Pathobiology of the sentinel node

Bilateral medial iliac lymph node excision by a ventral laparoscopic approach: technique description

The aim of this study was to describe a ventral laparoscopic technique for bilateral medial iliac lymphadenectomy in dogs. Twelve intact male purpose-bred research dogs, weighing less than 15 kg, were positioned in dorsal recumbency, and a 3-portal technique was used. Bilateral dissection was performed with vessel-sealing devices while tilting the surgical table by up to 30° towards the contralateral side of the target medial iliac lymph node (MILN) without changing the surgeon’s position. Using a ventral laparoscopic approach, bilateral MILNs were identified and excised in all dogs. The mean times for unilateral and bilateral MILN dissections were 9.7 ± 3.8 and 21.0 ± 6.0 min, respectively. The mean times for the right and left MILN dissections were 10.8 ± 4.3 and 9.8 ± 2.5 min, respectively. The mean total surgery time was 43.7 ± 7.7 min. In total, 26 MILNs were dissected. Several complications, including mild to moderate capillary hemorrhage from perinodal fat and vessels (controlled laparoscopically), mild spleen trauma caused by the first trocar insertion and capsular damage of MILNs, were observed. However, there were no other major complications. All MILN samples were evaluated and deemed suitable for histopathologic diagnosis. Laparoscopic excision of MILNs is a useful method of excisional biopsy for histopathologic diagnosis. Using this ventral laparoscopic approach with the 3-portal technique, bilateral MILN dissection suitable for obtaining histopathologic samples could be achieved in a short time in dogs weighing less than 15 kg.

[Sentinel lymph node biopsy in melanoma: our experience over 8 years in a universitary hospital]

BACKGROUND

Since the introduction of sentinel lymph node biopsy, its use as a standard of care for patients with clinically node-negative cutaneous melanoma remains controversial. Our experience of sentinel lymph node biopsy for melanoma is presented and evaluated.

MATERIAL AND METHODS

A cohort study was conducted on 69 patients with a primary cutaneous melanoma and with no clinical evidence of metastasis, who had sentinel lymph node biopsy from October-2005 to December-2013. Sentinel lymph node biopsy was identified using preoperative lymphoscintigraphy and subsequent intraoperative detection with gamma probe.

RESULTS

The sentinel lymph node biopsy identification rate was 98.5%. The sentinel lymph node biopsy was positive for metastases in 23 patients (33.8%). Postoperative complications after sentinel lymph node biopsy were observed in 4.4% compared to 38% of complications in patients who had complete lymphadenectomy.

CONCLUSION

The sentinel lymph node biopsy in melanoma offers useful information about the lymphatic dissemination of melanoma and allows an approximation to the regional staging, sparing the secondary effects of lymphadenectomy. More studies with larger number of patients and long term follow-up will be necessary to confirm the validity of sentinel lymph node biopsy in melanoma patients, and especially of lymphadenectomy in patients with positive sentinel lymph node biopsy.

Contemporary controversies and perspectives in the staging and treatment of patients with lymph node metastasis from melanoma, especially with regards positive sentinel lymph node biopsy

The management of melanoma lymph node metastasis particularly when detected by sentinel lymph node biopsy (SLNB) is still controversial. Results of the only randomized trial conducted to assess the therapeutic value of SLNB, the Multicenter Selective Lymphadenectomy Trial (MSLT-1), have not conclusively proven the effectiveness of this procedure but are interpreted by the authors and guidelines as indicating SLNB is standard of care. After surgery, interferon alpha had a small survival benefit and radiotherapy has limited effectiveness for patient at high-risk of regional recurrence. New drugs, including immune modulating agents and targeted therapies, already shown to be effective in patients with distant metastasis, are being evaluated in the adjuvant setting. In this regard, ensuring high quality of surgery through the identification of reliable quality assurance indicators and improving the homogeneity of prognostic stratification of patients entered onto clinical trials is paramount. Here, we review the controversial issues regarding the staging and treatment of melanoma patients with lymph node metastasis, present a summary of important and potentially practice changing ongoing research and provide a commentary on what it all means at this point in time.

Laparoscopic Extirpation of the Medial Iliac Lymph Nodes in Normal Dogs

OBJECTIVE

To describe a surgical technique for laparoscopic medial iliac lymph node (MILN) extirpation, and to describe the quality of biopsy specimens obtained.

