Sentinel lymph node biopsy in patients with thin primary cutaneous melanoma

Primary Melanoma Histopathologic Predictors of Sentinel Lymph Node Positivity: A Proposed Scoring System for Risk Assessment and Patient Selection in a Clinical Setting

Background and Objectives: The careful selection of adequate SLNB candidates not only aims at reducing the surgical risk while identifying SLN metastasis, but also plays a crucial role in identifying the patients eligible for adjuvant therapy. Objectives: The purpose of our study was to investigate the clinical and histologic aspects of primary melanomas that correlate with the likelihood of a positive SLNB result. Materials and Methods: A total of 101 primary melanoma patients who underwent sentinel lymph node biopsies were included in the study. General patient demographics were obtained as well as localization and melanoma-specific characteristics of primary melanoma from histologic reports in addition to data derived from SLNB melanoma histopathology reports. Results: The patients with positive SLN results had a statistically significant increased Breslow thickness (3.8 mm vs. 1.97 mm, p = 0.002), higher mitotic index rate (5/mm2 vs. 2/mm2, p = 0.009), as well as the presence of ulceration (68.4% vs. 31.6%, p = 0.007). Univariate regression analysis showed the Breslow thickness (p = 0.008), the mitotic index rate (p = 0.054), the presence of ulceration (p = 0.009), as well as the pT3-4 stage (p = 0.009) to be significant predictors of SLN positivity. The optimal cut-off values for Breslow thickness and the number of mitoses scores were determined based on ROC curve analysis. Using the Breslow thickness, mitotic index rate, presence of ulceration, and pT3-4 stage significant coefficients from the univariate regression model, a chance prediction score was developed. Conclusions: The newly developed and proposed scoring system can aid in patient selection for SLN biopsy by facilitating a more efficient risk assessment in the detection of lymph node metastases in melanoma patients.

Predictors of sentinel lymph node metastasis in very thin invasive melanomas

BACKGROUND

Melanomas < 0.8 mm in Breslow depth have less than a 5% risk for nodal positivity. Nonetheless, nodal positivity is prognostic for this group. Early identification of nodal positivity may improve the outcomes for these patients.

OBJECTIVES

To determine the degree to which ulceration and other high-risk features predict sentinel lymph node (SLN) positivity for very thin melanomas.

METHODS

The National Cancer Database was reviewed from 2012 to 2018 for patients with melanoma with Breslow thickness < 0.8 mm. Data were analysed from 7 July 2022 through to 25 February 2023. Patients were excluded if data regarding their ulceration status or SLN biopsy (SLNB) performance were unknown. We analysed patient, tumour and health system factors for their effect on SLN positivity. Data were analysed using χ2 tests and logistic regressions. Overall survival (OS) was compared by Kaplan-Meier analyses.

RESULTS

Positive nodal metastases were seen in 876 (5.0%) patients who underwent SLNB (17 692). Factors significantly associated with nodal positivity on multivariable analysis include lymphovascular invasion [odds ratio (OR) 4.5, P < 0.001], ulceration (OR 2.6, P < 0.001), mitoses (OR 2.1, P < 0.001) and nodular subtype (OR 2.1, P < 0.001). Five-year OS was 75% and 92% for patients with positive and negative SLN, respectively.

CONCLUSIONS

Nodal positivity has prognostic significance for very thin melanomas. In our cohort, the rate of nodal positivity was 5% overall in these patients who underwent SLNB. Specific tumour factors (e.g. lymphovascular invasion, ulceration, mitoses, nodular subtype) were associated with higher rates of SLN metastases and should be used to guide clinicians in choosing which patients will benefit from SLNB.

Sentinel lymph node biopsy in patients with T1a cutaneous malignant melanoma: A multicenter cohort study

BACKGROUND

Sentinel lymph node biopsy is not routinely recommended for T1a cutaneous melanoma due to the overall low risk of positivity. Prognostic factors for positive sentinel lymph node (SLN⁺) in this population are poorly characterized.

OBJECTIVE

To determine factors associated with SLN⁺ in patients with T1a melanoma.

METHODS

Patients with pathologic T1a (<0.80 mm, nonulcerated) cutaneous melanoma from 5 high-volume melanoma centers from 2001 to 2020 who underwent wide local excision with sentinel lymph node biopsy were included in the study. Patient and tumor characteristics associated with SLN⁺ were analyzed by univariate and multivariable logistic regression analyses. Age was dichotomized into ≤42 (25% quartile cutoff) and >42 years.

RESULTS

Of the 965 patients identified, the overall SLN⁺ was 4.4% (N = 43). Factors associated with SLN⁺ were age ≤42 years (7.5% vs 3.7%; odds ratio [OR], 2.14; P = .03), head/neck primary tumor location (9.2% vs 4%; OR, 2.75; P = .04), lymphovascular invasion (21.4% vs 4.2%; OR, 5.64; P = .01), and ≥2 mitoses/mm² (8.2% vs 3.4%; OR, 2.31; P = .03). Patients <42 years with ≥2 mitoses/mm² (N = 38) had a SLN⁺ rate of 18.4%.

LIMITATIONS

Retrospective study.

CONCLUSION

SLN⁺ is low in patients with T1a melanomas, but younger age, lymphovascular invasion, mitogenicity, and head/neck primary site appear to confer a higher risk of SLN⁺.

Tissue Biomarkers Predicting Lymph Node Status in Cutaneous Melanoma

Cutaneous melanoma is a severe neoplasm that shows early invasiveness of the lymph nodes draining the primary site, with increased risk of distant metastases and recurrence. The tissue biomarker identification could be a new frontier to predict the risk of early lymph node invasiveness, especially in cases considered by current guidelines to be at low risk of lymph node involvement and not requiring evaluation of the sentinel lymph node (SLN). For this reason, we present a narrative review of the literature, seeking to provide an overview of current tissue biomarkers, particularly vascular endothelium growth factors (VEGF), Tetraspanin CD9, lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1), D2-40, and gene expression profile test (31-GEP). Among these, 31-GEP seems to be able to provide a distinction between low or high risk for positive SLN classes. VEGF receptor-3 and CD9 expression may be independent predictors of positive SLN. Lastly, LYVE-1 and D2-40 allow an easier assessment of lymph vascular invasion, which can be considered a good predictor of SLN status. In conclusion, biomarkers to assess the lymph node status of cutaneous melanoma patients may play an important role in those cases where the clinician is in doubt whether or not to perform SLN biopsy.

