Detection Of Occult Lymph Node Metastases Research Articles

The Diagnostic Value of the Sentinel Node Procedure to Detect Occult Lymph Node Metastases in PSMA PET/CT Node-Negative Prostate Cancer Patients.

Our objective was to assess the diagnostic value of the sentinel node (SN) procedure for lymph node staging in primary intermediate- and high-risk prostate cancer patients with node-negative results on prostate-specific membrane antigen PET/CT (miN0). Methods: From 2016 to 2022, 154 patients with primary, miN0 PCa were retrospectively included. All patients had a Briganti nomogram-assessed nodal risk of more than 5% and underwent a robot-assisted SN procedure for nodal staging. The prevalence of nodal metastases at histopathology and the occurrence of surgical complications according to the Clavien-Dindo classification were evaluated. Results: The SN procedure yielded 84 (14%) tumor-positive lymph nodes with a median metastasis size of 3 mm (interquartile range, 1-4 mm). In total, 55 patients (36%) were reclassified as pN1. A complication of Clavien-Dindo grade 3 or higher occured in 1 patient (0.6%). Conclusion: The SN procedure classified 36% of patients with miN0 prostate cancer with an elevated risk of nodal metastases as pN1.

Prediction of Biochemical Recurrence Based on Molecular Detection of Lymph Node Metastasis After Radical Prostatectomy

BackgroundMolecular detection of lymph node (LN) micrometastases by analyzing mRNA expression of epithelial markers in prostate cancer (PC) patients provides higher sensitivity than histopathological examination. ObjectiveTo investigate which type of marker to use and whether molecular detection of micrometastases in LNs was predictive of biochemical recurrence. Design, setting, and participantsLN samples from PC patients undergoing radical prostatectomy with extended LN dissection between 2009 and 2011 were examined for the presence of micrometastases by both routine histopathology and molecular analyses. Outcome measurements and statistical analysisThe mRNA expression of a panel of markers of prostate epithelial cells, prostate stem cell–like cells, epithelial-to-mesenchymal transition, and stromal activation, was performed by quantitative real-time polymerase chain reaction. The expression levels of these markers in LN metastases from three PC patients were compared with the expression levels in LN from five control patients without PC in order to identify the panel of markers best suited for the molecular detection of LN metastases. The predictive value of the molecular detection of micrometastases for biochemical recurrence was assessed after a follow-up of 10 yr. Results and limitationsProstate epithelial markers are better suited for the detection of occult LN metastases than molecular markers of stemness, epithelial-to-mesenchymal transition, or reactive stroma. An analysis of 1023 LNs from 60 PC patients for the expression of prostate epithelial cell markers has revealed different expression levels and patterns between patients and between LNs of the same patient. The positive predictive value of molecular detection of occult LN metastasis for biochemical recurrence is 66.7% and the negative predictive value is 62.5%. Limitations are sample size and the hypothesis-driven selection of markers. ConclusionsMolecular detection of epithelial cell markers increases the number of positive LNs and predicts tumor recurrence already at surgery. Patient summaryWe show that a panel of epithelial prostate markers rather than single genes is preferred for the molecular detection of lymph node micrometastases not visible at histopathological examination.

Carbonic anhydrase IX stratifies patient prognosis and identifies nodal status in animal models of nasopharyngeal carcinoma using a targeted imaging strategy

