Sentinel Lymph Node Mapping in Melanoma in the Twenty-first Century

The Use and Technique of Sentinel Node Biopsy for Skin Cancer

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the indications for and prognostic value of sentinel lymph node biopsy in skin cancer. 2. Learn the advantages and disadvantages of various modalities used alone or in combination when performing sentinel lymph node biopsy. 3. Understand how to perform sentinel lymph node biopsy in skin cancer patients.

SUMMARY

Advances in technique used to perform sentinel lymph node biopsy to assess lymph node status have led to increased accuracy of the procedure and improved patient outcomes.

Optimization of Sentinel Lymph Node Imaging Methodology Using Anionic Liposome and Hyaluronidase

The sentinel lymph node (SLN) is the first lymph node into which lymphatic fluid from tumor tissues flows. The development of a highly sensitive probe for detecting SLNs is desired for the lymph node dissection through intraoperative biopsy. We have previously shown that anionic liposomes tend to accumulate in lymph nodes and that macrophage uptake of liposomes contributes to their accumulation. In the present study, we found that among anionic lipids, phosphatidylserine (PS)-containing liposomes were substantially taken up by macrophages. We identified a new lipid composition to improve the SNL-selectivity of liposome accumulation based on Design-of-Experiment. The optimized PS-containing particles were more selectively accumulate to SLN lymph nodes than existing imaging agents indocyanine green. These results indicate the effectiveness of PS-containing anionic particles in SLN imaging.

Compounding Benefits of Sentinel Lymph Node Biopsy for Perineal Melanoma: A Population-Based Retrospective Cohort Analysis

INTRODUCTION

Sentinel lymph node biopsy (SLNB) in the treatment of melanoma is known to provide valuable prognostic information. However, there is no literature describing an overall or disease-specific survival (DDS) benefit of SLNB. In the perineum, melanoma is often more advanced at presentation with current treatment guidelines translated from nonanatomic specific melanoma. As a result, there is little understanding surrounding the role of SLNB in melanoma of the perineum. Our objective is to better understand the therapeutic benefits of SLNB in perineal melanoma.

METHODS

The Surveillance, Epidemiology, and End Results program is a large population-based cancer registry including survival data from millions of patients in the United States. The registry was used to generate patient data for analysis from 2004 to 2016. Inclusion criteria included melanoma of the perineum; Breslow depth of 0.80 mm or greater and less than 0.80 mm with ulceration; SLNB or no intervention; clinically negative nodal disease; and available overall survival data.

RESULTS

For 879 patients from 2004 to 2016 with perineal melanoma, significant predictors of reduced survival include older than 75 years, Clark level IV-V, Breslow depth of greater than 4.00 mm, positive ulceration status, regional and distant nodal micrometastases, and clinically positive nodes on presentation. Aggregates for overall survival (OS) and disease-specific survival (DSS) were improved with implementation of SLNB. The 5-year survival rates with SLNB versus no SLNB were 54.0% and 43.0% for OS (P = 0.001) and 57.8% and 53.1% for DSS (P = 0.044). Stratification by Breslow depth yielded significant OS and DSS advantage for greater than 1.00 to 2.00 mm (21.3% benefit, P =0.021, and 16.8% benefit, P = 0.044) and greater than 4.00 mm (30.3% benefit, P = 0.005, and 21.0% benefit, P = 0.007) Breslow depths.

CONCLUSIONS AND RELEVANCE

Sentinel lymph node biopsy may provide therapeutic benefits in addition to prognostic information for melanoma of the perineum through an increase in 5-year OS.

Development of Sentinel LN Imaging with a Combination of HAase Based on a Comprehensive Analysis of the Intra-lymphatic Kinetics of LPs

The sentinel lymph node (LN) is the first LN to which lymph fluid flows from tumor tissue. We identified the key parameters of liposomes (LPs) that affect their accumulation in regional (primary) LNs with minimum leakage to its connecting (secondary) LNs by a comprehensive analysis of the LN-to-LN trafficking of LPs with various surface charges and various sizes. We used a lymphatic flow-modified (LFM) mouse that allows for the chronological analysis of inguinal (primary) LN-to-axillary (secondary) LN at the body surface. As a result, the anionic medium-sized LPs (130 nm on average) exhibited the highest accumulation in the primary LNs. A mechanism-based analysis revealed that CD169-positive macrophages in LNs were the dominant cell population that captures anionic LPs. Sentinel LN imaging was also performed by the intratumoral injection of fluorescent medium-sized anionic LPs using a breast cancer orthotopic model. In comparison with the typically used contrast agent indocyanine green, the anionic LPs were detected in sentinel LNs with a high sensitivity. Additionally, the co-injection of hyaluronidase significantly improved the sensitivity of detection of the fluorescent LPs in sentinel LNs. In conclusion, medium-sized anionic LPs combined with hyaluronidase represents a potent strategy for investigating sentinel LNs.

