Prognosis for patients with thin cutaneous melanoma: long-term survival data from New South Wales Central Cancer Registry and the Sydney Melanoma Unit

Topographical and Chronological Analysis of Thin Cutaneous Melanoma's Progressions: A Multicentric Study

A great portion of cutaneous melanoma's diagnoses nowadays is attributed to thin tumors with up to 1 mm in Breslow thickness (hereafter thin CMs), which occasionally metastasize. The objective of this study was to identify thin CM's metastatic patterns from a topographical and chronological standpoint. A total of 204 cases of metastatic thin CMs from five specialized centers were included in the study, and corresponding data were collected (clinical, epidemiological, histopathological information of primary tumor and the number, anatomical site, and time intervals of their progressions). First progressions occurred locally, in regional lymph nodes, and in a distant site in 24%, 15% and 61% of cases, respectively, with a median time to first progression of 3.10 years (IQR: 1.09-5.24). The median elapsed time between the first and second progression and between the second and third progression was 0.82 (IQR: 0.34-1.97) and 0.49 (IQR: 0.21-2.30) years, respectively, while the median survival time was about 4 years since first progression. Furthermore, the sequences of locations and time intervals of the progressions were associated with the clinicopathological and demographic features of the primary tumors along with the features of the preceding progressions. In conclusion, the findings of this study describe the natural history of thin CMs, thus highlighting the necessity to identify subgroups of thin CMs at a higher risk for metastasis and contributing to the optimization of the management and follow-up of thin CM patients.

Identification of Three Genes Associated with Metastasis in Melanoma and Construction of a Predictive Model: A Multiracial Identification

The aim of this study was to identify hub genes associated with metastasis and prognosis in melanoma. Weighted gene coexpression network analysis (WGCNA) was performed to screen and identify hub genes. ROC and K-M analyses were used to verify the hub genes in the internal and external data sets. The risk score model and nomogram model were constructed based on the IHC result. Through WGCNA, the three hub genes, SNRPD2, SNRPD3, and EIF4A3, were identified. In the external data set, the hub genes identified were associated with the worse prognosis (TCGA, SNRPD2, $P\le 0.02$ ; SNRPD3, $P=0.12$ ; EIF4A3, $P=0.11$ ; GSE65904, SNRPD2, $P=0.04$ ; SNRPD3, $P=0.10$ ; EIF4A3, $P<0.01$ ; GSE19234, SNRPD2, $P<0.01$ ; SNRPD3, $P<0.01$ ; EIF4A3, $P<0.01$ ). In the GSE8401, we found that the hub genes were highly expressed in the metastasis compared with the nonmetastasis group (SNRPD2, $988.5\pm 47.83$ vs. $738.4\pm 35.35$ , $P<0.01$ ; SNRPD3, $502.7\pm 25.7$ vs. $416.4\pm 23.88$ , $P=0.02$ ; EIF4A3, $567.6\pm 19.56$ vs. $495.2\pm 21.1$ , $P=0.01$ ). Moreover, the hub genes were identified by the IHC in our data set. The result was similar with the external data set. The hub genes could predict the metastasis and prognosis in the Chinese MM patients. Finally, the GSEA and Pearson analysis demonstrated that the SNRPD2 was associated with the immunotherapy. The three hub genes were identified and validated in MM patients in external and internal data sets. The risk factor model was constructed and verified as a powerful model to predict metastasis and prognosis in MM patients.

The Value of Total Body Photography for the Early Detection of Melanoma: A Systematic Review

Early detection of melanoma is critical to reduce the mortality and morbidity rates of this tumor. Total body photography (TBP) may aid in the early detection of melanoma. To summarize the current evidence on TBP for the early detection of melanoma, we performed a systematic literature search in Medline, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) for eligible records up to 6th August 2020. Outcomes of interest included melanoma incidence, incisional and excisional biopsy rates, as well as the Breslow's index of detected tumors. Results from individual studies were described qualitatively. The risks of bias and applicability of the included studies was assessed using the QUADAS-2 checklist. In total, 14 studies published between 1997 and 2020 with an overall sample size of n = 12082 (range 100-4692) were included in the qualitative analysis. Individuals undergoing TBP showed a trend towards a lower Breslow's thickness and a higher proportion of in situ melanomas compared to those without TBP. The number needed to excise one melanoma varied from 3:1 to 14.3:1 and was better for lesions that arose de novo than for tracked ones. The included studies were judged to be of unclear methodological concern with specific deficiencies in the domains "flow and timing" and "reference standard". The use of TBP can improve the early detection of melanoma in high-risk populations. Future studies are warranted to reduce the heterogeneity of phenotypic risk factor definition and the technical implementation of TBP. Artificial intelligence-assisted analysis of images derived from 3-D TBP systems and digital dermoscopy may further improve the early detection of melanoma.

Survival prediction in patients with cutaneous melanoma by tumour lymphangiogenesis

Objectives: Melanoma induces lymphangiogenesis by secreting lymphangiogenic growth factors. The aim of this study was to examine the role of tumour lymphangiogenesis in survival of patients with cutaneous melanoma. Methods: Immunostaining of one hundred melanoma specimens was done with lymphatic-specific antibody D2-40. The quantification of tumour lymphangiogenesis - lymphatic vessel density (LVD) and lymphatic vessel area (LVA) - was calculated by computer-assisted morphometric analysis. Results: High intratumoural LVD, high peritumoural LVD, male gender, greater tumour thickness and Clark level IV/V were significantly associated with shorter disease-free survival (p= 0.001, p= 0.004, p= 0.004, p= 0.000 and p= 0.008, respectively) and melanoma-specific survival (p= 0.002, p= 0.002, p= 0.001, p= 0.000 and p= 0.017, respectively), while the trunk melanoma site was significantly associated only with shorter disease-free survival (p= 0.033). No significant association of LVA with survival was found. At multivariate analysis, peritumoural LVD [hazard ratio (HR) = 2.143, 95% confidence interval (CI) 1.097-4.189, p= 0.026)] and melanoma thickness (HR = 1.276, 95%CI 1.106-1.473, p= 0.001) were independent predictors of disease-free survival, while intratumoural LVD (HR = 3.446, 95%CI 1.465-8.109, p= 0.005), peritumoural LVD (HR = 2.742, 95%CI 1.313-5.725, p= 0.007) and gender (HR = 2.880, 95%CI 1.304-6.362, p= 0.009) were independent predictors of melanoma-specific survival. Conclusion: Тhis study shows that LVD enables better prediction of survival than melanoma thickness and other clinical-pathological parameters. Intratumoural LVD is the most significant predictor of melanoma-specific survival, while only peritumoural LVD has a significant impact on both, a disease-free survival and a melanoma-specific survival.