Accurate identification of nodal status enables adequate neck irradiation for nasopharyngeal carcinoma (NPC). However, most conventional techniques are unable to pick up occult metastases, leading to underestimation of tumor extensions. Here we investigate the clinical significance of carbonic anhydrase IX (CAIX) in human NPC samples, and develop a CAIX-targeted imaging strategy to identify occult lymph node metastases (LNMs) and extranodal extension (ENE) in animal studies. A total of 211 NPC samples are performed CAIX staining, and clinical outcomes are analyzed. The metastatic murine models are generated by foot pad injection of NPC cells, and a CAIX-targeted imaging agent (CAIX-800) is intravenously administered. We adopt fluorescence molecular tomography and ultrasonography (US)-guided spectroscopic photoacoustic (sPA) imaging to perform in vivo studies. Histological and immunohistochemical characterization are carried out via node-by-node analysis. For clinical samples, 90.1% (91/101) primary tumors, 73.3% (66/90) metastases, and 100% (20/20) local recurrences are CAIX positive. In metastases group, 84.7% (61/72) nodal metastases and 22.2% (4/18) organ metastases are CAIX positive. CAIX expression in primary tumors is significantly associated with NPC stage and prognosis. For animal studies, CAIX-800-based fluorescence imaging achieves 81.3% sensitivity and 93.8% specificity in detecting occult LNMs in vivo, with a minimum detectable diameter of 1.7mm. Coupled with CAIX-800, US-guided sPA imaging could not only detect subcapsular deposits of metastatic cancer cells 2weeks earlier than conventional techniques, but also successfully track pathological ENE. CAIX remarkably expresses in human NPCs and stratifies patient prognosis. In preclinical studies, CAIX-800-based imaging successfully identifies occult LNMs and tracks early stage of pathological ENE. This attractive method shows potential in clinic, allowing medical workers to longitudinally monitor nodal status and helping to reduce unnecessary nodal biopsy for patients withNPC. The schematic diagram for the study. CAIX, carbonic anhydrase IX; NPC, nasopharyngeal carcinoma; US, ultrasonography; sPA, spectroscopic photoacoustic.

Multispectral optoacoustic tomography for in vivo detection of lymph node metastases in oral cancer patients using an EGFR-targeted contrast agent and intrinsic tissue contrast: A proof-of-concept study

Oral cancer patients undergo diagnostic surgeries to detect occult lymph node metastases missed by preoperative structural imaging techniques. Reducing these invasive procedures that are associated with considerable morbidity, requires better preoperative detection. Multispectral optoacoustic tomography (MSOT) is a rapidly evolving imaging technique that may improve preoperative detection of (early-stage) lymph node metastases, enabling the identification of molecular changes that often precede structural changes in tumorigenesis. Here, we characterize the optoacoustic properties of cetuximab-800CW, a tumor-specific fluorescent tracer showing several photophysical properties that benefit optoacoustic signal generation. In this first clinical proof-of-concept study, we explore its use as optoacoustic to differentiate between malignant and benign lymph nodes. We characterize the appearance of malignant lymph nodes and show differences in the distribution of intrinsic chromophores compared to benign lymph nodes. In addition, we suggest several approaches to improve the efficiency of follow-up studies.

Sentinel Nodal Metastasis Detection in Endometrial Carcinoma With Microcystic, Elongated, and Fragmented (MELF) Pattern by Cytokeratin Immunostaining.

The microcystic, elongated, and fragmented (MELF) pattern of myoinvasion in endometrial carcinoma (EC) is associated with an increased risk of lymph node metastasis. Our aim is to assess the role of cytokeratin immunohistochemical (IHC) stains in detecting sentinel nodal metastasis in MELF pattern tumors. We recovered 19 MELF pattern EC hysterectomies with lymphadenectomy from our files. Negative nodes were subjected to cytokeratin AE1/AE3 IHC. Ten additional cases with sentinel lymph node (SLN) biopsies primarily assessed by IHC were also analyzed. Of the 19 cases of EC, 6 had positive lymph nodes based on H&E-stained sections at the time of their initial diagnosis. With the addition of IHC stains, 8 previously negative cases were found to have node metastases, and 3 of these were SLNs. Among the 10 cases primarily assessed by IHC, 5 had malignant cells in their SLNs. Cytokeratin IHC staining detected malignant cells in 9 of 16 cases with SLNs in our sample of women with MELF pattern of myoinvasion. Immunohistochemical stains should be routinely performed on SLNs from all MELF-positive cases to detect occult lymph node metastases and isolated tumor cells.

Elective Neck Dissection or Sentinel Lymph Node Biopsy in Early Stage Oral Cavity Cancer Patients: The Dutch Experience.

