Enhanced sonographic imaging to diagnose lymph node metastasis: importance of blood vessel volume and density

Prospects of perfusion contrast-enhanced ultrasound (CE-US) in diagnosing axillary lymph node metastases in breast cancer: a comparison with lymphatic CE-US

Accurate diagnosis of lymph node (LN) metastasis is vital for prognosis and treatment in patients with breast cancer. Imaging 1modalities such as ultrasound (US), MRI, CT, and 18F-FDG PET/CT are used for preoperative assessment. While conventional US is commonly recommended due to its resolution and sensitivity, it has limitations such as operator subjectivity and difficulty detecting small metastases. This review shows the microanatomy of axillary LNs to enhance accurate diagnosis and the characteristics of contrast-enhanced US (CE-US), which utilizes intravascular microbubble contrast agents, making it ideal for vascular imaging. A significant focus of this review is on distinguishing between two types of CE-US techniques for axillary LN evaluation: perfusion CE-US and lymphatic CE-US. Perfusion CE-US is used to assess LN metastasis via transvenous contrast agent administration, while lymphatic CE-US is used to identify sentinel LNs and diagnose LN metastasis through percutaneous contrast agent administration. This review also highlights the need for future research to clarify the distinction between studies involving "apparently enlarged LNs" and "clinical node-negative" cases in perfusion CE-US research. Such research standardization is essential to ensure accurate diagnostic performance in various clinical studies. Future studies should aim to standardize CE-US methods for improved LN metastasis diagnosis, not only in breast cancer but also across various malignancies.

Docetaxel administered through a novel lymphatic drug delivery system (LDDS) improved treatment outcomes for lymph node metastasis

Recently, sentinel lymph nodes (LNs) have been recognized as a starting point of hematogenous metastasis; thus, an increase in the control rate of LN metastasis is expected to improve the survival rate. Although surgical treatment and radiation therapy are commonly used for the radical treatment of LNs, these treatments are associated with lymphedema, pain, and an extended hospital stay. In a recent mouse study, activation of metastatic tumors in distant organs was reported after removing LNs, with or without metastasis to the LNs. Thus, there is the necessity for cancer treatment that can replace LN removal. Here, we evaluated the treatment efficacy of lymphatic drug delivery system (LDDS) with osmotic pressure and viscosity escalated Docetaxel at the early stage of LN metastasis. MXH10/Mo/lpr mice were inoculated with mouse breast cancer cells into Subiliac LN to create the metastatic mouse model. Docetaxel was injected into mouse mammary carcinoma cells inoculated LN as a single shot (SS) or double shot (DS) to understand the therapeutic mechanism of a single shot or double shot intervention using an in vivo imaging system, histology, and qPCR. The results showed that the DS administration of docetaxel at 1,960 kPa (12 mPa∙s) had better therapeutic outcomes with increased complete response and improved survival with reduced adverse events. The results also revealed that administration of a DS of docetaxel enhances differentiation of T helper cells, and improves survival and therapeutic outcomes. From a safety perspective, LDDS-administered DS of low-concentration docetaxel without any other anticancer treatments to LNs a novel approach to cancer management of LN metastasis. We emphasize that LDDS is a groundbreaking method of delivering anticancer drugs specifically to cancer susceptible LNs and is designed to enhance the effectiveness of cancer treatment while minimizing side effects.

The Value of Percutaneous Contrast-Enhanced Ultrasound in Sentinel Lymph Node Identification, Metastatic Status and Burden Diagnosis in Early Breast Cancer

OBJECTIVE

The aim of this study was to evaluate the value of percutaneous contrast-enhanced ultrasound (PCEUS) in the identification and characterization of sentinel lymph node (SLN).

METHODS

A total of 102 breast cancer patients were collected and underwent preoperative PCEUS, which was used to identify SLN and lymphatic drainage. SLNs were classified into 4 enhancement patterns, including 6 subtypes: homogeneous (I), featured inhomogeneous (II) including inhomogeneous hypoenhancement (IIa) and annular or semi-annular enhancement (IIb), focal filling defect (III) including filling defect area < 50% (IIIa) and filling defect area ≥ 50% (IIIb), and no enhancement (IV). The enhancement patterns of SLNs were compared with the final pathological diagnosis.

RESULTS

The identification rate of SLNs using PCEUS was 100% (102/102); the rate of identification of LCs was 100% (102/102), and the coincidence rate was 98.0% (100/102). Four lymphatic drainage patterns (LDPs) including 5 subtypes were found: single LC/single SLN(74.5%), multiple LCs/ single SLN (13.7%) including 2 subtypes:2 LCs/1 SLN and 3 LCs/1 SLN, single LC/multiple SLNs (7.8%), and multiple LCs/multiple SLNs (3.9%). A total of 86.3% (44/51) of patients without axillary metastasis could be safely selected for types I, IIa, and IIb, while the axillary metastasis rates of types III and IV were 74.4% and 87.5%, respectively (P < .001). Compared with grayscale US, the PCEUS significant improvement in diagnosing metastatic SLNs (.794 versus .579, P < .001). For the SLN metastatic burden, Types I, IIa, IIb, and IIIa had ≤2 SLNs metastases, with a pathological coincidence rate of (64/67, 95.5%), and types IIIb and IV had >2 SLNs metastases, with a pathological coincidence rate of (25/35, 71.4%) (P < .001). The AUC of PCEUS for the diagnosis of SLN metastatic status and burden was .794 and .879, respectively (P < .001).

CONCLUSION

PCEUS has a high identification rate for SLN and has good potential for diagnosing SLN metastatic status and burden by enhancement patterns.

Predictive value for axillary lymph node metastases in early breast cancer: Based on contrast-enhanced ultrasound characteristics of the primary lesion and sentinel lymph node

OBJECTIVE

To evaluate the value of contrast-enhanced ultrasound (CEUS) characteristics based on primary lesion combined with lymphatic contrast-enhanced ultrasound (LCEUS) patterns of SLN in predicting axillary lymph node metastasis (ALNM) with T1-2N0 breast cancer.

METHODS

A retrospective study was conducted in 118 patients with clinically confirmed T1-2N0 breast cancer. Conventional ultrasound (CUS) and CEUS characteristics of the primary lesion and enhancement patterns of SLN were recorded. The risk factors associated with ALNM were selected by univariate and binary logistic regression analysis, and the receiver operating characteristic (ROC) curve was drawn for the evaluation of predictive ALNM metastasis performance.

RESULTS

Univariate analysis showed that age, HER-2 status, tumor size, nutrient vessels, extended range of enhancement lesion, and the enhancement patterns of SLN were significant predictive features of ALNM. Further binary logistic regression analysis indicated that the extended range of enhancement lesion (p <  0.001) and the enhancement patterns of SLN (p <  0.001) were independent risk factors for ALNM. ROC analysis showed that the AUC of the combination of these two indicators for predicting ALNM was 0.931 (95% CI: 0.887-0.976, sensitivity: 75.0%, specificity: 99.8%).

CONCLUSION

The CEUS characteristics of primary lesion combined with enhancement patterns of SLN are highly valuable in predicting ALNM and can guide clinical axillary surgery decision-making in early breast cancer.

Intralymphatic injection of chemotherapy drugs modulated with glucose improves their anticancer effect

Lymph node metastasis (LNM) has a significant impact on cancer prognosis, emphasizing the need for effective treatment strategies. This study investigated the potential use of high osmotic pressure drug solutions with low viscosity administration using a lymphatic drug delivery system (LDDS) to improve LNM treatment outcomes. The hypothesis was that injection of epirubicin or nimustine at high osmotic pressure but without altered viscosity would enhance drug retention and accumulation in LNs, thereby improving the efficacy of treatment. Biofluorescence analysis revealed enhanced drug accumulation and retention in LNs after administration using LDDS compared to intravenous (i.v) injection. Histopathological results demonstrated minimal tissue damage in the LDDS groups. Pharmacokinetic analysis revealed an improved treatment response with higher drug accumulation and retention in LNs. The LDDS approach offers the potential for greatly reduced side effects of chemotherapy drugs, lower dosage requirements and crucially increased drug retention in LNs. The results highlight the promise of high osmotic pressure drug solutions with low viscosity administrated using the LDDS for enhancing the treatment efficacy of LN metastasis. Further research and clinical trials are warranted to validate these results and optimize the clinical translation of this novel treatment technique.

Noninvasive prediction of axillary lymph node breast cancer metastasis using morphometric analysis of nodal tumor microvessels in a contrast-free ultrasound approach

PURPOSE

Changes in microcirculation of axillary lymph nodes (ALNs) may indicate metastasis. Reliable noninvasive imaging technique to quantify such variations is lacking. We aim to develop and investigate a contrast-free ultrasound quantitative microvasculature imaging technique for detection of metastatic ALN in vivo.