Survival in 31 670 patients with thin melanomas: a Swedish population-based study

BACKGROUND

The incidence of cutaneous malignant melanoma (CMM) continues to increase in most countries worldwide and the majority are diagnosed with thin tumours (≤ 1 mm).

OBJECTIVES

The aim of the present study was to investigate the melanoma-specific survival (MSS) as well as conditional MSS (CMSS) in patients with thin CMM in Sweden.

PATIENTS AND METHODS

Clinical and histological parameters were obtained from the Swedish Melanoma Registry for patients diagnosed with thin CMM between 1990 and 2017. Patients were followed until the end of 2017. MSS as well as CMSS for different thickness groups were calculated using the Kaplan-Meier method and Cox regression analyses were used to calculate for survival differences between thickness groups.

RESULTS

There were 31 670 patients included for final analyses. The overall 10- and 20-year MSS for thin CMMs was 97% [95% confidence interval (CI) 97-97] and 95% (95% CI 95-96), respectively. From 0·7 mm and above, MSS decreased significantly with increasing thickness level. All thickness groups had an increased survival over time. The lowest CMSS was confirmed for men with 1·0 mm in thickness but their 10-year CMSS increased steadily over time. Women had overall better MSS as well as CMSS than men. However, the relation between MSS and CMSS was similar for both sexes.

CONCLUSIONS

MSS was confirmed as excellent for patients with thin CMMs in Sweden. Although we could show a decreased MSS for patients with 0·7 mm thickness and above, the long-term survival and, in addition, a very favourable CMSS for those patients do not support more extended follow-up programmes than the current recommendations in Sweden.

Epidemiology of Skin Cancer: Update 2019

Melanoma and keratinocyte skin cancer (KSC) are the most common types of cancer in White-skinned populations. Both tumor entities showed increasing incidence rates worldwide but stable or decreasing mortality rates. Rising incidence rates of cutaneous melanoma (CM) and KSC are largely attributed to increasing exposure to ultraviolet (UV) radiation, the main causal risk factor for skin cancer.Incidence rates of KSC, comprising of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are much higher than that of melanoma. BCC development is mainly the cause of an intensive UV exposure in childhood and adolescence, while SCC development is related to chronic, cumulative UV exposure over decades. Although mortality is relatively low, KSC is an increasing problem for health care services causing significant morbidity.Cutaneous melanoma is rapidly increasing in White populations, with an estimated annual increase of around 3-7% over the past decades. In contrast to SCC, melanoma risk is associated with intermittent and chronic exposure to sunlight. The frequency of its occurrence is closely associated with the constitutive color of the skin and the geographical zone. Changes in outdoor activities and exposure to sunlight during the past 70 years are an important factor for the increasing incidence of melanoma. Mortality rates of melanoma show stabilization in the USA, Australia, and in European countries. In the USA even dropping numbers of death cases were recently reported, probably reflecting efficacy of the new systemic treatments.Among younger cohorts in some populations (e.g., Australia and New Zealand,), stabilizing or declining incidence rates of CM are observed, potentially caused by primary prevention campaigns aimed at reducing UV exposure. In contrast, incidence rates of CM are still rising in most European countries and in the USA. Ongoing trends towards thinner melanoma are largely ascribed to earlier detection.

Clinicopathological factors associated with death from thin (≤ 1·00 mm) melanoma

BACKGROUND

Thin cutaneous melanomas (≤ 1·00 mm) are increasing worldwide, causing around a quarter of all melanoma deaths in the U.S.A. and Australia. Identification of predictive factors for potentially fatal thin melanomas could allow better use of resources for follow-up.

OBJECTIVES

To identify the clinicopathological factors associated with fatal thin melanomas.

METHODS

This large, nested case-case study extracted data from the population-based Queensland Cancer Registry, Australia. Our cohort consisted of Queensland residents aged 0-89 years who were diagnosed with a single, locally invasive thin melanoma (≤ 1·00 mm) between 1995 and 2014. Fatal cases (eligible patients who died from melanoma) were individually matched to three nonfatal cases (eligible patients who were not known to have died from melanoma) according to sex, age, year of diagnosis and follow-up interval. Using conditional logistic regression, we calculated odds ratios (ORs) for melanoma-specific death, adjusting for all collected clinicopathological variables.

RESULTS

In the cohort, 27 660 eligible patients were diagnosed with a single, thin melanoma. The final case-case series included 424 fatal cases and 1189 nonfatal cases. Fatal cases were sixfold as likely to arise on the scalp as on the back [OR 6·39, 95% confidence interval (CI) 2·57-15·92] and six times as likely to be of thickness 0·80-1·00 mm as of < 0·30 mm (OR 6·00, 95% CI 3·55-10·17).

CONCLUSIONS

Scalp location is a strong prognostic factor of death from thin melanoma. Further, this study provides support that melanomas with a thickness of 0·80-1·00 mm are the more hazardous thin lesions. Patients with these tumour characteristics require specific attention during follow-up. What's already known about this topic? Thin invasive melanomas (≤ 1·00 mm) contribute a substantial proportion of melanoma fatalities, owing to the high volume of disease. There is a need to find prognostic factors that will better identify fatal thin melanomas at the time of diagnosis. What does this study add? In this large population-based study, fatal thin tumours were sixfold as likely to be located on the scalp as on the back. Thin melanomas of 0·80-1·00 mm thickness were six times as likely to be associated with death as tumours < 0·30 mm. Scalp location and increasing thickness are strong predictive factors of fatal thin melanomas, indicating that patients with these tumour characteristics require close follow-up.

A Population-Based Comparison of the AJCC 7th and AJCC 8th Editions for Patients Diagnosed with Stage III Cutaneous Malignant Melanoma in Sweden

BACKGROUND

Cutaneous melanoma is steadily increasing worldwide. The new AJCC 8th edition was recently launched and introduced several changes in melanoma staging, particularly for stage III. We conducted a population-based registry study with the purpose to evaluate the impact and prognostic accuracy of the new classification in Sweden.

METHODS

Consecutive patients diagnosed with stage III melanoma between January 2005 and September 2017 were identified by the Swedish Melanoma Registry (SMR) and included for analyses. Patients with multiple primary melanomas were excluded. Patients were classified according to the AJCC 7th as well as the 8th edition. Melanoma-specific survival (MSS) was retrieved from the Swedish Cause of Death Registry.

