Serial or Parallel Metastasis of Cutaneous Melanoma? A Study of the German Central Malignant Melanoma Registry

Stromal lipid species dictate melanoma metastasis and tropism

Cancer cells adapt to signals in the tumor microenvironment (TME), but the TME cues that impact metastasis and tropism are still incompletely understood. We show that abundant stromal lipids from young subcutaneous adipocytes, including phosphatidylcholines, are taken up by melanoma cells, where they upregulate melanoma PI3K-AKT signaling, fatty acid oxidation, oxidative phosphorylation (OXPHOS) leading to oxidative stress, resulting in decreased metastatic burden. High OXPHOS melanoma cells predominantly seed the lung and brain; decreasing oxidative stress with antioxidants shifts tropism from the lung to the liver. By contrast, the aged TME provides fewer total lipids but is rich in ceramides, leading to lower OXPHOS and high metastatic burden. Aged TME ceramides taken up by melanoma cells activate the S1P-STAT3-IL-6 signaling axis and promote liver tropism. Inhibiting OXPHOS in the young TME or blocking the IL-6 receptor in the aged TME reduces the age-specific patterns of metastasis imposed by lipid availability.

Metabolic insights into tumor lymph node metastasis in melanoma

Although accounting for only a small amount of skin cancers, melanoma contributes prominently to skin cancer-related deaths, which are mostly caused by metastatic diseases, and lymphatic metastasis constitutes the main route. In this review, we concentrate on the metabolic mechanisms of tumor lymph node (LN) metastasis in melanoma. Two hypotheses of melanoma LN metastasis are introduced, which are the premetastatic niche (PMN) and parallel progression model. Dysregulation of oxidative stress, lactic acid concentration, fatty acid synthesis, amino acid metabolism, autophagy, and ferroptosis construct the metabolic mechanisms in LN metastasis of melanoma. Moreover, melanoma cells also promote LN metastasis by interacting with non-tumor cells through metabolic reprogramming in TIME. This review will deepen our understanding of the mechanism of lymph node metastasis in melanoma.

Die Prognose des Melanoms im Kopf-Hals-Bereich im Stadium II hängt vom histologischen Subtyp ab

Hintergrund und Ziele

Die Melanom‐Leitlinie basiert hauptsächlich auf dem AJCC‐Stadium. Hierbei wird nicht zwischen den histologischen Subtypen wie dem superfiziell spreitenden Melanom (SSM), dem Lentigo‐maligna‐Melanom (LMM) oder dem nodulären malignen Melanom (NM) unterschieden. Ziel der Studie war es zu untersuchen, ob sich Patienten mit LMM im klinischen Verlauf von Patienten mit SSM/NM unterscheiden. Dies ist aktuell besonders wichtig, da die adjuvante Anti‐PD‐1‐Therapie für Melanome im Stadium IIB und IIC zugelassen wurde.

Patienten und Methodik

Die Daten wurden aus dem Zentralregister „malignes Melanom“ entnommen. Es wurden nur Patienten mit LMM, SSM oder NM des Kopf‐Hals‐Bereichs und Primärdiagnose zwischen dem 01.01.2000 und dem 31.12.2019 eingeschlossen. Das progressionsfreie Überleben (PFÜ), das melanomspezifische Überleben (MSÜ) und das Metastasierungsmuster wurden für die Gruppe der LMM im Vergleich zur Gruppe der SSM/NM analysiert.

Ergebnisse

Die LMM‐Kohorte (n = 902) hatte ein signifikant besseres MSÜ als die SSM/NM‐Kohorte (n = 604). Beim PFÜ gab es keinen Unterschied. Das 5‐Jahres‐MSÜ der LMM‐Kohorte im Stadium II betrug 88,5 % (95 % KI 81,4–95,6), im Vergleich dazu das der SSM/NM‐Kohorte im Stadium II 79,7 % (95 % KI 72,8–86,6).

