positive and HER2-negative. Both Dr. Blair and Dr. Goodwin are clear that this approach is not appropriate for patients with triple-negative or HER2-positive disease. For these subtypes, Dr. Goodwin explains, nodal status is essential information for the medical oncologist to determine the type and necessity of chemotherapy, even for very small primary tumors.

The Centrality of Multidisciplinary Communication

The decision to omit SLNB is not a surgical one in isolation but requires robust communication across specialties. As medical oncologist Dr. Robert Wesolowski notes, omitting SLNB can result in "missing information about lymph node involvement," which can complicate decisions regarding adjuvant systemic therapy, such as the use of Oncotype DX or chemotherapy. He relies on his surgical colleagues but stresses the importance of pre-operative discussion in a multimodality conference to ensure the entire team is aligned.

"Omitting sentinel lymph node biopsy can make it more difficult to decide whether additional testing, such as Oncotype DX, or chemotherapy would be recommended." Dr. Robert Wesolowski

This collaborative approach is essential for successful implementation. Dr. Goodwin describes the sentinel node as having evolved from a therapeutic tool to a primarily diagnostic one. She posits that if the medical and radiation oncology teams feel comfortable using other tools—such as genomic testing, imaging, and final pathology from the lumpectomy—to formulate a complete treatment plan, then omitting the SLNB seems appropriate. Dr. Wesolowski confirms this dynamic, stating that while the surgeon ultimately determines the surgical approach, active communication at tumor boards ensures that avoiding SLNB will not lead to incomplete information that could negatively affect subsequent therapy recommendations.

"The sentinel lymph node has now become more of a diagnostic tool than a therapeutic tool." Dr. Karen Goodwin

Practical Implementation and Patient Counseling

Translating this evidence into practice requires transparent patient counseling. Dr. Goodwin outlines her process of informing every eligible patient that final pathology may reveal unexpected findings. For instance, if a tumor thought to be 1.5 cm is found to be 2.5 cm, the patient would no longer meet the criteria, potentially necessitating a return to the operating room for an SLNB. She finds that when this low-probability event is discussed upfront, many patients still choose de-escalation, motivated by the benefits of avoiding numbness and tingling in the arm and minimizing the small risk of lymphedema.

Managing unexpected pathology is a key consideration. If SLNB is not performed and a tumor that appeared low-grade on biopsy is found to be a higher grade after surgery, Dr. Martynova notes that radiation therapy can still be considered as part of the management plan. The consensus is that de-escalation is safest for older women who are unlikely to be candidates for chemotherapy and have no clinical or imaging evidence of lymph node involvement. For these carefully selected patients, the oncologic outcomes appear secure without the morbidity of a staging procedure.