RESULTS

A total of 2067 eligible patients were identified from the SMR; 1150 patients (57%) changed stage III subgroup when reclassified according to the AJCC 8th edition. The median 5- and 10-year MSS for the whole cohort of stage III melanoma patients was 59% and 51% respectively. The MSS for substage IIIA, B, and C were all improved when patients were reclassified by using to the AJCC 8th edition. The newly defined substage IIID had the worst prognosis with a 10-year MSS of 16%.

CONCLUSIONS

A high proportion of patients diagnosed with stage III melanoma in Sweden between 2005 and 2017 was restaged to another subgroup, when they were reclassified according to the AJCC 8th of staging manual. We established an improved MSS for all substages compared with the former AJCC 7th edition. This may have implications on decisions about adjuvant treatment.

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.

Hospital-Based Study of Compliance with NCCN Guidelines and Predictive Factors of Sentinel Lymph Node Biopsy in the Setting of Thin Melanoma Using the National Cancer Database

Thin melanoma is the most common form of melanoma in the United States. The National Comprehensive Cancer Network (NCCN) has guidelines for sentinel lymph node biopsy (SLNB) which recommend “discuss and consider” SLNB for invasion >0.75 mm and “discuss and offer” SLNB for invasion >0.75 mm with suspicious features. This study looked at compliance with NCCN guidelines and factors that are predictive of a positive SLNB. This is a retrospective study of patients diagnosed with thin melanoma 2012–2013 using the National Cancer Database. A total of 26,456 patients met study qualifications. Univariate analysis showed that 76 per cent of patients meeting criteria underwent SLNB. Patients recommended to “discuss and consider” received SLNB 53 per cent of the time and those not recommended for SLNB received SLNB 20 per cent of the time. On multivariate analysis, depth was not predictive for positive SLNB whereas mitoses and ulceration were. Other factors predictive of positive SLNB were nodular cell type, lymphovascular invasion, and Clark's level greater than or equal to IV. Patients with thin melanoma that meet NCCN guidelines for SLNB undergo this procedure in good compliance but those who do not meet criteria continue to receive SLNB. Positive predictive factors for positive SLNB include mitoses, ulceration, Clark's level, and primary site.

Long-Term Survival of Patients with Thin (T1) Cutaneous Melanomas: A Breslow Thickness Cut Point of 0.8 mm Separates Higher-Risk and Lower-Risk Tumors

BACKGROUND

Counterintuitively, more deaths from melanoma occur among patients with thin (T1) primary melanomas (≤ 1 mm) than among those with thick primary melanoma because the great majority present with T1 tumors. Therefore, it is important to stratify their risk as accurately as possible to guide their management and follow-up. This study sought to explore the relationship between tumor thickness and prognosis for patients with thin primary melanomas.

METHODS

A retrospective, single-institution study investigated 6263 patients with cutaneous melanoma (including 2117 T1 cases) who had a minimum follow-up period of 10 years.

RESULTS

For the entire patient cohort, the 10-year melanoma-specific survival (MSS) rate ranged between 92% for the patients with primary melanomas up to 0.3 mm thick and 32% for those with melanomas thicker than 8 mm. When divided into 25-quantile-thickness groups there was a significant difference in 10-year MSS between the two consecutive groups 0.8 and 0.9 mm; the differences in survival were not significantly different for any other consecutive cut points within the less than or equal to 1 mm thickness range, indicating a biologically-relevant difference in outcome above and below 0.8 mm. For the patients treated initially at the authors' institution, the 10- and 20-year MSS rates for those with tumors up to 0.8 mm thick were respectively 93.4 and 85.7%, and for tumors 0.9 to 1.0 mm, the rates were respectively 81.1 and 71.4%. Only 29.3% of the T1 patients who died of melanoma were deceased within 5 years.

CONCLUSIONS

A naturally occurring thickness cut point of 0.8 mm predicts higher or lower risk for patients with thin primary cutaneous melanomas. Long-term follow-up assessment of patients with T1 melanoma is important because late mortality due to melanoma is more common than early mortality.

Trajectories of premalignancy during the journey from melanocyte to melanoma

A stepwise progression from melanocytic precursors to cutaneous melanoma is a well-established model, based on decades of careful observation and morphological analysis. The steps identified are benign melanocytic naevus, dysplastic naevus, 'radial growth phase' melanoma (including melanoma in situ) and 'vertical growth phase' melanoma (also termed tumourigenic melanoma). Recent genomic data have refined the understanding of the steps of melanoma development and their relationship to one another. These data support the existence of dysplastic naevi as distinct lesions; suggest the importance of clonal dynamics in the precursor steps of melanoma; and confirm the carcinogenic role of ultraviolet radiation throughout early melanoma development and progression. In this review, the steps of melanoma development and progression are summarised and discussed in the context of recent genomic studies. This new understanding of melanoma pathogenesis that has been facilitated through careful correlation of morphological and molecular features will allow the identification and development of robust biomarkers to assist in more accurate diagnosis and prognostication of melanocytic tumours.

Miscoding of Melanoma Thickness in SEER: Research and Clinical Implications

Melanoma-related deaths and metastases among patients with thin (≤1 mm) and ultrathin (≤0.25 mm) melanomas have been reported. These observations might reflect adverse biology and/or errors in administrative data. Cumulative melanoma-related death rates for thickness groups of patients with thin melanomas were compared among five cohorts including the Surveillance, Epidemiology, and End Results (SEER) registry. Thickness in one SEER region was reexamined in pathology reports. The 5-year cumulative melanoma-related death rate of patients with ultrathin melanomas was higher in SEER (2.8%) compared with other registries (0.6-0.9%). The rates across the 16 SEER regions were 0.25% to 8.4%. In SEER, 21% of thin melanomas were ultrathin; in other registries, they comprised 5.8-15%. A reexamination of thickness in one SEER site revealed that 114 of 447 ultrathin melanomas had errors; after correction, only 17 of the 114 remained ultrathin. The majority of errors were related to decimal point placement. The 86 thin melanomas reclassified to >1.00 mm included 96% of the original ultrathin-associated deaths and 100% of the original positive lymph nodes. Significant miscoding of thickness that is concentrated in ultrathin lesions is present in SEER and results in mischaracterization of patient outcomes. When using administrative data, validation of results can identify critical data issues.