DESIGN

Experimental study.

ANIMALS

Purpose-bred male hound-mix research dogs (n = 8).

METHODS

Dogs were randomized to groups of left or right-sided laparoscopic surgical approaches. Three transperitoneal portals were established with the dogs in lateral recumbency, and ipsilateral MILN dissection was achieved under CO2 pneumoperitoneum using a vessel-sealing device.

RESULTS

MILN ipsilateral to the approach were successfully identified and removed laparoscopically in 8 dogs. Observed complications included mild to moderate hemorrhage that was controlled laparoscopically in 4 dogs, and tearing of the MILN capsule during retraction and dissection in 3 dogs. No other major complications occurred and all dogs recovered uneventfully. Areas of either minor peripheral (9/9) or central (4/9) pinch artifact affected a median percentage of 5% of surface area (range, 5-30%) of bisected lymph nodes.

CONCLUSIONS

Laparoscopic MILN extirpation is feasible in dogs with normal MILN and may serve as a minimally invasive approach for excisional biopsy in the diagnostic staging of canine onocologic patients with normal-sized MILN. This lateral laparoscopic approach allows dissection of the ipsilateral MILN but precludes removal of the contralateral MILN. Minimal handling of the lymph node during dissection and removal is required to reduce the risk of capsular tear, or introduction of possible histologic artifact by tissue crush that may impact diagnosis.

Nonsentinel lymph node status in patients with cutaneous melanoma: results from a multi-institution prognostic study

PURPOSE

We investigated whether the nonsentinel lymph node (NSLN) status in patients with melanoma improves the prognostic accuracy of common staging features; then we formulated a proposal for including the NSLN status in the current melanoma staging system.

PATIENTS AND METHODS

We retrospectively collected the clinicopathologic data of 1,538 patients with positive SLN status who underwent completion lymph node dissection (CLND) at nine Italian centers. Multivariable Cox regression survival analysis was used to identify independent prognostic factors. Literature meta-analysis was used to summarize the available evidence on the prognostic value of the NSLN status in patients with positive SLN.

RESULTS

NSLN metastasis was observed in 353 patients (23%). After a median follow-up of 45 months, NSLN status was an independent prognostic factor for melanoma-specific survival (hazard ratio [HR] = 1.34; 95% CI, 1.18 to 1.52; P < .001). NSLN status efficiently stratified the prognosis of patients with two to three positive lymph nodes (n = 387; HR = 1.39; 95% CI, 1.07 to 1.81; P = .013), independently of other staging features. Searching the literature, this patient subgroup was investigated in other two studies. Pooling the results (n = 620 patients; 284 NSLN negative and 336 NSLN positive), we found that NSLN status is a highly significant prognostic factor (summary HR = 1.59; 95% CI, 1.27 to 1.98; P < .001) in patients with two to three positive lymph nodes.

CONCLUSION

These findings support the independent prognostic value of the NSLN status in patients with two to three positive lymph nodes, suggesting that this information should be considered for the routine staging in patients with melanoma.

Sentinel lymph node biopsy for cutaneous melanoma: a 6 years study

Background:

The aim of this study was to evaluate the results of sentinel lymph node biopsy (SLNB) in cutaneous melanoma at our institution.

Materials and Methods:

128 patients with primary cutaneous melanoma who underwent SLNB between April, 2004, and August, 2010 were studied. Univariate and multivariate analysis was performed to explore the effect of variables on mortality and sentinel node status. Survival analysis was performed using the Kaplan-Meier approach.

Results:

Positive SLNB were detected in 35 (27.3%) of 128 cases. Mean Breslow depths were 3.7 mm for SLNB positive patients and 1.99 mm for SLNB negative patients. False negative rate was 1%. The recurrence rate was 40% for positive patients and 6.5% for negative patients (odds ratio 9.7 [confidence interval 95 % 3.3-28.1]). 33 patients (29%) had an ulcerated melanoma, 12 (10.5%) in the positive group and 21 (18.5%) in the negative group. The disease recurred in a 48.5% of patients with ulcerated melanoma, but only in a 2.5% of patients with non-ulcerated melanoma. Upon multivariate analysis, only Breslow thickness (P = 0.005) demonstrate statistically significance for SLNB status. Multivariate analysis for clinicopathologic predictors of death demonstrate statistically significance for Breslow thickness (P = 0.020), ulceration (P = 0.030) and sentinel node status (P = 0.020).

