Patients with melanoma of unknown primary show better outcome under immune checkpoint inhibitor therapy than patients with known primary: preliminary results

Characteristics of long-survivor metastatic melanoma after polychemotherapy and interferon: a retrospective study

BACKGROUND

The development of immunotherapy and tyrosine kinase inhibitors dramatically improved the prognosis of metastatic melanoma. Consequently, chemotherapy is now rarely used. Here, we describe the characteristics of long-surviving patients with metastatic melanoma treated with immunochemotherapy.

MATERIAL AND METHODS

We retrieved retrospective clinical and pathological data for patients diagnosed with metastatic melanoma between January 1993 and December 2015 who received the CVD-INF (cisplatin, vinblastine, dacarbazine, and interferon α-2b) regimen at the Hôpitaux Universitaires de Genève. We estimated their progression-free survival and overall survival. This ad hoc study's primary aim was to describe the clinical and biological characteristics of long-term survivors, defined as patients surviving more than two years after immunochemotherapy initiation. The spatial distribution pattern of CD8+ T cells (inflamed, excluded, or desert) was immunohistochemically determined.

RESULTS

Ninety patients received CVD-INF. Their median age at metastatic melanoma diagnosis was 55 years (20-75). Their median progression-free survival was 2.8 months, and median overall survival was 7.2 months. Eleven (12%) patients were long-term survivors. In multivariate analysis, central nervous system metastases (hazard ratio [HR]: 2.66; 95% confidence interval [CI]: 1.43-4.95; p = 0.001), multiple metastases (HR: 1.82; 95% CI: 1.01-3.29; p = 0.047), and elevated lactate dehydrogenase (LDH) (HR: 1.92; 95% CI: 1.12-3.30; p = 0.016) were independently associated with shorter survival. Most long-survivors (6/8; 75%) had a tumour-inflamed pattern compared to 25% of non-long survivors (5/20; Fisher's test p = 0.030).

CONCLUSIONS

A subset of patients with metastatic melanoma and a tumour-inflamed phenotype treated with CVD-INF survived over two years. Factors associated with prolonged survival are consistent with those previously reported in metastatic melanoma.

Brain metastases in adult patients with melanoma of unknown primary in the Netherlands (2011-2020)

BACKGROUND

Although patients with melanoma of unknown primary (MUP) have a better prognosis than similar-staged melanoma patients with known primary, the occurrence of brain metastases (BM) entails a serious complication. This study provides an overview of the incidence, treatment patterns, and overall survival (OS) of adult patients with BM-MUP in the Netherlands.

METHODS

BM-MUP cases were retrieved from the Netherlands Cancer Registry. Patient, disease and treatment-related characteristics were summarised using descriptive statistics. Overall survival (OS) was calculated by the Kaplan-Meier method, and the impact of prognostic factors on OS was assessed using Cox proportional hazard regression analyses.

RESULTS

Among 1779 MUP patients, 450 were identified as BM-MUP (25.3%). Of these patients, 381 (84.7%) presented with BM along with other metastases, while 69 (15.3%) had BM only. BM-MUP patients were predominantly male (68.2%), and had a median age of 64 years at diagnosis (interquartile range 54-71 years). Over time, the proportion of BM along other metastatic sites increased, and the occurrence of BM decreased (p = 0.01). 1-Year OS improved for the total population, from 30.0% (95% confidence interval (CI): 19.8-40.9%) in 2011-2012 to 43.6% (95%CI: 34.5-52.3%) in 2019-2020, and median OS more than doubled from 4.2 months (95%CI: 3.3-6.2 months) to 9.8 months (95%CI: 7.0-13.2 months). Patient's age, localisation of BM, presence of synchronous liver metastasis and treatment were identified as independent predictors of OS.

CONCLUSION

Notwithstanding the progress made in OS for patients with BM-MUP in the past decade, their overall prognosis remains poor, and further efforts are needed to improve outcomes.

