Carbon dye histologically confirms the identity of sentinel lymph nodes in cutaneous melanoma

Association between air pollution and skin cutaneous melanoma: A Mendelian randomization study

There has been a consistent and notable increase in the global prevalence of skin cutaneous melanoma (SKCM). Although genetic factors are closely associated with the occurrence and development of melanoma, the potential influence of environmental factors cannot be overlooked. The existing literature lacks a definitive consensus on the correlation between air pollution and the incidence rate of SKCM. This study seeks to investigate the causal relationship between air pollution, specifically focusing on particulate matter (PM) 2.5, PM2.5-10, PM10, and nitrogen oxides, and the risk of SKCM. A 2-sample Mendelian randomization (MR) method was applied, utilizing extensive publicly accessible genome-wide association studies summary datasets within European populations. The primary analytical method employed was the inverse variance weighted method. Supplementary methods, including the weighted median model, MR-Egger, simple model, and weighted model, were chosen to ensure robust analysis. Heterogeneity assessment was conducted using Cochran's Q test. To identify potential pleiotropy, both MR-Egger regression and the MR-PRESSO global test were employed. Additionally, a sensitivity analysis was performed using the leave-one-out method. The analysis revealed no statistically significant association between air pollution and SKCM risk, with specific findings as follows: PM2.5 (P = .485), PM2.5-10 (P = .535), PM10 (P = .136), and nitrogen oxides (P = .745). While some results exhibited heterogeneity, all findings demonstrated an absence of pleiotropy. This study did not find substantive evidence supporting a causal relationship between air pollution and the risk of SKCM within European populations. The comprehensive MR analysis, encompassing various pollutants, suggests that environmental factors such as air pollution may not be significant contributors to the development of SKCM.

Genomic Approach to the Assessment of Adverse Effects of Particulate Matters on Skin Cancer and Other Disorders and Underlying Molecular Mechanisms

Air pollutants are in the spotlight because the human body can easily be exposed to them. Among air pollutants, the particulate matter (PM) represents one of the most serious toxicants that can enter the human body through various exposure routes. PMs have various adverse effects and classified as severe carcinogen by International Agency for Research on Cancer. Their physical and chemical characteristics are distinguished by their size. In this review, we summarized the published information on the physicochemical characteristics and adverse effects of PMs on the skin, including carcinogenicity. Through comparisons of biological networks constructed from relationships discussed in the previous scientific publications, we show it is possible to predict skin cancers and other disorders from particle-size-specific signaling alterations of PM-responsive genes. Our review not only helps to grasp the biological association between ambient PMs and skin diseases including cancer, but also provides new approaches to interpret chemical-gene-disease associations regarding the adverse effects of these heterogeneous particles.

Current and novel mapping substances in gynecologic cancer care

Many tracers have been introduced into current medical practice with the purpose of improving lymphatic mapping techniques, anatomic visualization, and organ/tissue perfusion assessment. Among them, three tracers have dominated the field: indocyanine green, technetium-99m radiocolloid (Tc99m), and blue dye. Tc99m and blue dye are used individually or in combination; however, given particular challenges with these tracers, such as the need for a preoperative procedure by nuclear medicine and cost, other options have been sought. Indocyanine green has proven to be a promising alternative for certain procedures, as it is easy to use and has quick uptake. Its use in the management of gynecologic cancers was first described for sentinel lymph node mapping in cervical cancer, and later for endometrial and vulvar cancers. This review provides an in-depth look at these mapping substances, their uses, and the potential for new discoveries.

Is sentinel node susceptibility to metastases related to nodal immune modulation?

Sentinel lymph nodes (SLNs), the initial site of regional metastases, directly receive lymph containing immune-modulatory cytokines and tumor cells from primary melanomas. Immune-suppressed SLNs are ideal for studies of tissue susceptibility to metastases. They show reduced antigen-presenting dendritic cells, activated T cells, high endothelial venules, and transvenular immigration of T cells. Tumor-induced immune suppression contributes to establishment of nodal metastases. SLNs may serve as an effective model to study reversal of tumor-induced immune suppression. We reviewed this topic in Nature Reviews of Immunology in 2006. We here summarize the Nature paper and provide additional results from ongoing studies and the recent literature.

The girl with the iron tattoo

We describe a young woman with profound anemia whose serum iron studies were incongruous with what we expected from iron deficiency anemia. Her high serum iron was not fully explainable until we examined the patient and noticed a large black tattoo on her left flank area. Apparently iron oxide in the ink used for the tattoo was absorbed transcutaneously and led to high serum iron in the face of the other data, which suggested iron deficiency. She was slow in mobilizing her serum iron for erythropoiesis and we discovered that there was a concurrent acute B19 parvovirus infection, which impeded utilization of the iron for red blood cell production. We believe that this case report reinforces the imperative to always do a careful physical examination with any patient who has anemia, and also illustrates the potential toxicity of tattoo ink. The impairment of utilization of the serum iron because of the patient's acute B19 parvovirus infection demonstrates the many consequences of infection induced aplastic anemia.