Regression in thin melanoma is associated with nodal recurrence after a negative sentinel node biopsy

Prognostic markers for nodal metastasis in thin melanoma patients are debated. We present a single institution study looking at factors predictive of nodal disease in thin melanoma patients. Retrospective review from 1997 to 2012 identified 252 patients with thin melanoma (≤1 mm) who underwent a sentinel lymph node biopsy (SLNB). Node‐positive patients included positive SLNB patients and negative SLNB patients who developed a nodal recurrence (false‐negative SLNB). Clinicopathologic characteristics were correlated with nodal status and outcome. Median follow‐up was 45.5 months. Twelve of 252 patients (4.8%) were node‐positive including six positive SLNB (2.4%) and six false‐negative SLNB (2.4%) patients. No clinicopathologic factors were significantly correlated with nodal disease. For the six false‐negative SLNB patients, median time to nodal recurrence was 37.5 months. Regression was seen in only 16% of cases, but the rate increased to 60% for false‐negative SLNB cases. Both age (odds ratio [OR]: 1.09, 95% CI: 1.01–1.17; P = 0.02) and regression (OR: 8.33, 95% CI: 1.34–52.63; P = 0.02) were significantly associated with nodal recurrence after a negative SLNB on univariable analysis. Nodal disease in thin melanoma patients was seen in 4.8% of cases. Although regression was not correlated with nodal metastasis, it was correlated with a false‐negative SLNB. Patients with thin melanoma and regression may need more intensive surveillance after a negative SLNB. Further study is needed to determine if the same immune mechanisms that result in regression in primary tumors also lead to regression in lymph nodes, which may decrease detection of melanoma nodal metastases.

Cutaneous Melanoma with Brain Metastasis: Report of 193 Patients with New Observations

BACKGROUND

Brain metastasis is a common endpoint in patients suffering from malignant melanoma. However, little is known about factors that predispose to brain metastases.

OBJECTIVE

We performed a retrospective clinical and pathological investigation of melanoma patients with brain metastases in order to better characterise this patient population.

METHODS

193 melanoma patients with brain metastasis histologically diagnosed between 1990 and 2015 at the University Hospital Zurich were retrospectively identified and further specified for sex, age at diagnosis and detection of brain metastasis, and localisation. In addition, data were extracted regarding the subtype of primary melanoma, Breslow tumour thickness, Clark Level, mutation status, extent of metastatic spread and history of a second melanoma.

RESULTS

We found a significant male predominance (n = 126/193; 65%; p < 0.001). Breslow tumour thickness showed a wide range from 0.2 to 12.0 mm (n = 99; median 2.3 mm). 14 of 101 melanomas (14%) were classified as T1, thereof 11 (79%) were found in men. In 32 of 193 patients (17%), the primary melanoma was unknown.

CONCLUSIONS

Of special interest in our series is the high incidence of male predominance (79%) in cases of thin metastasing melanoma (14%), implicating genetic or epigenetic (hormonal) gender differences underlying tumour progression. Additionally, the high percentage of unknown primary melanoma (17%), at least partly representing completely regressed melanomas, indicates the importance of immune surveillance in melanoma progression.

Sentinel Lymph Node Biopsy in Thin Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Most patients with melanoma have a thin (≤1.00 mm) lesion. There is uncertainty as to which patients with thin melanoma should undergo sentinel lymph node (SN) biopsy. We sought to quantify the proportion of SN metastases in patients with thin melanoma and to determine the pooled effect of high-risk features of the primary lesion on SN positivity.

METHODS

Published literature between 1980 and 2015 was searched and critically appraised. Primary outcome was the proportion of SN metastases in patients with thin cutaneous melanoma. Secondary outcomes included the effect of high-risk pathological features of the primary lesion on the proportion of SN metastases. Summary measures were estimated by Mantel-Haenszel method using random effects meta-analyses.

RESULTS

Sixty studies (10,928 patients) met the criteria for inclusion. Pooled SN positivity was 4.5 % [95 % confidence interval (CI) 3.8-5.2 %]. Predictors of a positive SN were: thickness ≥0.75 mm [adjusted odds ratio (AOR) 1.90 (95 % CI 1.08-3.34); with a likelihood of SN metastases of 8.8 % (95 % CI 6.4-11.2 %)]; Clark level IV/V [AOR 2.24 (95 % CI 1.23-4.08); with a likelihood of 7.3 % (95 % CI 6.2-8.4 %)]; ≥1 mitoses/mm² [AOR 6.64 (95 % CI 2.77-15.88); pooled likelihood 8.8 % (95 % CI 6.2-11.4 %)]; and the presence of microsatellites [unadjusted OR 6.94 (95 % CI 2.13-22.60); likelihood 26.6 % (95 % CI 4.3-48.9 %)].

CONCLUSIONS

The pooled proportion of SN metastases in thin melanoma is 4.5 %. Thickness ≥0.75 mm, Clark level IV/V, mitoses, and microsatellites significantly increased the odds of SN positivity and should prompt strong consideration of SN biopsy.

Identification of Patients with Intermediate Thickness Melanoma at Low Risk for Sentinel Lymph Node Positivity

INTRODUCTION

Sentinel lymph node (SLN) biopsy is recommended for all patients with intermediate-thickness melanomas. We sought to identify such patients at low risk of SLN positivity.

METHODS

All patients with intermediate-thickness melanomas (1.01-4 mm) undergoing SLN biopsy at a single institution from 1995-2011 were included in this retrospective cohort study. Univariate and multivariate logistic regression determined factors associated with a low risk of SLN positivity. Classification and regression tree (CART) analysis was used to stratify groups based on risk of positivity.

RESULTS

Of the 952 study patients, 157 (16.5 %) had a positive SLN. In the multivariate analysis, thickness <1.5 mm (odds ratio [OR] 0.29), age ≥60 (OR 0.69), present tumor-infiltrating lymphocytes (OR 0.60), absent lymphovascular invasion (OR 0.46), and absent satellitosis (OR 0.44) were significantly associated with a low risk of SLN positivity. CART analysis identified thickness of 1.5 mm as the primary cut point for risk of SLN metastasis. Patients with a thickness of <1.5 mm represented 36 % of the total cohort and had a SLN positivity rate of 6.6 % (95 % confidence interval 3.8-9.4 %). In patients with melanomas <1.5 mm in thickness, the presence of additional low risk factors identified 257 patients (75 % of patients with <1.5 mm melanomas) in which the rate of SLN positivity was <5 %.