EXPERIMENTAL DESIGN

The proposed ultrasound-based technique, high-definition microvasculature imaging (HDMI) provides superb images of tumor microvasculature at sub-millimeter size scales and enables quantitative analysis of microvessels structures. We evaluated the new HDMI technique on 68 breast cancer patients with ultrasound-identified suspicious ipsilateral axillary lymph nodes recommended for fine needle aspiration biopsy (FNAB). HDMI was conducted before the FNAB and vessel morphological features were extracted, analyzed, and the results were correlated with the histopathology.

RESULTS

Out of 15 evaluated quantitative HDMI biomarkers, 11 were significantly different in metastatic and reactive ALNs (10 with P << 0.01 and one with 0.01 < P < 0.05). We further showed that through analysis of these biomarkers, a predictive model trained on HDMI biomarkers combined with clinical information (i.e., age, node size, cortical thickness, and BI-RADS score) could identify metastatic lymph nodes with an area under the curve of 0.9 (95% CI [0.82,0.98]), sensitivity of 90%, and specificity of 88%.

CONCLUSIONS

The promising results of our morphometric analysis of HDMI on ALNs offer a new means of detecting lymph node metastasis when used as a complementary imaging tool to conventional ultrasound. The fact that it does not require injection of contrast agents simplifies its use in routine clinical practice.

Site-Specific Polyplex on CCR7 Down-Regulation and T Cell Elevation for Lymphatic Metastasis Blocking on Breast Cancer

Tumor metastasis contributes to high cancer mortality. Tumor cells in lymph nodes (LNs) are difficult to eliminate but underlie uncontrollable systemic metastasis. The CC chemokine receptor 7 (CCR7) is overexpressed in tumor cells and interacts with CC chemokine ligand 21 (CCL21) secreted from LNs, potentiating their lymphatic migration. Here, a site-specific polyplex is developed to block the CCR7-CCL21 signal and kill tumor cells toward LNs, greatly limiting their lymphatic infiltration. A CCR7-targeting small interfering RNA (siCCR7) is condensed by mPEG-poly-(lysine) with chlorin e6 (Ce6) modification (PPLC) to form PPLC/siCCR7. The knockdown of CCR7 by siCCR7 in tumor cells significantly reduced their response on CCL21 and LN tropism. Additionally, photodynamic therapy-mediated immune activation precisely targets and kills tumor cells released from the primary foci before they reaches the LNs, reducing the number of tumor cells entering the LNs. Consequently, the PPLC/siCCR7 polyplexes inhibited up to 92% of lung metastasis in 4T1 tumor bearing mice and reduced tumor cell migration to LNs by up to 80%. This site-specific strategy optimized anti-metastasis efficacy and promotes the clinical translational development of anti-metastatic therapy.

Prediction of pathological complete response to neoadjuvant chemotherapy in patients with breast cancer using a combination of contrast-enhanced ultrasound and dynamic contrast-enhanced magnetic resonance imaging

This study aimed to evaluate the value of dynamic contrast-enhanced ultrasound (CEUS) combined with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in predicting pathological complete response (pCR) in patients with breast cancer receiving neoadjuvant chemotherapy (NAC). Fifty-seven female patients with breast cancer (mean age, 50.46 years; range, 32-66 years) scheduled for NAC were recruited. CEUS and DCE-MRI were performed before and after NAC. Imaging features and their changes were compared with postoperative pathological results. After the clinical differences were balanced using propensity score matching, univariate and multiple logistic regression analyses were used to derive the characteristics independently associated with pCR. Receiver operating characteristic curve analysis was performed to assess diagnostic performance. After six to eight cycles of NAC, 24 (42.1%) patients achieved pCR, while 33 (57.9%) did not. Multivariate analysis showed that enhancement order on CEUS and DCE-MRI before NAC, reduction in diameter and enhancement shape on CEUS, maximum diameter on DCE-MRI, and the type of progressive dynamic contrast enhancement after NAC were independently associated with pCR after NAC. The area under the receiver operating characteristic curve for CEUS+DCE-MRI was 0.911 (95% confidence interval, 0.826-0.997), and the specificity and positive predictive values were 87.0% and 87.5%. CEUS and DCE-MRI have the potential for assessing the pathological response to NAC in patients with breast cancer; their combination showed the best diagnostic performance. CEUS+DCE-MRI has proved beneficial for comprehensive assessment and personalizing treatment strategies for patients with breast cancer.

Intranodal delivery of modified docetaxel: Innovative therapeutic method to inhibit tumor cell growth in lymph nodes

Delivery of chemotherapeutic agents into metastatic lymph nodes (LNs) is challenging as they are unevenly distributed in the body. They are difficult to access via traditional systemic routes of drug administration, which produce significant adverse effects and result in low accumulation of drugs into the cancerous LN. To improve the survival rate of patients with LN metastasis, a lymphatic drug delivery system (LDDS) has been developed to target metastatic LN by delivering chemotherapy agents into sentinel LN (SLN) under ultrasound guidance. The LDDS is an advanced method that can be applied in the early stage of the progression of tumor cells in the SLN before tumor mass formation has occurred. Here we investigated the optimal physicochemical ranges of chemotherapeutic agents’ solvents with the aim of increasing treatment efficacy using the LDDS. We found that an appropriate osmotic pressure range for drug administration was 700–3,000 kPa, with a viscosity < 40 mPa⋅s. In these physicochemical ranges, expansion of lymphatic vessels and sinuses, drug retention, and subsequent antitumor effects could be more precisely controlled. Furthermore, the antitumor effects depended on the tumor progression stage in the SLN, the injection rate, and the volumes of administered drugs. We anticipate these optimal ranges to be a starting point for developing more effective drug regimens to treat metastatic LN with the LDDS.

The diagnostic value of contrast-enhanced ultrasound for cervical tuberculous lymphadenitis

OBJECTIVE:

To investigate the value of contrast-enhanced ultrasound (CEUS) for the diagnosis of cervical tuberculous lymphadenitis (CTL).

METHODS:

The cohort study included 203 consecutive patients diagnosed with cervical lymph node. Before pathological or laboratory confirmation, all patients underwent CEUS examination, and the imaging findings were analyzed afterward. The diagnostic efficiency of the CEUS imaging findings of CTL was evaluated.

RESULTS:

Nighty-seven patients of the 203 (47.8%) were pathologically or laboratory confirmed with a CTL diagnosis while the remainder (52.2%) were diagnosed with non-tuberculous lymphadenitis. Regarding the imaging findings of CEUS, it was more common in CTL patients to find a pattern of heterogeneous enhancement inside the lymph nodes relative to non-tuberculous patients [81.44% (79/97) vs 15.09% (16/106), P < 0.01]. The sensitivity of the feature in diagnosis for CTL was 81.44% and the specificity was 84.91%, resepectively. Furthermore, a pattern of peripheral rim-like enhancement had been notable in CTL patients compared with non-tuberculous patients [86.60% (84/97) vs 12.26% (13/106), P < 0.01], associating with a diagnostic sensitivity of 86.60% and a specificity of 87.74%. When it came to the combination of both imaging findings mentioned above, the features were more prominent in CTL patients than compared with non-tuberculous patients [74.23% (72/97) vs 5.66% (6/106), P < 0.01], with a diagnostic sensitivity of 74.23% and a high specificity of 94.34%. Regarding area under curve (AUC) for the ROC analysis, the feature of internal heterogeneous enhancement, peripheral rim-like enhancement, and both features were 0.832, 0.872, and 0.843.

CONCLUSIONS:

CEUS patterns of heterogeneous enhancement and peripheral rim-like enhancement of lymph nodes are helpful characteristics for the diagnosis of CTL.

A novel targeted multifunctional nanoplatform for visual chemo-hyperthermia synergy therapy on metastatic lymph nodes via lymphatic delivery

Background

Distant metastasis to vital organs is the major contributor to breast cancer mortality, and regional lymph node metastasis is an important facilitator of distant metastasis and recurrence in this cancer. The early diagnosis and precise treatment of lymph node metastasis are crucial for staging and prognosis in breast cancer. Herein, we report a visualized precision medicine nanoplatform of metastatic lymph nodes for ultrasonic/photoacoustic (US/PA) dual modal imaging-guided in situ targeted hyperthermia-combined chemotherapy.