"Triple injection" lymphatic mapping technique to determine if parametrial nodes are the true sentinel lymph nodes in women with cervical cancer

OBJECTIVES

Lymphatic mapping studies in women with cervical cancer typically identify sentinel nodes (SLNs) in the pelvis and not the parametrium. We added India ink as a mapping agent to determine whether this would allow us to pathologically identify sentinel parametrial nodes and to test our hypothesis that the parametrial nodes are the true SLNs in women with cervical cancer.

METHODS

We performed lymphatic mapping and SLN biopsy in 20 women with early-stage cervical cancer undergoing radical hysterectomy or trachelectomy using a "triple injection" technique with blue dye, radiocolloid, and India ink. Pathologic processing of parametrium and nodal tissue was then performed to identify India ink in specimens.

RESULTS

On pathology review, 15 (75%) patients had a parametrial node identified, and 9 patients (45%) had bilateral parametrial nodes identified; the median number of parametrial nodes identified was 2 (range, 0-7). India ink was seen in at least 1 parametrial node in 13 (87%) of the 15 patients with a parametrial node identified pathologically. Of the 9 patients with bilateral parametrial nodes identified pathologically, only 5 (54%) had bilateral parametrial nodes containing India ink. India ink was found in 26 (44%) of 59 SLNs and only 1 (0.3%) of 289 non-SLNs. In 5 patients, India ink was seen in a SLN on the same side of the pelvis where a parametrial node was identified but not microscopically black.

CONCLUSIONS

There appears to be direct drainage of cervical lesions to pelvic nodal basins bypassing small parametrial nodes. Parametrial nodes, therefore, may not always be the SLNs in women with cervical cancer.

Epitrochlear Sentinel Lymph Nodes in Melanoma: Interval or Independent?

Most primary melanomas on the distal upper extremity metastasize to a sentinel lymph node (SLN) in the axillary basin, but occasionally a primary melanoma will drain to the epitrochlear basin. The relationship between tumor-draining axillary and epitrochlear SLNs is unclear. We hypothesize that the epitrochlear SLN functions in an interval manner with the axillary lymph node basin. We queried our melanoma database to identify patients who underwent SLN biopsy for a distal upper-extremity melanoma. Patient demographics, tumor characteristics, patterns of nodal drainage, and incidence of SLN metastasis were analyzed. Of 255 patients identified, 38 (14.9%) had an epitrochlear SLN. Mean Breslow thickness was 2.26 mm. All patients with epitrochlear drainage had concurrent axillary drainage and underwent axillary and epitrochlear SLN biopsies. Of these 38 patients, two (5.2%) had epitrochlear and axillary SLN metastasis, four (10.5%) had epitrochlear metastasis only, four (10.5%) had axillary metastasis only, and the remaining 28 (73.7%) had tumor-free SLNs. The invariable association of epitrochlear and axillary drainage in this study suggests that epitrochlear nodes function in an interval role with the axillary lymph node basin. Therefore we recommend that all patients with a positive epitrochlear SLN undergo completion axillary dissection.

Fast 18F labeling of a near-infrared fluorophore enables positron emission tomography and optical imaging of sentinel lymph nodes

We combine a novel boronate trap for F⁻ with a near-infrared fluorophore into a single molecule. Attachment to targeting ligands enables localization by positron emission tomography (PET) and near-infrared fluorescence (NIRF). Our first application of this generic tag is to label Lymphoseek (tilmanocept), an agent designed for receptor-specific sentinel lymph node (SLN) mapping. The new conjugate incorporates ¹⁸F⁻ in a single, aqueous step, targets mouse SLN rapidly (1 h) with reduced distal lymph node accumulation, permits PET or scintigraphic imaging of SLN, and enables NIRF-guided excision and histological verification even after ¹⁸F decay. This embodiment is superior to current SLN mapping agents such as nontargeted [^99mTc]sulfur colloids and Isosulfan Blue, as well as the phase III targeted ligand [^99mTc]SPECT Lymphoseek counterpart, species that are visible by SPECT or visible absorbance separately. Facile incorporation of ¹⁸F into a NIRF probe should promote many synergistic PET and NIRF combinations.

Decoding melanoma metastasis

Metastasis accounts for the vast majority of morbidity and mortality associated with melanoma. Evidence suggests melanoma has a predilection for metastasis to particular organs. Experimental analyses have begun to shed light on the mechanisms regulating melanoma metastasis and organ specificity, but these analyses are complicated by observations of metastatic dormancy and dissemination of melanocytes that are not yet fully malignant. Additionally, tumor extrinsic factors in the microenvironment, both at the site of the primary tumor and the site of metastasis, play important roles in mediating the metastatic process. As metastasis research moves forward, paradigms explaining melanoma metastasis as a step-wise process must also reflect the temporal complexity and heterogeneity in progression of this disease. Genetic drivers of melanoma as well as extrinsic regulators of disease spread, particularly those that mediate metastasis to specific organs, must also be incorporated into newer models of melanoma metastasis.