Regional nodal metastasis and 5-year survival in patients with thin melanoma in Queensland: a population-based study

BACKGROUND

Optimal management of regional lymph nodes for thin cutaneous melanoma is uncertain. We evaluated regional lymph node involvement and 5-year melanoma-specific survival (MSS) in patients with thin (≤1 mm) primary melanoma.

METHODS

Patients with a melanoma, American Joint Committee on Cancer Staging 8th Edition pT1a (<0.8 mm) or pT1b (ulceration; and/or 0.8-1.0 mm), diagnosed during 2001-2015 were identified from the Queensland Oncology Repository. We extracted demographic, pathology and clinical details, including sentinel lymph node biopsy (SLNB), regional nodal dissection and nodal recurrence. Poisson regression was used to assess recurrence risk in patients who did not undergo SLNB. The 5-year MSS was calculated using the Kaplan-Maier method with Cox regression to compare survival outcomes according to SLNB performance.

RESULTS

Of the 27 824 eligible patients, 240 (0.9%) underwent SLNB. One hundred and seventy-eight patients (0.6%) without SLNB had nodal recurrence. Of the 4848 patients with a pT1b lesion, 166 (3.4%) had SLNB with 12 (7.2%) positive; of the remainder, 99 (2.1%) had clinical recurrence. Risk of recurrence was higher in males, nodular subtype and T1b lesions and lower if patients were aged >60 years. The 5-year MSS was similar for observed and SLNB cohorts (99.66% versus 98.92%) but worse for T1b lesions (98.90%) and clinical nodal recurrence (66.89%).

CONCLUSION

Overall prognosis for T1 melanoma is excellent with nodal involvement being rare. However, the American Joint Committee on Cancer 8th Edition T1b melanoma correlates with significantly worse 5-year MSS and increased regional nodal recurrence (notably for 0.8-1.0 mm lesions with ulceration). Further characterization of high-risk groups for nodal positivity that impacts patient outcome is needed for the pT1 melanoma cohort.

The Basics of Sentinel Lymph Node Biopsy: Anatomical and Pathophysiological Considerations and Clinical Aspects

Sentinel lymph node (SLN) is the first node to receive the drainage directly from a tumor. Detection and pathological examination of the SLN is an important oncological procedure that minimizes morbidity related to extensive nodal dissection. SLN biopsy was first reported in 1960 but took approximately 40 years to come into general practice following reports of good outcomes in patients with melanoma. After many years of observation and research on its use in various malignancies SLN biopsy has become the standard surgical treatment in patients with malignant melanoma, breast, vulvar, and cervical cancers. Along with the introduction of new technologies, such as the fluorescent dyes indocyanine green (ICG) and near-infrared fluorescence (NIR), and pathologic ultrastaging, SLN detection rate has increased and false-negative rate has decreased. This literature review aimed to present an overview of the basic concepts and clinical aspects of SLN biopsy in the light of the current research.

Association between tumor-infiltrating lymphocytes and sentinel lymph node positivity in thin melanoma

BACKGROUND

Sentinel lymph node biopsy in thin invasive primary cutaneous melanoma (up to 1mm thick) is a controversial subject. The presence of tumor-infiltrating lymphocytes could be a factor to be considered in the decision to perform this procedure.

OBJECTIVE

To evaluate the association between the presence of tumor-infiltrating lymphocytes and lymph node metastases caused by thin primary cutaneous melanoma.

METHODS

Cross-sectional study with 137 records of thin invasive primary cutaneous melanoma submitted to sentinel lymph node biopsy from 2003 to 2015. The clinical variables considered were age, sex and topography of the lesion. The histopathological variables assessed were: tumor-infiltrating lymphocytes, melanoma subtype, Breslow thickness, Clark levels, number of mitoses per mm2, ulceration, regression and satellitosis. Univariate analyzes and logistic regression tests were performed as well the odds ratio and statistical relevance was considered when p <0.05.

RESULTS

Among the 137 cases of thin primary cutaneous melanoma submitted to sentinel lymph node biopsy, 10 (7.3%) had metastatic involvement. Ulceration on histopathology was positively associated with the presence of metastatic lymph node, with odds ratio =12.8 (2.77-59.4 95% CI, p=0.001). The presence of moderate/marked tumor-infiltrating lymphocytes was shown to be a protective factor for the presence of metastatic lymph node, with OR=0.20 (0.05-0.72 95% CI, p=0.014). The other variables - clinical and histopathological - were not associated with the outcome.

STUDY LIMITATIONS

The relatively small number of positive sentinel lymph node biopsy may explain such an expressive association of ulceration with metastatization.

CONCLUSIONS

In patients with thin invasive primary cutaneous melanoma, few or absent tumor-infiltrating lymphocytes, as well as ulceration, represent independent risk factors for lymph node metastasis.