Schlussfolgerung

Es scheint nicht angebracht zu sein, eine adjuvante Therapie bei LMM‐Patienten im Stadium II im gleichen Umfang durchzuführen, wie bei Patienten mit SSM/NM.

Prognosis in stage II melanoma of the head and neck depends on the histological subtype

BACKGROUND AND OBJECTIVES

The melanoma guideline is mainly based on the AJCC stage. There is no difference according to histological subtypes such as superficial spreading melanoma (SSM), lentigo maligna melanoma (LMM) or nodular malignant melanoma (NM). We aimed to evaluate whether patients with LMM have a different clinical course from patients with SSM/NM. This is particularly important as adjuvant anti-PD-1 therapy is approved for stage IIB and IIC melanoma.

PATIENTS AND METHODS

Data were extracted from the Central Registry of Malignant Melanoma. Only patients with LMM, SSM, and NM of the head and neck with primary diagnosis between 01/01/2000 and 12/31/2019 were included. Progression-free survival (PFS), melanoma-specific survival (MSS), and pattern of metastases were analyzed for the LMM group compared to SSM/NM.

RESULTS

The LMM cohort (n = 902) had significantly better MSS than the SSM/NM cohort (n = 604). There was no difference in PFS. The 5-year MSS of the stage II LMM cohort was 88.5% (95% CI 81.4-95.6) compared to 79.7% (95% CI 72.8-86.6) in the stage II SSM/NM cohort.

CONCLUSION

It does not appear appropriate to use adjuvant therapy in stage II LMM patients to the same extent as in patients with SSM/NM.

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.

What causes the death of patients with cutaneous squamous cell carcinoma? A prospective analysis in 1400 patients

INTRODUCTION

Cutaneous squamous cell carcinoma (cSCC) is a common tumor of elderly Caucasian patients.

METHODS

Competing multivariable risk models to analyze different types of cSCC associated death (local infiltration [LI], locoregional [LR], and distant metastases [DM]) in terms of prognostic factors.

RESULTS AND DISCUSSION

1400 patients were analyzed. In the adjusted multivariable subdistribution hazard approach for tumor volume, the best model for death of cSCC overall revealed the presence of desmoplasia (HR 4.52; p < 0.001), bone invasion (HR 10.06; p < 0.01), and immunosuppression (HR 3.19; p = 0.003) as significant factors. Death due to LI indicated desmoplasia (HR 15.39; p < 0.01) and bone invasion (HR 16.9; p < 0.001) as significant factors. For death by LM, immunosuppression with a HR of 3.27; p = 0.004 was the only significant prognostic factors as well as in death by DM with a HR of 4.54; p = 0.02.

CONCLUSIONS

The three types of death caused by cSCC can be distinguished based on risk factors with different weights. Patients with these factors should be monitored closely.

Clinical characteristics and therapy response in unresectable melanoma patients stage IIIB-IIID with in-transit and satellite metastases

INTRODUCTION

Cutaneous melanoma is notorious for the development of in-transit metastases (ITM). For unknown biological reasons, ITM remain the leading tumour manifestation without progression to distant sites in some patients.

METHODS

In total, 191 patients with initially unresectable stage III ITM and satellite metastases from 16 skin cancer centres were retrospectively evaluated for their tumour characteristics, survival and therapy response. Three groups according to disease kinetics (no distant progress, slow (>6 months) and fast (<6 months) distant progression) were analysed separately.