Sentinel node biopsy in melanoma: technical considerations of the procedure as performed at the John Wayne Cancer Institute

Since its first description in 1990, sentinel node (SN) biopsy has become the standard for accurate staging of a melanoma-draining regional lymphatic basin. This minimally invasive, multidisciplinary technique can detect occult metastases by selective sampling and focused pathologic analysis of the first nodes on the afferent lymphatic pathway from a primary cutaneous melanoma. An understanding of preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and the definition of SN are critical for surgical expertise with SN biopsy.

A new concept for the role of ex vivo sentinel lymph nodes in node-negative colorectal cancer

BACKGROUND

We recently introduced ex vivo, intra-arterial methylene blue injection as a simple method to improve the lymph node (LN) harvest in gastrointestinal cancer. We now combined it with a novel ex vivo sentinel lymph node (evSLN) mapping technique.

METHODS

evSLN mapping was performed by subserosal (n = 20) or submucosal (n = 30) India ink injection. Subsequently, methylene blue was injected intra-arterially to enhance visibility of all LNs to improve the overall LN harvest. Manual LN dissection was carried out after fixing overnight. evSLNs nodes were identified by detecting carbon particles during histological examination. In primary node-negative cases, all detected LNs were step sectioned and immunohistochemically stained for pan-cytokeratin.

RESULTS

India ink injection was easy to perform. Methylene blue injection failed in 1 case. The mean lymph node harvest was 42 ± 18 LNs, and the SLN detection rate was 78%. The sensitivity for detecting metastases was 75%. The mean SLN number was 3 ± 1. LN metastases were found in 20 of 47 malignant cases (43%). Skip metastases occurred in 4 cases. Of these cases, 3 showed involvement of at least 1 entire LN. True upstaging (N0 → N1mi) was found in 1 of 23 cases (4%) within a SLN after advanced evaluation.

CONCLUSIONS

Combination of methylene blue technique and ex vivo sentinel mapping is feasible, easy to perform, and cost effective. It guarantees an optimal LN harvest and has the potential to heighten the sensitivity of metastasis detection.

Ability of new vital dyes to stain intraocular membranes and tissues in ocular surgery

PURPOSE

To evaluate the ability of novel dyes to stain lens capsule (LC), internal limiting membrane (ILM), epiretinal membrane (ERM), and vitreous.

DESIGN

Experimental study in animal and human donor eyes.

METHODS

Thirteen dyes, methyl violet, crystal violet, eosin Y, sudan black B, methylene blue, toluidine blue, light green, indigo carmine, fast green, congo red, evans blue, brilliant blue, and bromophenol blue, were injected onto the LC and ILM of enucleated porcine eyes. The vitreous was stained with 2 mL of dyes for 1 minute. Six dyes (indigo carmine, evans blue, fast green, light green, bromophenol blue, and brilliant blue) were selected for experiments in human donor eyes and freshly removed ERM.

RESULTS

In the porcine eyes, ILM staining with methylene blue, toluidine blue, indigo carmine, evans blue, bromophenol blue, and fast green was moderate, and methyl violet, crystal violet, brilliant blue, or sudan black resulted in strong staining. Methyl violet, crystal violet, sudan black, toluidine blue, and methylene blue caused histologic damage in porcine retinas. Vitreous examination revealed moderate staining with congo red, crystal violet, fast green, eosin Y, methylene blue, toluidine blue, brilliant blue, bromophenol blue, and methyl violet and strong staining with light green and evans blue. ERMs showed strong staining with 0.5% evans blue and moderate staining with 0.5% light green, fast green, brilliant blue, and bromophenol blue. Evaluation of donor eyes disclosed moderate staining with evans blue, light green, and bromophenol blue and strong staining with 0.5% brilliant blue. Moderate or strong staining of the vitreous occurred with most dyes. LC evaluation showed moderate staining with 0.5% evans blue, fast green, and brilliant blue, whereas 0.5% light green produced strong LC staining.

CONCLUSIONS

Brilliant blue shows the best ILM staining, whereas bromophenol blue, evans blue, and light green also stain ILM. Most dyes bind well to LC, vitreous, and ERM.

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.

Coexisting Tattoo Pigment and Metastatic Melanoma in the Same Sentinel Lymph Node

Background:

The principle of sentinel lymph node states that metastatic melanoma spreads in a predictable sequential fashion from the primary site to the regional lymph node basin.

Objective and Conclusion:

Reports show that melanoma and tattoo pigment can be in the same regional lymph node basin on gross evaluation. We present two cases of melanoma arising within the setting of a tattoo where the sentinel lymph node contained both pigmented histiocytes and metastatic melanoma on gross inspection and histopathology.

