Does increased tumor burden of sentinel nodes in breast cancer affect detection procedure?

Factors predicting one or two sentinel lymph nodes to be accepted for sentinel lymph node biopsy alone after neoadjuvant therapy in initially node-positive breast cancer patients

BACKGROUND

Current guidelines recommend harvesting ≥3 sentinel nodes if sentinel lymph node biopsy (SLNB) alone is considered after neoadjuvant therapy (NAT) for initially node-positive (cN+) breast cancer. We attempted to investigate factors predicting one or two sentinel lymph nodes harvested to be accepted for SLNB alone after NAT in initially cN + patients.

METHODS

Overall, 157 patients who received NAT (clinically T1-3/N1-2/M0) and underwent SLNB were identified from a prospectively maintained database. Significant factors were identified using a multiple logistic regression model.

RESULTS

The overall SLN identification rate was 83.4%. Failed SLN identification was associated with a 2-day protocol using a single tracer (odds ratio: 0.331 [95% confidence interval {CI}: 0.132-0.830], p = 0.018), age >52 years (0.345 [0.131-0.913], p = 0.032), and lobular histology (0.156 [0.026-0.944], p = 0.043). The overall false-negative SLNB rate was 14.7%. Its increased risk was associated with radioactivity count >530 for any SLN during SLNB (96.4 [4.00-2320], p = 0.005), age ≥57 years (34.2 [1.92-610], p = 0.016), and taxane use (105 [1.02-10700], p = 0.049); its decreased risk was associated with more harvested SLNs (0.191 [0.054-0.669], p = 0.01) and dual tracers (0.101 [0.012-0.843], p = 0.034). A predictive model using these factors achieved an area under the curve of 0.935 (95% CI: 0.878-0.991).

CONCLUSION

When taxane was administered during NAT, the false-negative rate was predicted at <5% for patients aged <57 years, if 1-2 SLNs were harvested using dual tracers, and when the count of every SLN was lower than 530 after NAT in cN + breast cancer.

The role of axillary reverse mapping in intraoperative nodal palpation during sentinel lymph node biopsy

Intraoperative nodal palpation in the axilla is a mandatory part of sentinel lymph node biopsy. However, there is no consensus regarding the definition of suspicious palpable node. The sampling rate and involvement rate of suspicious palpable nodes are inconsistent. We hypothesized that axillary reverse mapping is helpful to select suspicious palpable sentinel lymph nodes more accurately. Patients with clinically negative nodes underwent sentinel lymph node biopsy with intraoperative nodal palpation and axillary reverse mapping. Blue and hot nodes were removed as sentinel lymph nodes. Suspicious palpable nodes that were neither blue nor hot were removed as palpable sentinel lymph nodes. Nodes around blue and hot sentinel lymph node were incidentally removed as para-sentinel lymph nodes. Fluorescent nodes were considered axillary reverse mapping nodes. Patients with positive sentinel lymph node underwent axillary lymph node dissection. Palpable sentinel lymph nodes and para-sentinel lymph nodes were removed in 130 (15%) of 850 patients with clinically negative nodes. Although palpable sentinel lymph nodes and para-sentinel lymph nodes were involved in 19 (15%) of 130 patients, fluorescent palpable sentinel lymph nodes were involved only in 2 patients and fluorescent para-sentinel lymph nodes were not involved. When excluding fluorescent palpable sentinel lymph nodes and para-sentinel lymph nodes, the sampling rate of suspicious palpable nodes significantly decreased (15% vs. 5%, p < 0.01) and the involvement rate of palpable sentinel lymph nodes significantly increased (15% vs. 31%, p < 0.05). Axillary reverse mapping is helpful to avoid an unnecessary removal of palpable nodes without metastases.