Results

Carbon nanoparticles (CNs), approved by the China Food and Drug Administration, were loaded with docetaxel and rationally combined with anti-hypoxia-inducible factor 1α antibody-modified poly (lactic-co-glycolic acid) (PLGA) nanoparticles to achieve the combination of passive targeting at the lymph nodes and intracellular targeting at HIF 1α factor. The accumulation and retention of nanoparticles in metastatic lymph nodes via lymphatic delivery were enhanced. Docetaxel could be effectively offloaded by CNs that have active carbon nanoparticles, and the PLGA membrane prevented drug leakage. The nanoparticles exhibited excellent photothermal performance with a photothermal conversion efficiency of 28.9%, killing tumor cells in metastatic lymph nodes through hyperthermia. In vitro and in vivo systematic evaluations revealed that hyperpyrexia triggered the rupture of nanoparticles caused by the phase transition of perfluorohexane, resulting in docetaxel release for achieving in situ hyperthermia-combined chemotherapy.

Conclusions

The laser-triggered highly efficient in situ chemotherapy nanosystem achieves targeted synergistic chemo-hyperthermia treatment of metastatic lymph nodes, and lymphatic delivery represents a strategy to avoid additional injury caused by drugs entering the blood circulation.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01186-8.

Characterizing perfusion defects in metastatic lymph nodes at an early stage using high-frequency ultrasound and micro-CT imaging

A perfusion defect in a metastatic lymph node (LN) can be visualized as a localized area of low contrast on contrast-enhanced CT, MRI or ultrasound images. Hypotheses for perfusion defects include abnormal hemodynamics in neovascular vessels or a decrease in blood flow in pre-existing blood vessels in the parenchyma due to compression by LN tumor growth. However, the mechanisms underlying perfusion defects in LNs during the early stage of LN metastasis have not been investigated. We show that tumor mass formation with very few microvessels was associated with a perfusion defect in a non-enlarged LN at the early stage of LN metastasis in a LN adenopathy mouse (LN size circa 10 mm). We found in a mouse model of LN metastasis, induced using non-keratinizing tumor cells, that during the formation of the perfusion defect in a non-enlarged LN, the number of blood vessels ≤ 50 μm in diameter decreased, while those of > 50 μm in diameter increased. The methods used were contrast-enhanced high-frequency ultrasound and contrast-enhanced micro-CT imaging systems, with a maximum spatial resolution of > 30 μm. Furthermore, we found no tumor angiogenesis or oxygen partial pressure (pO₂) changes in the metastatic LN. Our results demonstrate that the perfusion defect appears to be a specific form of tumorigenesis in the LN, which is a vascular-rich organ. We anticipate that a perfusion defect on ultrasound, CT or MRI images will be used as an indicator of a non-enlarged metastatic LN at an early stage.

Application of conventional ultrasonography combined with contrast-enhanced ultrasonography in the axillary lymph nodes and evaluation of the efficacy of neoadjuvant chemotherapy in breast cancer patients

Objective:

Axillary lymph node status assessment has always been an important issue in clinical treatment of breast cancer. However, there has been no effective method to accurately predict the pathological complete response (pCR) of axillary lymph node after neoadjuvant chemotherapy (NAC). The objective of our study was to investigate whether conventional ultrasonography combined with contrast-enhanced ultrasonography (CEUS) can be used to evaluate axillary lymph node status of breast cancer patients after NAC.

Methods:

A total of 74 patients who underwent NAC were recruited for the present study. Prior to and after NAC, examinations of conventional ultrasonography and CEUS were performed. After evaluating the images of conventional ultrasonography, four characteristics were recorded: lymph node medulla boundary, cortex of lymph node, lymph node hilus, and lymph node aspect ratio. Two additional imaging characteristics of CEUS were analyzed: CEUS way and CEUS pattern. Receiver operating characteristiccurve analysis was applied to evaluate their diagnostic performance.

Results:

After 6~8 cycles of NAC, 46 (71.9%) patients had negative axillary lymph node, and 18 (28.1%) patients turned out non-pCR. According to statistical analysis, lymph node medulla, lymph node aspect ratio and CEUS way were independently associated with pCR of axillary lymph node after NAC. The area under the curve of the prediction model with three imaging characteristics was 0.882 (95% confidence interval: 0.608–0.958), and the accuracy to predict the patients’ lymph node status was 78.1% (p < 0.01).

Conclusions:

Conventional ultrasonography combined with CEUS technology can accurately predict axillary lymph nodes status of breast cancer patients after NAC.

Advances in knowledge:

The usefulness of CEUS technology in predicting pCR after neoadjuvant chemotherapy is highlighted.

Study of the physicochemical properties of drugs suitable for administration using a lymphatic drug delivery system

Lymph node (LN) metastasis is thought to account for 20‐30% of deaths from head and neck cancer. The lymphatic drug delivery system (LDDS) is a new technology that enables the injection of drugs into a sentinel LN (SLN) during the early stage of tumor metastasis to treat the SLN and secondary metastatic LNs. However, the optimal physicochemical properties of the solvent used to carry the drug have not been determined. Here, we show that the osmotic pressure and viscosity of the solvent influenced the antitumor effect of cisplatin (CDDP) in a mouse model of LN metastasis. Tumor cells were inoculated into the proper axillary LN (PALN), and the LDDS was used to inject CDDP solution into the subiliac LN (SiLN) to treat the tumor cells in the downstream PALN. CDDP dissolved in saline had no therapeutic effects in the PALN after it was injected into the SiLN using the LDDS or into the tail vein (as a control). However, CDDP solution with an osmotic pressure of ~ 1,900 kPa and a viscosity of ~ 12 mPa⋅s suppressed tumor growth in the PALN after it was injected into the SiLN using the LDDS. The high osmotic pressure dilated the lymphatic vessels and sinuses to enhance drug flow in the PALN, and the high viscosity increased the retention of CDDP in the PALN. Our results demonstrate that optimizing the osmotic pressure and viscosity of the solvent can enhance the effects of CDDP, and possibly other anticancer drugs, after administration using the LDDS.

Utility of quantitative contrast-enhanced ultrasound for the prediction of lymph node metastasis in patients with papillary thyroid carcinoma

OBJECTIVES

The aim of this study was to find the optimal parameters and cutoffs to differentiate metastatic lymph nodes (LNs) from benign LNs in the patients with papillary thyroid carcinoma (PTC) on the quantitative contrast-enhanced ultrasound (CEUS) features.

METHODS

A total of 134 LNs in 105 patients with PTCs were retrospectively enrolled. All LNs were evaluated by conventional ultrasound (US) and CEUS before biopsy or surgery. The diagnostic efficacy of CEUS parameters was analyzed.

RESULTS

Univariate analysis indicated that metastatic LNs more often manifested centripetal or asynchronous perfusion, hyper-enhancement, heterogeneous enhancement, ring-enhancing margins, higher PI, larger AUC, longer TTP and DT/2 than benign LNs at pre-operative CEUS (p <  0.001, for all). Multivariate analysis showed that centripetal or asynchronous perfusion (OR = 3.163; 95% CI, 1.721-5.812), hyper-enhancement(OR = 0.371; 95% CI, 0.150-0.917), DT/2 (OR = 7.408; 95% confidence interval CI, 1.496-36.673), and AUC (OR = 8.340; 95% CI, 2.677-25.984) were predictive for the presence of metastatic LNs. The sensitivity and accuracy of the quantitative CEUS were higher than qualitative CEUS (75% vs 55 % and 83.6% vs 76.1 % , respectively).

CONCLUSIONS

Quantitative CEUS parameters can provide more information to distinguish metastatic from benign LNs in PTC patients; In particular, DT/2 and AUC have a higher sensitivity and accuracy in predicting the presence of metastatic LNs and reduce unnecessary sampling of benign LNs.

Use of a Lymphatic Drug Delivery System and Sonoporation to Target Malignant Metastatic Breast Cancer Cells Proliferating in the Marginal Sinuses

Lymph node (LN) metastasis through the lymphatic network is a major route for cancer dissemination. Tumor cells reach the marginal sinuses of LNs via afferent lymphatic vessels (LVs) and form metastatic lesions that lead to distant metastasis. Thus, targeting of metastatic cells in the marginal sinuses could improve cancer treatment outcomes. Here, we investigated whether lymphatic administration of a drug combined with sonoporation could be used to treat a LN containing proliferating murine FM3A breast cancer cells, which are highly invasive, in its marginal sinus. First, we used contrast-enhanced high-frequency ultrasound and histopathology to analyze the structure of LVs in MXH10/Mo-lpr/lpr mice, which exhibit systemic lymphadenopathy. We found that contrast agent injected into the subiliac LN flowed into the marginal sinus of the proper axillary LN (PALN) and reached the cortex. Next, we examined the anti-tumor effects of our proposed technique. We found that a strong anti-tumor effect was achieved by lymphatic administration of doxorubicin and sonoporation. Furthermore, our proposed method prevented tumor cells in the marginal sinus from invading the parenchyma of the PALN and resulted in tumor necrosis. We conclude that lymphatic administration of a drug combined with sonoporation could exert a curative effect in LNs containing metastatic cells in their marginal sinuses.