Sentinel node biopsy status is strongly predictive of survival in cutaneous melanoma: Extended follow-up of Oxford patients from 1998 to 2014

INTRODUCTION

Sentinel lymph node biopsy (SLNB) is widely used as a key investigatory tool for cutaneous melanoma, with results incorporated into the latest AJCC staging guidelines. We present the results of our extended follow-up of sentinel lymph node biopsy for melanoma over a sixteen-year period.

METHODS

Data were collected prospectively from June 1998 to December 2014 from a single tertiary skin cancer referral centre. Chi-squared analysis was used to analyse patient demographics and primary tumour pathology. Survival analysis was conducted using Cox regression models and Kaplan-Meier survival curves.

RESULTS

Over a sixteen-year period 1527 patients underwent SLNB in 1609 basins, with 2876 nodes harvested. 347 patients (23%) had a positive biopsy. The most common primary tumour sites for males was the back (32%); women had a significantly higher number of melanomas occurring on the lower and upper limbs (45% and 26% respectively) [all p < 0.0001, Chi-squared]. Mean follow-up time was 4.9 years. Patients with a positive SLNB at diagnosis were significantly more likely to die from melanoma (subhazard ratio 5.59, p = 0.000, 95% CI 3.59-8.69). Breslow thickness and ulceration were also significant predictors of melanoma-specific mortality. For patients with a primary Breslow >4.0 mm ten-year disease free survival was 52% for SLNB negative and 26% for SLNB positive patients. For Breslow thicknesses of 2.01-4 mm these values were 66% and 32% respectively.

CONCLUSIONS

Sentinel lymph node biopsy status is strongly predictive of survival across all thicknesses of primary cutaneous melanoma.

Head and neck desmoplastic melanoma: Utility of sentinel node biopsy

PURPOSE

The utility of sentinel lymph node biopsy in desmoplastic melanoma has been questioned due to multiple reports of a low rate of occult nodal metastasis in this variant of melanoma. We describe a single institution experience with management of desmoplastic melanoma of the head and neck and discuss the utility of sentinel lymph node biopsy.

MATERIALS AND METHODS

A retrospective review was performed of 49 patients with desmoplastic melanoma of the head and neck at a tertiary care center from 1994 to 2014.

RESULTS

Sentinel lymph node biopsy was performed in 15 patients. Only 1 (6.7%) of these patients was found to have a positive sentinel node. Of the 46 patients without evidence of neck disease at presentation, 3 (6.5%) were found to have occult nodal disease or developed neck recurrences. When looking at the entire cohort, there were a total of 16 recurrences in 14 patients (28.6%). The majority (85.7%) of recurrences were either local or distant metastasis with only 2 (14.3%) recurrences being in regional lymph node basins. The overall rates of local, regional, and distant recurrences were 14.2%, 4.1%, and 10.2% respectively. The mixed pathologic subtype was not associated with a higher rate of nodal metastasis.

CONCLUSIONS

Desmoplastic melanoma has a low rate of occult nodal metastasis and a high propensity to recur locally or as a distant metastasis, regardless of regional node status. Our experience combined with the uncertain impact that sentinel node status has on survival raises the question of the utility of routine sentinel node biopsy in this specific variant of melanoma.

Penile melanoma: a 20-Year analysis of six patients at the National Cancer Institute of Peru, Lima

Melanoma of the urogenital tract is extremely rare, accounting for less than 0.1% of melanoma cases. The global literature currently describes only 220 cases of penile melanoma, most commonly located on the glans penis.

RESULTS

Penile melanoma accounts for 0.7% of penile cancers and 0.18% of melanoma cases. The average patient age for the six cases we reviewed was 44.5 years. Three of these cases (50%) involved ulceration, one case (16.7%) involved lymphovascular invasion, and three cases (50%) involved mitosis ≥ 1 mm² (0.38-4.7 mm). The average depth of invasion (Breslow) in the five cases that reported this measure was 2.1 mm (0.38-4.7 mm). Applying the American Joint Committee on Cancer tumour, node, metastases (AJCC TNM) staging system, one case was Tx (16.7%), two cases were T1 (33.3%), one case was T2 (16.7%), one case was T3 (16.7%), and one case was T4 (16.7%). Five cases (83.3%) involved wide local resection, and only one case involved partial penile amputation. Four cases (66.7%) involved primary bilateral inguinocrural lymphadenectomy, and only one of those four cases involved lymphatic metastatic disease. One case (16.7%) involved lymphatic recurrence at 12 months in a patient who survived 38 months. One case (16.7%) involved local recurrence at 13 months in a patient who has survived 53 months. Eighty per cent of these patients remain alive, with no evidence of disease after an average follow-up of 96.7 months.

CONCLUSION

Penile melanoma prognosis depends on the initial clinical stage of the disease. The risk of lymphatic involvement seems to be related to the same risk factors used to assess cutaneous melanoma. Clinicians can thus assess penile melanoma using the AJCC staging system. The use of sentinel lymph node biopsy to determine staging is also becoming more common and could replace prophylactic bilateral inguinal dissection.