Tumor lymphatics

In this article we survey more than three centuries of observation and research into tumor-associated lymphatic vessels, and their role in the metastatic spread of cancer. This historical overview documents how questions regarding tumor lymphatics have been central to concepts about the process of metastasis, and how this has subsequently influenced the clinical treatment of cancer. In turn, we show how analysis of the efficacy of these treatments has challenged long-standing notions regarding the tumor lymphatics. Starting with the discovery of VEGFR-3 and its ligands VEGF-C and VEGF-D, we also review how the rapid developments over the last 15 years in the molecular analysis of the lymphatic system and in particular lymphangiogenesis have contributed to this debate. Finally we speculate on how apparently paradoxical bodies of evidence regarding the role of tumor lymphatics in determining patterns of metastatic spread might be reconciled.

A prospective feasibility trial to determine the significance of the sentinel node gradient in breast cancer: a predictor of nodal metastasis location

BACKGROUND

Sentinel lymph node (SN) biopsy is standard for breast cancer staging, but SN dye gradients and their significance have never been characterized. If predictive of SN metastasis location, their use for focused pathology examination might improve intraoperative imprint cytology sensitivity.

METHODS

This prospective trial enrolled clinically lymph node-negative patients with invasive breast cancer not undergoing neoadjuvant chemotherapy. Surgeons marked SN gradients at their bluest end. Nodal halves were examined separately by imprint cytology, and the marked SN half was correlated to metastasis location. Demographic, pathologic, and prognostic features were recorded.

RESULTS

Mean patient age and tumor size for the 102 patients was 59.6 years and 2.2 cm, respectively. Of 169 SNs, 159 (94.1%) had dye gradients, which varied by tumor quadrant, but not by histology, diagnosis method, grade, or stage. Among 41 marked SNs with metastases, 92.7% were present in the halves marked by the surgeon. Fourteen were confined to 1 nodal half, with 11 on the marked side and 3 on the unmarked side (P = .029). Metastases were smaller when confined to 1 versus both SN halves (0.14 vs 0.75 cm; P = .005), and smaller (0.87 vs 0.13 cm; P < .0001) when missed intraoperatively.

CONCLUSIONS

Dye gradients occur in most SNs and predict metastasis location. The smallest metastases are hardest to detect intraoperatively and are usually confined to the marked SN half. This suggests that marking an SN's bluest half warrants further study to explore whether its correlation to metastasis location may be exploited to focus pathologic examination and decrease the reoperative axillary dissection rate.

Pathologic examination of sentinel lymph nodes from melanoma patients

In melanoma patients, the sentinel node biopsy (SNB) procedure is a highly accurate staging method, and the tumor-harboring status of the sentinel node (SN) is the most important prognostic factor for patients with early stage disease. For the SN to provide accurate prognostic information, however, it is essential that all "true" SNs are removed and examined diligently. Pathologists should examine multiple hematoxylin-eosin and immunohistochemically stained sections from each SN, but it is unclear from the currently available evidence what is the most appropriate sectioning and staining protocol. Relevant factors to consider include the accuracy of the procedure, the time, labor, and costs involved, and clinical follow-up data which are likely to vary between institutions; hence, individual protocols should be developed locally by pathologists in consultation with their surgical colleagues. At the Sydney Melanoma Unit, four sequential sections of both halves of each SN are examined. The first and fourth sections are stained with hematoxylin-eosin, the second section is stained for S-100 protein, and the third section is stained for HMB-45. Pathologists should not only identify the presence of melanoma metastases within the SN, but also record the size of the largest metastatic focus, tumor penetrative depth (measured from the inner margin of the node capsule to the deepest tumor cell within the SN), and the percentage nodal cross-sectional area involved (as measured on the slides). Potential diagnostic pitfalls in SN evaluation include the misinterpretation of nevus cells, macrophages, or antigen-presenting interdigitating dendritic cells as melanoma. Careful assessment of the morphologic characteristics of the cells and their immunohistochemical profile should prevent misdiagnosis. Routine frozen section examination of SNs from melanoma patients is not recommended. The utility of ultrasound to detect SN metastases (confirmed by fine needle biopsy) is currently being investigated. Whereas potentially this may avoid the need for formal sentinel lymphadenectomy and histopathologic evaluation in some patients, the lack of sensitivity of currently available ultrasound technologies to detect the small micrometastases (<2 mm in diameter), that are typically present in most melanoma patients with a positive SN, limits its current role. In the future, other techniques, such as the use of carbon particles or antimony analysis, may better localize the site of metastases within SNs and permit more focused and efficient pathologic examination of SNs. At present, the role of nonhistopathologic methods of SN evaluation, such as reverse transcription polymerase chain reaction (RT-PCR) and magnetic resonance spectroscopy, remains unclear, and these techniques require further evaluation.