Impact of systemic therapies in metastatic melanoma of unknown primary: A study from MELBASE, a French multicentric prospective cohort

BACKGROUND

Clinical outcomes of advanced melanoma of unknown primary (MUP) in the era of novel therapies have been scarcely studied.

OBJECTIVE

To investigate the efficacy and safety of systemic treatments in patients with advanced MUP compared to patients with stage-matched melanoma of known cutaneous primary (cMKP).

METHODS

Based on the nationwide MelBase prospective database, this study included advanced melanoma patients treated from March 2013 to June 2021 with first-line immunotherapies, targeted therapies, or chemotherapy. Co-primary outcomes were progression-free survival and overall survival. Secondary outcome was treatment-related toxicities. Multivariate and propensity score analyses were performed.

RESULTS

Of 1882 patients, 265 (14.1%) had advanced MUP. Patients with advanced MUP displayed more often unfavorable initial prognostic factors than those with cMKP. Progression-free and overall survival did not differ significantly between the groups (P = .73 and P = .93, respectively), as well as treatment-related toxicity rate and severity, regardless of treatment type.

LIMITATIONS

No record of standard diagnostic criteria of MUP used in the participating centers.

CONCLUSIONS

Although patients with MUP had less favorable baseline prognostic factors, they benefited from the novel therapies as much as those with cMKP. They should be managed according to similar strategies.

Treatment of Metastatic Melanoma at First Diagnosis: Review of the Literature

Metastatic melanoma (MM) is a pathological entity with a very poor prognosis that, until a few decades ago, had a low response rate to systemic treatments. Fortunately, in the last few years, new therapies for metastatic melanoma have emerged. Currently, targeted therapy and immunotherapy are the mainstays of the therapeutic arsenal available for patients with unresectable or metastatic melanoma. However, both clinical evolution and drug efficacy in melanoma patients are very different depending on the stage at which it is diagnosed. In fact, the aggressiveness of melanoma is different depending on whether it debuts directly as metastatic disease or if what occurs is a relapse after a first diagnosis at an early stage, although the biological determinants are largely unknown. Another key aspect in the clinical management of metastatic melanoma at first diagnosis strives in the different prognosis of melanoma of unknown primary (MUP) compared to melanoma of known primary (MPK). Understanding the mechanisms behind this, and the repercussion of implementing targeted and immune therapies in this specific form is crucial for designing diagnosis and treatment decision algorithms that optimize the current strategies. In this review article, we recapitulate the information available thus far regarding the epidemiology and response to immunotherapy treatments or targeted therapy in patients diagnosed with metastatic melanoma as a first diagnosis, with especial emphasis on the emerging specific information of the subpopulation formed by MUP patients.

Management of Regional Lymph Nodes in Head and Neck Melanoma

The utilization of sentinel lymph node (SLN) biopsy has transformed the workup and staging of intermediate-thickness cutaneous melanomas. SLN biopsy, performed at the time of primary tumor excision, accurately maps lymph nodes at risk of harboring occult metastatic deposits from head and neck cutaneous melanomas and represents the current standard of care. Completion lymphadenectomy identifies additional tumor in 12% to 24% of SLN biopsy positive cases but does not affect melanoma-specific survival.

Comparative genomic characterization of melanoma of known and unknown primary

BACKGROUND

This study aims to genomically characterize melanoma of unknown primary (MUP) in comparison to melanomas of cutaneous primary (MCP).

METHODS

Eligible cases were collected from the MSK-IMPACT™ Clinical Sequencing Cohort published in the cBioPortal database. Genomic analysis was performed using a hybridization-capture-based next-generation sequencing assay designed to detect mutations, small insertions and deletions, copy number alterations, and genomic rearrangements.

