Improved survival for stage IV melanoma from an unknown primary site

Diagnostic Performance of [18F]F-FDG Positron Emission Tomography (PET) in Non-Ophthalmic Malignant Melanoma: A Systematic Review and Meta-Analysis of More Than 10,000 Melanoma Patients

We described the diagnostic performance of [18F]F-FDG-PET in malignant melanoma by conducting a comprehensive systematic review and meta-analysis of the existing literature. The study was designed following PRISMA-DTA. Original articles with adequate crude data for meta-analytic calculations that evaluated [18F]F-FDG-PET and compared it with a valid reference standard were considered eligible. The pooled measurements were calculated based on the data level (patient/lesion-based). Regarding sub-groups, diagnostic performances were calculated for local, regional and distant involvement. The bivariate model was employed to calculate sensitivity and specificity. The initial search resulted in 6678 studies. Finally, 100 entered the meta-analysis, containing 82 patient-based (10,403 patients) and 32 lesion-based (6188 lesions) datasets. At patient level, overall, [18F]F-FDG-PET had pooled sensitivity and specificity of 81% (95%CI: 73-87%) and 92% (95%CI: 90-94%), respectively. To detect regional lymph node metastasis, the pooled sensitivity and specificity were 56% (95%CI: 40-72%) and 97% (95%CI: 94-99%), respectively. To detect distant metastasis, they were 88% (95%CI: 81-93%) and 94% (95%CI: 91-96%), respectively. At lesion level, [18F]F-FDG-PET had a pooled sensitivity and specificity of 70% (95%CI: 57-80%) and 94% (95%CI: 88-97%), respectively. Thus, [18F]F-FDG-PET is a valuable diagnostic modality for melanoma assessment. It was accurate in various clinical scenarios. However, despite its high specificity, it showed low sensitivity in detecting regional lymph node metastasis and could not replace lymph node biopsy.

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.

Survival after lymphadenectomy of nodal metastases from melanoma of unknown primary site

Although the vast majority of melanomas have a primary site, 3%-4% of all melanomas in distant sites display no known primary site (MUP). This phenomenon is not fully understood and various hypotheses have been introduced. The prognostic significance of MUP has been unclear, with some studies showing no survival benefit while others find improved survival compared to stage-matched patients with melanoma of known primary site (MKP). Between 1997 and 2014, 864 patients underwent an en bloc resection of clinical nodal metastases at a referral centre for metastatic melanoma in Norway. The MUP (n = 113) and MKP (n = 751) patients were graded with stage III or IV. The overall survival (OS) was calculated with the Kaplan-Meier method, and multivariate analysis identified factors of significance for the two groups. A significant five-year OS emerged for stage III, MUP = 58% and 42% for MKP, but not for stage IV. The five-year relapse-free survival (RFS) was 41% and 31% for MUP and MKP respectively (p = 0.049). The statistically significant inter-group differences (MUP/MKP) were observed in the univariate and multivariate analyses of age, gender, number of affected nodes, tumour size and perinodal growth within stage III and tumour size within stage IV. After regional lymphadenectomy, MUP patients with clinical nodal metastases had a better outcome than MKP patients. This finding supports the theory that an endogenously mediated immune response may promote the regression of a cutaneous melanoma.

A rare case of endobronchial melanoma of unknown primary

A 62-year-old man who presented with complaints of cough and hemoptysis was found to have an endobronchial tumor which obstructed the lingular bronchus. Histopathologic examination of a bronchoscopic biopsy of the tumor was consistent with malignant melanoma. Skin, mucosal, and eye examinations failed to detect the primary site of melanoma and the patient was diagnosed with endobronchial melanoma of unknown primary (MUP). Although the patient underwent a curative surgical resection, recurrence was detected in 4 months. Endobronchial MUP is a rare presentation of melanoma and better therapeutic strategies need to be established.

