Sentinel node biopsy for breast cancer: past, present, and future

Lymphatic drainage of sinonasal malignancies and the role of sentinel node biopsies

BACKGROUND

Locoregional recurrence is a critical factor in the prognosis of sinonasal malignancies. Due to the rarity of these tumours, as well as the heterogeneity of histologies and anatomical subsites, there is little evidence regarding the rate and location of regional metastases in sinonasal malignancies. Elective regional lymph node dissection in the therapy of sinonasal malignancies has become controversial. On the one hand, elective regional lymph node dissection is considered to be an overtreatment in the cN0 cases. On the other hand, undetected occult lymphatic metastases are associated with a poor prognosis. In this study, we discuss the role of sentinel lymph node biopsy as a minimally invasive procedure in the treatment of sinonasal malignancies based on our two years of practical experience and the currently available data.

RESULTS

This is a descriptive, monocentric, retrospective study, including 20 cases of cN0 malignant sinonasal neoplasm, that underwent a surgical therapy between 2020 and 2022. The following aspects were investigated: tumour entity, localisation of the primary tumour, tumoral stage, localisation of the sentinel lymph nodes, and postoperative complications. Squamous cell carcinoma was the most frequently diagnosed tumour entity (50%), followed by adenocarcinoma (20%) and malignant melanoma (15%), adenoid cystic carcinoma and mucoepidermoid carcinoma. Sentinel lymph nodes were most frequently found in the ipsilateral neck region I (45%), followed by the ipsilateral neck region II (40%). In all cases, the removed lymph nodes were free of malignancy. There were no postoperative complications due to lymph node biopsy. There were no recurrences during the study period.

CONCLUSION

Sentinel node biopsy could add more safety to the management of cN0 sinonasal malignancies due to its low morbidity. Whether SNB could provide an alternative to elective neck dissection in the management of SNM should be investigated in further studies.

Sentinel Lymph Node Mapping and Biopsy in Cats with Solid Malignancies: An Explorative Study

There is increasing evidence on the utility of sentinel lymph node (SLN) biopsy (SLNB) for the staging of dogs with various malignancies; however, comparable information is missing in cats. This multi-institutional study aims at reporting the feasibility and detection rate of SLNB guided by lymphoscintigraphy and the blue dye or near-infrared fluorescent lymphography (NIRF-L) in cats with solid tumors. In total, 12 cats presented with 14 solid malignancies that underwent curative-intent surgical excision of the primary tumor and SLNB were retrospectively enrolled. The mapping technique used, location and number of SLN, correspondence with the regional lymph node (RLN), and histological status of the SLN were retrieved. The detection rate and complications of SLNB were also recorded. NIRF-L was performed in 64.3% of tumors and lymphoscintigraphy in 35.7%. The detection rate was 100% for both techniques. The SLN did not correspond (fully or partially) to the RLN in 71.4% of cases, with multiple SLN being excised in 9/14 tumors. No complications related to SLNB were recorded. At histopathology, metastases were identified in 41.7% of cats, all with mast cell tumors (MCT). SLNB guided by NIRF-L or lymphoscintigraphy is feasible and safe in cats with solid tumors and should be suggested for correct tumor staging in cats, especially with MCT.

Is Routine Intraoperative Frozen Section Analysis of Sentinel Lymph Nodes Necessary in Every Early-Stage Breast Cancer?

Purpose

Clinical application of the ACOSOG Z0011 trial results allows clinically node-negative breast cancer patients who meet criteria to avoid axillary dissection even when 1–2 sentinel lymph nodes (SLNs) are positive for metastatic disease. Intraoperative frozen section (iFS) analyses of SLNs were thought to reduce re-operation rates despite variable reported sensitivity and possibility of a false negative result. This study evaluated the rate of re-operations prevented by SLN iFS in a tertiary care hospital in Bangkok, Thailand, over a 6-year time-frame.