RESULTS

Median follow-up time was 30.5 (range 0.8-154.0) months from unresectable ITM. Progression to stage IV was observed in 56.5% of cases. Patients without distant metastasis were more often female, older (>70 years) and presented as stage III with lymph node or ITM at initial diagnosis in 45.7% of cases. Melanoma located on the leg had a significantly better overall survival (OS) from time of initial diagnosis compared to non-leg localised primaries (hazard ratio [HR] = 0.61, 95% confidence interval [CI] 0.40-0.91; p = 0.017), but not from diagnosis of unresectable stage III (HR = 0.67, 95% CI 0.45-1.02; p = 0.06). Forty percent of patients received local therapy for satellite and ITM. Overall response rate (ORR) to all local first-line treatments was 38%; disease control rate (DCR) was 49%. In total, 72.3% of patients received systemic therapy for unresectable stage IIIB-D. ORR for targeted therapy (n = 19) was highest with 63.2% and DCR was 84.2% compared to an ORR of 31.4% and a DCR of 54.3% in PD-1 treated patients (n = 70). Patients receiving PD-1 and intralesional talimogene laherparepvec (n = 12) had an ORR of 41.7% and a DCR of 75%.

CONCLUSION

Patients with unresectable ITM and without distant progression are more often female, older, and have a primary on the leg. Response to PD-1 inhibitors in this cohort was lower than expected, but further investigation is required to elucidate the biology of ITM development and the interplay with the immune system.

The Prognosis and Natural History of In-Transit Melanoma Metastases at a High-Volume Centre

BACKGROUND

Patients with in-transit melanoma metastases (ITM) experience a diverse spectrum of clinical presentations and a highly variable disease course. There is no standardized treatment protocol for these patients due to the limited data comparing treatment modalities for ITM. This is the first study to describe the disease trajectory and natural history of a large cohort of patients with ITM.

METHODS

A retrospective study of patients treated for ITM between 2004 and 2018 at the Peter MacCallum Cancer Centre was performed. Clinical and pathological characteristics for primary and in-transit episodes were analyzed for predictors of relapse-free survival (RFS), distant metastasis-free survival (DMFS), and melanoma-specific survival.

RESULTS

A total of 109 patients with 303 episodes of ITM were identified: 52 (48%) females, median age 70.1 years (range 35-92). The median RFS for all episodes was 5 months (95% confidence interval [CI] 4.2-5.7). Eighty-seven percent of episodes involving isolated in-transit lesions underwent surgical excision, compared with 17% involving more than five in-transit lesions. A trend was seen between a greater number of lesions and shorter RFS (p = 0.055). The median DMFS was 34.8 months (95% CI 22.8-51.6). Factors associated with shorter DMFS included primary tumor thickness (hazard ratio [HR] 1.08, 95% CI 1.01-1.15; p = 0.026), site of primary tumor (p = 0.008), and BRAF mutation (HR 2.12, 95% CI 1.14-3.94; p = 0.018).

CONCLUSIONS

Locoregional relapse is common in patients with ITM regardless of treatment modality. Characteristics of the ITM may predict for RFS, while primary tumor characteristics remain important predictors of DMFS.

TERT Promoter Mutations are Associated with Visceral Spreading in Melanoma of the Trunk

Survival predictions are currently determined on the basis of NRAS/BRAF mutations, even though TERT promoter mutations have been recently associated with a poor prognosis in stage I-II melanomas. Usually, it is not recommended to perform a mutational test on primary melanoma, as the results do not always reflect the mutational status of metastases. In particular, trunk melanomas have been reported to have an unfavourable prognosis. A series of 105 advanced melanoma patients were analysed by TERT promoter Sanger sequencing. Univariate/multivariate binary logistic regression models were performed using progression to a visceral site as the dependent variable and patient/tumour characteristics as covariates. Performance of the model was assessed in an external independent primary melanoma patients' dataset. Male gender (odds ratio (OR), 344; 95% CI, 1.12⁻10.6; p = 0.031), AJCC (American Joint Committee on Cancer) classification (OR, 022; 95% CI, 0.07⁻0.67; p = 0.008), SLNB (Sentinel Lymph Node Biopsy) status (OR, 3.05; 95% CI, 1.06⁻8.78; p = 0.039) and TERT-mutated trunk lesions (OR, 3.78; 95% CI, 1.35⁻10.6; p =  0.011) were significantly associated with the risk of developing a visceral spreading as first site of progression using multivariate logistic regression analysis. These results were confirmed in the external validation control group. Therefore, in trunk primary melanomas, due to their high risk of progression to visceral sites, we encourage somatic TERT mutation analysis at diagnosis to identify those patients who would potentially benefit from a more intensive follow-up protocol and a prompt initiation of therapy.