RESULTS

Among 462 patients of whom 18.4% had MUP, brain metastasis was more common among patients with MUP (23% vs 7.1%). The differences in genomic profiling between MCP and MUP did not reach statistical significance. The 187 MCP and 44 MUP patients treated with immune checkpoint inhibitors had a median overall survival of 49 and 44 months, respectively (p = 0.705).

CONCLUSIONS

The differences in somatic mutation patterns and survival outcomes were not statistically significant. These findings may allude to similar carcinogenic processes but should be considered exploratory and interpreted with caution.

Clinical outcome of patients with metastatic melanoma of unknown primary in the era of novel therapy

Melanoma of unknown primary (MUP) is considered different from melanoma of known primary (MKP), and it is unclear whether these patients benefit equally from novel therapies. In the current study, characteristics and overall survival (OS) of patients with advanced and metastatic MUP and MKP were compared in the era of novel therapy. Patients were selected from the prospective nation-wide Dutch Melanoma Treatment Registry (DMTR). The following criteria were applied: diagnosis of stage IIIc unresectable or IV cutaneous MKP (cMKP) or MUP between July 2012 and July 2017 and treatment with immune checkpoint inhibition and/or targeted therapy. OS was estimated using the Kaplan–Meier method. The stratified multivariable Cox regression model was used for adjusted analysis. A total of 2706 patients were eligible including 2321 (85.8%) patients with cMKP and 385 (14.2%) with MUP. In comparative analysis, MUP patients more often presented with advanced and metastatic disease at primary diagnosis with poorer performance status, higher LDH, and central nervous system metastases. In crude analysis, median OS of cMKP or MUP patients was 12 months (interquartile range [IQR] 5 – 44) and 14 months (IQR 5 – not reached), respectively (P = 0.278). In adjusted analysis, OS in MUP patients was superior (hazard rate 0.70, 95% confidence interval 0.58–0.85; P < 0.001). As compared to patients with advanced and metastatic cMKP, MUP patients have superior survival in adjusted analysis, but usually present with poorer prognostic characteristics. In crude analysis, OS was comparable indicating that patients with MUP benefit at least equally from treatment with novel therapies.

Melanoma of Unknown Primary: Evaluation of the Characteristics, Treatment Strategies, Prognostic Factors in a Monocentric Retrospective Study

Background

Melanoma of unknown primary (MUP), accounts for up to 3% of all melanomas and consists of a histologically confirmed melanoma metastasis to either lymph nodes, (sub)cutaneous tissue, or visceral sites without any evidence of a primary cutaneous, ocular, or mucosal melanoma. This study aimed to investigate the characteristics, treatment strategies, and prognostic factors of MUP patients, in order to shed some light on the clinical behavior of this malignancy.

Methods

All the consecutive patients with a diagnosis of MUP referring to our institutions between 1985 and 2018 were considered in this retrospective cohort study. The records of 173 patients with a suspected diagnosis of MUP were retrospectively evaluated for inclusion in the study. Patient selection was performed according to the Das Gupta criteria, and a total of 127 MUP patients were finally included in the study, representing 2.7% of the patients diagnosed with melanoma skin cancer at our institutions during the same study period. A second cohort of all consecutive 417 MKP patients with AJCC stages IIIB–IV, referring tions in the period considered (1985–2018), was included in the study to compare survival between MUP and MKP patients. All the diagnoses were based on histopathologic, cytologic and immunohistochemical examination of the metastases. All tumors were re-staged according to the 2018 American Joint Committee on Cancer (AJCC) 8^th Edition.