Evaluation of the Indications for Sentinel Node Biopsy in Early-Stage Melanoma with the Advent of Adjuvant Systemic Therapy: An International, Multicenter Study

BACKGROUND

Patients presenting with early-stage melanoma (AJCC pT1b-pT2a) reportedly have a relatively low risk of a positive SNB (~5-10%). Those patients are usually found to have low-volume metastatic disease after SNB, typically reclassified to AJCC stage IIIA, with an excellent prognosis of ~90% 5-year survival. Currently, adjuvant systemic therapy is not routinely recommended for most patients with AJCC stage IIIA melanoma. The purpose was to assess the SN-positivity rate in early-stage melanoma and to identify primary tumor characteristics associated with high-risk nodal disease eligible for adjuvant systemic therapy METHODS: An international, multicenter retrospective cohort study from 7 large-volume cancer centers identified 3,610 patients with early primary cutaneous melanomas 0.8-2.0 mm in Breslow thickness (pT1b-pT2a; AJCC 8th edition). Patient demographics, primary tumor characteristics, and SNB status/details were analyzed.

RESULTS

The overall SNB-positivity rate was 11.4% (412/3610). Virtually all SNB-positive patients (409/412; 99.3%) were reclassified to AJCC stage IIIA. Multivariate analysis identified age, T-stage, mitotic rate, primary site and subtype, and lymphovascular invasion as independent predictors of sentinel node status. A mitotic rate of >1/mm2 was associated with a significantly increased SN-positivity rate and was the only significant independent predictor of high-risk SNB metastases (>1 mm maximum diameter).

CONCLUSIONS

The new treatment paradigm brings into question the role of SNB for patients with early-stage melanoma. The results of this large international cohort study suggest that a reevaluation of the indications for SNB for some patients with early-stage melanoma is required.

Classification and Staging of Melanoma in the Head and Neck

The rates of melanoma continue to rise, with recent estimates have shown that 18% to 22% of new melanoma cases occur within the head and neck in the United States each year. The mainstay of treatment of nonmetastatic primary melanomas of the head and neck includes the surgical resection and management of regional disease as indicated. Thorough knowledge of the classification and staging of melanoma is paramount to evaluate prognosis, determine the appropriate surgical intervention, and assess eligibility for adjuvant therapy and clinic trials. The traditional clinicopathologic classification of melanoma is based on morphologic aspects of the growth phase and distinguishes 4 of the most common subtypes as defined by the World Health Organization: superficial spreading, nodular, acral lentiginous, and lentigo maligna melanoma. The data used to derive the AJCC TNM Categories are based on superficial spreading melanoma and nodular subtypes. Melanoma is diagnosed histopathologically following initial biopsy that will assist with classifying the tumor to guide treatment. Classification is based on tumor thickness and ulceration (T stage, Breslow Staging), Regional Lymph Node Involvement (N Stage), and presence of metastasis (M Stage). Tumor thickness (Breslow thickness) and ulceration are 2 independent prognostic factors that have been shown to be the strongest predictors of survival and outcome. Clark level of invasion and mitotic rate are no longer incorporated into the current AJCC staging system, but still have shown to be important prognostic factors for cutaneous melanoma. For patients with metastatic (Stage IV) disease Lactate Dehydrogenase remains an independent predictor of survival. The Maxillofacial surgeon must remain up to date on the most current management strategies in this patient population. Classification systems and staging provide the foundation for clinical decision making and prognostication for the Maxillofacial surgeon when caring for these patients.

Predictive Values of Pathological and Clinical Risk Factors for Positivity of Sentinel Lymph Node Biopsy in Thin Melanoma: A Systematic Review and Meta-Analysis

Background

The indications for sentinel lymph node biopsy (SLNB) for thin melanoma are still unclear. This meta-analysis aims to determine the positive rate of SLNB in thin melanoma and to summarize the predictive value of different high-risk features for positive results of SLNB.

Methods

Four databases were searched for literature on SLNB performed in patients with thin melanoma published between January 2000 and December 2020. The overall positive rate and positive rate of each high-risk feature were calculated and obtained with 95% confidence intervals (CIs). Both unadjusted odds ratios (ORs) and adjusted ORs (AORs) of high-risk features were analyzed. Pooled effects were estimated using random-effects model meta-analyses.

Results

Sixty-six studies reporting 38,844 patients with thin melanoma who underwent SLNB met the inclusion criteria. The pooled positive rate of SLNB was 5.1% [95% confidence interval (CI) 4.9%-5.3%]. Features significantly predicted a positive result of SLNB were thickness≥0.8 mm [AOR 1.94 (95%CI 1.28-2.95); positive rate 7.0% (95%CI 6.0-8.0%)]; ulceration [AOR 3.09 (95%CI 1.75-5.44); positive rate 4.2% (95%CI 1.8-7.2%)]; mitosis rate >0/mm2 [AOR 1.63 (95%CI 1.13-2.36); positive rate 7.7% (95%CI 6.3-9.1%)]; microsatellites [OR 3.8 (95%CI 1.38-10.47); positive rate 16.6% (95%CI 2.4-36.6%)]; and vertical growth phase [OR 2.76 (95%CI 1.72-4.43); positive rate 8.1% (95%CI 6.3-10.1%)].

Conclusions

The overall positive rate of SLNB in thin melanoma was 5.1%. The strongest predictor for SLN positivity identified was microsatellites on unadjusted analysis and ulceration on adjusted analysis. Breslow thickness ≥0.8 mm and mitosis rate >0/mm² both predict SLN positivity in adjusted analysis and increase the positive rate to 7.0% and 7.7%. We suggest patients with thin melanoma with the above high-risk features should be considered for giving an SLNB.

More sentinel lymph node biopsies for thin melanomas after transition to AJCC 8th edition do not increase positivity rate: A Danish population-based study of 7148 patients

BACKGROUND

We evaluated the outcome of sentinel lymph node biopsies (SLNB) in patients with thin melanoma before and after the implementation of AJCC 8th edition (AJCC8) and identified predictors of positive sentinel lymph nodes (+SLN).

METHODS

Patients diagnosed with T1 melanomas (Breslow thickness ≤1 mm) during 2016-2017 as per AJCC 7th edition (AJCC7) (n = 3414) and 2018-2019 as per AJCC8 (n = 3734) were identified in the Danish Melanoma Database.

RESULTS

More SLNBs were performed in the AJCC8 cohort compared to the AJCC7 (22.2% vs. 16.2%, p < 0.001), with no significant difference in +SLN rates (4.7% vs. 6.7%, p = 0.118). In the AJCC7 + SLN subgroup, no melanomas were ulcerated, 94.6% had mitotic rate (MR) ≥ 1, 67.6% were ≥0.8 mm and 32.4% would be T1a according to AJCC8. In the AJCC8 + SLN subgroup, 10.3% were ulcerated, 74.4% had MR≥ 1, 97.4% were ≥0.8 mm and 23.1% would be T1a according to AJCC7. On multivariable analysis younger age and MR ≥ 1 were significant predictors of +SLN.

CONCLUSION

More SLNBs were performed in T1 melanomas after transition to AJCC8 without an increase in +SLN rate. None of the AJCC8 T1b criteria were significant predictors of +SLN. We suggest that mitosis and younger age should be considered as indications for SLNB in thin melanoma.