Sentinel lymph node biopsy for melanoma: aspects of pathologic assessment

Sentinel lymph node (SLN) biopsy affords an accurate, minimally invasive means of staging and determining prognosis in patients with melanoma and for identifying those patients who may benefit from complete regional lymph node dissection. Careful and accurate histopathologic assessment of SLNs is critical to achieving optimal reliability of the technique. Micromorphometric parameters of melanoma deposits in SLNs have been shown to be predictive of regional non-SLN involvement and of clinical outcomes. Several non-histopathologic methods of SLN evaluation have been investigated, and while some of them show promise for the future, excision and histopathologic examination currently remains the gold standard for the evaluation of SLNs.

Confirmation of sentinel lymph node identity by analysis of fine-needle biopsy samples using inductively coupled plasma-mass spectrometry

Background

The sentinel lymph node (SLN) biopsy technique is a reliable means of determining the tumor-harboring status of regional lymph nodes in melanoma patients. When technetium 99 m-labeled antimony trisulfide colloid (^99 mTc-Sb₂S₃) particles are used to perform preoperative lymphoscintigraphy for SLN identification, they are retained in the SLN but are absent or present in only tiny amounts in non-SLNs. The present study investigated the potential for a novel means of assessing the accuracy of surgical identification of SLNs. This involved the use of inductively coupled plasma–mass spectrometry (ICP-MS) to analyze antimony concentrations in fine-needle biopsy (FNB) samples from surgically procured lymph nodes.

Methods

A total of 47 FNB samples from surgically excised lymph nodes (32 SLNs and 15 non-SLNs) were collected. The SLNs were localized by preoperative lymphoscintigraphy that used ^99 mTc-Sb₂S_3, blue dye, and gamma probe techniques. The concentrations of antimony were measured in the FNB samples by ICP-MS.

Results

The mean and median antimony concentrations (in parts per billion) were .898 and .451 in the SLNs, and .015 and .068 in the non-SLNs, the differences being highly statistically significant (P < .00005).

Conclusions

Our results show that ICP-MS analysis of antimony concentrations in FNB specimens from lymph nodes can accurately confirm the identity of SLNs. Used in conjunction with techniques such as proton magnetic resonance spectroscopy for the nonsurgical evaluation of SLNs, ICP-MS analysis of antimony concentrations in FNB samples could potentially serve as a minimally invasive alternative to surgery and histopathologic evaluation to objectively classify a given node as sentinel or nonsentinel and determine its tumor-harboring status.

Pathological Evaluation of Sentinel Lymph Nodes

The sentinel lymph nodes are the most likely site of nodal metastasis. Their focused analysis results in upstaging cancers, although the extra yield from a more intensive work-up is generally dominated by micrometastases and isolated tumor cells. Nodal staging is generally done to reflect systemic spread of solid tumors and guide treatment accordingly. However, in general, the two processes of haematogenous and lymphogenic spread are not causally interrelated, and the extrapolation from low-volume nodal involvement to systemic involvement and therapeutic consequences of this extrapolation are still under investigation.

The role of sentinel lymph node biopsy in the management of melanoma

During the last 2 decades, the development and wide acceptance of SLN biopsy have affected the management of melanoma profoundly. This technique represents a considerable improvement in the ability to evaluate the tumor status of the regional lymph node basin, which is the most important predictor of survival in patients who have melanoma. Histopathologic and molecular assessment of the SLN has enhanced the detection of clinically occult nodal metastases, thereby distinguishing patients who might benefit from immediate lymphadenectomy from those for whom this procedure is unlikely to be helpful. This technique also identifies patients who would be candidates for clinical trials of adjuvant therapy. Centers can offer SLN biopsy without routine CLND once they reach a level of proficiency that usually corresponds to a learning phase of 55 cases. The role of molecular technology in the identification and analysis of the SLN remains to be established. Although molecular evidence of SLN metastasis has been identified in patients who have early-stage melanoma, its clinical relevance cannot be determined until marker selection is improved. The markers presently under study lack sensitivity and specificity. The role of molecular biomarkers can be validated only through large, multicenter, randomized. controlled trials such as the MSLT-II, a trial that will determine the benefit of multimarker RT-PCR assay in SLN specimens. SLN offers a promising future in staging lymph nodes and will improve the management of patients who have melanoma. Although SLN biopsy has become widely accepted as a minimally invasive technique of staging regional lymph nodes, its use in patients who have melanoma continues to be challenged. The future of SLN biopsy holds promise if prospective multicenter trials confirm a survival benefit for SLN biopsy as compared with watch-and-wait observation.