Patients and Methods

From April 2016 to April 2022, 1284 sentinel lymph node biopsy (SLNB) procedures were performed. Of these, 214 cases were breast-conserving surgery in accordance with the ACOSOG criteria with concomitant usage of iFS. Clinicopathological features of these cases were collected and analyzed. Re-operation rates prevented by the additional intervention were reported.

Results

Only five additional operations were prevented with the usage of 214 iFS. The discordance rate between frozen and permanent sections in terms of presence of metastatic disease and number of total lymph nodes was around 15%. Tumor staging, node staging, Nottingham histologic grading and lymphovascular invasion are significant predictors of SLN metastasis.

Conclusion

iFS results in a very low prevention rate for follow-up ALND in patients with preoperative clinically negative axillary nodes and is associated with a non-negligible discordance rate with permanent sections. Our study suggests iFS may be avoided in most cases of early-stage clinically and radiographically node-negative breast cancer patients. Doing so may reduce surgical costs and total operative time without a significant impact on the overall quality of treatment and standard of care.

Sentinel Lymph Node Biopsy Is Feasible in Dogs with Scars from Prior Local Excision of Solid Malignancies

Simple Summary

Sentinel lymph node (SLN) excision is gaining relevance in the management of various canine malignancies due to its recognized impact on staging and treatment choices. However, the technologies to perform SLN mapping are only available to a few referral centers, and there is increasing demand for secondary nodal staging after prior tumor excision at the primary care institution. This retrospective study investigated the feasibility and usefulness of SLN biopsy in dogs with surgical scars resulting from the removal of various solid tumors referred for further staging and/or adjuvant treatment options. Thirty-three dogs with 34 scars underwent SLN biopsy at a median of 50 days after primary tumor excision. An SLN was identified for 31/34 scars, translating to a detection rate of 91.2%. Metastases were identified with histopathology in 13/31 dogs (41.9%) and they all had an excision of a mast cell tumor. SLN biopsy should be suggested in dogs presenting with scars from prior solid tumor excision, considering the observed detection rate and the importance of knowing the metastatic status of the SLN in oncological diseases.

Abstract

Sentinel lymph node (SLN) biopsy is a well-established staging tool in canine oncology. This study aims to explore the feasibility of SLN biopsy in dogs with scars from prior excised solid malignancies that were referred for further tumor staging and/or adjuvant treatment options. Mapping was either performed using radiopharmaceutical, methylene blue, and/or near-infrared fluorescent (NIRF) imaging. Thirty-three dogs with 34 scars from prior excision of the mast cell tumor (MCT) (n = 29), soft tissue sarcoma (n = 2), oral melanoma (n = 1), subungual melanoma (n = 1), and mammary adenocarcinoma (n = 1) were retrospectively enrolled. Primary treatment consisted of curative intent/wide tumor excisions in 50.0% of dogs and marginal excision in the remaining 50.0%. The median time between tumor excision and SLN biopsy was 50 days (range 17–110 days). The procedure was successful in 31/34 scars, translating to a detection rate of 91.2%. The SLN did not correspond to the regional lymph node in 19/31 scars (61.3%). SLN metastases were histologically identified in 13/31 (41.9%) dogs, all of them affected by MCT. Based on our results, SLN biopsy using lymphoscintigraphy/methylene blue and/or NIRF is feasible in dogs presenting with scars from the prior surgical excision of solid tumors, and should be suggested for accurate nodal staging.