Integrating 31-Gene Expression Profiling With Clinicopathologic Features to Optimize Cutaneous Melanoma Sentinel Lymph Node Metastasis Prediction

National guidelines recommend sentinel lymph node biopsy (SLNB) be offered to patients with > 10% likelihood of sentinel lymph node (SLN) positivity. On the other hand, guidelines do not recommend SLNB for patients with T1a tumors without high-risk features who have < 5% likelihood of a positive SLN. However, the decision to perform SLNB is less certain for patients with higher-risk T1 melanomas in which a positive node is expected 5%-10% of the time. We hypothesized that integrating clinicopathologic features with the 31-gene expression profile (31-GEP) score using advanced artificial intelligence techniques would provide more precise SLN risk prediction.

American Joint Committee on Cancer Staging and Other Platforms to Assess Prognosis and Risk

The eighth edition of the American Joint Committee on Cancer melanoma staging system relies on assessments of the primary tumor (T), regional lymph nodes (N), and distant metastatic sites (M). Its notable updates include tumor thickness measurements to the nearest 0.1 mm, revision of T1a and T1b definitions, re-evaluation of N category descriptors, increased number of stage III subgroupings, and incorporation of a new M1d designation, among others. These changes were based on analyses of a large contemporary international melanoma database. Ultimately, these revisions were made to improve staging and prognostication, risk stratification, and selection of patients for clinical trials.

Sentinel Lymph Node Biopsy, Lymph Node Dissection, and Lymphedema Management Options in Melanoma

Melanoma tumor thickness and ulceration are the strongest predictors of nodal spread. The recommendations for sentinel lymph node biopsy (SLNB) have been updated in recent American Joint Committee on Cancer and National Comprehensive Cancer Network guidelines to include tumor thickness ≥0.8 mm or any ulcerated melanoma. Mitotic rate is no longer considered an indicator for determining T category. Improvements in disease-specific survival conferred from SLNB were demonstrated through level I data in the Multicenter Selective Lymphadenectomy Trial (MSLT) I. The role for completion lymph node dissection has evolved to less surgery in lieu of recent domestic (MSLT II) and international (Dermatologic Cooperative Oncology Group Selective Lymphadenectomy Trial [DeCOG-SLT]) level I data having similar melanoma-specific survival. Treatment options for the prevention of treatment of lymphedema have progressed to include immediate lymphatic reconstruction, lymphovenous anastomosis, and vascularized lymph node transfer.

Compliance with sentinel lymph node biopsy guidelines for invasive melanomas treated with Mohs micrographic surgery

BACKGROUND

Sentinel lymph node biopsy (SLNB) has not been studied for invasive melanomas treated with Mohs micrographic surgery using frozen-section MART-1 immunohistochemical stains (MMS-IHC). The primary objective of this study was to assess the accuracy and compliance with National Comprehensive Cancer Network (NCCN) guidelines for SLNB in a cohort of patients who had invasive melanoma treated with MMS-IHC.

METHODS

This retrospective cohort study included all patients who had primary, invasive, cutaneous melanomas treated with MMS-IHC at a single academic center between March 2006 and April 2018. The primary outcomes were the rates of documenting discussion and performing SLNB in patients who were eligible based on NCCN guidelines. Secondary outcomes were the rate of identifying the sentinel lymph node and the percentage of positive lymph nodes.

RESULTS

In total, 667 primary, invasive, cutaneous melanomas (American Joint Committee on Cancer T1a-T4b) were treated with MMS-IHC. The median patient age was 69 years (range, 25-101 years). Ninety-two percent of tumors were located on specialty sites (head and/or neck, hands and/or feet, pretibial leg). Discussion of SLNB was documented for 162 of 176 (92%) SLNB-eligible patients, including 127 of 127 (100%) who had melanomas with a Breslow depth >1 mm. SLNB was performed in 109 of 176 (62%) SLNB-eligible patients, including 102 of 158 melanomas (65%) that met NCCN criteria to discuss and offer SLNB and 7 of 18 melanomas (39%) that met criteria to discuss and consider SLNB. The sentinel lymph node was successfully identified in 98 of 109 patients (90%) and was positive in 6 of those 98 patients (6%).

CONCLUSIONS

Combining SLNB and MMS-IHC allows full pathologic staging and confirmation of clear microscopic margins before reconstruction of specialty site invasive melanomas. SLNB can be performed accurately and in compliance with consensus guidelines in patients with melanoma using MMS-IHC.

Risk factors and patterns of recurrence after sentinel lymph node biopsy for thin melanoma

While having a thin melanoma (defined as AJCC 8 T1 stage tumor ≤ 1.0 mm) with negative sentinel lymph node biopsy (SLNB) provides an excellent prognosis, some patients still develop recurrence and die. To determine risk factors for any recurrence (local/in-transit, nodal, distant) in thin melanoma patients with negative SLNB and assess survival outcomes. Retrospective review of thin melanomas with negative SLNB from 1999 to 2018 was performed. Two hundred and nine patients were identified. Clinicopathologic characteristics of the primary melanoma were collected. Patterns of recurrence for local/in-transit, nodal or distant recurrence and survival outcomes were analyzed. Eighteen patients (8.6%) developed recurrence: 3 (1.9%) local/in-transit, 4 (2.9%) regional/nodal, and 11 (5.3%) distant recurrence during a median follow-up time of 62 months. A multivariate Cox regression model showed that head and neck site (HR 3.52), ulceration (HR 10.8), and mitotic rate (HR 1.39) were significant risk factors for recurrence. Median time to first recurrence was 49 months. Patients with recurrence had a significantly worse 5 year overall survival than those without recurrence (82.2 vs 99.2%). A retrospective single center study and limited sample size. Did not factor in possible false negative SLNBs when calculating hazard ratios. For thin melanoma patients with negative SLNB, heightened surveillance is warranted for those with ulceration, primary tumor location on the head or neck, and elevated mitotic rate.

Multiple combinations of melanocytic and vascular endothelial markers enhance the detection rate of lymphovascular invasion in cutaneous melanoma

BACKGROUND

Lymphovascular invasion (LVI) is believed to be the mechanism by which melanoma cells can disseminate to regional lymph nodes and distant sites and may be predictive of adverse outcome. Lymphovascular invasion often difficult to detect on hematoxylin-eosin (HE) stained sections, are readily identified with dual immunohistochemistry (IHC) for melanocytic and vascular markers.

METHODS

A total of 100 primary cutaneous malignant melanoma cases that had a Breslow thickness of 1-4 mm and lacked LVI by conventional HE assessment were included. We compared the LVI detection rates of double staining for CD31/S100 and CD34/S100, and D2-40/S100, and examined the association of LVI with clinical outcomes.