Diagnostic value of MRI combined with ultrasound for lymph node metastasis in breast cancer: Protocol for a meta-analysis

BACKGROUND

Early diagnosis and treatment of breast cancer are important to prevent fatal tumor progression. Axillary lymph node (ALN) status is the most significant prognostic factor for diagnosing overall survival in breast cancer patients. Axillary lymph node dissection (ALND) is regarded as the reference standard for determining ALN status. However, ALND is an invasive therapy with high morbidity and complications such as lymphedema, seroma and nerve injury. Comparatively, magnetic resonance imaging (MRI) and ultrasound are noninvasive and non-radiative techniques that are common imaging methods to diagnose breast cancer lymph node metastasis. Many studies have investigated the diagnostic value of MRI combined with ultrasound for breast cancer ALN metastasis, but the evidence has been insufficient to apply these modalities when diagnosing new patients.

METHODS

We will search electronic databases including PubMed, EMbase, The Cochrane Library, Chinese Biomedical Database, WangFang Database, and China National Knowledge Infrastructure. The language of studies is limited in English or Chinese. The final search includes articles published in June, 2018. Stata 14.0 software will be used for all statistical analyses, and Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) will be utilized to evaluate the quality of the included studies. Meta-regression and subgroup analyses will be performed to explore heterogeneity, which will be derived from the different countries of origin of the included studies. Deeks' funnel plot asymmetry test will be demonstrated the inexistence of publication bias.

RESULT

This study will provide a rational synthesis of current evidences for magnetic resonance imaging combined with ultrasound for breast cancer.

CONCLUSION

The conclusion of this study will provide evidence for the diagnostic value of MRI combined with ultrasound for lymph node metastasis in breast cancer.

REGISTRATION

PROS-PERO CRD42019134474.

Treatment of false-negative metastatic lymph nodes by a lymphatic drug delivery system with 5-fluorouracil

Metastatic lymph nodes (LNs) may be the origin of systemic metastases. It will be important to develop a strategy that prevents systemic metastasis by treating these LNs at an early stage. False‐negative metastatic LNs, which are found during the early stage of metastasis development, are those that contain tumor cells but have a size and shape similar to LNs that do not host tumor cells. Here, we show that 5‐fluorouracil (5‐FU), delivered by means of a novel lymphatic drug delivery system (LDDS), can treat LNs with false‐negative metastases in a mouse model. The effects of 5‐FU on four cell lines were investigated using in vitro cytotoxicity and cell survival assays. The therapeutic effects of LDDS‐administered 5‐FU on false‐negative metastatic LNs were evaluated using bioluminescence imaging, high‐frequency ultrasound (US), and histology in MHX10/Mo‐lpr/lpr mice. These experimental animals develop LNs that are similar in size to human LNs. We found that all cell lines showed sensitivity to 5‐FU in the in vitro assays. Furthermore, a concentration‐dependent effect of 5‐FU to inhibit tumor growth was observed in tumor cells with low invasive growth characteristics, although a significant reduction in metastatic LN volume was not detected in MHX10/Mo‐lpr/lpr mice. Adverse effects of 5‐FU were not detected. 5‐Fluorouracil administration with a LDDS is an effective treatment method for false‐negative metastatic LNs. We anticipate that the delivery of anticancer drugs by a LDDS will be of great benefit in the prevention and treatment of cancer metastasis via LNs.

Lymph node resection induces the activation of tumor cells in the lungs

Lymph node (LN) dissection is a crucial procedure for cancer staging, diagnosis and treatment, and for predicting patient survival. Activation of lung metastatic lesions after LN dissection has been described for head and neck cancer and breast cancer. Preclinical studies have reported that dissection of a tumor‐bearing LN is involved in the activation and rapid growth of latent tumor metastases in distant organs, but it is also important to understand how normal (non‐tumor‐bearing) LN resection influences secondary cancer formation. Here, we describe how the resection of tumor‐bearing and non‐tumor‐bearing LN affects distant metastases in MXH10/Mo‐lpr/lpr mice. Tumor cells were administered intravenously and/or intranodally into the right subiliac lymph node (SiLN) to create a mouse model of lung metastasis. Luciferase imaging revealed that tumor cells in the lung were activated after resection of the SiLN, irrespective of whether it contained tumor cells. No luciferase activity was detected in the lungs of mice that did not undergo LN resection (excluding the intravenous inoculation group). Our results indicate that resection of an LN can activate distant metastases regardless of whether the LN contains tumor cells. Hence, lung metastatic lesions are suppressed while metastatic LN are present but activated after LN resection. If this phenomenon occurs in patients with cancer, it is likely that lung metastatic lesions may be activated by elective LN dissection in clinical N0 cases. The development of minimally invasive cancer therapy without surgery would help to minimize the risk of activation of distant metastatic lesions by LN resection.

Sentinel Lymph Node Characterization with a Dual-Targeted Molecular Ultrasound Contrast Agent

PURPOSE

The purpose of this study was to assess the performance of molecular ultrasound with dual-targeted microbubbles to detect metastatic disease in the sentinel lymph nodes (SLNs) in swine model of naturally occurring melanoma. The SLN is the first lymph node in the lymphatic chain draining primary tumor, and early detection of metastatic SLN involvement is critical in the appropriate management of melanoma.

PROCEDURE

Nine Sinclair swine (weight 3-7 kg; Sinclair BioResources, Columbia, MO, USA) with naturally occurring melanoma were examined. Siemens S3000 scanner with a 9L4 probe was used for imaging (Siemens Healthineers, Mountain View, CA). Dual-targeted contrast agent was created using Targestar SA microbubbles (Targeson, San Diego, CA, USA) labeled with α_νβ₃-integrin and P-selectin antibodies. Targestar SA microbubbles labeled with IgG-labeled were used as control. First, peritumoral injection of Sonazoid contrast agent (GE Healthcare, Oslo, Norway) was performed to detect SLNs. After that, dual-targeted and IGG control Targestar SA microbubbles were injected intravenously with a 30-min interval between injections. Labeled Targestar SA microbubbles were allowed to circulate for 4 min to enable binding. After that, two sets of image clips were acquired several seconds before and after a high-power destruction sequence. The mean intensity difference pre- to post-bubble destruction within the region of interest placed over SLN was calculated as a relative measure of targeted microbubble contrast agent retention. This process was repeated for non-SLNs as controls. All lymph nodes evaluated on imaging were surgically removed and histologically examined for presence of metastatic involvement.

RESULTS

A total of 43 lymph nodes (25 SLNs and 18 non-SLNs) were included in the analysis with 18 SLNs demonstrating metastatic involvement greater than 5 % on histology. All non-SLNs were benign. The mean intensity (± SD) of the dual-targeted microbubbles for metastatic SLNs was significantly higher than that of benign LNs (18.05 ± 19.11 vs. 3.30 ± 6.65 AU; p = 0.0008), while IgG-labeled control microbubbles demonstrated no difference in retained contrast intensity between metastatic and benign lymph nodes (0.39 ± 1.14 vs. 0.03 ± 0.24 AU; p = 0.14).

CONCLUSIONS

The results indicate that dual-targeted microbubbles labeled with P-selectin and α_νβ₃-integrin antibodies may aid in detecting metastatic involvement in SLNs of melanoma.

Perfusion contrast-enhanced ultrasound to predict early lymph-node metastasis in breast cancer

PURPOSE

To evaluate whether quantitative analysis of perfusion contrast-enhanced ultrasound (CE-US) could predict early lymph-node (LN) metastasis in clinically node-negative breast cancer.

MATERIALS AND METHODS

In this prospective study, 64 breast cancer patients were selected for perfusion CE-US imaging. Regions of interest were placed where the strongest and weakest signal increases were found to obtain peak intensities (PIs; PI_max and PI_min, respectively) for time-intensity curve analyzes. The PI difference and PI ratio were calculated as follows: PI difference = PI_max-PI_min; PI ratio = PI_max/PI_min.

