Multidisciplinary Approach Drives De-escalation of Breast Cancer Surgery Through Targeted Axillary Management
核心洞察
Multidisciplinary collaboration between surgeons and medical oncologists enables tailored preoperative therapies that can shrink tumors and downstage axillary lymph nodes, reducing surgical burden in breast cancer (搜索) patients.
Recent clinical trials including SOUND and INSEMA demonstrate that axillary surgery can be safely omitted in select patients with hormone receptor (搜索)-positive, HER2 (搜索)-negative breast cancer (搜索) and negative axillary ultrasounds.
The SENOMAC trial expands de-escalation strategies to broader patient populations, showing that patients with higher-risk features but limited nodal involvement can safely avoid lymph node dissection.
Collaboration between surgeons and medical oncologists is transforming breast cancer (搜索) management by enabling more precise treatment de-escalation strategies that reduce surgical morbidity while maintaining oncologic outcomes. This multidisciplinary approach leverages molecular subtyping and preoperative therapies to tailor surgical interventions, particularly in axillary management.
Molecular Subtyping Guides Treatment Strategy
The evolution of breast cancer (搜索) treatment has been driven by improved understanding of molecular subtypes and their differential responses to systemic therapies. According to Tari A. King, MD, FACS, FSSO, FASCO, chief surgical officer for the cancer service line at Winship Cancer Institute (搜索), "Understanding the biology and the expected response to different treatments in different biological subtypes of breast cancer has helped us promote this multidisciplinary team, with the surgeon and medical oncologist working together to decide which patients would benefit from a preoperative therapy approach vs going to upfront surgery."
Preoperative therapy offers significant surgical advantages by shrinking tumors to enable smaller lumpectomies or avoid mastectomies, while also providing opportunities to downstage axillary lymph nodes. This approach is particularly effective in HER2-positive breast cancer (搜索), where approximately 70% to 80% of patients experience complete eradication of nodal disease with preoperative therapy. In contrast, hormone receptor (搜索)-positive disease shows more modest downstaging rates of 20% to 25%.
Clinical Trials Support Axillary Surgery Omission
Recent prospective randomized trials have demonstrated the safety of omitting axillary surgery entirely in carefully selected patient populations. The SOUND (NCT02167490) and INSEMA (NCT02466737) trials randomly assigned patients with negative axillary ultrasounds to undergo sentinel node surgery or no axillary surgery. Despite 13.7% and 11.4% of patients having positive sentinel nodes in the respective trials, there was no difference in long-term outcomes between groups.
These studies primarily enrolled postmenopausal women with smaller, hormone receptor (搜索)-positive, HER2 (搜索)-negative tumors. "Most of those women can still be treated with endocrine therapy (搜索) alone," King noted. "We also now live in an era where in those patients with ER-positive, HER2-negative breast cancer (搜索), we're using genomic testing to determine their risk of recurrence and help understand the potential benefit of chemotherapy (搜索) in addition to endocrine therapy."
The landmark CALGB 9343 trial previously demonstrated that women at least 70 years of age with early, clinically node-negative, HR-positive breast cancers could safely omit sentinel lymph node staging without significant increases in axillary recurrence rates or differences in disease-free survival.
SENOMAC Expands De-escalation to Higher-Risk Populations
The SENOMAC trial (NCT02240472) built upon the foundational ACOSOG Z0011 trial by expanding eligibility criteria to include patients with higher-risk features. While Z0011 was limited to T1 and T2 tumors in patients undergoing breast conservation, SENOMAC included patients with T3 tumors up to 5 cm, those undergoing mastectomy, male patients, and more patients with lobular breast cancers.
"SENOMAC also enrolled patients undergoing mastectomy, whereas Z0011 was limited to patients having breast conservation," King explained. The trial required macrometastatic disease in 1 or 2 positive nodes, addressing previous concerns about the applicability of Z0011 results to patients with micrometastases.
Results showed that 34.5% of SENOMAC patients had additional nonsentinel nodal disease compared to 27% in Z0011, indicating a higher-risk population. However, patients who did not undergo lymph node dissection showed no increased rates of axillary failure and no differences in disease-free survival compared to those receiving axillary dissection.
Treatment Decision Framework
The multidisciplinary approach considers multiple factors when evaluating candidates for treatment de-escalation. For patients presenting with nodal disease, teams assess whether preoperative therapy can downstage the axilla based on molecular subtype. HER2 (搜索)-positive patients are excellent candidates for preoperative therapy, while hormone receptor (搜索)-positive patients with limited nodal involvement may proceed directly to sentinel lymph node staging.
"It doesn't matter whether a patient is having breast conservation or a mastectomy. It doesn't matter whether a patient is older or younger. It doesn't matter if they have micrometastatic or macrometastatic disease," King emphasized. "We now have data that encompass all the nuances we see in clinical practice."
Clinical Impact and Future Directions
These advances represent a fundamental shift in breast cancer (搜索) surgical management, moving from routine axillary lymph node dissection to increasingly selective approaches based on individual patient characteristics and molecular profiles. The integration of genomic testing has reduced reliance on nodal information for treatment decisions in estrogen receptor (搜索)-positive, HER2 (搜索)-negative disease, enabling further surgical de-escalation.
The success of these strategies depends on appropriate patient selection, with negative axillary ultrasounds serving as a key criterion for omitting axillary surgery. This approach is most applicable to hormone receptor (搜索)-positive, HER2 (搜索)-negative disease, where nodal status has less impact on systemic therapy recommendations compared to HER2-positive or triple-negative subtypes.