RESULTS

The dual immunohistochemical positivity for CD31/S100, CD34/S100, and D2-40/S100 were 40(40%), 17(17%) and 35(35%), respectively. On multivariate analysis, LVI was an independent predictor of SLN status. Multivariate analysis revealed that LVI and male gender were independent risk factors for overall survival.

CONCLUSIONS

The recognition of LVI is improved by dual IHC and predicts SLN metastasis. The detection of LVI using dual IHC, especially by a combination of CD31/S100 and D2-40/S100 is a useful step that inclusion should be recommended in basic evaluation parameters for cutaneous melanoma.

Re-evaluation of Sentinel Lymph Node Biopsy for Melanoma

OPINION STATEMENT

The vast majority of patients newly diagnosed with melanoma present with clinically localized disease, and sentinel lymph node biopsy (SLNB) is a standard of care in the management of these patients, particularly in intermediate thickness cases, in order to provide important prognostic data. However, SLNB also has an important role in the management of patients with other subtypes of melanoma such as thick melanomas, certain thin melanomas, and specific histologic variants of melanoma such as desmoplastic melanoma. Furthermore, there have been technical advances in the SLNB technique, such as the development of newer radiotracers and use of SPECT/CT, and there is some data to suggest performing a SLNB may be therapeutic. Finally, the management of patients with a positive sentinel lymph node (SLN) has undergone dramatic changes over the past several years based on the results of recent important clinical trials. Treatment options for patients with SLN metastases now include surveillance, completion lymph node dissection, and adjuvant therapy with checkpoint inhibitors and targeted therapy. SLNB continues to play a crucial role in the management of patients with melanoma, allowing for risk stratification, potential regional disease control, and further treatment options for patients with a positive SLN.

Differences in cutaneous melanoma survival between the 7th and 8th edition of the American Joint Committee on Cancer (AJCC). A multicentric population-based study

BACKGROUND

The 8th edition of the AJCC manual for melanoma includes many changes leading to major substage migrations, which could lead to important clinical reassessments.

OBJECTIVES

To evaluate the differences and prognostic value of the 8th AJCC classification in comparison with the 7th edition.

METHODS

Clinical and histopathological data were retrieved from five melanoma referral centers including 7815 melanoma patients diagnosed between January 1998 and December 2018. All patients were reclassified and compared using the 7th and 8th classifications of the AJCC. Sankey plots were used to evaluate the migration of patients between the different versions. The primary outcome was overall survival (OS), and curves based on the Kaplan-Meier method were used to investigate survival differences between the 7th and 8th editions.

RESULTS

The number of patients classified as stages IB, IIIA, and IIIB decreased while the patients classified as stages IA and IIIC increased notably. Migration analysis showed that many patients in group I were understaged whereas a significant percentage of patients in group III were upstaged. Indirect OS analysis showed a loss in the linearity in the AJCC 8th edition and the groups tended to overlap. Direct OS analysis between groups and versions of the AJCC showed a better prognosis within the new stage III patients, with no effect on those in stages I and II.

CONCLUSION

The 8th AJCC edition represents an important change in the classification of patients. We observe that the main migratory changes occur in stage I and III, that severity linearity is lost and groups overlap, and that a more advanced stage does not mean a worse prognosis.

High Mitotic Rate Predicts Sentinel Lymph Node Involvement in Thin Melanomas

BACKGROUND

Indications for sentinel lymph node (SLN) biopsy in the population with thin melanoma have frequently changed over time. The objective of our study was to evaluate T1 melanoma pathologic features predictive of SLN positivity with a primary focus on identifying a specific mitotic value that is most predictive of lymph node disease. Further detailed predictive features would help physicians select patients with thin melanoma for SLN biopsy.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for all patients diagnosed with trunk or extremity cutaneous melanoma with ≤1 mm depth who underwent SLN biopsy between the years of 2010 and 2013. Patient demographics and tumor characteristics including depth, mitotic rate (MR), ulceration, and tumor location were evaluated. MR was dichotomized at multiple cut points to identify the ideal number of mitosis for MR as a predictor of SLN status. Multivariable logistic regression analyses were performed to identify the factors affecting nodal positivity and the impact of MR threshold. Kaplan-Meir curves were used for overall survival (OS) analysis.

RESULTS

Factors significantly associated with SLN positivity in the entire cohort included MR (P < 0.001, OR 1.24, 95% CI 1.18-1.31), tumor location (P = 0.017, OR 1.48, 95% CI 1.07-2.05), and ulceration (P < 0.001, OR 2.01, 95% CI 1.39-2.93,). An MR ≥ 4 was significant for SLN positivity (P = 0.049, OR 1.08, 95% CI 1.01-1.38). Mean OS was 46.7 mo for MR < 4 compared with 43.2 mo for MR ≥ 4 (P < 0.001).

CONCLUSIONS

MR ≥ 4 was significant and associated with SLN positivity in thin melanomas and asulceration. Thus, MR ≥ 4 should be considered as an indication for SLN biopsy in thin melanoma.

A brief synopsis on scalp melanoma

Melanoma constitutes one of the most sinister and troublesome malignancies encountered by humanity. Generally, the diagnosis of advanced melanoma connotes a grave prognosis, prompting a sense of looming threat of death, however, the early-stage detected disease responds well to robust treatment resulting in reasonable survivorship. Scalp melanomas are even more troublesome, because they typically exhibit more aggressive biologic behavior and are often diagnosed at a late stage. This review tries to comprehensively highlight the various diagnostic, therapeutic, and outcome aspects of scalp melanomas. The literature research includes peer-reviewed articles (clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) till May 2020 and reference lists of respective articles. Only articles published in English language were included.

Is it Necessary to Perform Sentinel Lymph Node Biopsy in Thin Melanoma? A Retrospective Single Center Analysis

Sentinel lymph node biopsy (SLNB) is a standard procedure for regional lymph node staging and still has the most important prognostic value for the outcome of patients with thin melanoma. In addition to ulceration, SLNB had to be considered even for a single mitotic figure in thin (<1 mm) melanoma according to AJCC7th guideline, therefore, a retrospective review was conducted involving 403 pT1 melanoma patients. Among them, 152 patients suffered from pT1b ulcerated or mitotic rate ≥ 1/ mm2 melanomas according to the AJCC7th staging system. SLNB was performed in 78 cases, of which nine (11.5%) showed SLN positivity. From them, interestingly, we found a relatively high positive sentinel rate (6/78-8%) in the case of thin primary melanomas ˂0.8 mm. Moreover, the presence of regression increased the probability of sentinel positivity by 5.796 fold. After reassessing pT stage based on the new AJCC8th, 37 pT1b cases were reordered into pT1a category. There was no significant relation between other characteristics examined (age, gender, Breslow, Clark level, and mitosis index) and sentinel node positivity. Based on our data, we suggest that mitotic rate alone is not a sufficiently powerful predictor of SLN status in thin melanomas. If strict histopathological definition criteria are applied, regression might be an additional adverse feature that aids in identifying T1 patients most likely to be SLN-positive. After reassessing of pT1b cases according to AJCC8th regression proved to be independent prognostic factor on sentinel lymph node positivity. Our results propose that sentinel lymph node biopsy might also be considered at patients with regressive thin (˂0.8 mm) melanomas.