RESULTS

Forty-seven cases were histologically diagnosed as negative for LN metastasis and 17 were positive. There was a significant difference in PI_min and the PI ratio between the LN-negative and -positive metastasis groups (p = 0.0053 and 0.0082, respectively). Receiver-operating curve analysis revealed that the area under the curve of PI_min and the PI ratio were 0.73 and 0.72, respectively. The most effective threshold for the PI ratio was 1.52, and the sensitivity, specificity, positive predictive value, and negative predictive value were 59% (10/17), 87% (41/47), 63% (10/16), and 85% (41/48), respectively.

CONCLUSIONS

Parameters from the quantitative analysis of perfusion CE-US imaging showed significant differences between the LN-negative and -positive metastasis groups in clinically node-negative breast cancer.

Superselective Drug Delivery Using Doxorubicin-Encapsulated Liposomes and Ultrasound in a Mouse Model of Lung Metastasis Activation

Conventional treatment of lymph node metastasis involves dissection of the tumor and regional lymph nodes, but this may cause activation of latent metastatic tumor cells. However, there are few reports on animal models regarding the activation of latent metastatic tumor cells and effective methods of treating activated tumor cells. Here, we report the use of a superselective drug delivery system in a mouse model of lung metastasis in which activated tumor cells are treated with doxorubicin-encapsulated liposomes (DOX-LP) and ultrasound. The axillary lymph node was injected with DOX-LP and exposed to ultrasound so that the released DOX would be delivered from the axillary lymph node to the metastatic lung via the subclavian vein, heart and pulmonary artery. The size of the DOX-LP was optimized to a diameter of 460 nm using indocyanine green-encapsulated liposomes, and the ultrasound intensity was 0.5 W/cm². We found that compared with DOX or DOX-LP alone, the superselective drug delivery system was effective in the treatment of metastasis in both the lung and axillary lymph node. We anticipate that this superselective drug delivery system will be a starting point for the development of new techniques for treating lung metastasis in the clinical setting. Furthermore, the superselective drug delivery system may be used to screen novel drugs for the treatment of lung cancer and investigate the mechanisms of tumor cell activation after resection of a primary tumor or lymph nodes.

Evaluation of metastatic niches in distant organs after surgical removal of tumor-bearing lymph nodes

Background

Surgical removal of primary tumors can promote the incidence of tumor metastasis. However, molecular mechanisms underlying this process remain unclear.

Methods

We inoculated tumor cells expressing luciferase gene  into subiliac lymph node (SiLN) of the MXH10/Mo-lpr/lpr mice. The tumor-bearing SiLNs were surgically removed at a certain period of time after inoculation.

Results

In vivo bioluminescence imaging system and histological staining revealed metastasis in lung, proper axillary lymph node (PALN) and liver. The lung metastasis rate in SiLN removal groups was significantly higher than in the control group using Fisher exact test. Mann-Whitney U-test indicated that the luciferase-positive tumor cells in the lung and liver were significantly higher than in the control groups. The lung samples in SiLN removal groups had strong expression of lysine oxidase (LOX). Moreover, the number of CD11b⁺ cells in the lung and liver in the SiLN removal groups was significantly increased, which was positively correlated with LOX expression level. In addition, the condition of LOX and CD11b in liver was similar to lung. In the SiLN surgical removal groups, the matrix metalloproteinase (MMP)-2 and VEGFA expression in the lung tissues was significantly higher than in the control groups; the collagen fibers per area around the pulmonary vessels was quite significantly lower and negatively correlated with the expression of MMP-2 by Spearman’s analysis. Our data indicated that the reticular fibers were deposited and disordered in the tumor tissues of the lungs in the removal groups, and the reticular fibers per area was higher than in the control groups. The tumor cells in the PALN of control groups were significantly higher than in the SiLN removal groups, and CD169⁺ and CD11c⁺ cells were also higher than in the SiLN removal groups.

Conclusions

Altogether, surgical removal of the tumor-bearing lymph node promoted tumor metastasis through changing the niche in lung and liver. Treatment targeting the metastatic niche might be an effective strategy to prevent tumor metastasis, thereby possibly increasing the survival and reducing the incidence of metastasis in cancer patients.

Association between contrast-enhanced ultrasonography and histopathological findings of the metastatic lymph nodes of patients with head and neck cancer: A preliminary study

The present study aimed to investigate the usefulness of contrast-enhanced ultrasonography (CEUS) and a newly developed analysis software for the detection of microcapillary network distribution in lymph nodes of patients with head and neck cancer (HNC) by comparing the CEUS and histopathological findings. Patients that were diagnosed with HNC between February and September 2016 were enrolled. A total of five patients underwent resection of the primary tumor and neck dissection as their initial treatment. The cervical lymph nodes of these patients were analyzed by CEUS intraoperatively, and their surgical specimens were examined histopathologically. The patients were diagnosed using a combination of physical examination, computed tomography, magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography. For CEUS examination, the microbubble contrast agent Sonazoid™ was injected into a peripheral vein. Video images of the metastatic lymph nodes were captured, and these were subjected to analysis by a newly developed image-analysis software. It was possible to perform intraoperative CEUS of metastatic lymph nodes and obtain accurate matched sections for histopathological examination. Hematoxylin and eosin and cluster of differentiation (CD)34 staining revealed that the software was able to accurately detect capillary vessels in metastatic lymph nodes. However, a number of perfusion deficits were observed in these lymph nodes. In conclusion, by using CEUS with the analysis software, the density and distribution of blood vessels in the metastatic lymph nodes of patients with HNC was revealed. Although the present study was limited and preliminary, it was concluded that this method may be useful to evaluate and to map the capillary vessels in the metastatic lymph nodes of patients with HNC.

A cerebellar window for intravital imaging of normal and disease states in mice

The cerebellum is a prominent part of the vertebrate hindbrain that is critically involved in the regulation of important body functions such as movement coordination, maintenance of balance and posture, and motor control. Here, we describe a cerebellar window that provides access to the mouse cerebellum for intravital imaging, thereby allowing for a detailed characterization of the dynamic processes in this region of the brain. First, the skull overlying the cerebellum is removed, and then the window is applied to the region of interest. Windows may be exchanged depending on the desired imaging modality. This technique has a variety of applications. In the setting of medulloblastoma, spontaneous or orthotopically implanted lesions can be imaged, and tumor morphology and size can be monitored using ultrasonography. Multiphoton laser-scanning microscopy (MPLSM) or optical-frequency-domain imaging (OFDI) can be applied for in vivo visualization and analysis of cellular and vascular structures in a variety of disease states, including malignancies and ataxia telangiectasia. This protocol describes a novel and rapid method for cerebellar window construction that can be set up in under an hour.

Therapeutic effect of cisplatin given with a lymphatic drug delivery system on false-negative metastatic lymph nodes

Systemic administration of drugs into the blood circulation is standard treatment for prevention of metastasis. However, systemic delivery cannot maintain sufficiently high concentrations of anticancer drugs in lymph nodes (LN). Here, we show that giving cisplatin (CDDP) using a lymphatic drug delivery system (LDDS) has the potential to treat false-negative metastatic LN. We found that in MXH10/Mo-lpr/lpr mice, which develop systemic swelling of LN up to 10 mm in diameter, accumulation of indocyanine green (ICG), which has a similar molecular weight to CDDP, in a target LN was greater for lymphatic delivery of ICG than for systemic (i.v.) administration. Furthermore, CDDP administration with a LDDS inhibited tumor growth in false-negative metastatic LN and produced fewer adverse effects than systemically given CDDP. We anticipate that drug delivery using a LDDS will, in time, replace systemic chemotherapy for the treatment of false-negative metastatic LN.

Evaluation of the enhanced permeability and retention effect in the early stages of lymph node metastasis

Most solid cancers spread to new sites via the lymphatics before hematogenous dissemination. However, only a small fraction of an intravenously administered anti‐cancer drug enters the lymphatic system to reach metastatic lymph nodes (LN). Here, we show that the enhanced permeability and retention (EPR) effect is not induced during the early stages of LN metastasis. Luciferase‐expressing tumor cells were injected into the subiliac LN of the MXH10/Mo‐lpr/lpr mouse to induce metastasis to the proper axillary LN (PALN). In vivo biofluorescence imaging was used to confirm metastasis induction and to quantify the EPR effect, measured as PALN accumulation of intravenously injected indocyanine green (ICG) liposomes. PALN blood vessel volume changes were measured by contrast‐enhanced high‐frequency ultrasound imaging. The volume and density of blood vessels in the PALN increased until day 29 after inoculation, whereas the LN volume remained constant. ICG retention was first detected on day 29 post‐inoculation. While CD31‐positive cells increased up to day 29 post‐inoculation, α‐smooth muscle actin‐positive cells were detected on day 29 post‐inoculation for the first time. These results suggest that the EPR effect was not induced in the early stages of LN metastasis; therefore, systemic chemotherapy would likely not be beneficial during the early stages of LN metastasis. The development of an alternative drug delivery system, independent of the EPR effect, is required for the treatment of LN metastasis.

