Sentinel Lymph Node Biopsy After Breast Cancer Chemotherapy: Evidence Review

Core Concepts

SLNB following NACT is safe and effective, but data from randomized trials are lacking.

Abstract

Abstract and Introduction: SLNB is the gold-standard for axillary staging in early breast cancer. NACT enables downstaging, reducing surgery impact and morbidity. Controversy exists regarding SLNB role post-NACT due to lack of randomized trials. Clinically Negative Nodes at Diagnosis and SLNB After NACT: SLNB post-NACT in cN0 patients shows FNRs around 10%. Studies indicate low axillary recurrence rates post-SLNB. Meta-analyses confirm SLN identification rates and FNRs. Initially Positive Axilla (cN1/2) and Negative SLNB Following NACT: FNRs for SLNB in cN1/2 patients post-NACT were considered high. Studies show techniques to reduce FNRs, such as clipping the lymph node. Single-center data suggest low axillary recurrence rates post-SLNB. Positive SLN Following NACT: Trend to omit axillary dissection in patients with positive SLN post-NACT. Studies show high residual cancer burden post-NACT. Controversy exists regarding oncological outcomes and axillary dissection omission. Omitting Axillary Surgery in Good Responders: SLNB provides prognostic information with less morbidity than axillary dissection. Debate on avoiding axillary surgery in specific cases with excellent responders. Importance of evaluating residual disease for adjuvant therapy decisions.

Stats

"FNRs are generally acceptable (≤10%)". "SLN identification rate was 90.9%, FNR of 10.5%". "Overall FNRs reported by studies for patients submitted to NACT were 14.2%, 12.6% and 13.3%". "FNR of 7.2% was found in a subgroup of patients in whom the metastatic lymph node was marked with a clip prior to NACT". "A FNR of 7.2% for the clipped lymph node technique and 4.2% for the I-125 seed technique". "SLNB will identify residual disease in more than 50% of cases in patients with initially positive axilla who achieve clinical complete response to NACT". "Residual disease in axillary lymph nodes was found in 1.0%, 1.6%, 2.1% and 4% of cases of HER2-positive/HR-negative, triple-negative, HER2-positive/HR-positive and HR-positive/HER2-negative tumors, respectively".

Quotes

"SLNB following NACT has been performed over the years, principally on the basis of FNRs similar to those found with upfront surgery." "The efforts made to reduce the FNR in these circumstances reflect the absence of data from randomized clinical trials on oncological safety." "The advances made in these NACT regimes, with the addition of new drugs and a more appropriate selection of patients has, on the other hand, resulted in a high rate of pathologic complete response."

Key Insights Distilled From

Sentinel Lymph Node Biopsy After Breast Cancer Chemotherapy

by Francisco Pi... at www.medscape.com 07-17-2023

http://www.medscape.com/viewarticle/990076

Deeper Inquiries

What are the implications of the lack of randomized trials on the long-term oncological safety of SLNB post-NACT

The lack of randomized trials on the long-term oncological safety of Sentinel Lymph Node Biopsy (SLNB) post-Neoadjuvant Chemotherapy (NACT) has significant implications for clinical decision-making. Without robust randomized studies, the true impact of SLNB after NACT on long-term oncological outcomes remains uncertain. This lack of data poses challenges in determining the efficacy and safety of SLNB in this specific context. Randomized trials are crucial in providing high-quality evidence to guide clinical practice. In the case of SLNB post-NACT, the absence of such trials means that decisions regarding axillary management are based on retrospective studies and observational data, which may not fully capture the nuances of patient outcomes over time. The reliance on non-randomized studies introduces potential biases and limitations in interpreting the true benefits and risks of SLNB in this setting. Furthermore, the lack of randomized trials hinders the establishment of clear guidelines and protocols for axillary management post-NACT. Clinicians may face uncertainty in determining the most appropriate course of action for patients, leading to variations in practice and potentially suboptimal outcomes. Without randomized trials, the long-term oncological safety of SLNB post-NACT remains a subject of debate and requires further research to establish definitive conclusions.

How might the high residual cancer burden post-NACT impact the decision to omit axillary dissection in patients with positive SLN

The high residual cancer burden post-Neoadjuvant Chemotherapy (NACT) can significantly impact the decision to omit axillary dissection in patients with positive Sentinel Lymph Node (SLN). In cases where patients have a substantial residual disease burden following NACT, there is a concern that omitting axillary dissection based solely on SLN status may lead to undertreatment. Patients with a high residual cancer burden post-NACT may have a greater likelihood of harboring additional disease in the axilla beyond what is detected by SLNB. Omitting axillary dissection in these cases could result in leaving residual disease untreated, potentially compromising long-term oncological outcomes. The risk of undertreatment is particularly relevant in patients with a high residual cancer burden, as the presence of undetected disease in the axilla may impact disease recurrence and overall survival. Therefore, the decision to omit axillary dissection in patients with positive SLN post-NACT should consider the extent of residual disease and the potential for undetected axillary involvement. Clinicians must carefully assess the balance between minimizing surgical morbidity and ensuring adequate treatment of residual disease when determining the appropriate axillary management strategy in these cases.

How can the findings regarding pathologic complete response in axillary lymph nodes post-NACT influence adjuvant therapy decisions

The findings regarding pathologic complete response in axillary lymph nodes post-Neoadjuvant Chemotherapy (NACT) can have a significant impact on adjuvant therapy decisions. Patients who achieve pathologic complete response in the axillary lymph nodes following NACT may have a lower likelihood of residual disease and a more favorable prognosis. In cases where patients demonstrate pathologic complete response in the axillary lymph nodes post-NACT, the decision regarding adjuvant therapy may be influenced by the absence of residual disease in this region. This information can guide clinicians in tailoring adjuvant treatment strategies, potentially avoiding unnecessary systemic therapies or additional regional treatments. For example, in patients with HER2-positive breast cancer, the presence of pathologic complete response in the axillary lymph nodes post-NACT may impact the decision to use targeted therapies such as trastuzumab emtansine (T-DM1) in the adjuvant setting. Similarly, in triple-negative breast cancer, achieving pathologic complete response in the axillary lymph nodes may influence the use of adjuvant therapies like capecitabine to improve disease-free and overall survival. Overall, the findings of pathologic complete response in axillary lymph nodes post-NACT provide valuable information for optimizing adjuvant therapy decisions, ensuring that patients receive tailored treatments based on their individual response to neoadjuvant treatment.