Speed rate (SR) as a new dynamic index of melanoma behavior

Melanomas are skin tumors that show a variety of biological behavior. Some develop very fast and some other grow extremely slow, with metastasis appearing, eventually, many years after the diagnosis. The number of mitoses in primary melanoma has been related to a more aggressive tumor and may have a potential as predictive factor for cutaneous melanoma survival. However, tumor mitotic rate is a static measure and in multivariate analysis on tumor survival, it has scored less than other tumor characteristics. We tried to evolve tumor mitotic rate from a static parameter to a time-dependent one. Similar to the already described growth rate (GR), we propose the speed rate (SR). SR is defined as the ratio of tumor mitotic rate to time to melanoma development. A prospective series of 345 patients with melanoma was investigated for the role of SR as predictive factor for sentinel lymph node (SLN) positivity and tumor progression. We calculated the best threshold for SR and GR to predict the risk of recurrence. Melanoma clinical and histological characteristics as well as GR were correlated in a multivariated analysis with SR. SR values >0.2 mitoses/month were associated with negative prognostic factors such as ulceration (82.8%), SLN positivity (80%), progression (82.8%), and death (85.7%). The association of GR > 0.3 mm/months and SR > 0.2 mitoses/month had a significant predictive value in terms of SLN positivity, progression, and recurrence-free survival. We propose SR as a new "dynamic" predictor of histological SLN positivity and melanoma recurrence risk. We think that he association with this new feature with GR may be helpful in improving the accuracy of predicted clinical outcome of patient especially with thin melanomas.

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.

Risk of Melanoma Recurrence After Diagnosis of a High-Risk Primary Tumor

Importance

With emerging new systemic treatments for metastatic melanoma, early detection of disease recurrence is increasingly important.

Objective

To investigate the risk of melanoma recurrence in patients with a localized melanoma at a high risk of metastasis.

Design, Setting, and Participants

A total of 1254 patients with newly diagnosed, histologically confirmed tumor category T1b to T4b melanoma in Queensland, Australia, were recruited prospectively between October 1, 2010, and October 1, 2014, for participation in a cohort study. Data analysis was conducted from February 8, 2018, to February 20, 2019. We used Cox proportional hazards regression analysis to examine associations between patient and tumor factors and melanoma recurrence.

Exposures

Disease-free survival (DFS) by melanoma tumor category defined by the 7th vs 8th editions of the AJCC Cancer Staging Manual (AJCC 7 vs AJCC 8).

Main Outcomes and Measures

Melanoma recurrences were self-reported through follow-up questionnaires administered every 6 months and confirmed by histologic or imaging findings.

Results

Of 1254 patients recruited, 825 individuals (65.8%) agreed to participate. Thirty-six were found to be ineligible after providing consent and a further 89 patients were excluded after reclassifying tumors using AJCC 8, leaving 700 participants with high-risk primary melanoma (mean [SD] age, 62.2 [13.5] years; 410 [58.6%] men). Independent predictors of recurrence were head or neck site of primary tumor, ulceration, thickness, and mitotic rate greater than 3/mm2 (hazard ratio, 2.36; 95% CI, 1.19-4.71). Ninety-four patients (13.4%) developed a recurrence within 2 years of diagnosis: 66 tumors (70.2%) were locoregional, and 28 tumors (29.8%) developed at distant sites. After surgery for locoregional disease, 37 of 64 patients (57.8%) remained disease free at 2 years, 7 patients (10.9%) developed new locoregional recurrence, and 20 patients (31.3%), developed distant disease. Two-year DFS was similar when comparing AJCC 7 and AJCC 8, for T1b (AJCC 7, 253 [93.3% DFS]; AJCC 8, 242 [93.0% DFS]) and T4b (AJCC 7 and AJCC 8, 50 [68.0% DFS] category tumors in both editions. Patients with T2a to T4a tumors who did not have a sentinel lymph node biopsy (SLNB) at diagnosis had lower DFS than patients with the same tumor category and a negative SLNB (T2a: 136 [91.1%; 95% CI, 86.4-95.9] vs 96 [96.9%; 95 % CI, 93.4-100.0]; T4a: 33 [78.8%; 95% CI, 64.8-92.7] vs 6 [83.3; 95% CI, 53.5-100.0]).

Conclusions and Relevance

These findings suggest that 13.4% of patients with a high-risk primary melanoma will experience disease recurrence within 2 years. Head or neck location of initial tumor, SLNB positivity, and signs of rapid tumor growth may be associated with primary melanoma recurrence.

Evolving management of positive regional lymph nodes in melanoma: Past, present and future directions

Sentinel lymph node (SLN) biopsy has become the standard of care for lymph node staging in melanoma and the most important predictor of survival in clinically node-negative disease. Previous guidelines recommend completion lymph node dissection (CLND) in cases of positive SLN; however, the lymph nodes recovered during CLND are only positive in a minority of these cases. Recent evidence suggests that conservative management (i.e. observation) has similar outcomes compared to CLND. We sought to review the most current literature regarding the management of SLN in metastatic melanoma and to discuss potential future directions.

Nonsurgical Management of Lymph Node Basins in Melanoma

In this article we provide a critical review of the evidence available for surgical management of the nodal basin in melanoma, with an aim to ensure an understanding of risks and benefits for all lymph node surgery offered to patients, and alternatives to surgical management where appropriate.

Staging Melanoma: What's Old and New

The melanoma expert panel devised the evidence-based eighth edition American Joint Committee on Cancer staging system by conducting vigorous analyses of stage I, II, and III patients from the International Melanoma Database and Discovery Platform. Key changes in the eighth edition are regarding subcategorization of T1, M1, pathologic stage grouping of stage I and III, and refining the definitions and terminologies used in the staging system. As the knowledge of tumor biology improves, the staging of melanoma will continue to evolve to enable betterment of care.

A nomogram to predict node positivity in patients with thin melanomas helps inform shared patient decision making

OBJECTIVE

To develop a nomogram to estimate the probability of positive sentinel lymph node (+SLN) for patients with thin melanoma and to characterize its potential impact on sentinel lymph node biopsy (SLNB) rates.

METHODS

Patients diagnosed with thin (0.5-1.0 mm) melanoma were identified from the National Cancer Database 2012 to 2015. A multivariable logistic regression model was used to examine factors associated with +SLN, and a nomogram to predict +SLN was constructed. Nomogram performance was evaluated and diagnostic test statistics were calculated.