Conclusions:

This study confirms that the status of the sentinel node is a strong independent prognostic factor with a higher risk of death and lower survival. Patients with ulcerated melanoma are more likely to develop recurrence, and also higher risk of death than patients with non-ulcerated melanoma.

Joint practice guidelines for radionuclide lymphoscintigraphy for sentinel node localization in oral/oropharyngeal squamous cell carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method of determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histological nodal staging and avoids over-treating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This article was designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. These guidelines were prepared by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial Committee.

Sentinel lymph node biopsy in melanoma patients

Appropriate surgical management of regional lymph nodes is critical in patients with cutaneous melanoma. The use of intraoperative lymphatic mapping and sentinel lymph node biopsy (SLNB) has increased significantly in the past decade. SLNB is performed as minimally invasive procedure that provides accurate staging of melanoma patients with no clinically detectable nodal disease. In many melanoma units across the world, it became the standard for detection of occult regional node metastasis in patients with intermediate-thickness primary melanoma. Use of SLNB in patients with thin melanomas is still under evaluation. Although SLNB has been established as staging procedure in melanoma patients, its therapeutic role is still not clear. Large-scale ongoing randomized trials should elucidate whether SLNB with complete lymphadenectomy has a survival benefit in melanoma patients with early lymph node metastases compared to 'watch-and-wait' policy (observation).

EANM-EORTC general recommendations for sentinel node diagnostics in melanoma

The accurate diagnosis of a sentinel node in melanoma includes a sequence of procedures from different medical specialities (nuclear medicine, surgery, oncology, and pathology). The items covered are presented in 11 sections and a reference list: (1) definition of a sentinel node, (2) clinical indications, (3) radiopharmaceuticals and activity injected, (4) dosimetry, (5) injection technique, (6) image acquisition and interpretation, (7) report and display, (8) use of dye, (9) gamma probe detection, (10) surgical techniques in sentinel node biopsy, and (11) pathological evaluation of melanoma-draining sentinel lymph nodes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for good-quality evaluation of possible spread to the lymphatic system in intermediate-to-high risk melanoma without clinical signs of dissemination.

Evaluation of sentinel lymph nodes for melanoma metastases by pathologists

The pathologic evaluation of sentinel lymph nodes for melanoma metastases is not without significant challenges. It is affected by significant variation in approaches, which may compromise the final interpretation, leading to nonrepresentative spurious results. This article discusses various approaches along with recommended dos and don'ts for optimum evaluation of sentinel lymph nodes for melanoma metastases.

Sentinel lymph node biopsy from the vantage point of an oncologic surgeon

Sentinel lymph node biopsy has greatly influenced the surgical management of clinically localized primary melanoma. Lymphatic mapping and sentinel lymph node biopsy have been used for the selective management of the draining regional lymph node basin of primary cutaneous melanoma. Oncologic surgeons have adopted this procedure to selectively identify occult nodal status in melanoma patients who are at a higher risk of regional metastasis. The current standard of treatment of tumor-positive sentinel lymph node metastasis is immediate completion lymphadenectomy, but considerable debate surrounds the utility of this procedure. This contribution reviews development, technical aspects, selective management of the lymph node basin, and sentinel lymph node biopsy techniques.

Joint Practice Guidelines for Radionuclide Lymphoscintigraphy for Sentinel Node Localization in Oral/Oropharyngeal Squamous Cell Carcinoma

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision of whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method for determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histologic nodal staging and avoids overtreating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This document is designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. Preparation of this guideline was carried out by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial (SENT) Committee.

Head and neck sentinel lymph node biopsy: current state of the art

Sentinel node biopsy is an alternative to elective neck dissection for the management of T1/T2 oral and oro-pharyngeal squamous cell carcinomas and is also finding application to head and neck cancer at other sites. The main clinical aim of sentinel node biopsy is to achieve better staging and there is now evidence that the procedure reduces morbidity. Reported detection rates for sentinel neck nodes are greater than 95% and there is also a negative predictive value of 95% for negative sentinel nodes. Current histopathological protocols have been developed for use in the research setting and are designed to identify all micrometastatic disease. However the use of step serial sectioning at 150 micron intervals with pan-cytokeratin immunohistochemistry is currently advised and appears to upstage nodes by approximately 20% over the initial single routine stained section. Adoption of the UICC/TNM definitions is recommended for future sentinel node studies, but further refinements and descriptions are required. The SENT trial has recruited over 300 cases from 10 European centres and a quality control study of the pathological material is in progress. At the first consensus meeting of the SENT pathology group there were excellent levels of agreement on the diagnosis of positive and negative nodes, and a number of potential pitfalls such as non-malignant inclusions and staining artefacts were identified.