CONCLUSIONS

Despite a SLN positivity rate of 16.5 % overall, substantial heterogeneity of risk exists among patients with intermediate-thickness melanoma. Most patients with melanoma between 1.01 and 1.5 mm have a risk of SLN positivity similar to that in patients with thin melanomas.

Comparative effectiveness in melanoma

The worldwide incidence of melanoma continues to rise. It is a leading cause of cancer death and the second leading cause of loss of productive years of life. Although the diagnosis of melanoma is straightforward, there remain many controversies regarding treatment and surveillance. This chapter addresses important questions in melanoma treatment such as sentinel lymph node biopsy, what to do with a positive sentinel lymph node, margins of resection for melanoma, radiation for primary, nodal and metastatic melanoma, and routine use imaging. Through this chapter, the evidence for these controversial subjects and the barriers to resolution will be elucidated.

Follow-up in patients with low-risk cutaneous melanoma: is it worth it?

Follow-up examinations in melanoma aim to detect recurrences or secondary melanomas in an early phase of development. Follow-up guidelines that have been developed in many European countries, the USA and Australia show varying recommendations and are controversial, especially in patients with melanomas of 1.0 mm tumor thickness or less. This group contains 50-70% of all melanoma patients and the majority is unlikely to develop recurrences. On the other hand, within this entity, subgroups at higher risk for recurrences can be defined who require a more intense follow-up. This article discusses recommendations for the frequency, duration and costs of follow-up in low-risk melanoma patients. Patient preferences are addressed and a risk-adapted follow-up scheme is proposed.

Predictive factors for loco regional recurrence and distant metastasis following primary surgical treatment of cutaneous melanoma

Background:

Cutaneous melanoma (CM) has a high propensity for regional and systemic spread. This is one of the largest series of CM reported from India.

Aims:

To predict factors for loco regional recurrence (LRR) and distant metastasis in patients with CM primarily treated with surgery.

Study Design:

Retrospective analysis of patient database at a tertiary care cancer center with evaluation of factors for LRR and distant metastasis for CM.

Materials and Methods:

Data from 68 patients treated for CM between January 2006 and December 2010 were reviewed. Data recorded included age, sex, symptoms, investigations, treatment given, histopathology, recurrence and follow-up. Patient factors, tumor factors, pathologic variables, and adjuvant treatment were investigated as predictors’ of LRR and distant metastasis.

Results:

Mean age of patients was 54 years. Melanoma was more common in males (44). Tumor thickness > 4 mm was found in 43 patients. Lymph node involvement was found in 43 patients. Adjuvant radiotherapy was given in seven patients. At mean follow-up of 16.5 months, LRR was seen in 34 patients and distant metastasis in 28 patients. LRR and distant metastasis were more commonly found in females, age > 40 years, Clark's level IV and V, Breslow's depth > 4 mm, patients with lymph node involvement and extra-capsular spread.

Conclusion:

The age, sex, site, thickness of lesion, involvement of lymph node, and extra-capsular spread were important factors in predicting LRR and distant metastasis. Distant metastasis was also more commonly found in patients with LRR.

Estimating the cure proportion of malignant melanoma, an alternative approach to assess long term survival: a population-based study

OBJECTIVES

A large proportion of patients with cutaneous malignant melanoma (CMM) do not experience excess mortality due to their disease. This group of patients is referred to as the cure proportion. Few studies have examined the possibility of cure for CMM. The aim of this study was to estimate the cure proportion of patients with CMM in a Swedish population.

METHODS

We undertook a population-based study of 5850 CMM patients in two Swedish health care regions during 1996-2005. We used flexible parametric cure models to estimate cure proportions and median survival times (MSTs) of uncured by stage, sex, age and anatomical site.

RESULTS

Disease stage at diagnosis was the most important factor for the probability of cure, with a cure proportion of approximately 1.0 for stage IA. While the probability of cure decreased with older age, the influence of age was smaller on the MST of uncured. Differences in prognosis between males and females were mainly attributed to differences in cure as opposed to differences in MST of uncured.

CONCLUSIONS

This population-based study showed approximately 100% cure among stage IA disease. Almost 50% of patients had stage IA disease and the high cure proportion for this large patient group is reassuring.

Impact of the 2009 (7th edition) AJCC melanoma staging system in the classification of thin cutaneous melanomas

CONTEXT

The 7th (2009) edition of the AJCC melanoma staging system incorporates tumor (Breslow) thickness, MR, and ulceration in stratifying T1 primary melanomas. Compared to the prior 6th (2001) edition, MR has replaced CL for thin melanomas.

OBJECTIVE

We sought to identify and report differences of the classification of thin melanomas as well as outcome of SLNB in patients according to the 6th and 7th editions at our institution.

RESULTS

106 patients were identified with thin melanomas verified by wide excision. 31 of 106 thin melanomas were reclassified according to the 7th edition of the AJCC. Of those 31, 15 CL II/III patients (6th edition T1a) were reclassified as T1b based on the presence of mitoses while 16 CL IV patients (6th edition T1b) were categorized as T1a based on the absence of mitoses. 26/31 reclassified patients underwent SLNB, and all were negative. Patients with thin melanoma and a +SLNB (N = 3) were all classified as T1b according to both staging systems.

CONCLUSIONS

In our experience, 29% of thin melanomas were reclassified according to the 7th edition with similar proportions of patients re-distributed as T1a (14%) and T1b (15%). Cases with +SLN corresponded with T1b lesions in both 6th and 7th editions.

Clinicopathologic predictors of sentinel lymph node metastasis in thin melanoma

PURPOSE

Indications for sentinel lymph node biopsy (SLNB) for thin melanoma are continually evolving. We present a large multi-institutional study to determine factors predictive of sentinel lymph node (SLN) metastasis in thin melanoma.

PATIENTS AND METHODS

Retrospective review of the Sentinel Lymph Node Working Group database from 1994 to 2012 identified 1,250 patients who had an SLNB and thin melanomas (≤ 1 mm). Clinicopathologic characteristics were correlated with SLN status and outcome.

RESULTS

SLN metastases were detected in 65 (5.2%) of 1,250 patients. On univariable analysis, rates of Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, ulceration, and absence of regression differed significantly between positive and negative SLN groups (all P < .05). These four variables and mitotic rate were used in multivariable analysis, which demonstrated that Breslow thickness ≥ 0.75 mm (P = .03), Clark level ≥ IV (P = .05), and ulceration (P = .01) significantly predicted SLN metastasis with 6.3%, 7.0%, and 11.6% of the patients with these respective characteristics having SLN disease. Melanomas < 0.75 mm had positive SLN rates of < 5% regardless of Clark level and ulceration status. Median follow-up was 2.6 years. Melanoma-specific survival was significantly worse for patients with positive versus negative SLNs (P = .001).

