The Role of Lymphatic Mapping and Sentinel Lymph Node Biopsy in the Staging and Treatment of Melanoma

A TMVP1-modified near-infrared nanoprobe: molecular imaging for tumor metastasis in sentinel lymph node and targeted enhanced photothermal therapy

BACKGROUND

TMVP1 is a novel tumor targeting polypeptide screened by our laboratory with a core sequence of five amino acids LARGR. It specially binds to vascular endothelial growth factor receptor-3 (VEGFR-3), which is mainly expressed on neo-lymphatic vessels in sentinel lymph node (SLN) with tumor metastasis in adults. Here, we prepared a targeted nanoprobe using TMVP1-modified nanomaterials for tumor metastasis SLN imaging.

RESULTS

In this study, TMVP1-modified polymer nanomaterials were loaded with the near-infrared (NIR) fluorescent dye, indocyanine green (ICG), to prepare a molecular imaging TMVP1-ICG nanoparticles (NPs) to identify tumor metastasis in SLN at molecular level. TMVP1-ICG-NPs were successfully prepared using the nano-precipitation method. The particle diameter, morphology, drug encapsulation efficiency, UV absorption spectrum, cytotoxicity, safety, and pharmacokinetic properties were determined. The TMVP1-ICG-NPs had a diameter of approximately 130 nm and an ICG loading rate of 70%. In vitro cell experiments and in vivo mouse experiments confirmed that TMVP1-ICG-NPs have good targeting ability to tumors in situ and to SLN with tumor metastasis by binding to VEGFR-3. Effective photothermal therapy (PTT) with TMVP1-ICG-NPs was confirmed in vitro and in vivo. As expected, TMVP1-ICG-NPs improved ICG blood stability, targeted tumor metastasis to SLN, and enhanced PTT/photodynamic (PDT) therapy, without obvious cytotoxicity, making it a promising theranostic nanomedicine.

CONCLUSION

TMVP1-ICG-NPs identified SLN with tumor metastasis and were used to perform imaging-guided PTT, which makes it a promising strategy for providing real-time NIR fluorescence imaging and intraoperative PTT for patients with SLN metastasis.

Development and characterization of an all-in-one gamma probe with auto-peak detection for sentinel lymph node biopsy based on NEMA NU3-2004 standard

Background

A gamma probe is a handheld device used for intraoperative interventions following interstitial injection of a radiotracer to locate regional lymph nodes through the external detection of radiation. This work reports on the design and performance evaluation of a novel fully integrated gamma probe (GammaPen), recently developed by our group.

Materials and methods

GammaPen is an all-in-one pocket gamma probe with low weight and adequate dimensions, consisting of a detector, a control unit and output all together. The detector module consists of a cylindrical Thallium-activated Cesium Iodide [CsI (Tl)] crystal optically coupled to a Silicon photomultiplier (SiPM), shielded using Tungsten housing on side and back faces. The electronics of the probe consists of two small boards to handle signal processing and analog peak detection tasks. A number of parameters, including probe sensitivity in air/water, spatial resolution in air/water, angular resolution in air/water, and side and back shielding effectiveness, were measured to evaluate the performance of the probe based on NEMA NU3-2004 standards.

Results

The sensitivity of the probe in air at distances of 10, 30, and 50 mm is 18784, 3500, and 1575 cps/MBq. The sensitivity in scattering medium was also measured at distances of 10, 30, and 50 mm as 17,680, 3050, and 1104 cps/MBq. The spatial and angular resolutions in scattering medium were 47 mm and 87 degree at 30 mm distance from the probe, while they were 40 mm and 77 degree in air. The detector shielding effectiveness and leakage sensitivity are 99.91% and 0.09%, respectively.

Conclusion

The performance characterization showed that GammaPen can be used effectively for sentinel lymph node localization. The probe was successfully used in several surgical interventions by an experienced surgeon confirming its suitability in a clinical setting.

Sentinel lymph node biopsy for melanoma: is there a correlation of preoperative lymphatic mapping with sentinel lymph nodes harvested?

BACKGROUND

Nodal status is the most significant prognostic factor in melanoma. No study has examined the relationship between lymphoscintigraphy, γ probe counts, harvested nodes, and nodal status.