A novel treatment for metastatic lymph nodes using lymphatic delivery and photothermal therapy

Systemic delivery of an anti-cancer agent often leads to only a small fraction of the administered dose accumulating in target sites. Delivering anti-cancer agents through the lymphatic network can achieve more efficient drug delivery for the treatment of lymph node metastasis. We show for the first time that polymeric gold nanorods (PAuNRs) can be delivered efficiently from an accessory axillary lymph node to a tumor-containing proper axillary lymph node, enabling effective treatment of lymph node metastasis. In a mouse model of metastasis, lymphatic spread of tumor was inhibited by lymphatic-delivered PAuNRs and near-infrared laser irradiation, with the skin temperature controlled by cooling. Unlike intravenous injection, lymphatic injection delivered PAuNRs at a high concentration within a short period. The results show that lymphatic administration has the potential to deliver anti-cancer agents to metastatic lymph nodes for inhibition of tumor growth and could be developed into a new therapeutic method.

Quantitative Analysis of Contrast-Enhanced Ultrasound Imaging in Invasive Breast Cancer: A Novel Technique to Obtain Histopathologic Information of Microvessel Density

We examined whether enhancement area ratios obtained by the new bubble detection method correlate with histologic microvessel density in invasive breast cancer. Forty consecutive patients with invasive breast cancer lesions underwent contrast-enhanced ultrasound. The ratio of enhanced area to manually segmented tumor area (enhancement area ratio) was obtained with the new method at peak and delayed phases (50-54, 55-59, 60-64 and 65-69 s). We also analyzed time-intensity curves to obtain peak intensity and area under curve. Enhancement area ratios in both peak and delayed phases (50-54, 55-59, 60-64 and 65-69 s) were significantly correlated with microvessel density (r = 0.57, 0.62, 0.68, 0.61 and 0.58; p = 0.0001, <0.0001, <.0001, <.0001 and 0.0001, respectively). In time-intensity curve analysis, peak intensity was significantly correlated (r = 0.43, p = 0.0073), whereas area under the curve was not (r = 0.29, p = 0.0769). Enhancement area ratios obtained by the new method were correlated with microvessel density in invasive breast cancer.

Monitoring of Blood Vessel Density Using Contrast-Enhanced High Frequency Ultrasound May Facilitate Early Diagnosis of Lymph Node Metastasis

Time-dependent alterations in the ultrasonography characteristics of lymph nodes during early-stage metastasis have not been compared with those of tumor-draining lymph nodes that do not develop tumor; this is partly due to the absence of an appropriate experimental model. In a previous study of lymph nodes with experimental early-stage metastasis, we used contrast-enhanced high-frequency ultrasound to demonstrate that an increase in lymph node blood vessel density preceded any changes in lymph node volume. In the present study, we used an experimental model of lymph node metastasis in which tumor cells metastasized from the subiliac lymph node to the proper axillary lymph node (the tumor-draining lymph node). We utilized contrast-enhanced high-frequency ultrasound to perform a longitudinal analysis of tumor-draining lymph nodes, comparing those at an early-stage of metastasis with those that did not develop detectable metastasis. We found that the normalized blood vessel density of an early-stage metastatic lymph node exhibited a progressive rise, whereas that of a tumor-draining lymph node not containing tumor began to increase later. For both types of lymph nodes, the normalized blood vessel density on the final day of experiments showed a trend towards being higher than that measured in controls. We further found that mice with an initially low value for lymph node blood vessel density subsequently showed a larger increase in the blood vessel density of the metastatic lymph node; this differed significantly from measurements in controls. The present study indicates that a longitudinal analysis of the blood vessel densities of tumor-draining lymph nodes, made using contrast-enhanced high-frequency ultrasound imaging, may be a potentially promising method for detecting early-stage lymph node metastasis in selected patients. Furthermore, our findings suggest that tumor in an upstream lymph node may induce alteration of the vascular structures in draining lymph nodes that do not contain tumor.

Study of fluid dynamics reveals direct communications between lymphatic vessels and venous blood vessels at lymph nodes of mice

Cancer cells metastasize to lymph nodes, with distant metastasis resulting in poor prognosis. The role of lymph node metastasis (LNM) in the spread of cancer to distant organs remain incompletely characterized. The visualization of flow dynamics in the lymphatic and blood vessels of MXH10/Mo-lpr/lpr mice, which develop systemic swelling of lymph nodes up to 10mm in diameter, has revealed that lymph nodes have the potential to be a direct source of systemic metastasis. However, it is not known whether these fluid dynamics characteristics are universal phenomena present in other strains of laboratory mice. Here we show that the fluid dynamics observed in MXH10/Mo-lpr/lpr mice are the same as those observed in C57BL/6J, BALB/cAJcl and NOD/ShiJic-scidJcl mice. Furthermore, when fluorescent solution was injected into a tumor-bearing lymph node, the flow dynamics observed in the efferent lymphatic vessels and thoracoepigastric vein depended on the type of tumor cell. Our results indicate that fluid dynamics in the lymphatic and blood vessels of MXH10/Mo-lpr/lpr mice are generalized phenomena seen in conventional laboratory mice. We anticipate our results can facilitate studies of the progression of lymphatic metastasis to hematogenous metastasis via lymph nodes and the early diagnosis and treatment of LNM.

Role of contrast-enhanced endoscopic ultrasound in lymph nodes

Diagnosing unclear lymph node (LN) enlargements in the mediastinum and abdomen is the most important indication of endoscopic ultrasound (EUS)-fine needle aspiration (FNA) after the diagnosis and treatment of pancreatic diseases. Investigating LNs in these areas can happen in different clinical settings. Mostly, it is the first modality in general LN diseases without any peripheral LN enlargements. On the other hand, it can be the question of LN involvement in a known or suspected primary tumor. Due to EUS-FNA cytology, those questions can be answered highly, accurately. However, a primary discrimination of LNs might be helpful to increase the diagnostic value of the FNA cytology, especially in cases with multiple LN enlargements and hard to reach enlarged LNs for example by vessel interposition. Because of the unreliability of B-mode criteria, further diagnostic improvements such as elastography and contrast-enhanced EUS are investigated to increase the accuracy of the initial diagnosis.

Clustering Tree-Structured Data on Manifold

Tree-structured data usually contain both topological and geometrical information, and are necessarily considered on manifold instead of euclidean space for appropriate data parameterization and analysis. In this study, we propose a novel tree-structured data parameterization, called Topology-Attribute matrix (T-A matrix), so the data clustering task can be conducted on matrix manifold. We incorporate the structure constraints embedded in data into the non-negative matrix factorization method to determine meta-trees from the T-A matrix, and the signature vector of each single tree can then be extracted by meta-tree decomposition. The meta-tree space turns out to be a cone space, in which we explore the distance metric and implement the clustering algorithm based on the concepts like Fréchet mean. Finally, the T-A matrix based clustering (TAMBAC) framework is evaluated and compared using both simulated data and real retinal images to illustrate its efficiency and accuracy.

Meta analysis of lymph node metastasis of breast cancer patients: Clinical value of DWI and ADC value

OBJECTIVES

To evaluate the diagnostic utility of DWI in the assessment of node metastases and investigate whether the ADC value could be used to discriminate between metastatic and non-metastatic lymph nodes in breast cancer patients.

MATERIALS AND METHODS

13 studies with a total of 676 metastatic and 811 non-metastatic lymph nodes were included.

RESULTS

(1) The pooled sensitivity, specificity, PPV and NPV of DWI were 0.83, 0.82, 0.83 and 0.85, respectively. The PLR and NLR were 4.95 and 0.23, respectively. The AUC and Q* index were 0.91 and 0.85, respectively. (2) The ADC value of metastatic lymph nodes was lower than non-metastatic lymph nodes (WMD=-0.213, 95% CI -0.349 to -0.076, Z=3.05, P<0.05). (3) Subgroup meta-analysis of the group of b(0800): The pooled sensitivity, specificity, PPV and NPV of DWI were 0.86, 0.86, 0.82 and 0.90, respectively. The PLR and NLR were 6.76 and 0.18, respectively. The AUC and Q* index were 0.93 and 0.87. The ADC value of metastatic lymph nodes was lower than non-metastatic lymph nodes(WMD=-0.267, 95% CI -0.348 to -0.185, Z=6.40, P<0.05).