Results

Median follow-up was 32 months (IQR: 15–84). 3-year progression-free survival (PFS) was 54%, while 3-year overall survival (OS) was 62%. Worse OS and PFS were associated with older age (P = 0.0001 for OS; P = 0.008 for PFS), stage IV (P < 0.0001 for OS; P = 0.0001 for PFS) and higher Charlson Comorbidity Index (P < 0.0001 for OS and P = 0.01 for PFS). Patients with lymph node disease showed longer PFS (P = 0.001) and OS (P = 0.0008) than those with (sub)cutis disease. Complete lymph node dissection (CLND) was the most common surgical treatment; a worse OS in these patients was associated with the number of positive lymph nodes (P = 0.01), without significant association with the number of retrieved lymph nodes (P = 0.79). Survival rates were lower in patients undergoing chemotherapy (CT) and target therapy (TT), and higher in those receiving immunotherapy (IT). 417 patients with AJCC stages IIIB–IV of Melanoma Known Primary (MKP) were included for the survival comparison with MUP. 3-year PFS rates were 54 and 58% in MUP and MKP, respectively (P = 0.30); 3-year OS rates were 62 and 70% in MUP and MKP, respectively (P = 0.40).

Conclusions

The most common clinical scenario of our series was a male patient around 59 years with lymph node disease. We report that CLND associated with IT was the best treatment in terms of survival outcome. In the current era of IT and TT for melanoma, new studies have to clarify the impact of novel drugs on MUP.

Multidisciplinary Care for Melanoma of Unknown Primary: Experience in the Era of Molecular Profiling

BACKGROUND

Melanoma of unknown primary (MUP) accounts for approximately 3% of melanoma diagnoses. This study sought to evaluate treatment and outcomes for a modern MUP cohort.

METHODS

A retrospective review of MUP was performed at a tertiary referral cancer center.

RESULTS

Of 815 melanoma patients, 67 (8.2%) had MUP. Men were more likely to have MUP than women (67% vs. 55%; p = 0.04). The most common sites of MUP were lymph nodes (28%), visceral solid organs (25%), brain (16%), and skin/subcutaneous tissues (10%). Of the patients who underwent tumor genomic profiling, 52% harbored pathogenic BRAF mutations. Of the 24 patients who underwent multi-gene panel testing, all had pathogenic mutations and 21 (88%) had mutations in addition to or exclusive of BRAF, including 11 patients (46%) with telomerase reverse transcriptase promoter mutations. Checkpoint inhibitors (39%) and BRAF-MEK inhibitors (7%) were the most common first-line treatments. Upfront surgical resection was used for 25% of the MUP patients, and 12 of these resections were for curative intent. During a median follow-up period of 22.1 months, the median overall survival (OS) was not met for the patients with MUP isolated to lymph nodes. At 56.8 months, 75% of these patients were alive. The median OS was 37.4 months for skin/soft tissue MUP, 33.3 months for single solid organ viscera MUP, and 29.8 months for metastatic brain MUP.

CONCLUSION

Multigene panel testing identified pathogenic mutations in all tested MUP patients and frequently identified targets outside BRAF. Despite advanced stage, aggressive multimodal therapy for MUP can be associated with 5-year OS and should be pursued for appropriate candidates.

Uncommon Subtypes of Malignant Melanomas: A Review Based on Clinical and Molecular Perspectives

Malignant melanoma represents the most aggressive type of skin cancer. Modern therapies, including targeted agents and immune checkpoint inhibitors, have changed the dismal prognosis that characterized this disease. However, most evidence was obtained by studying patients with frequent subtypes of cutaneous melanoma (CM). Consequently, there is an emerging need to understand the molecular basis and treatment approaches for unusual melanoma subtypes. Even a standardized definition of infrequent or rare melanoma is not clearly established. For that reason, we reviewed this challenging topic considering clinical and molecular perspectives, including uncommon CMs-not associated with classical V600E/K BRAF mutations-malignant mucosal and uveal melanomas, and some unusual independent entities, such as amelanotic, desmoplastic, or spitzoid melanomas. Finally, we collected information regarding melanomas from non-traditional primary sites, which emerge from locations as unique as meninges, dermis, lymph nodes, the esophagus, and breasts. The aim of this review is to summarize and highlight the main scientific evidence regarding rare melanomas, with a particular focus on treatment perspectives.