Tumour-induced immune modulation of sentinel lymph nodes

Sentinel lymph nodes (SLNs), being the first nodes to receive lymph from a primary tumour and the preferential site of initial tumour metastases, are intensively exposed to the bioactive products of tumour cells and other associated cells. This makes them ideal for studies of the factors that determine selective tissue susceptibility to metastases. We postulate that tumour-induced immune modulation of SLNs facilitates lymph-node metastases by inhibiting the generation of tumour-specific cytotoxic T cells that are active against tumour cells of primary and metastatic melanomas. Immune modulation of the lymph nodes can be reversed by granulocyte/macrophage colony-stimulating factor (GM-CSF), a finding that has implications for the future therapy of lymph-node metastases.

Carbon dye staining of sentinel lymph nodes facilitates microstaging of colon cancer patients

BACKGROUND

Carbon dye, when peritumourally injected, permanently marks the drainage site of sentinel lymph nodes (SLN). The objective of the current study was to evaluate whether the use of carbon dye facilitated the detection of small nodal tumour infiltrates in colon cancer patients.

METHODS

In a prospective trial, 19 patients underwent open, oncological resections of localized colon cancer and SLN procedure according to a standardized protocol. Isosulfan blue 1% and sterile filtered carbon dye (mixed 1:1) were injected into the subserosa circumferentially around the tumour. Lymph nodes staining blue were marked as SLN. Serial sections of each SLN were stained with hematoxylin and eosin (H&E) and with the pancytokeratin marker AE1/AE3. The intranodal presence and site of carbon particles were noted and compared with the location of possible tumour infiltrates.

RESULTS

Identification of at least one SLN was successful in 18 patients (identification rate 95%). Four patients (22%) were pN+, 11 (61%) were pN0(i-). Three patients (17%) were upstaged from pN0(i-) to pN0(i+) as isolated tumour cells were detected in their SLN: in two (11%) of the three patients, carbon dye and isolated tumour cells were found in the same nodal compartment, hence facilitating the recognition of isolated tumour cells by the pathologist.

CONCLUSION

The use of carbon dye in the SLN procedure for colon cancer may facilitate the detection of small nodal tumour infiltrates.

Experimental frontiers for clinical applications: Novel approaches to understanding mechanisms of lymph Node metastases in melanoma

Sentinel lymph nodes are the first nodes to receive lymph from primary tumors and are the preferential site of initial metastases. Sentinel nodes show morphology changes that suggests immune modulation with reduced antigen-presenting dendritic cells, activated T lymphocytes, high endothelial venules and transvenular migration of T lymphocytes. Tumor cells generate down-regulatory molecules. We postulate that tumor-induced immune dysfunction facilitates establishment of nodal metastases. Nodal immune modulation can be reversed by granulocyte macrophage colony-stimulating factor (GMCSF), a finding with implications for future therapy to prevent or reverse these nodal metastases.

Molecular diagnostics in melanoma

Molecular pathology is rapidly evolving, featuring continuous technologic improvements that offer novel clinical opportunities for the recognition of disease predisposition, for identifying sub-clinical disease, for more accurate diagnosis, for selecting efficacious and non-toxic therapy, and for monitoring of disease outcome. Currently, the identification and prognosis of primary cutaneous melanoma is based on histologic factors (tumor depth and ulceration) and clinical factors (number of lymph node and/or distant metastases). However, metastasis can occur in patients with thin melanomas, and sentinel lymph node biopsy does not identify all patients at risk for distant metastasis. New markers exist that correlate with melanoma progression, which may aid in melanoma identification, prognostication, and detection of minimal residual disease/early recurrence. Moreover, not many therapeutic options exist for melanoma as no regimen prolongs survival. Emerging data with investigational therapies suggest that certain markers might play a crucial role in identifying patients who will respond to therapy or show utility in the monitoring the response to therapy. Herein, molecular diagnostics that can potentially benefit the individual melanoma patient will be discussed.

Characterization of micrometastatic disease in melanoma sentinel lymph nodes by enhanced pathology: recommendations for standardizing pathologic analysis