RESULTS

Of the 21 971 patients included 10 108 (46.0%) underwent SLNB, with a 4.0% +SLN rate. On multivariable analysis, age, Breslow thickness, lymphovascular invasion, ulceration, and Clark level were significantly associated with SLN status. The area under the receiver operating curve was 0.67 (95% confidence interval, 0.65-0.70). While 15 249 (69.4%) patients had either T1b tumors or T1a tumors with at least one adverse feature, only 2846 (13.0%) had a nomogram predicted probability of a +SLN ≥5%. Using this cut-off, the indication for a SLNB in these patients would be reduced by 81.3% as compared to the American Joint Committee on Cancer 8th edition staging criteria.

CONCLUSIONS

The risk predictions obtained from the nomogram allow for more accurate selection of patients who could benefit from SLNB.

The eighth edition American Joint Committee on Cancer (AJCC) melanoma staging system: implications for melanoma treatment and care

INTRODUCTION

The eighth edition of the American Joint Committee on Cancer (AJCC) melanoma staging system was implemented in the United States on 1 January 2018. Areas covered: This article provides an overview of important changes in the eighth edition AJCC staging system from the seventh edition based on analyses of a large international melanoma database. The clinical implications of these changes for melanoma treatment are also discussed. Expert commentary: A standardized and contemporary cancer staging system that facilitates accurate risk stratification is essential to guide patient treatment. The eighth edition of the AJCC staging system is currently the most widely accepted approach to melanoma staging and classification at initial diagnosis.

Predictors of sentinel lymph node positivity in thin melanoma using the National Cancer Database

BACKGROUND

Sentinel lymph node biopsy (SLNB) specimens are often obtained from patients for further staging after these patients have undergone melanoma excision. Limited data regarding predictors of SLNB positivity in thin melanoma are available.

OBJECTIVE

We sought to evaluate predictors of SLNB positivity in thin melanoma.

METHODS

Patients with cutaneous melanoma with a Breslow thickness ≤1.00 mm who received a SLNB were identified from the National Cancer Database between 2004 and 2014 (n = 9186). Predictors of SLNB positivity were analyzed using logistic regression.

RESULTS

In a multivariate analysis, patients <60 years of age (P < .001) and Breslow thickness >0.8 mm (P = .03) were at increased risk for positive sentinel lymph node (SLN). Moreover, on multivariate analysis, the presence of dermal mitoses increased the odds of SLN positivity by 95% (odds ratio [OR] 1.95 [95% confidence interval {CI} 1.53-2.5], P < .001), ulceration by 63% (OR 1.63 [95% CI 1.21-2.18], P < .001), and Clark level IV to V by 48% (OR 1.48 [95% CI 1.19-1.85]). Patients without ulceration but with dermal mitoses had 92% (OR 1.92 [95% CI 1.5-2.48], P < .001) increased SLN positivity.

LIMITATIONS

Limited survival data are available.

CONCLUSIONS

Younger age, a Breslow thickness >0.8 mm, the presence of dermal mitoses, ulceration, and Clark level IV to V are positive predictors of positive SLN. While the new American Joint Committee on Cancer system has removed dermal mitotic rate from staging, continued evaluation of dermal mitotic rate could be valuable for guiding surgical decision making about SLNB.

Current management of regional lymph nodes in patients with melanoma

The publication of recent randomized trials has prompted a significant shift in both our understanding and the management of patients with melanoma. Here, the current management of the regional lymph nodes in patients with melanoma is discussed. This review focuses on selection for sentinel lymph node biopsy, management of the positive sentinel node, management of the clinically positive node, and the controversy over the therapeutic value of early nodal intervention.

Guidelines of care for the management of primary cutaneous melanoma

The incidence of primary cutaneous melanoma continues to increase each year. Melanoma accounts for the majority of skin cancer-related deaths, but treatment is usually curative following early detection of disease. In this American Academy of Dermatology clinical practice guideline, updated treatment recommendations are provided for patients with primary cutaneous melanoma (American Joint Committee on Cancer stages 0-IIC and pathologic stage III by virtue of a positive sentinel lymph node biopsy). Biopsy techniques for a lesion that is clinically suggestive of melanoma are reviewed, as are recommendations for the histopathologic interpretation of cutaneous melanoma. The use of laboratory, molecular, and imaging tests is examined in the initial work-up of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, recommendations for surgical margins and the concepts of staged excision (including Mohs micrographic surgery) and nonsurgical treatments for melanoma in situ, lentigo maligna type (including topical imiquimod and radiation therapy), are updated. The role of sentinel lymph node biopsy as a staging technique for cutaneous melanoma is described, with recommendations for its use in clinical practice. Finally, current data regarding pregnancy and melanoma, genetic testing for familial melanoma, and management of dermatologic toxicities related to novel targeted agents and immunotherapies for patients with advanced disease are summarized.

The prognostic significance of tumor-infiltrating lymphocytes for primary melanoma varies by sex

BACKGROUND

The immune response to melanoma is manifested locally by tumor-infiltrating lymphocytes (TILs). Men and women are known to have varying patterns of immunity, yet sex-specific prognostic implications of TILs have not been explored.

METHODS

Patients who had clinically localized primary melanoma with a Breslow thickness of 0.76 mm or more and underwent sentinel lymph node (SLN) biopsy at our institution were identified. The association between TILs (absent, nonbrisk, and brisk) and SLN positivity was evaluated by using logistic regression. Overall survival (OS) was evaluated by TIL status and sex.

RESULTS

Among 1367 patients identified, 794 were men. TILs were brisk in 143 lesions, nonbrisk in 903, and absent in 321, which did not vary by sex (P = .71). SLN positivity was associated with TILs among men (brisk, 3.8%; nonbrisk, 16.9%; and absent, 26.6% [P < .001]). In contrast, there was no association between SLN positivity and TILs among women (P = .49). Interaction between brisk TILs and sex on SLN positivity was significant (P = .029). Among men, presence of brisk TILs was associated with prolonged OS (P = .038) but not after adjustment for SLN status (P = .42). There was no association between TIL status and OS among women.

LIMITATIONS

Findings from this single-institution study have yet to be validated by other research groups.

CONCLUSIONS

The implications of TILs in predicting SLN positivity appear to be more relevant for men than for women.

Mitotic rate is associated with positive lymph nodes in patients with thin melanomas

BACKGROUND

The American Joint Commission on Cancer will remove mitotic rate from its staging guidelines in 2018.

OBJECTIVE

Using a large nationally representative cohort, we examined the association between mitotic rate and lymph node positivity among thin melanomas.

METHODS

A total of 149,273 thin melanomas in the National Cancer Database were examined for their association of high-risk features of mitotic rate, ulceration, and Breslow depth with lymph node status.