Establishing a prediction model of axillary nodal burden based on the combination of CT and ultrasound findings and the clinicopathological features in patients with early-stage breast cancer

Background

Axillary lymph node (ALN) management in early-stage breast cancer (ESBC) patients has become less invasive during the past decades. Here, we tried to explore whether high nodal burden (HNB) in ESBC patients could be predicted preoperatively, so as to avoid unnecessary sentinel lymph node biopsy (SLNB).

Methods

The clinicopathological and imaging data of patients with early invasive breast cancer (cT_1-2N₀M₀) were analyzed retrospectively. Univariate and multivariate analyses were performed for the risk factors of axillary HNB in ESBC patients, and a risk prediction model of HNB was established.

Results

HNB was identified in 105 (8.0%) of 1,300 ESBC patients. Multivariate analysis showed that estrogen receptors (ER) status, human epidermal growth factor receptor 2 (HER2) status, number of abnormal lymph nodes (LNs) on computed tomography (CT), and axillary score on ultrasound (US) were the risk factors of HNB (all P<0.05). The area under the receiver operating characteristic (ROC) curve in the prediction model was 0.914, with the sensitivity being 85.7% and the specificity being 82.4%. The calibration curve showed that the prediction model had good performance.

Conclusions

As a valuable tool for predicting HNB in ESBC patients, this newly established model helps clinicians to make reasonable axillary surgery decisions and thus avoid unnecessary SLNB.

Biomarker phenotyping drives clinical management in axillary sentinel node: A retrospective study on women with primary breast cancer in 2002

The current study examined if cancer biomarker phenotyping could predict the clinical/pathological status of axillary nodes in women with primary breast cancer. Primary breast cancers from 2002 were analyzed for tumor size, estrogen receptor (ER), progesterone receptor (PgR), Ki-67MIB expression and Her2/neu amplification. Relationships between the clinical and pathological status of the axilla and the biological subtypes classification were analyzed using univariate, multivariate and regression tree analysis. A total of 65% of women with axillary nodes clinically involved had complete axillary node dissection (ALND) while 705 women with clinically negative axillary underwent sentinel lymph node biopsy (SLNB), 18.5% of the latter had at least one pathologically SLNB involved node. Multivariate analysis revealed that the Luminal A subtype was significantly associated (OR 0.62; P<10^-9) with clinical negative axilla while HER2pos/not Luminal was associated with clinical positivity (OR 1.71; P<0.01). No significant association between biological subtypes and SLNB status was demonstrated. Regression tree analysis revealed that subgroups with significantly different probability of SLNB status were separated according to tumor size and PgR values. In conclusion, the current study demonstrated that biomarker breast cancer phenotyping is significantly associated with clinical status of axillary nodes but not with pathological involvement of nodes at SLNB. Regression tree analysis could represent a valid attempt to individualize some patients subgroups candidate to different surgical axilla approaches.

Real-time sentinel lymph node biopsy guidance using combined ultrasound, photoacoustic, fluorescence imaging: in vivo proof-of-principle and validation with nodal obstruction

Precise sentinel lymph node (SLN) identification is crucial not only for accurate diagnosis of micro-metastases at an early stage of cancer progression but also for reducing the number of SLN biopsies (SLNB) to minimize their severe side effects. Furthermore, it is desirable that an SLNB guidance should be as safe as possible in routine clinical use. Although there are currently various SLNB guidance methods for pre-operative or intra-operative assessment, none are ideal. We propose a real-time SLNB guidance method using contrast-enhanced tri-modal images (i.e., ultrasound, photoacoustic, and fluorescence) acquired by a recently developed hand-held tri-modal probe. The major advantage of tri-modal imaging is demonstrated here through an in vivo study of the technically-difficult case of nodal obstruction that frequently leads to false-negative results in patients. The results in a tumor model in rabbits and normal controls showed that tri-modal imaging is capable of clearly identifying obstructed SLNs and of indicating their metastatic involvement. Based on these findings, we propose an SLNB protocol to help surgeons take full advantage of the complementary information obtained from tri-modal imaging, including for pre-operative localization, intra-operative biopsy guidance and post-operative analysis.