CONCLUSION

Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, and ulceration significantly predict SLN disease in thin melanoma. Most SLN metastases (86.2%) occur in melanomas ≥ 0.75 mm, with 6.3% of these patients having SLN disease, whereas in melanomas < 0.75 mm, SLN metastasis rates are < 5%. By using a 5% metastasis risk threshold, SLNB is indicated for melanomas ≥ 0.75 mm, but further study is needed to define indications for SLNB in melanomas < 0.75 mm.

Clark level risk stratifies patients with mitogenic thin melanomas for sentinel lymph node biopsy

BACKGROUND

The role for sentinel lymph node biopsy (SLNB) in patients with thin melanoma (≤1 mm) remains controversial. We examined a large cohort of patients with thin melanoma to better define predictors of SLN positivity.

METHODS

From 1995 to 2011, 781 patients with thin primary melanoma and evaluable clinicopathologic data underwent SLNB at our institution. Predictors of SLN positivity were determined using univariate and multivariate regression analyses, and patients were risk-stratified using a classification and regression tree (CART) analysis.

RESULTS

In the study cohort (n = 781), 29 patients (3.7%) had nodal metastases. In the univariate analysis, mitotic rate [odds ratio (OR) = 8.11, p = 0.005], Clark level (OR 4.04, p = 0.003), and thickness (OR 3.33, p = 0.011) were significantly associated with SLN positivity. In the multivariate analysis, MR (OR 7.01) and level IV-V (OR 3.45) remained significant predictors of SLN positivity. CART analysis initially stratified lesions by mitotic rate; nonmitogenic lesions (n = 273) had a 0.7% SLN positivity rate versus 5.6% in mitogenic lesions (n = 425). Mitogenic lesions were further stratified by Clark level; patients with level II-III had a 2.9% SLN positivity rate (n = 205) versus 8.2% with level IV-V (n = 220). With median follow-up of 6.3 years, five SLN-negative patients developed nodal recurrence and four SLN-positive patients died of disease.

CONCLUSIONS

SLN positivity is low in patients with thin melanoma (3.7%) and exceedingly so in nonmitogenic lesions (0.7%). Appreciable rates of SLN positivity can be identified in patients with mitogenic lesions, particularly with concurrent level IV-V regardless of thickness. These factors may guide appropriate selection of patients with thin melanoma for SLNB.

Melanoma biomolecules: independently identified but functionally intertwined

The majority of patients diagnosed with melanoma present with thin lesions and generally these patients have a good prognosis. However, 5% of patients with early melanoma (<1 mm thick) will have recurrence and die within 10 years, despite no evidence of local or metastatic spread at the time of diagnosis. Thus, there is a need for additional prognostic markers to help identify those patients that may be at risk of recurrent disease. Many studies and several meta-analyses have compared gene and protein expression in melanocytes, naevi, primary, and metastatic melanoma in an attempt to find informative prognostic markers for these patients. However, although a large number of putative biomarkers have been described, few of these molecules are informative when used in isolation. The best approach is likely to involve a combination of molecules. We believe one approach could be to analyze the expression of a group of interacting proteins that regulate different aspects of the metastatic pathway. This is because a primary lesion expressing proteins involved in multiple stages of metastasis may be more likely to lead to secondary disease than one that does not. This review focuses on five putative biomarkers – melanoma cell adhesion molecule (MCAM), galectin-3 (gal-3), matrix metalloproteinase 2 (MMP-2), chondroitin sulfate proteoglycan 4 (CSPG4), and paired box 3 (PAX3). The goal is to provide context around what is known about the contribution of these biomarkers to melanoma biology and metastasis. Although each of these molecules have been independently identified as likely biomarkers, it is clear from our analyses that each are closely linked with each other, with intertwined roles in melanoma biology.

Sentinel node biopsy in thin and thick melanoma

BACKGROUND

Although sentinel node biopsy (SNB) has become standard of care in patients with melanoma, its use in patients with thin or thick melanomas remains a matter of debate.

METHODS

This was a retrospective analysis of patients with thin (≤1 mm) or thick (≥4 mm) melanomas who underwent SNB at two Italian centers between 1998 and 2011. The associations of clinicopathologic features with sentinel lymph node positive status and overall survival (OS) were analyzed.

RESULTS

In 492 patients with thin melanoma, sentinel node was positive for metastatic melanoma in 24 (4.9 %) patients. No sentinel node positivity was detected in patients with primary tumor thickness <0.3 mm. Mitotic rate was the only factor significantly associated with sentinel node positivity (p = 0.0001). Five-year OS was 81 % for patients with positive sentinel node and 93 % for negative sentinel node (p = 0.001). In 298 patients with thick melanoma, 39 % of patients had positive sentinel lymph nodes (median Breslow thickness 5 mm). In patients with positive sentinel node, 93 % had mitotic rate >1/mm(2). Five-year OS was 49 % for patients with positive sentinel lymph nodes and 56 % for patients with negative sentinel nodes (p = 0.005).

CONCLUSIONS

The rate of sentinel node positivity in patients with thin melanoma was 4.9 %. The only clinicopathologic factor related to node positivity was mitotic rate. Given its prognostic importance, SNB should be considered in such patients. SNB should also be the standard method for melanoma ≥4 mm, not only for staging, but also for guiding therapeutic decisions.

Competing risk analysis of mortality from invasive cutaneous melanoma in New South Wales: a population-based study, 1988-2007

OBJECTIVE

Accurate estimates of risk of death from melanoma, based on the most recent information, are desirable, especially if secular improvements in survival have occurred. This study aims to investigate prognostic factors and temporal changes in mortality from primary invasive cutaneous melanoma (CM) and to predict cumulative probabilities of death from CM.

METHODS

Cases of CM from the NSW Central Cancer Registry (NSWCCR) diagnosed in 1988-2007 were analysed. We used Fine and Gray competing risks models to investigate prognostic factors associated with CM mortality, along with period effects of year of diagnosis. Adjusted cumulative probabilities of CM death were then estimated.