Lymphatic mapping and sentinel lymph node (SLN) biopsy are widely used as a staging technique for patients with cutaneous malignant melanoma who are at risk for metastases. SLN status has been shown to be a strong predictor of prognosis, and a variety of techniques have been used to identify minimal metastatic disease in SLNs. However, there is no validated consensus method for the optimal histologic analysis of SLNs harvested from melanoma patients. This study was conducted: 1) to assess the yield of metastatic melanoma detected in SLNs deemed negative by initial routine pathologic analysis (RPA) by subjecting them (after review of the original slides) to enhanced pathologic analysis (EPA) that included complete step-sectioning and immunohistochemistry (IHC); 2) to characterize the distribution of metastatic melanoma deposits within the SLNs; 3) to determine a preferred method of pathologic analysis applicable to daily practice; and 4) to attempt to assess the clinical significance of disease detected by EPA. A total of 105 SLNs were harvested from 49 patients who underwent successful SLN biopsy procedures during the period of study. Ten SLNs from 10 patients were positive on initial RPA and were not analyzed further. Ninety-five SLNs from the remaining 39 patients were reviewed and processed with additional hematoxylin and eosin, S-100 protein, and HMB-45 stains at 50-microm intervals for 20 levels or until the SLN tissue was exhausted. A single pathologist reviewed all sections without knowledge of the results of the other stains. Overall, metastatic melanoma was discovered in SLNs from 20 of the 39 patients: SLNs from 6 patients were found to have melanoma on review of the original hematoxylin and eosin slides, and SLNs from 14 patients were positive only after EPA. Twenty-one individual positive SLNs from these 14 patients were detected by EPA; of these, 10 positive SLNs were identified solely by IHC, representing 12% of the patient cohort and 10% of all SLNs studied by EPA. Detection rates were significantly associated with the staining method and the number of levels performed (P < 0.01). S-100 protein staining resulted in the highest yield of SLN positivity (86%), followed by HMB-45 (81%) and hematoxylin and eosin (52%). No single method detected all of the micrometastases. A detailed topographic mapping of metastatic deposits in SLNs was carried out. When using all three staining techniques, all 20 levels were required to identify 100% of the micrometastases; 95% of positive SLNs were identified with 17 levels, 90% with 15 levels, 75% with 10 levels, and 42% with 3 levels. Projected rates of detection for various different sectioning strategies were determined, with alteration of either the number of levels examined, the interval between the levels, or both. Detection of SLN positivity can be increased to 71% by performing three levels at 250-mum intervals, each level being composed of a set of three sections stained with hematoxylin and eosin, S-100 protein, and HMB-45, respectively. Therefore, this is the methodology we propose for the study of SLNs in melanoma patients. After a median follow-up of 87 months (range, 9-134 months), patients with EPA-detected disease and those with negative SLNs by EPA demonstrated improved recurrence-free and disease-specific survival compared with patients with RPA-detected disease in SLNs. Sampling error introduced by variations in pathologic processing should be addressed by standardization of pathologic methods, and the clinical significance of minimal SLN disease should be addressed in prospective studies of homogeneously staged patients.

Dynamic sentinel node biopsy in penile carcinoma: evaluation of 10 years experience

PURPOSE

The aim of this study was to evaluate the results of 10 years dynamic sentinel node biopsy experience in penile carcinoma at our institute.

PATIENTS AND METHODS

140 patients with clinically node-negative groins were prospectively included. Lymphoscintigraphy was performed after injection of 99mTechnetium-nanocolloid around the primary tumour. The sentinel node was intraoperatively identified with the aid of patent blue dye and a gamma ray detection probe. Lymph node dissection was performed only if sentinel node metastasis was found. Median follow-up was 52 months (range 5-129).

RESULTS

Lymphoscintigraphy visualized at least 1 sentinel node in 138 patients. Sentinel node metastasis was found in 37 inguinal regions of 31 patients. The sentinel node was the only tumour-positive node in 78% (29/37) of the dissection specimens. Complications occurred in 8% (17/206) of the operated groins. False-negative results were encountered in 6 patients resulting in a false-negative rate of 16% (6/37 patients). 5-year disease-specific survival was 96% and 66% for patients with a tumour-negative sentinel node and tumour-positive sentinel node, respectively (p=0.001).

CONCLUSION

Dynamic sentinel node biopsy in penile carcinoma is of important diagnostic, prognostic, and therapeutic value at the cost of only minor morbidity.

Selective sentinel lymphadenectomy: progress to date and prospects for the future

The sentinel node (SN) concept was clearly outlined by Virchow in the mid-nineteenth century, and Braithwaite used the term "glands sentinel" in 1923. However, it was not until Morton, Cochran et al. published their landmark report in 1992 that the clinical relevance of the SN was fully appreciated. Since then, the validity of the concept has been confirmed in studies undertaken at a number of centers worldwide. It has become clear that SN status accurately reflects the status of the entire regional node field, not only in patients with melanoma but also in those with breast cancer and a wide range of other primary malignancies. New insights into lymphatic anatomy have been gained by preoperative lymphoscintigraphy, and the original blue dye mapping technique for SN identification has been supplemented by intraoperative use of a hand-held gamma probe to identify radioactivity in colloid particles injected at the primary tumor site. It has become clear that all three methods are required to achieve optimal accuracy of SN identification. Although SN assessment provides very important prognostic information, the results of randomized trials must be awaited to determine whether selective sentinel lymphadenectomy, with full regional node dissection if a positive SN is found, is of any therapeutic value. It is possible that SN positivity is merely a marker of disease that has the potential for hematogenous dissemination and systemic metastasis. As follow-up times extend, reported false-negative SN rates are increasing, and ways to reduce these false-negative rates are therefore being actively sought. Attempts are being made to increase the accuracy of SN identification, and to confirm true SN identity both at the time of surgery and retrospectively. The ultimate objective is to develop minimally invasive and even non-invasive methods of SN assessment, Proton magnetic resonance spectroscopy is one technique that might make it possible to achieve this goal, and avoid the present morbidity and cost of operative SN removal.