Background: Sentinel lymph node biopsy (SLNB) has been introduced as a diagnostic staging modality for detection of occult metastases in patients with early stage oral cancer. Comparisons regarding accuracy to the routinely used elective neck dissection (END) are lacking in literature. Methods: A retrospective, multicenter cohort study included 390 patients staged by END and 488 by SLNB. Results: The overall sensitivity (84% vs. 81%, p = 0.612) and negative predictive value (NPV) (93%, p = 1.000) were comparable between END and SLNB patients. The END cohort contained more pT2 tumours (51%) compared to the SLNB cohort (23%) (p < 0.001). No differences were found for sensitivity and NPV between SLNB and END divided by pT stage. In floor-of-mouth (FOM) tumours, SLNB had a lower sensitivity (63% vs. 92%, p = 0.006) and NPV (90% vs. 97%, p = 0.057) compared to END. Higher disease-specific survival (DSS) rates were found for pT1 SLNB patients compared to pT1 END patients (96% vs. 90%, p = 0.048). Conclusion: In the absence of randomized clinical trials, this study provides the highest available evidence that, in oral cancer, SLNB is as accurate as END in detecting occult lymph node metastases, except for floor-of-mouth tumours.

Propensity-score adjusted comparison of pathologic nodal upstaging by robotic, video-assisted thoracoscopic, and open lobectomy for non–small cell lung cancer

ObjectiveTo assess the effectiveness of intraoperative lymph node (LN) staging by comparing upstaging between robotic-assisted surgery, video-assisted thoracoscopic surgery (VATS), and open thoracotomy approach for lobectomy for non–small cell lung cancer. MethodsWe retrospectively analyzed 1053 patients with clinical stage N0/N1 non–small cell lung cancer who underwent lobectomy at 2 centers between 2011 and 2018. Propensity score adjustment by inverse probability of treatment weighting was used to balance baseline characteristics. The primary end point was LN upstaging. ResultsA total of 911 patients (254 robotic, 296 VATS, and 261 open) were included in the inverse probability of treatment weighting adjusted analysis. The overall rate of LN upstaging was highest with open lobectomy (21.8%), followed by robotic (16.2%), and VATS (12.3%) (P = .03). Mediastinal N2 upstaging was observed in similar frequencies (open 6.9% vs robotic 6.3% vs VATS 4.4%; P = .6). No differences were seen for total LN counts, but were observed in the number of stations sampled (mean, open 4.0 vs robotic 3.8 vs VATS 3.6; P = .001). On multivariate analysis, LN upstaging was lower for VATS compared with open (odds ratio, 0.50; 95% confidence interval, 0.29-0.85), but not different between robotic and open (odds ratio, 0.72; 95% confidence interval, 0.44-1.18). No significant differences were seen in mediastinal N2 upstaging between groups. ConclusionsPathologic LN upstaging following lobectomy for clinically N0/N1 NSCLC remains high. Compared with a traditional thoracotomy approach, robotic lobectomy was associated with similar and VATS with lower overall nodal upstaging. A thorough evaluation of hilar and mediastinal LNs remains critical to ensure accurate staging by detection of occult LN metastases.

Endometrioid endometrial carcinomas with microcystic, elongated, and fragmented (MELF) type of myoinvasion: role of immunohistochemistry in the detection of occult lymph node metastases and their clinical significance

In endometrioid endometrial carcinomas (EECs), microcystic, elongated, and fragmented (MELF) myoinvasion is associated with easily overlooked lymph node metastases; however, the role of immunohistochemistry in their detection and their clinical significance have not been addressed. We identified MELF in 43 of 101 (43%) myoinvasive EECs. Nodes were removed in 49 (49%), 25 with MELF and 24 without MELF. Metastases were initially reported in 3 of the former (12%) and 2 of the latter (8%). All negative nodes were reviewed, and cytokeratin immunohistochemistry was performed. Three metastases were identified in the MELF group but none in the EECs without MELF. By immunohistochemistry, metastatic nodal isolated tumor cells (ITCs) were found in 6 of the remaining 19 MELF-positive cases. In contrast, lymph node metastases were detected in only 2 of the 22 EECs without MELF. MELF-positive cases had more lymph node metastases (P=.03) than myoinvasive EECs without MELF. At follow-up, all 6 patients with grade 1-2 EECs and nodal ITCs/micrometastases were alive (5 no evidence of disease and 1 with perineal disease). In contrast, 3 of 4 patients with grade 3 EECs and nodal ITCs/micrometastases died of disease, and the other patient was alive with tumor. In MELF, the frequency of ITCs/micrometastases in apparently negative lymph nodes is high. In patients with grade 1-2 EEC who had not received chemotherapy, the presence of nodal ITCs/micrometastases did not affect survival. In contrast, in high-grade tumors, ITCs/micrometastases were associated with unfavorable prognosis. Immunohistochemistry should be done in MELF-positive cases to detect occult lymph node metastases, especially in high-grade tumors.