RESULTS

Of 52,330 CM cases, 5291 (10%) died from CM and 8290 (16%) from other causes. Patients with tumours thicker than 4 mm had 9.5 times the risk of death from CM compared to those with tumours 1 mm or less (subhazard ratio [SHR] 9.52; 95%CI:8.42-10.77). Risk of melanoma death was 31% lower in 2003-2007 compared to 1988-1992 (SHR 0.69; 95%CI: 0.63-0.76). Other risk factors for CM mortality included older age and male gender. Assuming the estimated period effect for a diagnosis in 2003-2007 applies now, the predicted probability of CM death within 10 years of diagnosis of a tumour 4+ mm thick is 26% in males and 19% in females.

CONCLUSION

This study highlights the importance of awareness and early detection and shows a significant improvement in survival from CM since 1988.

High MCM3 expression is an independent biomarker of poor prognosis and correlates with reduced RBM3 expression in a prospective cohort of malignant melanoma

Background

Malignant melanoma is the most lethal form of skin cancer with a variable clinical course even in patients with thin melanomas and localized disease. Despite increasing insights into melanoma biology, no prognostic biomarkers have yet been incorporated into clinical protocols. Reduced expression of the RNA binding motif protein 3 (RBM3) has been shown to correlate with tumour progression and poor prognosis in melanoma and several other cancer forms. In ovarian cancer, an inverse association was found between expression of RBM3 and the minichromosome maintenance 3 (MCM3) gene and protein. In melanoma, gene expression analysis and immunohistochemical validation has uncovered MCM3 as a putative prognostic biomarker. The aim of the present study was to examine the associations of MCM3 expression with clinical outcome and RBM3 expression in a prospective, population-based cohort of melanoma.

Methods

Immunohistochemical MCM3 expression was examined in 224 incident cases of primary melanoma from the Malmö Diet and Cancer Study, previously analysed for RBM3 expression. Spearman´s Rho and Chi-Square tests were used to explore correlations between MCM3 expression, clinicopathological factors, and expression of RBM3 and Ki67. Kaplan Meier analysis, the log rank test, and univariable and multivariable Cox proportional hazards modelling were used to assess the impact of MCM3 expression on disease-free survival (DFS) and melanoma-specific survival (MSS).

Results

High MCM3 expression was significantly associated with unfavourable clinicopathological features and high Ki67 expression. A significant inverse correlation was seen between expression of MCM3 and RBM3 (p = 0.025). High MCM3 expression was associated with a reduced DFS (HR = 5.62) and MSS (HR = 6.03), and these associations remained significant in multivariable analysis, adjusted for all other factors (HR = 5.01 for DFS and HR = 4.96 for MSS). RBM3 expression remained an independent prognostic factor for MSS but not DFS in the multivariable model.

Conclusions

These findings provide validation of the utility of MCM3 expression as an independent biomarker for prognostication of patients with primary melanoma. Moreover, the inverse association and prognostic impact of MCM3 and RBM3 expression indicate a possible interaction of these proteins in melanoma progression, the functional basis for which merits further study.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1814908129755401

Sentinel node biopsy is indicated for thin melanomas ≥0.76 mm

BACKGROUND

A consensus for which patients with thin melanomas (≤1 mm) should undergo sentinel lymph node biopsy (SLNB) is not established. We describe a large single institution experience with SLNB for thin melanomas to determine factors predictive of nodal metastases.

METHODS

Retrospective review from 2005 to 2010 identified 271 patients with thin melanomas who underwent SLNB, along with 13 additional patients not treated with SLNB who developed a nodal recurrence as first site of recurrence. Clinicopathologic characteristics were correlated with nodal status and outcome.

RESULTS

Median age was 55 years, and 53% of patients were male. Median Breslow thickness was 0.85 mm. Overall, a positive sentinel lymph node (SLN) was found in 22 (8.1%) of 271 cases; 8.4% of melanomas ≥0.76 mm were SLN positive with 5% of T1a melanomas ≥0.76 mm and 13% of T1b melanomas ≥0.76 mm having SLN metastases. Only two of 33 highly selected patients with melanomas <0.76 mm (both T1b) had a positive SLN. Logistic regression analysis demonstrated that mitotic rate ≥1/mm(2) significantly correlated with nodal disease (p < 0.05) and ulceration correlated with SLN metastases (p < 0.05). Median follow-up was 2.1 years. Overall survival did not differ between positive and negative SLN patients (p = 0.53) but was worse for patients presenting with a nodal recurrence (p < 0.01).

CONCLUSIONS

SLN metastases were seen in 8.4% of thin melanomas ≥0.76 mm, including 5% of T1a melanomas ≥0.76 mm. We believe these rates are sufficient to justify consideration of SLNB in these patients, while the indications for SLNB in melanomas <0.76 mm remain to be defined.

Modifying effect of gender on the prognostic value of clinicopathological factors and Ki67 expression in melanoma: a population-based cohort study

Background

Malignant melanoma is the most deadly form of skin cancer. Female sex is known to have a protective effect on incidence, tumour characteristics, and mortality from melanoma. However, the potentially modifying effect of sex on the prognostic significance of clinicopathological and investigative factors is generally not taken into consideration in biomarker studies. In this study, we compared the sex-specific distribution and prognostic value of established tumour characteristics and Ki67 expression in 255 cases of incident primary melanoma in a prospective, population-based cohort study.

Methods

The study included 255 incident cases of melanoma, 132 females and 123 males, in the Malmö Diet and Cancer Study. Tumours from 226 (88.6%) cases had been assembled in tissue microarrays. Clinicopathological factors and immunohistochemical Ki67 expression were assessed and correlated with disease-free survival (DFS) and overall survival (OS) using Kaplan-Meier analysis, log rank test and univariable and multivariable Cox regression analyses, stratified for gender. Effect of gender on melanoma-specific survival (MSS) after first recurrence was also analysed.

Results

Women were significantly younger at diagnosis than men (p = 0.012). The most common tumour sites were the legs in women (37.5%) and the dorsal trunk in men (37.8%). Kaplan-Meier analysis revealed that tumour location had no prognostic impact in women, but in men, location to the frontal trunk was significantly associated with a reduced DFS compared with all other locations combined and location to the dorsal trunk was significantly associated with a prolonged OS. High Ki67 expression was significantly associated with a reduced DFS and OS in men but not in women, also when adjusted for other factors. In men, but not in women, ulceration was an independent prognostic factor for both DFS and OS. MSS after first local, regional or distant recurrence was significantly shorter for men than for women.