Tuning Excitation Field Frequency for Magnetic Particle Sensing using Superparamagnetic Quantifier

Nonlinear handheld detection of magnetic nanoparticles is used to assess the lymph node status of cancer patients. Joint sensitivity and resolving power of nonlinear handheld detection can be maximized by optimizing the frequency of the excitation field, which is strongly influenced by Brownian and Néel relaxation. The characteristic frequency of magnetic nanoparticles that defines sensitivity and resolving power is usually assessed by AC susceptometry. In this study, we used SPaQ data to predict handheld detection performance for magnetic nanoparticles with various particle sizes. SPaQ assesses dynamics by measuring the derivative of the magnetization originating from magnetic nanoparticles activated by an alternating excitation field. The ratio between the maximum signal difference and full-width-at-half-maximumis used to estimate the optimal excitation frequency. Thereupon, it was shown that a particle with a combination of Brownian and Néel relaxation is superior in nonlinear handheld detection compared to Brownian or Néel only particles. Moreover, the optimal excitation frequency is generally established at a slightly higher frequency compared to the characteristic frequency assessed by AC susceptometry. Consequently, this insight into the consequences of the dynamic behavior of magnetic nanoparticles under an alternating magnetic field enables the optimization of nonlinear handheld detection for specific clinical applications.

Comparison of shear-wave velocities obtained with shear-wave elastography of various peripheral lymph nodes in healthy Beagles

OBJECTIVE

To compare shear-wave velocities (SWVs) with shear-wave elastography of various peripheral lymph nodes (LNs).

ANIMALS

11 healthy Beagles.

PROCEDURES

For each dog, bilateral mandibular, medial retropharyngeal, superficial cervical, axillary, superficial inguinal, and popliteal LNs were evaluated with shear-wave elastography in sagittal and transverse scanning planes. Depth of each lymph node was recorded, and intra- and interobserver reliability was determined.

RESULTS

SWVs for all LNs were significantly higher in the sagittal scanning plane, compared with those in the transverse scanning plane. The SWV of the most superficial LN, the mandibular LN, was significantly higher, compared with that for the other LNs, except for the medial retropharyngeal LN. The SWV of the deepest LN, the medial retropharyngeal LN, was as high as that for the mandibular LN. Intra- and interobserver reliability was excellent.

CONCLUSIONS AND CLINICAL RELEVANCE

SWVs for normal peripheral LNs of Beagles may serve as a reference to compare with those for other breeds and diseased LNs. Scanning plane, LN depth, and interfering tissues between the LN and the transducer may affect SWV. Shear-wave elastography may not be operator dependent.

Comparison of shear-wave velocities obtained with shear-wave elastography of various peripheral lymph nodes in healthy Beagles

OBJECTIVE

To compare shear-wave velocities (SWVs) with shear-wave elastography of various peripheral lymph nodes (LNs).

ANIMALS

11 healthy Beagles.

PROCEDURES

For each dog, bilateral mandibular, medial retropharyngeal, superficial cervical, axillary, superficial inguinal, and popliteal LNs were evaluated with shear-wave elastography in sagittal and transverse scanning planes. Depth of each lymph node was recorded, and intra- and interobserver reliability was determined.

RESULTS

SWVs for all LNs were significantly higher in the sagittal scanning plane, compared with those in the transverse scanning plane. The SWV of the most superficial LN, the mandibular LN, was significantly higher, compared with that for the other LNs, except for the medial retropharyngeal LN. The SWV of the deepest LN, the medial retropharyngeal LN, was as high as that for the mandibular LN. Intra- and interobserver reliability was excellent.

CONCLUSIONS AND CLINICAL RELEVANCE

SWVs for normal peripheral LNs of Beagles may serve as a reference to compare with those for other breeds and diseased LNs. Scanning plane, LN depth, and interfering tissues between the LN and the transducer may affect SWV. Shear-wave elastography may not be operator dependent.