Lymphatic versus Hematogenous Melanoma Metastases: Support for Biological Heterogeneity without Clear Clinical Application

Melanoma demonstrates considerable biological heterogeneity and is associated with several routes of dissemination including lymphatic and hematogenous. Locoregional control via surgery may improve outcomes for patients with limited lymphatic metastases. Once stage IV disease is diagnosed, clinical outcomes are determined by molecular and/or immunologic factors and identification of tumor/microenvironmental features correlating with distant metastases is critical for future prognostic stratification.

Management of in-transit melanoma metastases: a review

In-transit metastases (ITM) of cutaneous melanoma are locoregional recurrences confined to the superficial lymphatics that occur in 3.4-6.2% of patients diagnosed with melanoma. ITM are a heterogeneous disease that poses a therapeutic dilemma. Patients may have a prolonged disease trajectory involving multiple or repeat treatment modalities for frequent recurrences. The management of ITM has evolved without the development of a standardized protocol. Owing to the variability of the disease course there are few dedicated clinical trials, with a number of key trials in stage III melanoma excluding ITM patients. Thus, there is a paucity of quality data on the efficacy of the treatment modalities available for ITM and even fewer studies directly comparing modalities. At present the mainstay of ITM treatment is surgical resection, with intralesional therapies, isolated limb infusion and radiotherapy utilized as second-line measures. The developing role of targeted therapies and immunotherapy has yet to be explored completely in these patients. This review addresses the evidence base of the efficacy of the various treatment modalities available and those factors that have impacted their clinical uptake.

Tumour mutation status and melanoma recurrence following a negative sentinel lymph node biopsy

BACKGROUND

A proportion of patients develop recurrence following a tumour-negative sentinel lymph node biopsy (SLNB). This study aimed to explore whether melanoma patients with BRAF or NRAS mutant tumours have an increased risk of developing disease recurrence following a negative SLNB compared to patients with wild-type tumours.

METHODS

Prospective cohort study of melanoma patients at three tertiary referral centres in Melbourne, who underwent SLNB. Clinical, pathological and molecular characteristics and recurrence data were prospectively recorded. Multivariate Cox proportional hazards regression models estimated the adjusted hazard ratio (aHR) and corresponding 95% confidence interval (CI) for the association between mutation status and development of recurrence following a negative-SLNB.

RESULTS

Overall, 344/477 (72.1%) patients had a negative SLNB. Of these, 54 (15.7%) developed subsequent recurrence. The risk of disease recurrence following a negative SLNB was increased for patients with either a BRAF or NRAS mutant tumour compared to wild-type tumours (aHR 1.92, 95% CI: 1.02-3.60, p = 0.04).

CONCLUSION

Melanoma patients with BRAF or NRAS mutant tumours had an increased risk compared to patients with BRAF/NRAS wild-type tumours of developing disease recurrence following a tumour-negative SLNB. The findings also confirm the importance of continued surveillance to monitor for disease recurrence among SLNB-negative patients.

Lymph Node Dissection in Patients With Melanoma and Sentinel Lymph Node Metastasis: An Updated, Evidence-Based Decision Algorithm

Recent publication of the results of clinical trials in which lymph node dissection was not associated with any survival benefit in patients with sentinel node metastasis makes it necessary to reconsider the treatment of patients with melanoma. This article provides an update on the available evidence on the diverse factors (routes of metastatic spread, predictors, adjuvant therapy, etc.) that must be considered when treating patients with sentinel node-positive melanoma. The authors propose a decision-making algorithm for use in this clinical setting. The current evidence no longer supports lymph node dissection in patients with low-risk sentinel node metastasis (sentinel node tumor load ≤1mm).