RESULTS

Among 17,204 patients with thin melanomas with data on Breslow depth, ulceration, and mitotic rate who underwent a lymph node biopsy, there was a strong linear relationship between odds of having a positive lymph node and mitotic rate (R² = 0.96, P < .0001, β = 3.31). The odds of having a positive node increased by 19% with each 1-point increase in mitotic rate (odds ratio, 1.19; 95% confidence interval, 1.17-1.21). Cases with negative nodes had a mean mitotic rate of 1.54 plus or minus 2.07 mitoses/mm² compared with 3.30 plus or minus 3.54 mitoses/mm² for those with positive nodes (P < .0001).

LIMITATIONS

The data collected do not allow for survival analyses.

CONCLUSIONS

Mitotic rate was strongly associated with the odds of having a positive lymph node and should continue to be reported on pathology reports.

Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual

Answer questions and earn CME/CNE To update the melanoma staging system of the American Joint Committee on Cancer (AJCC) a large database was assembled comprising >46,000 patients from 10 centers worldwide with stages I, II, and III melanoma diagnosed since 1998. Based on analyses of this new database, the existing seventh edition AJCC stage IV database, and contemporary clinical trial data, the AJCC Melanoma Expert Panel introduced several important changes to the Tumor, Nodes, Metastasis (TNM) classification and stage grouping criteria. Key changes in the eighth edition AJCC Cancer Staging Manual include: 1) tumor thickness measurements to be recorded to the nearest 0.1 mm, not 0.01 mm; 2) definitions of T1a and T1b are revised (T1a, <0.8 mm without ulceration; T1b, 0.8-1.0 mm with or without ulceration or <0.8 mm with ulceration), with mitotic rate no longer a T category criterion; 3) pathological (but not clinical) stage IA is revised to include T1b N0 M0 (formerly pathologic stage IB); 4) the N category descriptors "microscopic" and "macroscopic" for regional node metastasis are redefined as "clinically occult" and "clinically apparent"; 5) prognostic stage III groupings are based on N category criteria and T category criteria (ie, primary tumor thickness and ulceration) and increased from 3 to 4 subgroups (stages IIIA-IIID); 6) definitions of N subcategories are revised, with the presence of microsatellites, satellites, or in-transit metastases now categorized as N1c, N2c, or N3c based on the number of tumor-involved regional lymph nodes, if any; 7) descriptors are added to each M1 subcategory designation for lactate dehydrogenase (LDH) level (LDH elevation no longer upstages to M1c); and 8) a new M1d designation is added for central nervous system metastases. This evidence-based revision of the AJCC melanoma staging system will guide patient treatment, provide better prognostic estimates, and refine stratification of patients entering clinical trials. CA Cancer J Clin 2017;67:472-492. © 2017 American Cancer Society.

Association Between Patient Age and Lymph Node Positivity in Thin Melanoma

Importance

More than half of all new melanoma diagnoses present as clinically localized T1 melanoma, yet sentinel lymph node biopsy (SLNB) is controversial in this population given the overall low yield. Guidelines for SLNB have focused on pathologic factors, but patient factors, such as age, are not routinely considered.

Objectives

To identify indicators of lymph node (LN) metastasis in thin melanoma in a large, generalizable data set and to evaluate the association between patient age and LN positivity.

Design, Setting, and Participants

A retrospective cohort study using the National Cancer Database, an oncology database representing patients from more than 1500 hospitals throughout the United States, was performed (2010-2013). Data analysis was conducted from October 1, 2016, to January 15, 2017. A total of 8772 patients with clinical stage I 0.50 to 1.0 mm thin melanoma undergoing wide excision and surgical evaluation of regional LNs were included for study.

Main Outcome and Measures

The primary outcome of interest was presence of melanoma in a biopsied regional LN. Clinicopathologic factors associated with LN positivity were characterized, using logistic regression. Age was categorized as younger than 40 years, 40 to 64 years, and 65 years or older for multivariable analysis. Classification tree analysis was performed to identify high-risk groups for LN positivity.

Results

Among the study cohort (n = 8772), 333 patients had nodal metastases, for an overall positivity rate of 3.8% (95% CI, 3.4%-4.2%). A total of 4087 (54.0%) patients were women. Median age was 56 years (interquartile range [IQR], 46-67) in patients with negative LNs and 52 years (IQR, 41-61) in those with positive LNs (P < .001). In multivariable analysis, younger age, female sex, thickness of 0.76 mm or larger, increasing Clark level, mitoses, ulceration, and lymphovascular invasion were independently associated with LN positivity. In decision tree analysis, patient age was identified as an important risk stratifier for LN metastases, after mitoses and thickness. Patients younger than 40 years with category T1b tumors 0.50 to 0.75 mm, who would generally not be recommended for SLNB, had an LN positivity rate of 5.6% (95% CI, 3.3%-8.6%); conversely, patients 65 years or older with T1b tumors 0.76 mm or larger, who would generally be recommended for SLNB, had an LN positivity rate of only 3.9% (95% CI, 2.7%-5.3%).

Conclusions and Relevance

Patient age is an important factor in estimating lymph node positivity in thin melanoma independent of traditional pathologic factors. Age therefore should be taken into consideration when selecting patients for nodal biopsy.

Polo-like kinase-1 immunoreactivity is associated with metastases in cutaneous melanoma

BACKGROUND

Polo-like kinase-1 (PLK-1) is one of the key regulators of cell cycle progression. Increased expression of PLK-1 was observed in several tumor types.

METHODS

We immunohistochemically assessed PLK-1 expression in neoplastic and stromal compartments of 96 cutaneous melanomas, and analyzed associations between PLK-1 expression and clinicopathological characteristics.

RESULTS

PLK-1 expression in cancer cells was not associated with basic clinical (eg, age, gender and tumor location) or histopathological (eg, Breslow thickness, mitotic rate and ulceration) parameters. However, increased PLK-1 was more frequent in tumors with concurrent regional nodal metastases and positive sentinel lymph node biopsy status. All primary tumors associated with co-existing distant metastases exhibited high PLK-1 expression in melanoma cells. Conversely, PLK-1 expression in stromal cells was more frequent in tumors without nodal metastases. PLK-1 expression in both compartments was not associated with survival.

CONCLUSION

PLK-1 expression is associated with metastatic potential in cutaneous melanoma.

The natural history of thin melanoma and the utility of sentinel lymph node biopsy

BACKGROUND AND OBJECTIVES

Current literature may overestimate the risk of nodal metastasis from thin melanoma due to reporting of data only from lesions treated with SLNB. Our objective was to define the natural history of thin melanoma, assessing the likelihood of nodal disease, in order to guide selection for SLNB.

METHODS

Retrospective review. The primary outcome was the rate of nodal disease. Clinicopathologic factors were evaluated to find associations with nodal disease.