Sentinel lymph node biopsy in breast cancer guided by CT lymphography; History, evolution and current applications

Sentinel lymph node biopsy (SLNB) has efficiently replaced axillary lymph node dissection (ALND) in axillary staging in node-negative breast cancer patients. Dual sentinel lymph node (SLN) localization using radioisotopes and blue dye is the standard technique for SLN mapping. Yet, nuclear medicine facilities are not widely available worldwide. In Japan, Computed tomography lymphography (CTLG) is presented as an SLN mapping technique which was first suggested in 2003 by Suga et al. Multiple subsequent studies confirmed the efficacy of CTLG in SLN mapping in breast cancer. Further applications of the technique followed; such as prediction of SLN metastasis using CTLG, the use of CTLG guided SLN biopsy after neoadjuvant therapy, video-assisted CTLG guided SLN biopsy, the use of real-time virtual sonography with 3-D CTLG, and preoperative localization of the CTLG mapped SLN using either real-time virtual sonography (RVS) guided Indocyanine green (ICG) injection or its marking using liquid charcoal and silver wire and the use of SPIO enhanced magnetic resonance imaging (MRI) for prediction of metastasis in SLNs detected by CTLG. This efficacy and variable applications open the door for conducting wide-scale randomized controlled trials to suggest using CTLG as an efficient alternative for the use of radioisotopes in SLN mapping in breast cancer patients, especially in low and middle-income countries.

Preoperative Contrast-Enhanced Ultrasound (CEUS) Combined with 125I Seeds Localization in Sentinel Lymph Node Biopsy for Breast Cancer

Objective

To assess the clinical value of contrast-enhanced ultrasound (CEUS) technology in predicting axillary lymph nodes status before surgery, and to explore the feasibility of sentinel lymph nodes (SLNs) localization guided by CEUS combined with ¹²⁵I implantation for breast cancer.

Methods

From August 2017 to February 2019, 115 patients were included in this prospective study. Before surgery, a microbubble (SonoVue) was injected intradermally next to the areola. The enhancement patterns of SLNs were recorded and ¹²⁵I seeds were deployed into the enhanced nodes. Then, all patients underwent standard sentinel lymph node biopsy (SLNB) and all ¹²⁵I seeds were found out guided by a gamma detector in surgery. The localization was considered successful if ¹²⁵I seeds were implanted in/beside the nodes.

Results

SLNs in 103 cases were successfully identified, the success rate was 89.6% (103/115), 118 SLNs were detected in total. ¹²⁵I seeds were deployed successfully in 99 cases, and all of the ¹²⁵I-labeled SLNs were then successfully detected by combined method (radionuclides and blue dye). The accuracy of ¹²⁵I seeds localization was 96.1% (99/103). Based on the enhancement patterns recorded, 34 cases were predicted to have SLNs metastasis (metastasis in 27 cases and no metastasis in 7 cases confirmed by postoperative pathology) and 65 cases were predicted to have no SLNs metastasis (metastasis in 5 cases and no metastasis in 60 cases by pathology). The positive predictive value and negtive predictive value of CEUS in assessing axillary status were 79.4% (27/34) and 92.3% (60/65), respectively. The axillary metastasis rate in CEUS combined with ¹²⁵I seeds localization was 27.3% (27/99), while the metastasis rate in the combined method of SLNB was 32.3% (32/99). The sensitivity of ¹²⁵I seeds localization was 84.4% (27/32), the false-negative rate was 15.6% (5/32), and the consistency evaluation was excellent (Kappa value=0.880, P<0.001).

Conclusion

CEUS combined with ¹²⁵I seeds implantation can locate SLNs accurately and has excellent consistency with the combined method. The enhancement patterns can provide helpful predicting information of axillary status preoperatively. However, more studies are needed to be carried out to verify our outcomes and explore the feasibility of applying CEUS technology in clinical work.

Clinical value of postoperative sentinel lymph node biopsy

Background

This study analyzed the clinical data and general information of breast cancer patients who were admitted by the Affiliated Hospital of Nantong University and underwent lumpectomy, followed by sentinel lymph node biopsy (SLNB) to investigate the effect of tumor location on the sentinel lymph node (SLN) detection rate, obtain a clear understanding of the SLNB procedure and further promote the use of this procedure in the local area.