Dynamic MR lymphangiography and carbon dye for sentinel lymph node detection: A solution for sentinel lymph node biopsy in mucosal head and neck cancer

BACKGROUND

The practical application of sentinel lymph node biopsy in squamous cell carcinoma of the head and neck is restricted by the time sensitivity of blue dye and lack of spatial resolution and nonspecific node enhancement with radiocolloid. This study evaluates the use of magnetic resonance (MR) lymphangiography and carbon dye labeling to circumvent these limitations.

METHODS

Gadomer/carbon dye mixture was injected into the tongue and stifle of adult swine (n = 4). MR lymphatic mapping was followed by intraoperative mapping with isosulfan blue dye. Sentinel lymph node biopsy and completion node dissection were performed 60 minutes after injection in four nodal basins and at 7 days after injection in eight.

RESULTS

The technique was successful in all 12 nodal basins. The sentinel lymph nodes were stained black at the time of the immediate and delayed dissections.

CONCLUSIONS

MR lymphangiography provides temporal and anatomic localization of the sentinel lymph node with a single investigation. Carbon dye is a sensitive and persistent visual marker of MRI-targeted sentinel lymph nodes.

Update on lymphatic mapping and sentinel node biopsy in the management of patients with melanocytic tumours

AIMS

To communicate best practices for sentinel lymph node evaluation and assessment of prognosis for patients with melanoma.

METHODS

Description and justification of approaches derive from experience with management of more than 2000 melanoma patients evaluated by lymphatic mapping and sentinel node biopsy (LMSNB).

RESULTS

Pathologists, by detecting blue dye or carbon particles or alterations in nodal cell populations should attempt to confirm that a node submitted as sentinel is truly sentinel. Pathologists must adequately sample the node by examining multiple tissue sections and determine the presence or absence of metastatic melanoma using sections stained by H&E and immunocytochemistry. Approximately 20% of patients have melanoma in the sentinel node (SN) and accurate evaluation of SN tumour status is the most precise technique for staging clinically localised cutaneous melanoma. The remaining non-sentinel nodes (NSN) in the basin are tumour-free in 67% of patients with melanoma in the SN. Breslow thickness of the primary, the area of tumour in the SN (relative to total nodal area) and density of dendritic leukocytes in the SN paracortex (factors that are combinable in prognostic algorithms) predict metastases in the NSN and the likelihood of recurrence and melanoma-specific death.

CONCLUSIONS

Careful pathological analysis is essential to determine the presence or absence of metastatic melanoma in sentinel nodes, findings that indicate whether completion lymphadenectomy is required. Quantitative analysis of the primary melanoma and the amount of tumour in the sentinel node, with evaluation of the dendritic cells in that node, provide invaluable information that predicts non-sentinel node tumour status with increased accuracy and the likelihood of future recurrence and death from melanoma. While these activities require considerable effort from pathologists, their clinical impact justifies the increased workload.

Antimony concentrations in nodal tissue can confirm sentinel node identity

The sentinel node biopsy procedure is a highly accurate method of staging patients with cutaneous melanoma and the tumor-harboring status of sentinel nodes is the most important prognostic factor. For the procedure to provide accurate prognostic information, however, it is essential that 'true' sentinel nodes are removed and examined thoroughly. A technique to confirm sentinel node identity may reduce the false-negative rate of the procedure. We have found that antimony (originating from the antimony sulfide colloid used for preoperative lymphoscintigraphy in our institution) can be measured in tissue sections of sentinel nodes using inductively coupled plasma mass spectrometry. The aims of this study were to determine whether antimony concentrations can be used to confirm that removed sentinel nodes are 'true' sentinel nodes and to differentiate sentinel nodes from nonsentinel nodes. In all, 24 patients who had both a tumor-positive sentinel node and a tumor-negative nonsentinel node removed from one regional node field during the same operation, were identified. Tissue sections (50 microm) thick were cut from archival paraffin blocks of each of the sentinel nodes and nonsentinel nodes. Antimony concentrations in the tissue sections were measured using inductively coupled plasma mass spectrometry. The median and mean concentrations of antimony in parts per billion were 0.526 and 1.198, respectively (range 0.020-7.596) in the sentinel nodes, and 0.043 and 0.123 (range 0-0.800) in the nonsentinel nodes (P = 0.004). In four of the 24 pairs, both the presumed sentinel nodes and the nonsentinel nodes had very low antimony levels (less than 0.18 parts per billion), suggesting that nodes designated as sentinel nodes may not have been 'true' sentinel nodes. It is concluded that determination of antimony concentrations within sentinel nodes using the highly sensitive method of inductively coupled plasma mass spectrometry can confirm the identity of sentinel nodes and validate the sentinel node technique.