Conclusions

The results from this study demonstrate that the prognostic value of tumour location, Ki67 expression and ulceration in melanoma differs according to gender. These findings need to be validated in future studies, as they may help improve prognostication in patients with melanoma. Moreover, our findings demonstrate that sex-stratified analyses add valuable information to biomarker studies.

Population-based 20-year survival among people diagnosed with thin melanomas in Queensland, Australia

PURPOSE

The 20-year survival rates are unknown for the majority of melanoma patients-those with thin melanomas. We determined 20-year survival rates of patients diagnosed with thin melanomas (≤ 1.00 mm) in the general population and also determined the main prognostic factors.

PATIENTS AND METHODS

Available clinical and histologic data from the Queensland Cancer Registry were obtained for all patients diagnosed with a single thin invasive melanoma from 1982 to 2006 and matched against national death registration data. Melanoma-specific survival estimates to December 31, 2007, were assessed, and subgroup differences in prognosis were determined by fitting multivariate Cox proportional hazard models.

RESULTS

Among 26,736 people in the state of Queensland diagnosed with thin melanomas, the 20-year survival was 96%. The most influential determinants of prognosis were tumor thickness ≥ 0.75 mm (adjusted hazard ratio [HR], 4.33; 95% CI, 2.8 to 6.8 compared with tumors < 0.25 mm) and patient age at diagnosis older than 65 years (HR, 2.8; 95% CI, 1.8 to 4.5) compared with age younger than 25 years. Acral lentiginous and nodular tumors, male sex, tumor site on the scalp or neck, or tumor invasion of the entire papillary dermis each independently increased the risk of dying from thin invasive melanoma.

CONCLUSION

The outlook for patients with thin invasive melanoma is positive, although continued clinical vigilance is warranted for patients with nodular melanoma and those with the thickest tumors.

Sentinel lymph node biopsy in patients with thin primary cutaneous melanoma

OBJECTIVES

To determine the rate and clinicopathologic factors predictive of sentinel lymph node (SLN) positivity, regional lymph node recurrence, and survival in a large series of patients with thin primary cutaneous melanoma who underwent SLN biopsy (SLNB).

METHODS

Patients with thin (≤1 mm) melanomas who underwent SLNB between 1992 and 2009 at Melanoma Institute Australia were identified from the Melanoma Institute Australia database. The association of clinicopathologic features with SLN status, lymph node recurrence, and survival was analyzed.

RESULTS

In 432 patients [226 men, 206 women; median age 49.5 years (range: 14.4-85.0 years)], SLNB was positive for metastatic melanoma in 29 (6.7%) patients. No SLN positivity was detected in 37 patients with primary tumor thickness 0.50 mm or less. Breslow thickness (P = 0.012) and presence of lymphovascular invasion (P = 0.018) were the only factors significantly associated with SLN positivity. Regional lymph node recurrence was significantly more common in tumors located in the head/neck region (4/33, 12%) than in extremities (3/245, 1.2%) and trunk (2/154, 1.3%) (P < 0.001). Primary tumor mitotic rate was a significant predictor of melanoma-specific survival (Hazard Ratio [HR] = 1.2, 95% confidence interval: 1.09-1.35, P < 0.001).

CONCLUSIONS

There is a low but significant rate of SLN positivity in patients with primary melanomas 0.51 to 1.0 mm in thickness. Given its prognostic importance, SLNB should be considered in such patients, particularly if there is lymphatic permeation by melanoma at the primary tumor site. More frequent regional node field recurrences in patients with head/neck primary tumors may be a consequence of complex lymphatic drainage patterns in this region.

Melanoma update: diagnostic and prognostic factors that can effectively shape and personalize management

Routine light microscopy remains a powerful tool to diagnose, stage and prognose melanoma. Although it is very economical and efficient, it requires a significant level of expertise and, in difficult cases the final diagnosis is affected by subjective interpretation. Fortunately, new insights into the genomic aberrations characteristic of melanoma, coupled with ancillary studies, are further refining evaluation and management allowing for more confident diagnosis, more accurate staging and the selection of targeted therapy. In this article, we review the standard of care and new updates including four probe FISH, the 2009 American Joint Commission on Cancer staging of melanoma and mutant testing of melanoma, which will be crucial for targeted therapy of metastatic melanoma.

Low RBM3 protein expression correlates with tumour progression and poor prognosis in malignant melanoma: an analysis of 215 cases from the Malmö Diet and Cancer Study

Background

We have previously reported that expression of the RNA- and DNA-binding protein RBM3 is associated with a good prognosis in breast cancer and ovarian cancer. In this study, the prognostic value of immunohistochemical RBM3 expression was assessed in incident cases of malignant melanoma from a prospective population-based cohort study.

Methods

Until Dec 31^st 2008, 264 incident cases of primary invasive melanoma had been registered in the Malmö Diet and Cancer Study. Histopathological and clinical information was obtained for available cases and tissue microarrays (TMAs) constructed from 226 (85.6%) suitable paraffin-embedded tumours and 31 metastases. RBM3 expression was analysed by immunohistochemistry on the TMAs and a subset of full-face sections. Chi-square and Mann-Whitney U tests were used for comparison of RBM3 expression and relevant clinicopathological characteristics. Kaplan Meier analysis and Cox proportional hazards modelling were used to assess the relationship between RBM3 and recurrence free survival (RFS) and overall survival (OS).

Results

RBM3 could be assessed in 215/226 (95.1%) of primary tumours and all metastases. Longitudinal analysis revealed that 16/31 (51.6%) of metastases lacked RBM3 expression, in contrast to the primary tumours in which RBM3 was absent in 3/215 (1.4%) cases and strongly expressed in 120/215 (55.8%) cases. Strong nuclear RBM3 expression in the primary tumour was significantly associated with favourable clinicopathological parameters; i.e. non-ulcerated tumours, lower depth of invasion, lower Clark level, less advanced clinical stage, low mitotic activity and non-nodular histological type, and a prolonged RFS (RR = 0.50; 95% CI = 0.27-0.91) and OS (RR = 0.36, 95%CI = 0.20-0.64). Multivariate analysis demonstrated that the beneficial prognostic value of RBM3 remained significant for OS (RR = 0.33; 95%CI = 0.18-0.61).

Conclusions

In line with previous in vitro data, we here show that RBM3 is down-regulated in metastatic melanoma and high nuclear RBM3 expression in the primary tumour is an independent marker of a prolonged OS. The potential utility of RBM3 in treatment stratification of patients with melanoma should be pursued in future studies.