CONCLUSIONS

DWI and ADC value appear to be a reliable method to differentiate metastatic and non-metastatic lymph nodes. The combination of b=0 and 800s/mm(2) resulted in higher diagnostic accuracy and more pronounced ADC value difference. If only a couple of b values are used, those of b=0 and 800s/mm(2) are recommended.

Early diagnosis of lymph node metastasis: Importance of intranodal pressures

Regional lymph node status is an important prognostic indicator of tumor aggressiveness. However, early diagnosis of metastasis using intranodal pressure, at a stage when lymph node size has not changed significantly, has not been investigated. Here, we use an MXH10/Mo-lpr/lpr mouse model of lymph node metastasis to show that intranodal pressure increases in both the subiliac lymph node and proper axillary lymph node, which are connected by lymphatic vessels, when tumor cells are injected into the subiliac lymph node to induce metastasis to the proper axillary lymph node. We found that intranodal pressure in the subiliac lymph node increased at the stage when metastasis was detected by in vivo bioluminescence, but when proper axillary lymph node volume (measured by high-frequency ultrasound imaging) had not increased significantly. Intravenously injected liposomes, encapsulating indocyanine green, were detected in solid tumors by in vivo bioluminescence, but not in the proper axillary lymph node. Basic blood vessel and lymphatic channel structures were maintained in the proper axillary lymph node, although sinus histiocytosis was detected. These results show that intranodal pressure in the proper axillary lymph node increases at early stages when metastatic tumor cells have not fully proliferated. Intranodal pressure may be a useful parameter for facilitating early diagnosis of lymph node metastasis.

High-Accuracy Ultrasound Contrast Agent Detection Method for Diagnostic Ultrasound Imaging Systems

An accurate method for detecting contrast agents using diagnostic ultrasound imaging systems is proposed. Contrast agents, such as microbubbles, passing through a blood vessel during ultrasound imaging are detected as blinking signals in the temporal axis, because their intensity value is constantly in motion. Ultrasound contrast agents are detected by evaluating the intensity variation of a pixel in the temporal axis. Conventional methods are based on simple subtraction of ultrasound images to detect ultrasound contrast agents. Even if the subject moves only slightly, a conventional detection method will introduce significant error. In contrast, the proposed technique employs spatiotemporal analysis of the pixel intensity variation over several frames. Experiments visualizing blood vessels in the mouse tail illustrated that the proposed method performs efficiently compared with conventional approaches. We also report that the new technique is useful for observing temporal changes in microvessel density in subiliac lymph nodes containing tumors. The results are compared with those of contrast-enhanced computed tomography.

Organ-wide 3D-imaging and topological analysis of the continuous microvascular network in a murine lymph node

Understanding of the microvasculature has previously been limited by the lack of methods capable of capturing and modelling complete vascular networks. We used novel imaging and computational techniques to establish the topology of the entire blood vessel network of a murine lymph node, combining 63,706 confocal images at 2 μm pixel resolution to cover a volume of 3.88 mm(3). Detailed measurements including the distribution of vessel diameters, branch counts, and identification of voids were subsequently re-visualised in 3D revealing regional specialisation within the network. By focussing on critical immune microenvironments we quantified differences in their vascular topology. We further developed a morphology-based approach to identify High Endothelial Venules, key sites for lymphocyte extravasation. These data represent a comprehensive and continuous blood vessel network of an entire organ and provide benchmark measurements that will inform modelling of blood vessel networks as well as enable comparison of vascular topology in different organs.

A Novel Treatment Method for Lymph Node Metastasis Using a Lymphatic Drug Delivery System with Nano/Microbubbles and Ultrasound

Chemotherapy based on hematogenous administration of drugs to lymph nodes (LNs) located outside the surgically resected area shows limited tissue selectivity and inadequate response rates, resulting in poor prognosis. Here, we demonstrate proof of concept for a lymphatic drug delivery system using nano/microbubbles (NMBs) and ultrasound (US) to achieve sonoporation in LNs located outside the dissection area. First, we demonstrated the in vitro effectiveness of doxorubicin (Dox) delivered into three different tumor cell lines by sonoporation. Sonoporation increased the Dox autofluorescence signal and resulted in a subsequent decrease in cell viability. Next, we verified the antitumor effects of Dox in vivo using MXH10/Mo-lpr/lpr mice that exhibit systemic lymphadenopathy, with some peripheral LNs reaching 10 mm in diameter. We defined the subiliac LN (SiLN) as the upstream LN within the dissection area, and the proper axillary LN (PALN) as the downstream LN outside the dissection area. Dox and NMBs were injected into the SiLN and delivered to the PALN via lymphatic vessels; the PALN was then exposed to US when it had filled with solution. We found that sonoporation enhanced the intracellular uptake of Dox leading to high cytotoxicity. We also found that sonoporation induced extravasation of Dox from lymphatic endothelia and penetration of Dox into tumor tissues within the PALN. Furthermore, our method inhibited tumor growth and diminished blood vessels in the PALN while avoiding systemic toxic effects of Dox. Our findings indicate that a lymphatic drug delivery system with sonoporation represents a promising method for treating metastatic LNs located outside the dissection area.

Preclinical imaging and translational animal models of cancer for accelerated clinical implementation of nanotechnologies and macromolecular agents

The majority of animal models of cancer have performed poorly in terms of predicting clinical performance of new therapeutics, which are most often first evaluated in patients with advanced, metastatic disease. The development and use of metastatic models of cancer may enhance clinical translatability of preclinical studies focused on the development of nanotechnology-based drug delivery systems and macromolecular therapeutics, potentially accelerating their clinical implementation. It is recognized that the development and use of such models are not without challenge. Preclinical imaging tools offer a solution by allowing temporal and spatial characterization of metastatic lesions. This paper provides a review of imaging methods applicable for evaluation of novel therapeutics in clinically relevant models of advanced cancer. An overview of currently utilized models of oncology in small animals is followed by image-based development and characterization of visceral metastatic cancer models. Examples of imaging tools employed for metastatic lesion detection, evaluation of anti-tumor and anti-metastatic potential and biodistribution of novel therapies, as well as the co-development and/or use of imageable surrogates of response, are also discussed. While the focus is on development of macromolecular and nanotechnology-based therapeutics, examples with small molecules are included in some cases to illustrate concepts and approaches that can be applied in the assessment of nanotechnologies or macromolecules.

Accurate evaluation of axillary sentinel lymph node metastasis using contrast-enhanced ultrasonography with Sonazoid in breast cancer: a preliminary clinical trial

Breast cancer is the most common type of cancer in women. The 5-year survival rate in patients with breast cancer ranges from 74 to 82 %. Sentinel lymph node biopsy has become an alternative to axillary lymph node dissection for nodal staging. We evaluated the detection of the sentinel lymph node and metastasis of the lymph node using contrast enhanced ultrasonography with Sonazoid. Between December 2013 and May 2014, 32 patients with operable breast cancer were enrolled in this study. We evaluated the detection of axillary sentinel lymph nodes and the evaluation of axillary lymph nodes metastasis using contrast enhanced computed tomography, color Doppler ultrasonography and contrast enhanced ultrasonography with Sonazoid. All the sentinel lymph nodes were identified, and the sentinel lymph nodes detected by contrast enhanced ultrasonography with Sonazoid corresponded with those detected by computed tomography lymphography and indigo carmine method. The detection of metastasis based on contrast enhanced computed tomography were sensitivity 20.0 %, specificity 88.2 %, PPV 60.0 %, NPV 55.6 %, accuracy 56.3 %. Based on color Doppler ultrasonography, the results were sensitivity 36.4 %, specificity 95.2 %, PPV 80.0 %, NPV 74.1 %, accuracy 75.0 %. Based on contrast enhanced ultrasonography with Sonazoid, the results were sensitivity 81.8 %, specificity 95.2 %, PPV 90.0 %, NPV 90.9 %, accuracy 90.6 %. The results suggested that contrast enhanced ultrasonography with Sonazoid was the most accurate among the evaluations of these modalities. In the future, we believe that our method would take the place of conventional sentinel lymph node biopsy for an axillary staging method.

Five cases of axillary lymph node metastatic breast cancer on contrast-enhanced sonography

This study was performed to determine the importance of contrast-enhanced sonography for axillary lymph node metastatic breast cancer. Contrast-enhanced sonographic findings in 5 patients with breast cancer and axillary lymph node metastasis are discussed, and imaging-pathologic correlations are also presented in 3 cases. In all 5 cases, lymph nodes showed a perfusion defect in the late phase. Rapid arterial enhancement and wash-out were observed in 2 cases in which we performed second injections. Contrast-enhanced sonography may be effective for identifying metastatic lesions in lymph nodes, especially in the early stages.