METHODS

Two-hundred sixty two patients were identified who underwent sentinel lymph node biopsy for melanoma between 2001 and 2010. Clinicopathologic and treatment information was collected. The number of lymph nodes and basins demonstrated on lymphoscintigraphy was compared to those at surgery. γ Probe counts were compared.

RESULTS

Median age was 54.5 years (range, 18-90 years) with 52.3% male. Average Breslow depth was 2.0 (1.9) mm; 99.6% of lymphoscintigraphy studies identified at least 1 basin, 80% showed only 1 (range, 0-4). Lymphoscintigraphy identified on average 1.5 (0.9) sentinel nodes and 31% with secondary node. Surgery excised on average 2.6 (1.4) nodes involving 1.2 (0.5) basins; 17.6% had a positive sentinel lymph node. There was no difference in the sum or average of γ counts between positive and negative sentinel lymph node groups (P = 0.2, P = 0.5). When comparing lymphoscintigraphy and surgical excision, the correlation of lymphatic basins was r = 0.67 and of lymph node numbers was r = 0.33.

CONCLUSIONS

Lymphoscintigraphy should be used to identify the proper lymphatic basins for a sentinel node procedure, however, the removal of nodes must continue until the background count is less than 10%. The correlation of lymph node number identified on lymphoscintigraphy to surgical excision is weak. γ Probe counts cannot be used to differentiate positive from negative nodes and the positive lymph node is not always the hottest node.

Managing malignant melanoma

The incidence of melanoma is increasing worldwide. Melanomas represent 3 percent of all skin cancers but 65 percent of skin cancer deaths. Melanoma is now the fifth most common cancer diagnosed in the United States. Excisional biopsy should be performed for lesions suspicious for melanoma. The pathologist's report provides essential information for surgical treatment; the most important information is the Breslow depth of the lesion. In addition to wide surgical excision of the primary lesion, sentinel lymph node biopsy is the standard of care for early identification of regional metastasis. Nodal metastasis found in the sentinel lymph node biopsy should be followed with a complete lymph node dissection. Although surgery remains the primary treatment of melanoma, recent advances in chemotherapy may offer further survival benefits to patients with metastatic disease.

The role of elective supraomohyoidal neck dissection in the treatment of early, node-negative oral squamous cell carcinoma (OSCC): a retrospective analysis of 122 cases

The adequate treatment of the neck in early, clinically node-negative oral squamous cell carcinoma (OSCC) remains controversial. To assess whether elective supraomohyoid neck dissection is reasonable and efficient in early, locally circumscribed OSCC, the outcomes of treatment of 122 patients with an OSCC of clinical UICC stage I or II were retrospectively analysed in this study. Occult lymph node metastases were detected in 13.9% (17/122) of cases. They were more frequently found in T2 compared to T1 tumours (19.7% (14/71) vs. 5.9% (3/51), p=0.03), age, gender and grading had no influence on the prevalence of occult lymph node metastases (all p-values>0.05) in a multivariate logistic regression model. Subsequent multivariate survival analysis found that the presence of occult metastases was an independent predictor of reduced disease-free survival after 5 years (82.2% vs. 62.5%, p=0.004, and 61.9% vs. 17.8%, p<0.001, respectively). Elective supraomohyoid neck dissection detects occult metastases in early, node-negative OSCC, and patients with early OSCC exhibiting occult metastases should be considered as high risk patients, warranting additional therapeutic regimes.

Lymphatic mapping and sentinel lymphadenectomy in primary cutaneous melanoma

The management of clinically normal regional lymph nodes in early-stage melanoma has been controversial for over a century. Lymphatic mapping and sentinel lymphadenectomy (LM/SL) has been developed as a minimally invasive surgical technique to stage the regional lymph nodes without the associated morbidity of elective complete lymph node dissection. Multiple retrospective studies have validated the accuracy of LM/SL and the importance of the sentinel nodes as a staging tool for melanoma. Two multicenter, prospective, randomized trials have been performed to validate the data from the Phase II studies and determine if a therapeutic benefit exists for LM/SL.