Prediction of occult lymph node metastasis in squamous cell carcinoma of the oral cavity and the oropharynx using peritumoral Prospero homeobox protein 1 lymphatic nuclear quantification.

The use of lymphatic vessel density as a predictor of occult lymph node metastasis (OLNM) in head and neck squamous cell carcinoma (HNSCC) has never been reported. Staining of the specific lymphatic endothelial cells nuclear marker, PROX1, as an indicator of lymphatic vessel density was determined by counting the number of positive cells in squamous cell carcinomas (SCCs) of the oral cavity and the oropharynx with clinically negative necks. Correlation with histopathological data was established. Peritumoral PROX1 lymphatic nuclear count significantly correlated with the detection of OLNM in multivariate analysis (p < .005). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of this parameter was 60%, 95%, 85%, and 90%, respectively. Peritumoral PROX1 lymphatic nuclear count in primary SCCs of the oral cavity and the oropharynx allows accurate prediction of occult lymph node metastasis. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1407-1415, 2016.

Advances in diagnostic modalities to detect occult lymph node metastases in head and neck squamous cell carcinoma.

Regional metastasis is a prominent feature of head and neck squamous cell carcinoma (HNSCC) and is an important prognostic factor. The currently available imaging techniques for assessment of the neck have limitations in accuracy; thus, elective neck dissection has remained the usual choice of management of the clinically N0 neck (cN0) for tumors with significant (≥20%) incidence of occult regional metastasis. As a consequence, the majority of patients without regional metastasis will undergo unnecessary treatment. The purpose of this review was to discuss new developments in techniques that potentially improve the accuracy of the assessment of the neck in patients with HNSCC. Although imaging has improved in the last decades, a limitation common to all imaging techniques is a lack of sensitivity for small tumor deposits. Therefore, complementary to improvements in imaging techniques, developments in more invasive diagnostic procedures, such as sentinel node biopsy (SNB) will add to the accuracy of diagnostic algorithms for the staging of the neck.

Intraoperative ultrasonography is useful in surgical management of neck metastases in differentiated thyroid cancers.

Differentiated thyroid carcinomas are the most common malignancies of endocrine organs. Metastases to cervical lymph nodes occur in 20-50% of cases. Recurrence and survival rates are closely related to the type of surgery performed. High-resolution ultrasonography (USG) is a sensitive imaging method used to detect occult lymph node metastases in patients with thyroid cancer. We evaluated how intraoperative USG affected surgical success. This was a retrospective study comparing two groups of patients with thyroid carcinoma who underwent cervical lymph node dissection. A total of 101 patients (33 males and 68 females) were included. Group 1 included 53 patients who underwent surgery with intraoperative USG guidance. Group 2 included 48 patients who underwent surgery without the use of USG. All patients were followed up (mean 23 months; range 5-44 months) with thyroglobulin measurements and USG evaluations. Group 1 (intraoperative USG) had a residual/recurrent tumor rate of 1.9% (1/53 patients). Group 2 had a residual/recurrent tumor rate of 12.5% (6/48 patients). A statistically significant difference appeared between the residual/recurrent tumor rates in Groups 1 and 2 (p<0.05). In addition to its classical use in diagnosis and follow-up, intraoperative use of high-resolution USG can improve surgical success and may decrease the number of residual/recurrent tumors encountered during follow-up.

Sentinel lymph node biopsy using blue dye as guidance for central neck dissection in patients with clinically node-negative papillary thyroid carcinoma

Background Sentinel lymph node biopsy has recently been used to detect occult lymph node metastases. Occult lymph node metastasis of papillary thyroid carcinoma (PTC) can be detected by sentinel lymph node (SLN) biopsy, but studies in larger patient cohorts undergoing complete central neck dissection are required to assess the diagnostic accuracy of SLN. Materials and methods A total of 25 consecutive patients with clinically and ultrasonographically node-negative PTC were enrolled and underwent sentinel lymph node biopsy. After injection of 0.2-0.3 ml methylene blue around the tumor or 0.5-1.0 ml into the thyroid nodule, blue-stained SLNs were collected from the central compartments. Results SLNs were identified in 21 of 25 patients (84%); of these, 14 SLNs were positive and seven SLNs were negative by hematoxylin and eosin staining. The false-negative rate was detected in two patients (8%), identified by immunohistochemical staining. The non-SLNs were positive in five patients (20%) from positive SLN patients, and no positive non-SLNs were present in negative SLN patients. Conclusion SLN biopsy in patients with PTC without gross clinical or ultrasonographical lymph node involvement was able to detect occult metastasis and may have the potential to select patients who require central neck dissection using methylene blue dye technique in PTC, and it is a safe and technically feasible procedure.

