Perfusion defects in non-enlarged metastatic lymph nodes using vessel wall magnetic resonance imaging: Detection performance and diagnostic value

Attenuation Estimation and Acoustic Characterization of Mouse Lymph Node Tumor Using High-frequency Ultrasound

PURPOSE

Lymph node (LN) biopsy is the gold standard for diagnosing metastasis. While ultrasound imaging is a non-invasive method for real-time LN metastasis diagnosis and tumor assessment, its accuracy depends on operator skill and system settings. Quantitative ultrasound can characterize tissue microstructure changes due to tumors, offering operator-independent parameters, and one of the quantitative ultrasound methods, the backscatter coefficient, is necessary to compensate for tissue attenuation. However, the change in the attenuation coefficient (AC) in the tumor growth is uncertain. Using in vivo high-frequency ultrasound (25 MHz) measurement and scanning acoustic microscopy (80 and 300 MHz) for ex vivo samples, we aim to investigate how tumor growth is linked to the attenuation and acoustic properties such as acoustic impedance and speed of sound related to ultrasonic wave propagation.

PROCEDURES

FM3 A-Luc mammary carcinoma cells were inoculated into the subiliac LNs of mice, and tumor progression was monitored over time. Bioluminescence imaging was used to assess tumor growth, while ultrasound measurements focused on estimating AC and other acoustic properties.

RESULTS

Results indicated that the mean of AC decreased, and its standard deviation increased as tumors grew, correlating with bioluminescence intensity. Furthermore, acoustic impedance and speed of sound varied between normal and tumor tissues, revealing differences in tissue microstructure from the histopathological images.

CONCLUSIONS

The finding of a decrease in AC observed with tumor growth may play a crucial role in enhancing the accuracy of quantitative ultrasound on attenuation compensation, potentially improving the differentiation between metastatic and non-metastatic LNs.

Development of an intranodal drug delivery system using a mouse model with lymphadenopathy: novel discoveries and clinical application

INTRODUCTION

The low drug delivery rate of systemic chemotherapy to metastatic lymph nodes (LNs) may be due to tumor growth without tumor neovascularization in the LNs, loss of existing blood vessels and lymph sinuses due to the tumor growth, and increased intranodal pressure. The lymphatic drug delivery system (LDDS) is a method of injecting anticancer drugs directly into the LNs and can overcome these problems. The world's first specific clinical study using the LDDS for head and neck cancer started in 2024 in Japan. In this review, the background of the development of LDDS up to the present clinical trials is described.

AREAS COVERED

The MXH10/Mo-lpr/lpr (MXH10/Mo/lpr) recombinant inbred model mouse, vascular and lymphatic flow through LNs, the clinical N0 (cN0) LN model, preclinical studies of the LDDS, and its clinical application to treat head and neck cancer.

EXPERT OPINION

Conventionally, hematogenous and lymphatic administration have been the focus of attention for drug delivery to LNs. The LDDS is a method for injecting drugs directly to LNs, so it is important to develop a solvent and injecting method that can increase the uniformity of drug distribution within LNs.

The role of magnetic resonance imaging and computed tomography in oral squamous cell carcinoma patients' preoperative staging

INTRODUCTION

The aim of the study was to evaluate the accuracy of MRI and CT with regard to the detection of lymph node metastases based on the data of specific patients with OSCC who received bilateral neck dissection.

MATERIALS AND METHODS

In a retrospective analysis from 01/2014 to 12/2020 patients who underwent primary tumor resection and bilateral neck dissection were evaluated.

RESULTS

174 preoperative MRI (78.74%, N=137) and CT (21.26%, N=37) were correlated with the histopathological findings. CT had a sensitivity of 67% and specificity of 68% (p=0.76). MRI showed an overall sensitivity of 66% and a specificity of 68% (p=0.76). In 52.87% of all cases no differences between cN and pN were found. MRI is the method to overestimate lymph node involvement compared to CT (overestimation in 27% vs. 21.62%).

CONCLUSION

The current data indicate that MR and CT show poor efficacy in the detection of cervical metastases. Accordingly, attention must be paid to alternatives to correct local staging modalities. The application of structured bilateral neck dissection needs to be questioned.

Combination therapy of lymphatic drug delivery and total body irradiation in a metastatic lymph node and lung mouse model

Chemotherapy using a lymphatic drug delivery system (LDDS) targeting lymph nodes (LNs) in the early stage of metastasis has a superior antitumor effect to systemic chemotherapy. An LDDS produces a higher drug retention rate and tissue selectivity in LNs. To expand the therapeutic coverage of LDDS from local treatment of metastatic LNs to prevention of distant metastases, the combination of treatment with therapies that enhance systemic tumor immune effects is an important therapeutic strategy. Recently, total body irradiation (TBI) has been shown to activate immune responses and alter the tumor microenvironment. Here we show that combination therapy with TBI and LDDS improves the antitumor effect of metastatic LNs and lung metastasis. Tumor cells were inoculated into the subiliac LN (SiLN) to induce metastasis into the proper axillary LN (PALN) and lung in a mouse model. TBI was carried out on day 4 after inoculation using a gamma irradiator. Lymphatic drug delivery into the accessory axillary LN was used to treat PALN. In vivo bioluminescence imaging, high-frequency ultrasound, and histology showed that combination therapy using TBI (total dose 1.0 Gy once) and the LDDS suppressed tumor growth in LNs and lung metastases and was more effective than using LDDS or TBI alone. Quantitative RT-PCR of spleens after combination therapy revealed increased expression of CD4, CD8, and IL-12b, indicating an activated immune response. The results show that combination therapy with TBI and LDDS is a method to improve the efficacy of LN metastases and distant metastases therapy and is a promising novel approach to treat cancer patients.