Multicolor imaging of lymphatic function with two nanomaterials: quantum dot-labeled cancer cells and dendrimer-based optical agents

AIM

The lymphatics, critical conduits of metastases, are difficult to study because of their size and location. Two approaches to lymphatic imaging have been employed; cancer cell labeling provides information on cell migration and metastasis and macromolecular contrast agents enable visualization of the lymphatic drainage and identification of sentinel lymph node. Only one of these approaches is typically employed during an imaging examination. Here, we demonstrate the combined use of both approaches.

METHOD

In this study, we simultaneously visualize migration of quantum dot-labeled melanoma cells and the lymphatics using optically labeled dendrimers in vivo.

RESULTS

The appropriate use of two nanomaterials, quantum dots and dendrimers, enabled the simultaneous tracking of cancer cells within draining lymphatics.

CONCLUSION

This technique could enable better understanding of lymph node metastasis.

Inhibitors of melanogenesis increase toxicity of cyclophosphamide and lymphocytes against melanoma cells

High mortality rate for metastatic melanoma is related to its resistant to the current methods of therapy. Melanogenesis is a metabolic pathway characteristic for normal and malignant melanocytes that can affect the behavior of melanoma cells or its surrounding environment. Human melanoma cells in which production of melanin pigment is dependent on tyrosine levels in medium were used for experiments. Peripheral blood mononuclear cells were derived from the buffy coats purchased from Lifeblood Biological Services. Cell pigmentation was evaluated macroscopically, and tyrosinase activity was measured spectrophotometrically. Cell proliferation and viability were measured using lactate dehydrogenase release MTT, [(3)H]-thymidine incorporation and DNA content analyses, and gene expression was measured by real time RT-PCR. Pigmented melanoma cells were significantly less sensitive to cyclophosphamide and to killing action of IL-2-activated peripheral blood lymphocytes. The inhibition of melanogenesis by either blocking tyrosinase catalytic site or chelating copper ions sensitized melanoma cells towards cytotoxic action of cyclophosphamide, and amplified immunotoxic activities of IL-2 activated lymphocytes. Exogenous L-DOPA inhibited lymphocyte proliferation producing the cell cycle arrest in G1/0 and dramatically inhibited the production of IL-1beta, TNF-alpha, IL-6 and IL-10. Thus, the active melanogenesis could not only impair the cytotoxic action of cyclophosphamid but also has potent immunosuppressive properties. This resistance to a chemotherapeutic agent or immunotoxic activity of lymphocytes could be reverted by the action of tyrosinase inhibitors. Thus, the inhibition of melanogenesis might represent a valid therapeutic target for the management of advanced melanotic melanomas.

Current concepts of metastasis in melanoma

The main cause of death in melanoma patients is widespread metastases. Staging of melanoma is based on the primary tumor thickness, ulceration, lymph node and distant metastases. Metastases develop in regional lymph nodes, as satellite or in-transit lesions, or in distant organs. Lymph flow and chemotaxis is responsible for the homing of melanoma cells to different sites. Standard pathologic evaluation of sentinel lymph nodes fails to find occult melanoma in a significant proportion of cases. Detection of small numbers of malignant melanoma cells in these and other sites, such as adjacent to the primary site, bone marrow or the systemic circulation, may be enhanced by immunohistochemistry, reverse transcription PCR, evaluation of lymphatic vessel invasion and proteomics. In the organs to which melanoma cells metastasize, extravasation of melanoma cells is regulated by adhesion molecules, matrix metalloproteases, chemokines and growth factors. Melanoma cells may travel along external vessel lattices. After settling in the metastatic sites, melanoma cells develop mechanisms that protect them against the attack of the immune system. It is thought that one of the reasons why melanoma cells are especially resistant to killing is the fact that melanocytes (cells from which melanoma cells derive) are resistant to such noxious factors as ultraviolet light and reactive oxygen species. Targeted melanoma therapies are, so far, largely unsuccessful, and new ones, such as adjuvant inhibition of melanogenesis, are under development.