Clinical Efficacy of Sentinel Lymph Node Biopsy Using Methylene Blue Dye in Clinically Node-Negative Papillary Thyroid Carcinoma

Sentinel lymph node biopsy (SLNB) has recently been used to detect occult lymph node metastases. The aim of this study was to assess the feasibility and clinical efficacy of SLNB in the treatment of clinically node-negative papillary thyroid carcinoma. A total of 114 consecutive patients with clinically node-negative papillary thyroid carcinoma were enrolled and underwent SLNB. After injection of 1% methylene blue around the tumors, blue-stained sentinel lymph nodes (SLN) were collected from the central compartments. All the patients underwent total thyroidectomy with bilateral central compartment neck dissection after SLNB. SLN were identified in 84 (73.7%) of the 114 patients. Of these 84 patients, 24 (28.6%) had metastases in the SLN. Among the 60 patients who had no metastases in their SLN in frozen biopsy samples, seven had metastatic foci in their SLN in the permanent biopsy samples and six had metastases in their non-SLN samples. Central compartment lymph node metastases were detected in 11 of the 30 patients in whom SLN were not identified. Thus, the sensitivity, specificity, and positive and negative predictive values of SLNB were 64.9, 100, 100, and 78.3%, respectively. The false-positive and false-negative rates were 0 and 35.1%, respectively. The detection of SLN led to no major complications. SLNB using methylene blue in papillary thyroid carcinoma is a safe and technically feasible procedure. However, it is of limited use in the management of clinically node-negative papillary thyroid carcinoma because of low sensitivity and a high false-negative rate.

Detection of Occult Metastases in Sentinel Lymph Nodes From Colon Cancer Patients by K-ras Mutation Peptide Nucleic Acid Clamp PCR

To identify colon cancer patients with occult lymph node metastases. The prognostic value of regional lymph node (LN) metastases in colorectal cancer patients is well established. The disease recurrences nevertheless experienced by 20% to 30% of the LN negative patients suggest a potential for improvement in current LN diagnostics. We suspect that a subgroup of the patients that are LN negative by routine examination has occult LN metastases that are prognostically relevant. To identify these patients we applied ex vivo sentinel lymph node (SLN) mapping to colon cancer patients and analyzed the SLNs by a sensitive peptide nucleic acid clamp PCR (polymerase chain reaction) assay for K-ras mutations, using these mutations as a surrogate marker for tumor cells. SLNs were identified in 158 (96%) of 164 prospectively recruited patients with localized colon cancer. Of the 158 patients with successful SLN mapping, 67 (42%) had K-ras mutations detected in their primary tumors. We analyzed the SLNs from these patients by peptide nucleic acid clamp PCR for K-ras mutations and found mutations in SLNs from 35 (52%) patients. At least one SLN from 14 (70%) of 20 patients with histologically proven regional LN metastases was positive for the K-ras mutation test. Interestingly, 21 (45%) of the 47 patients without known LN metastases had K-ras mutations detected in their SLNs. Sensitive detection of K-ras mutations in SLNs from colon cancer patients indicates the presence of occult metastases with potential prognostic implications.

Recent advances in surgery for head and neck cancer

This paper reviews the advances in surgery in head and neck cancer patients. Sentinel node biopsy is a promising diagnostic technique to detect occult lymph node metastases, especially in oral carcinomas. Fludeoxyglucose-PET seems to be useful in detecting recurrent (laryngeal) carcinoma after radiotherapy. The role of fludeoxyglucose-PET to detect residual disease in the neck after radiotherapy with or without chemotherapy is not yet clear. The armamentarium of reconstructive surgery is still expanding. Endonasal endoscopic, robotic surgery and image-guided surgery are used as minimal invasive surgery in selected patients. Other advances include photodynamic therapy, ultrasonic surgery and mechanical sutures. New diagnostic techniques are used to avoid futile extensive surgery. Technical improvements have been made to treat head and neck cancer patients with minimal invasive surgery. Large prospective trials are needed to determine the indications for each technique.