Methods

This study involved a total of 118 patients who were diagnosed with breast cancer and admitted by the Affiliated Hospital of Nantong University for lumpectomy and SLNB between July 2015 and June 2019. An analysis was conducted to explore the role of tumor location in the detection of SLNs.

Results

Tumor location was associated with the success rate of post-lumpectomy SLNB. In the case of tumor location in the upper outer quadrant (UOQ) of the breast near the axilla, the SLN detection rate was relatively low. In contrast, when a tumor occurred in any of the other quadrants or the UOQ next to the areola, the tumor location had no significant impact on the SLN detection rate. SLNB indicated that 102 out of the 118 patients had SLNs, with the detection rate of 86.4%. Particularly, for patients whose tumors were located in the UOQ near their axillae, the SLN detection rate was 30% (3/10). As to tumor location in other quadrants or the UOQ next to the areola, the SLN detection rate was up to 90.8% (99/109).

Conclusions

The performance of post-lumpectomy SLNB is associated with tumor location. SLNB is recommended when the tumor site lies in the upper inner/lower outer/lower inner quadrants (UIQ/LOQ/LIQ) of the breast or the UOQ next to the areola. If the SLNB result turns out to be negative, there is no need to perform axillary lymph node dissection (ALND). For tumor location in the UOQ of the breast, especially when it is near the axilla, SLNB is not a favorable option after lumpectomy. It is recommended that the patient receive a core needle biopsy (CNB) before SLNB.

Percutaneous contrast-enhanced ultrasound for localization and diagnosis of sentinel lymph node in early breast cancer

This study assessed the efficacy of percutaneous contrast-enhanced ultrasound (CEUS) in localization sentinel lymph node (SLNs) for biopsy and diagnosis of metastatic SLNs in patients with early breast cancer. From January to November 2017, seventy-five patients with early breast cancer confirmed by pathology were enrolled in this study. CEUS was performed after subdermal injection of ultrasound contrast agent (SonoVue, 2.0 ml in total dose) around the areola on the ipsilateral side of the breast. The contrast-enhanced lymphatic vessels and associated SLNs were observed and traced in real time. The lymphatic vessels and SLN were mapped and labeled on the skin surface. Sentinel lymph node biopsy (SLNB) was performed after injection of 2.0 ml methylene blue at same injection site of SonoVue. The accuracy of percutaneous CEUS localization of SLNs was determined compared to blue dye injection technique. The pathological results under blue dye guided biopsy were used as the reference standard to calculate the sensitivity and specificity of CEUS for the diagnosis of SLNs. A total of 163 SLNs obtained through SLNB following methylene blue tracing in 75 patients. There were 116 SLNs identified by percutaneous CEUS. The difference of detection rates between blue dye and CEUS was statistically significant (Z = -2.651, P = 0.008). The identification rate of SLNs by CEUS was 71.17% (116/163). The accuracy of percutaneous CEUS localization of axillary SLNs was 94.67% (71/75) compared to blue dye-guided biopsy. Among the 116 SLNs detected by percutaneous CEUS, pathologic results showed 51 positive SLNs and 65 negative SLNs whiles CEUS findings indicated 83 positive SLNs and 33 negative SLNs. Only 50 of 83 SLNs had metastasis on pathology, while 33 were detected as false positive. The sensitivity and specificity of CEUS for the diagnosis of metastatic SLN was 98.04%(50/51) and 49.23%(32/65), respectively. Percutaneous CEUS can be used as an effective method to localize the SLNs for guiding SLNB. This method has excellent sensitivity for identifying the SLNs but lower specificity for detecting metastatic SLNs in patients with early stage breast cancer.

