Sentinel node involvement with or without completion axillary lymph node dissection: treatment and pathologic results of randomized SERC trial

MRI radiomics and biological correlations for predicting axillary lymph node burden in early-stage breast cancer

BACKGROUND AND AIMS

Preoperative prediction of axillary lymph node (ALN) burden in patients with early-stage breast cancer is pivotal for individualised treatment. This study aimed to develop a MRI radiomics model for evaluating the ALN burden in early-stage breast cancer and to provide biological interpretability to predictions by integrating radiogenomic data.

METHODS

This study retrospectively analyzed 1211 patients with early-stage breast cancer from four centers, supplemented by data from The Cancer Imaging Archive (TCIA) and Duke University (DUKE). MRI radiomic features were extracted from dynamic contrast-enhanced MRI images and an ALN burden-related radscore was constructed by the backpropagation neural network algorithm. Clinical and combined models were developed, integrating ALN-related clinical variables and radscore. The Kaplan-Meier curve and log-rank test were used to assess the prognostic differences between the predicted high- and low-ALN burden groups in both Center I and DUKE cohorts. Gene set enrichment and immune infiltration analyses based on transcriptomic TCIA and TCIA Breast Cancer dataset were used to investigate the biological significance of the ALN-related radscore.

RESULTS

The MRI radiomics model demonstrated an area under the curve of 0.781-0.809 in three validation cohorts. The predicted high-risk population demonstrated a poorer prognosis (log-rank P < .05 in both cohorts). Radiogenomic analysis revealed migration pathway upregulation and cell differentiation pathway downregulation in the high radscore groups. Immune infiltration analysis confirmed the ability of radiological features to reflect the heterogeneity of the tumor microenvironment.

CONCLUSIONS

The MRI radiomics model effectively predicted the ALN burden and prognosis of early-stage breast cancer. Moreover, radiogenomic analysis revealed key cellular and immune patterns associated with the radscore.

Omission of Completion Axillary Lymph Node Dissection for Patients with Breast Cancer Treated by Upfront Mastectomy and Sentinel Node Isolated Tumor Cells or Micrometastases

Omission of completion axillary lymph node dissection (cALND) in patients undergoing mastectomy with sentinel node (SN) isolated tumor cells (ITC) or micrometastases is debated due to potential under-treatment, with non-sentinel node (NSN) involvement detected in 7% to 18% of patients. This study evaluated the survival impact of cALND omission in a cohort of breast cancer (BC) patients treated by mastectomy with SN ITC or micrometastases. Among 554 early BC patients (391 pN1mi, 163 ITC), the NSN involvement rate was 13.2% (49/371). With a median follow-up of 66.46 months, multivariate analysis revealed significant associations between cALND omission and overall survival (OS, HR: 2.583, p = 0.043), disease-free survival (DFS, HR: 2.538, p = 0.008), and metastasis-free survival (MFS, HR: 2.756, p = 0.014). For Her2-positive or triple-negative patients, DFS was significantly affected by cALND omission (HR: 38.451, p = 0.030). In ER-positive Her2-negative BC, DFS, OS, recurrence-free survival (RFS), and MFS were significantly associated with cALND omission (DFS HR: 2.358, p = 0.043; OS HR: 3.317; RFS HR: 2.538; MFS HR: 2.756). For 161 patients aged ≤50 years with ER-positive/Her2-negative cancer, OS and breast cancer-specific survival (BCSS) were notably impacted by cALND omission (OS HR: 103.47, p = 0.004; BCSS HR: 50.874, p = 0.035). These findings suggest a potential negative prognostic impact of cALND omission in patients with SN micrometastases or ITC. Further randomized trials are needed.

The Ongoing Necessity of Sentinel Lymph Node Biopsy for cT1-2N0 Breast Cancer Patients

Background

Recent clinical trials attempt to determine whether it is appropriate to omit axillary lymph node surgery in patients with cT1-2N0 breast cancer. The study aimed to investigate the true extent of axillary node disease in patients with clinically negative nodes and explore the differences between negative axillary ultrasound (AUS-cN0) and suspicious axillary ultrasound with negative fine-needle aspiration (FNA-cN0).

Methods

Pathologically identified T1-2 invasive breast cancer patients with clinically negative nodes were retrospectively analyzed at our center between January 2019 and December 2022. Patients who received any systematic treatment before surgery were excluded from this study.

Results

A total of 538 patients were enrolled in this study. 134 (24.9%) patients had pathologically positive nodes, and 404 (75.1%) patients had negative nodes. Univariate analysis revealed that tumor size, T stage, Ki67 level, and vascular invasion (VI) were strongly associated with pathological axillary lymph node positivity. In multivariate analysis, VI was the only independent risk factor for node positivity in patients with cT1-2N0 disease (OR: 3.723, confidence interval [CI]: 2.380-5.824, p < 0.001). Otherwise, pathological node positivity was not significantly different between AUS-cN0 and FNA-cN0 groups (23.4% vs. 28.8%, p = 0.193). However, the rate of high nodal burden (≥3 positive nodes) was significantly higher in FNA-cN0 group. Further investigation revealed that FNA-cN0 and VI were independently associated with a high nodal burden (OR: 2.650, CI: 1.081-6.496, p = 0.033; OR: 3.521, CI: 1.249-9.931, p = 0.017, respectively).