GUCY2C reverse transcriptase PCR to stage pN0 colorectal cancer patients

The most important prognostic marker of survival and predictive marker of response to adjuvant chemotherapy in colon cancer patients is tumor cells in regional lymph nodes. Despite their importance, standard techniques to assess nodal metastases remain imperfect, as approximately 30% of patients with histology-negative lymph nodes (pN0) die of recurrent disease, reflecting occult metastases that escape detection. These observations highlight the clinical need for novel, accurate approaches to detect occult lymph node metastases in patients with colon cancer. GUCY2C is a biomarker whose expression normally is restricted to intestinal cells, but is near universally overexpressed by colorectal cancer cells. Recently, a prospective, multicenter, blinded clinical trial demonstrated for the first time that the prognostic utility of GUCY2C quantitative reverse transcriptase (qRT)-PCR to detect occult lymph node metastases in pN0 colorectal cancer patients. Molecular staging revealed that approximately 13% of pN0 patients were free of tumor cells, while approximately 87% had GUCY2C results that suggested occult metastases. The presence of occult lymph node metastases was the strongest independent predictor of time to recurrence and disease-free survival. These observations establish the utility of molecular detection of occult lymph node metastases for estimating prognostic risk in pN0 colorectal cancer patients. Advancing this molecular diagnostic into staging paradigms in clinical laboratories will require validation in independent patient populations, definition of the relationship between the quantity of occult tumor metastases and risk, and determination of the utility of GUCY2C qRT-PCR to identify pN0 patients who might benefit from adjuvant chemotherapy.

Carcinoid of pancreas: Case report

Carcinoid tumors are very common tumors of gastro-intestinal tract even though they are very rare in pancreatic area. A large number of patients with pancreatic carcinoma have nonspecific symptoms of disease which is the main cause of late operative treatment of advanced tumors as well as for a low rate of 5-years surviving (28,9% +/- 16%). A 69-year-old female patient was operated for a 7 cm large carcinoid in pancreatic corpus. Prior to the operation the patient did not have any symptoms of disease. Serotonin and 5-HIAA level was normal before the operation as well as afterwards. In this case distal hemipancreatectomy was done along with celiac, hepatic and lienal lymphadenoctomy. Liver metastasis was not found. The diagnosis of carcinoid was verified by postoperative histopathologic and imunohistochemical analysis. According to the experience of other authors, the operative treatment of pancreatic carcinoid is very often undertaken when dimensions of tumor exceed 7 cm. In this stage of disease distant metastases are present in more than 60% of patients. Only 23% of examinated patients have had carcinoid syndrome symptoms. According to this conclusion, the main role of diagnostic procedures is attributed to the computer tomography of abdomen as well as ERCP. The radical resection of pancreas with lymphadenectomy is recommended in order to have a precise histological examination and detect occult lymph node metastases. With radical surgical procedures even at this stage of disease the operation may be curative. Any kind of radical surgical treatment (depending of localizations of tumor, proximal or distal) is the main therapeutic procedure in pancreatic carcinoid.

Evaluation of dynamic lymphoscintigraphy and sentinel lymph‐node biopsy for detecting occult metastases in patients with penile squamous cell carcinoma

To evaluate the introduction of dynamic lymphoscintigraphy and sentinel lymph-node (SLN) biopsy (used to detect occult lymph node metastases in patients with penile cancer and clinically impalpable inguinal lymph nodes at presentation) at a UK tertiary referral centre for penile cancer. In all, 75 patients with penile squamous cell carcinoma of stage T1, grade > or = 2, and unilateral or bilateral impalpable groin nodes, were prospectively enrolled over a 2-year period. Patients underwent lymphoscintigraphy with (99m)technetium-labelled nanocolloid which was injected intradermally around the tumour or into the distal penile shaft skin. Four hours later, the SLN(s) were identified during surgery using a hand-held gamma-probe and intradermal injections with blue dye. Completion lymph node dissection was subsequently used in patients with tumour-positive SLNs. In all, 255 SLNs were removed from 143 groins; all excised nodes had taken up the radioactive marker, and the blue dye was evident in 87%. Eighteen of 75 (24%) patients and 21 of 143 groins (15%) had a tumour-positive SLN. All but one patient went on to completion lymph node dissection. Three of these 18 (17%) had further disease in other than SLNs. Six of 143 (4%) groins developed minor complications. One false-negative result was reported at a median (range) follow-up of 11 (2-24) months. This technique is feasible for managing penile cancer in a UK tertiary referral centre. The initial results suggest that it can accurately identify the SLN(s), which can then be removed for pathological review with minimal morbidity.