Preoperative localization of sentinel lymph node in breast cancer patients by silver wire insertion or liquid charcoal injection guided by CT lymphography

Dual localization of SLN in breast cancer patients using isotope & dye is the best-approved modality with limitations such as high cost of radioactive materials, complex logistic preparations & scheduling issues, especially in developing countries. We investigated the feasibility & accuracy of a novel technique for SLN localization using silver wire insertion or liquid charcoal injection guided by CT lymphography. 120 patients with clinically node-negative breast cancer were enrolled. In the test group, SLN was localized using preoperative CTLG guided injection of liquid charcoal or by placing a 3 cm silver wire. In addition, intraoperative SLN mapping was performed using methylene blue dye followed by searching for the SLN localized by both methods. In the control group, SLN was localized by the blue dye only. Feasibility, accuracy, detection rates, and number of SLNs retrieved were reported as well as matching between the LN detected with the CTLG and that detected with the dye technique. SLN could be detected in 59 out of 60 patients (98.3%) in the test group and in 54 out of 60 patients (90%) in the control group (P = .057). In self-controlled analysis of the test group comparing CTLG only to dye only was significant (P = .050). Comparing charcoal to silver wire in detection was statistically insignificant (P = .5). This novel method can offer advantages which are as follows: being more accurate than the dye alone, saving operative time, abandoning complex logistic preparations for the radioisotope, and solving the problem of timing.

The predictive value of sentinel node biopsy in early breast cancer after neo-adjuvant chemotherapy: A prospective study

OBJECTIVE

A sentinel Node (SN) has replaced axillary lymph node dissection (ALND) in patients with clinically node negative axilla (cN0). SN after Neo-adjuvant chemotherapy (NACT) is feasible but not accurate in clinically node positive (cN1-3) patients. The goal of this study is to determine the negative predictive value (NPV) of SN in cN0 breast cancer after NACT. A secondary endpoint is to determine if ALND can be avoided after NACT regardless of the pre-treatment clinical staging of the axilla, in case of a normalization of the ¹⁸F-fluoro-2-deoxy-glucose positron emission tomography scan (PET-CT scan).

DESIGN

A single institution prospective study regarding the negative predictive value of the SN in breast cancer after NACT was conducted in the Multidisciplinary Breast Clinic of the Antwerp University Hospital from 29/03/2010 until 01/12/2015 (Study number: B30020108368). Inclusion criteria for study participation were: breast cancer, age above 18 years, female, tumor stages T2-T4 N0-3 or T1N1-N3. All patients were staged by a mammography, ultrasound of the axilla, MRI of the breast, PET-CT scan and bone scintigraphy. They received NACT consisting of 12 cycles of paclitaxel or 4 cycles of docetaxel followed by dose dense doxorubicin or epirubicin/cyclofosfamide or vice versa as a standard initial treatment. After 6 weeks, a PET-CT scan was performed for early tumour response evaluation. At the day of operation, a ⁹⁹mTC-labelled nanocolloid was used to identify the SN. During the surgery the SN were removed separately together with a complete ALND.

RESULTS

A total of 150 patients were enrolled in our study of which 129 were eligible for analysis. 53 patients had a positive SN of which 32 have a positive axillary lymph nodes (ALN), positive predictive value (PPV) was 60%; 76 patients had a negative SN of which 6 had a positive ALN (NPV 92%). The sensitivity is 84% and the specificity 76% with a false omission rate (FOR) of 8%. In total 45 patients ALN were clinical negative and no suspect lymph nodes were seen on ultrasound, MRI and PET-CT scan) and 45 patients had negative a SN, with no ALN and 2 patients had a positive SN of which 1 patients had axillary involvement (NPV 100%). The FOR of cN1: 5%, cN2: 37%, cN3 33%. A total of 22 patients out of 84 patients (26%) of which 15/49 cN1 (30%), 6/23 (26%) cN2, 1/12 (8%) have after 6 weeks of chemotherapy and normalization on PET-CT scan. A total of 17 patients had a negative SN and ALN. The FOR was in this group was 0%.

CONCLUSION

A SNB should become the standard after NACT if case of a cN0. If after NACT the PET CT has normalized, no ALND should be performed if the SN is negative.