Conclusions

cT1-2 breast cancer patients with clinically negative axillary lymph nodes may have pathologically positive lymph nodes and even a high nodal burden. False negatives in AUS and AUS-guided FNA should not be ignored, and sentinel lymph node biopsy remains an ongoing necessity for cT1-2N0 breast cancer patients.

Negative Survival Impact of Occult Lymph Node Involvement in Small HER2-Positive Early Breast Cancer Treated by Up-Front Surgery

(1) Background: The independent negative prognostic value of isolated tumor cells or micro-metastases in axillary lymph nodes has been established in triple-negative breast cancers (BC). However, the prognostic significance of pN0(i+) or pN1mi in HER2-positive BCs treated by primary surgery remains unexplored. Therefore, our objective was to investigate the impact of pN0(i+) or pN1mi in HER2-positive BC patients undergoing up-front surgery on their outcomes. (2) Methods: We retrospectively analyzed 23,650 patients treated in 13 French cancer centers from 1991 to 2013. pN status was categorized as pN0, pN0(i+), pN1mi, and pNmacro. The effect of pN0(i+) or pN1mi on outcomes was investigated both in the entire cohort of patients and in pT1a-b tumors. (3) Results: Of 1771 HER2-positive BC patients included, pN status distributed as follows: 1047 pN0 (59.1%), 60 pN0(i+) (3.4%), 118 pN1mi (6.7%), and 546 pN1 macro-metastases (30.8%). pN status was significantly associated with sentinel lymph node biopsy, axillary lymph node dissection, age, ER status, tumor grade, and size, lymphovascular invasion, adjuvant systemic therapy (ACt), and radiation therapy. With 61 months median follow-up (mean 63.2; CI 95% 61.5-64.9), only pN1 with macro-metastases was independently associated with a negative impact on overall, disease-free, recurrence-free, and metastasis-free survivals in multivariate analysis. In the pT1a-b subgroup including 474 patients, RFS was significantly decreased in multivariate analysis for pT1b BC without ACt (HR 2.365, 1.04-5.36, p = 0.039) and for pN0(i+)/pN1mi patients (HR 2.518, 1.03-6.14, p = 0.042). (4) Conclusions: Survival outcomes were not adversely affected by pN0(i+) and pN1mi in patients with HER2-positive BC. However, in the case of pT1a-b HER2-positive BC, a negative impact on RFS was observed specifically for patients with pN0(i+) and pN1mi diseases, particularly among those with pT1b tumors without ACt. Our findings highlight the importance of considering the pN0(i+) and pN1mi status in the decision-making process when discussing trastuzumab-based ACt for these patients.

Surgical Management of the Axilla for Breast Cancer

This review discusses the contemporary surgical management of the axilla in patients with breast cancer. Surgical paradigms are highlighted by clinical nodal status at presentation and treatment approach, including upfront surgery and neoadjuvant systemic therapy settings. This review focuses on the increasing opportunities for de-escalating the extent of axillary surgery in the era of sentinel lymph node biopsy, while also reviewing the remaining indications for axillary clearance with axillary lymph node dissection.

Trends in axillary surgery and clinical outcomes among breast cancer patients with sentinel node metastasis

Background

There is a lack of studies examining the long-term trend and survival of axillary surgery for breast cancer patients with sentinel node metastasis, especially for the patients with 3–5 node metastases.

Methods

Breast cancer patients with 1–5 sentinel node metastases from the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2016. Our study presented the trend of axillary surgery and assessed the long-term survival of sentinel lymph node biopsy (SLNB) alone vs axillary lymph node dissection (ALND) for those patients.

Results

Of the 41,996 patients diagnosed with T_1-2 breast cancer after lumpectomy and radiation included, 34,940 had 1-2 sentinel node metastases and 7056 had 3-5 sentinel node metastases. The percentage of patients undergoing SLNB alone increased from 22.4% in 2000 to 81.0% in 2016 for patients with 1–2 sentinel node metastases, and quadrupled from 5.2% in 2009 to 20.6% in 2016 for those with 3–5 sentinel node metastases. Completion of ALND did not benefit the long-term survival of 1–2 sentinel node metastasis patients (hazard ratio [HR] = 1.02, P = 0.539), but improved the long-term survival of 3–5 node metastasis patients (HR = 0.73, P < 0.001). Subgroup analysis demonstrated the inferiority of SLNB to ALND in all subgroups of 3–5 sentinel node metastases.

Conclusion

For patients with T_1-2 breast cancer after lumpectomy and radiation, SLNB alone was an efficient and safe surgical choice for 1–2 sentinel node metastases but not for 3–5 sentinel node metastases. It is worth noting that for patients with 3–5 node metastasis, the proportion of omitted ALND quadrupled after 2009.

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Using SEER database, the research presents the long-term trend and survival of axillary surgery for breast cancer patients with 1-2 and 3-5 sentinel nodes metastasis.

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For patients with T1-2 breast cancer after lumpectomy and radiation, SLNB alone was efficient for 1–2 sentinel node metastases but not for 3–5 sentinel node metastases.

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Among patients with 3–5 node metastasis, the proportion of omitted ALND quadrupled from 2009 to 2016.