Sentinel Lymph Node Biopsy and Melanoma Biology

Minimally invasive intraoperative lymphatic mapping and sentinel node biopsy has become the standard approach for staging the regional lymph nodes for early-stage melanoma. The procedure requires close collaboration of surgeon, pathologist, and nuclear medicine physician. The strength of lymphatic mapping and sentinel node biopsy is its accuracy of detecting occult lymph node metastases. Reverse transcriptase-PCR (RT-PCR) analyses of either fresh-frozen or paraffin-embedded sections of the sentinel lymph nodes have been found to be more sensitive than H&E staining or immunohistochemistry techniques, but lack of specificity and limits in the availability of tissue specimens make this technique impractical for routine use. Three randomized clinical trials are examining the therapeutic value of lymphatic mapping and sentinel node biopsy for melanoma. Preliminary results of the Multicenter Lymphadenectomy Trial I show the high level of accuracy and low morbidity of lymphatic mapping and sentinel node biopsy done through an international working group. The therapeutic value of lymphatic mapping and sentinel node biopsy is still unclear. Multicenter Lymphadenectomy Trial II will test the clinical significance of lymph nodes evaluated by RT-PCR and the value of completion lymph node dissection for patients found to have tumor-positive sentinel lymph nodes by H&E, immunohistochemistry, or RT-PCR. The Sunbelt Melanoma Trial examines the therapeutic value of completion dissection and benefits of Intron A. The ability to detect occult nodal metastases and evaluate the interaction of primary tumor with the regional lymph nodes may provide for better understanding of the metastatic process in patients with melanoma and help to determine the function of the regional lymph nodes as markers of metastases or incubators of tumor cells in the metastatic cascade.

Molecular classification of melanoma using real‐time quantitative reverse transcriptase‐polymerase chain reaction

The early detection and characterization of metastatic melanoma are important for prognosis and management of the disease. Molecular methods are more sensitive in detecting occult lymph node metastases compared with standard histopathology and are reported to have utility in clinical diagnostics. Using real-time quantitative reverse transcriptase-polymerase chain reaction ([q]RT-PCR), the authors examined 36 samples (30 melanomas, 4 benign nevi, and 2 reactive lymph nodes) for the expression of 20 melanoma-related genes that function in cell growth and differentiation (epidermal growth factor receptor [EGFR], WNT5A, BRAF, FOS, JUN, MATP, and TMP1), cell proliferation (KI-67, TOP2A, BUB1, BIRC5, and STK6), melanoma progression (CD63, MAGEA3, and GALGT), and melanin synthesis (TYR, MLANA, SILV, PAX3, and MITF). In addition, samples were tested for mutations in BRAF (exons 11 and 15) and NRAS (exons 2 and 3). Hierarchical clustering analysis of the expression data was able to distinguish between the melanoma and nonmelanoma samples and further stratified the melanoma samples into two groups differentiated by high expression of the genes involved in beta-catenin activation (EGFR and WNT5A) and the MAPK/ERK pathway (BRAF, FOS, and JUN). Eighteen of the 28 patients (64%) were found to have mutations in either exon 15 of BRAF (V599 substitution) or codon 61 of NRAS. The mutations were mutually exclusive and did not appear to be associated with the different expression subtypes. The results of the current study demonstrate that real-time qRT-PCR can be analyzed using hierarchical clustering to identify expression patterns that differentiate between melanomas and other tissue types. Using a supervised analysis of the data, the authors found that the best discriminators for molecularly distinguishing between melanoma, benign nevi, and lymph nodes were MLANA, CD63, and BUB1. These markers could have diagnostic utility for the detection of melanoma micrometastasis in sentinel lymph nodes.