Communication between lymphatic and venous systems in mice

The lymphatic system in mice consists of lymphatic vessels and 22 types of lymph nodes. Metastatic tumor cells in the lymphatic system spread to distant organs through the venous system. However, the communication routes between the lymphatic and venous systems have not been fully elucidated. Here, we identify the communication routes between the lymphatic and venous systems in the axillary and subiliac regions of MXH10/Mo-lpr/lpr inbred mice, which develop systemic swelling of lymph nodes up to 10mm in diameter, allowing investigation of the topography of the lymph nodes and lymphatic vessels. Using a gross anatomy dissection approach, the efferent lymphatic vessels of the proper axillary lymph node were shown to communicate with the subclavian vein. Furthermore, we found that the thoracoepigastric vein, which connects the subclavian vein and inferior vena cava, runs adjacent to the subiliac and proper axillary lymph nodes, and receives venous blood from these lymph nodes routed through small branches. The direction of blood flow in the thoracoepigastric vein occurred in two directions in the intermediate region between the proper axillary lymph node and subiliac lymph node; one to the subclavian vein, the other to the inferior vena cava. This paper reveals the anatomy of the communication between the lymphatic and venous systems in the axillary and subiliac regions of the mouse, and provides new insights relevant to the investigation of the mechanisms of lymph node metastasis and cancer immunology, and the development of diagnostic and treatment methods for lymph node metastasis, including drug delivery systems.

Delivery of molecules to the lymph node via lymphatic vessels using ultrasound and nano/microbubbles

Lymph node (LN) dissection is the primary option for head and neck cancer when imaging modalities and biopsy confirm metastasis to the sentinel LN. However, there are no effective alternative treatments to dissection for LN metastasis. Here, we describe a novel drug delivery system combining nano/microbubbles (NMBs) with ultrasound (US) that exhibits considerable potential for the delivery of exogenous molecules into LNs through the lymphatic vessels. A solution containing fluorophores (as a model of a therapeutic molecule) and NMBs was injected into the subiliac LNs of MXH10/Mo-lpr/lpr mice, which develop systemic swelling of LNs (up to 13 mm in diameter, similar to human LNs). It was found that the NMBs were delivered to the entire area of the proper axillary LN (proper-ALN) via the lymphatic channels and that these were retained there for more than 8 min. Furthermore, exposure to US in the presence of NMBs enhanced the delivery of fluorophores into the lymphocytes near the lymphatic channels, compared with exposure to US in the absence of NMBs. It is proposed that a system using US and NMBs to deliver therapeutic drugs via lymphatic vessels can serve as a new treatment method for LN metastasis.

Direct delivery of a cytotoxic anticancer agent into the metastatic lymph node using nano/microbubbles and ultrasound

Direct injection of an anticancer agent into a metastatic lymph node (LN) has not been used as a standard treatment because evidence concerning the efficacy of local administration of a drug into a metastatic LN has not been established. Here we show that the combination of intralymphatic drug delivery with nano/microbubbles (NMBs) and ultrasound has the potential to improve the chemotherapeutic effect. We delivered cis-diamminedichloroplatinum (II) (CDDP) into breast carcinoma cells in vitro and found that apoptotic processes were involved in the antitumor action. Next, we investigated the antitumor effect of intralymphatic chemotherapy with NMBs and ultrasound in an experimental model of LN metastasis using MXH10/Mo-lpr/lpr mice exhibiting lymphadenopathy. The combination of intralymphatic chemotherapy with NMBs and ultrasound has the potential to improve the delivery of CDDP into target LNs without damage to the surrounding normal tissues. The present study indicates that intralymphatic drug delivery with NMBs and ultrasound will potentially be of great benefit in the clinical setting.

Activation of latent metastases in the lung after resection of a metastatic lymph node in a lymph node metastasis mouse model

Iatrogenic induction of regional and distant cancer metastases is a risk associated with clinical resection of tumor-positive sentinel lymph nodes. However, there have been no studies of this risk in a mouse model of cancer metastasis. Here, we report that resection of a tumor-bearing subiliac lymph node (SiLN) enhanced lung metastasis in a mouse model of lymph node metastasis. Bioluminescence imaging revealed that metastatic tumor cells in the secondary lymph node continued to grow after resection of the SiLN, and that the probability of metastasis to the lungs was increased when the interval between SiLN inoculation and resection was reduced. Futhermore, histological analysis demonstrated that latents in the lung were stimulated to grow after resection of the SiLN. Fluorescence imaging indicated that the route of tumor cell dissemination from SiLN to the lung was the venous system located over the SiLN. We speculate that our mouse model will be useful for studying the mechanisms of tumor cell latency, with a view to improving the detection and treatment of latent metastases.

Visualization of fluid drainage pathways in lymphatic vessels and lymph nodes using a mouse model to test a lymphatic drug delivery system

Curing/preventing micrometastasis to lymph nodes (LNs) located outside the surgically resected area is essential for improving the morbidity and mortality associated with breast cancer and head and neck cancer. However, no lymphatic therapy system exists that can deliver drugs to LNs located outside the dissection area. Here, we demonstrate proof of concept for a drug delivery system using MXH10/Mo-lpr/lpr mice that exhibit systemic lymphadenopathy, with some peripheral LNs being as large as 10 mm in diameter. We report that a fluorescent solution injected into the subiliac LN (defined as the upstream LN within the dissection area) was delivered successfully to the proper axillary LN (defined as the downstream LN outside the dissection area) through the lymphatic vessels. Our results suggest that this approach could be used before surgical resection to deliver drugs to downstream LNs outside the dissection area. We anticipate that our methodology could be applied clinically, before surgical resection, to cure/prevent micrometastasis in LNs outside the dissection area, using techniques such as ultrasound-guided internal jugular vein catheterization.

A review of sentinel lymph node biopsy for thin melanoma

INTRODUCTION

Although there is a lack of established survival benefit of sentinel lymph node biopsy (SLNB), this technique has been increasingly applied in the staging of patients with thin (≤1.00 mm) melanoma (T1Nx), without clear supportive evidence.

METHODS

We review the guidelines and available literature on the indications and rationale for performing SLNB in thin melanoma.

RESULTS

As a consequence of the paucity of evidence of SLNB in thin melanoma, there is considerable variability in the guidelines. It is difficult to define clinicopathologic factors that reliably predict the presence of nodal metastasis. SLNB does not yet inform management in thin melanoma to improve survival outcome.

CONCLUSION

Based on available evidence, high risk patients with melanomas between 0.75 and 1.00 mm may be appropriate candidates to be considered for SLN biopsy after discussing the likelihood of finding evidence of nodal progression, the risks of sentinel node biopsy, and the lack of proven survival benefit from any form of surgical nodal staging.

Contrast-enhanced ultrasound (CEUS) facilitated US in detecting lateral neck lymph node metastasis of thyroid cancer patients: diagnosis value and enhancement patterns of malignant lymph nodes

OBJECTIVES

To examine the value of CEUS as a non-invasive tool in detecting lateral neck metastasis (LNM) and the enhancement patterns of malignant lymph nodes (LN) for thyroid cancer patients.

METHODS

Eighty-two consecutive patients, who underwent both preoperative non-enhanced US and CEUS examinations, were retrospectively reviewed. All patients underwent lateral neck dissection (LND). Enhancement patterns of 102 collected LNs matching to CEUS findings were analyzed.

RESULTS

CEUS detected LNM in 53 of 65 patients, showing a higher sensitivity and accuracy than that of conventional US (p = 0.109 and p = 0.154, respectively). Thirteen patients' surgical procedures were altered by CEUS findings, including nine true positive and four false positive cases. Five patients' surgical procedures were altered by conventional US findings, including two true positive and three false positive cases. Heterogeneous enhancement, perfusion defects, microcalcification, and centripetal/hybrid enhancement were all specific criteria for malignant LNs in univariate analysis. In multivariate analysis, only heterogeneous enhancement and centripetal/hybrid enhancement were significantly related to LN metastasis (p = 0.000 and p = 0.037, respectively).

CONCLUSIONS

CEUS may be a potential tool to facilitate conventional US in detecting LNM. Heterogeneous enhancement and centripetal/hybrid enhancement are useful criteria to distinguish between malignant and benign LNs.

KEY POINTS

• CEUS findings facilitated conventional US in detecting LNM. • Heterogeneous, centripetal/hybrid enhancement, microcalcification and perfusion defects were specific criteria of malignant LNs. • Heterogeneous and centripetal/hybrid enhancement were significantly related to LN metastasis in multivariate analysis.