RESULTS

Five hundred and twelve lesions, follow up available for 488 (median: 48 months). Lesions treated with WLE/SLNB compared to WLE alone were more likely to have high-risk features. The rate of nodal disease was higher in the WLE/SLNB group (24 positive SLNB, five false-negative SLNB with nodal recurrence: 10.2%) compared to WLE alone (four nodal recurrences: 2.0%). Univariate analysis showed age ≤45, Breslow depth ≥0.85 mm, mitotic rate >1 mm² , and ulceration were associated with nodal disease. Multivariate analysis confirmed the association of age ≤45 and ulceration.

CONCLUSIONS

SLNB for melanoma 0.75-0.99 mm should be considered in patients age ≤45, Breslow depth ≥0.85 mm, mitotic rate >1 mm² , and/or with ulceration. Thin melanoma <0.85 mm without high-risk features may be treated with WLE alone.

Lymphatic invasion and angiotropism in primary cutaneous melanoma

Access of melanoma cells to the cutaneous vasculature either via lymphatic invasion or angiotropism is a proposed mechanism for metastasis. Lymphatic invasion is believed to be a mechanism by which melanoma cells can disseminate to regional lymph nodes and to distant sites and may be predictive of adverse outcomes. Although it can be detected on hematoxylin- and eosin-stained sections, sensitivity is markedly improved by immunohistochemistry for lymphatic endothelial cells. Multiple studies have reported a significant association between the presence of lymphatic invasion and sentinel lymph node metastasis and survival. More recently, extravascular migratory metastasis has been suggested as another means by which melanoma cells can spread. Angiotropism, the histopathologic correlate of extravascular migratory metastasis, has also been associated with melanoma metastasis and disease recurrence. Although lymphatic invasion and angiotropism are not currently part of routine melanoma reporting, the detection of these attributes using ancillary immunohistochemical stains may be useful in therapeutic planning for patients with melanoma.

Thin Melanoma with Nodal Involvement: Analysis of Demographic, Pathologic, and Treatment Factors with Regard to Prognosis

BACKGROUND

Although only a small proportion of thin melanomas result in lymph node metastasis, the abundance of these lesions results in a relatively large absolute number of patients with a diagnosis of nodal metastases, determined by either sentinel lymph node (SLN) biopsy or clinical nodal recurrence (CNR).

METHODS

Independent cohorts with thin melanoma and either SLN metastasis or CNR were identified at two melanoma referral centers. At both centers, SLN metastasis patients were included. At center 1, the CNR cohort included patients with initial negative clinical nodal evaluation followed by CNR. At center 2, the CNR cohort was restricted to those presenting in the era before the use of SLN biopsy. Uni- and multivariable analyses of melanoma-specific survival (MSS) were performed.

RESULTS

At center 1, 427 CNR patients were compared with 91 SLN+ patients. The 5- and 10-year survival rates in the SLN group were respectively 88 and 84 % compared with 72 and 49 % in the CNR group (p < 0.0001). The multivariate analysis showed age older than 50 years (hazard ratio [HR] 1.5; 95 % confidence interval [CI] 1.2-1.9), present ulceration (HR 1.9; 95 % CI 1.2-2.9), unknown ulceration (HR 1.6; 95 % CI 1.3-2.1), truncal site (HR 1.6; 95 % CI 1.2-2.2), and CNR (HR 3.3; 95 % CI 1.8-6.0) to be associated significantly with decreased MSS (p < 0.01 for each). The center 2 cohort demonstrated remarkably similar findings, with a 5-year MSS of 88 % in the SLN (n = 29) group and 76 % in the CNR group (n = 39, p = 0.09).

CONCLUSION

Patients with nodal metastases from thin melanomas have a substantial risk of melanoma death. This risk is lower among patients whose disease is discovered by SLN biopsy rather than CNR.

Prognostic role of sentinel lymph node biopsy for patients with cutaneous melanoma: A retrospective study of surveillance, epidemiology, and end-result population-based data

Sentinel lymph node biopsy (SLNB) is a sensitive operation for finding micro-metastasis in patients with cutaneous melanoma without evidence of clinically positive lymph node findings. However, until now, no clinical trials or retrospective studies with large samples have been performed to investigate the clinical role of SLNB for cutaneous melanoma patients. In this study, we used the data of cutaneous melanoma from the Surveillance, Epidemiology, and End Results (SEER) database to compare overall survival (OS) and melanoma-specific survival (MSS) outcomes with clinical lymph node and SLN status. In total, 56,285 eligible patients were identified in this study. Cutaneous melanoma patients with clinically-positive lymph nodes had significantly shorter OS (46.1% vs 78.6%, p = 0.000) and MSS (55.8% vs 90.5, p = 0.000) compared with clinically-negative lymph node patients. Patients who underwent SLNB had significantly longer 5-year rates for OS (84.3% vs 70.1, p = 0.000) and MSS (91.5% vs 90.3, p = 0.000) compared with patients who did not undergo SLNB (lymph node observation). Patients with a negative SLNB had a significantly longer 5-year rate for OS (86.5% vs 68.1% vs 46.1, p = 0.000) and MSS (93.7% vs 75.1% 55.8%, p = 0.000) than patients who were SLNB-positive or had clinically-positive lymph nodes. This present study showed that the status of SLN is a valuable prognostic factor in patients with Breslow thickness greater than 1 mm in clinically-negative lymph node cutaneous melanoma.

Gene expression analyses of primary melanomas reveal CTHRC1 as an important player in melanoma progression

Melanoma is notorious for its high tendency to metastasize and its refractoriness to conventional treatments after metastasis, and the responses to most targeted therapies are short-lived. A better understanding of the molecular mechanisms behind melanoma development and progression is needed to develop more effective therapies and to identify new markers to predict disease behavior. Here, we compared the gene expression profiles of benign nevi, and non-metastatic and metastatic primary melanomas to identify any common changes in disease progression. We identified several genes associated with inflammation, angiogenesis, and extracellular matrix modification to be upregulated in metastatic melanomas. We selected one of these genes, collagen triple helix repeat containing 1 (CTHRC1), for detailed analysis, and found that CTHRC1 was expressed in both melanoma cells and the associated fibroblasts, as well as in the endothelium of tumor blood vessels. Knockdown of CTHRC1 expression by shRNAs in melanoma cells inhibited their migration in Transwell assays and their invasion in three-dimensional collagen and Matrigel matrices. We also elucidated the possible down-stream effectors of CTHRC1 by gene expression profiling of the CTHRC1-knockdown cells. Our analyses showed that CTHRC1 is regulated coordinately with fibronectin and integrin β3 by the pro-invasive and -angiogenic transcription factor NFATC2. We also found CTHRC1 to be a target of TFGβ and BRAF. These data highlight the importance of tumor stroma in melanoma progression. Furthermore, CTHRC1 was recognized as an important mediator of melanoma cell migration and invasion, providing together with its regulators-NFATC2, TGFβ, and BRAF-attractive therapeutic targets against metastatic melanomas.