A Case of Metastatic CNS Melanoma of Unknown Primary Presenting with Seizures

Seizures are a common occurrence. The goal of evaluating a seizure is to identify the etiology and to determine the likelihood of recurrence as well as guide management. We present a unique presentation of a 47-year-old female that presented with late onset seizures admitted due to status epilepticus. Brain magnetic resonance indicated diffuse supratentorial hemorrhagic lesions. Neurological workup including brain vessel imaging, CT chest, abdomen, and pelvis as well as CSF and serological workup for vasculitis failed to demonstrate the cause of her brain lesions. Ultimately, a brain biopsy showed metastatic melanoma of unknown primary origin.

Primary malignant melanoma of the esophagogastric junction: A case report

RATIONALE

Most gastrointestinal melanomas are metastatic from an oculocutaneous primary lesion; however, primary gastrointestinal melanomas have been found in all levels of the gastrointestinal tract. We present the case of Primary malignant melanoma of the esophagus and discuss the diagnostic methods, differentiation from metastatic lesions and treatment options.

PATIENT CONCERNS

A 78-year-old male patient presented with fresh blood vomiting and tarry stools for 1 day.

DIAGNOSES

Esophagogastroduodenoscopy of this patient revealed a tumor ∼4 cm in size at the cardia side of the esophagogastric junction with dark-red and gray pigmentation. Immunohistochemical stains of the biopsy specimens were positive for S-100 and HMB-45, which are specific markers of melanoma.

INTERVENTIONS

Laparotomy with proximal gastrectomy was performed by the surgeon. Histological examination of the surgical specimen revealed the tumor arose from the distal esophagus with invasion of the proximal stomach. Primary malignant melanoma of the esophagus was diagnosed after a full skin and ophthalmic examination and positron emission tomography, which revealed no lesions elsewhere in the body.

OUTCOMES

No tumor recurrence was noted at the 1-year follow-up.

LESSONS

Primary malignant melanoma of the esophagus is an extremely rare but highly aggressive tumor. The special pattern of pigmentation should be recognized while performing endoscopy. Early detection and radical resection of the tumor are critical to ensure favorable outcomes.

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.

Combined immune checkpoint inhibitors of CTLA4 and PD-1 for hepatic melanoma of unknown primary origin: A case report

BACKGROUND

Melanoma is uncommonly found in lymph nodes, subcutaneous tissue, or visceral organs without a primary lesion, where it is identified as metastatic melanoma with unknown primary (MUP). Hepatic MUP is extremely rare and has a poor prognosis. There is limited information on its pathogenesis, clinical and imaging features, and pathological findings. There are no guidelines for the use of immune checkpoint inhibitors (ICIs) in hepatic MUP, and the treatment outcome has rarely been reported.

CASE SUMMARY

A 42-year-old woman presented to our hospital with hepatic tumors found incidentally during a routine check-up. Contrast-enhanced abdominal com-puterized tomography showed multiple mass lesions in the liver. Pathological results revealed melanoma, which was confirmed by immunohistochemical staining for HMB-45(+), Melan-A(+), S-100(+), and SOX10(+). There was no evidence of primary cutaneous, ocular, gastrointestinal, or anal lesion on a comprehensive examination. The patient was diagnosed with hepatic MUP. She received combined antibodies against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4, ipilimumab) and programmed death protein-1 (PD-1, nivolumab). She died of hepatic failure 9 mo after hepatic MUP was diagnosed. This the first case of hepatic MUP treated with combined ipilimumab and nivolumab, who showed better outcome than previous cases.

CONCLUSION

Combined ICIs of PD-1 and CTLA-4 may be considered as the first-line therapy for patients with hepatic MUP.

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) 8th 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.

Genetic Biomarkers in Melanoma of the Ocular Region: What the Medical Oncologist Should Know

Melanoma of the ocular region (ocular melanoma) comprises about 5% of all patients with melanoma and covers posterior uveal melanoma, iris melanoma, and conjunctival melanoma. The risk of metastasis is much higher in patients with ocular melanoma compared to a primary melanoma of the skin. The subtypes of ocular melanoma have distinct genetic features, which should be taken into consideration when making clinical decisions. Most relevant for current practice is the absence of BRAF mutations in posterior uveal melanoma, although present in some iris melanomas and conjunctival melanomas. In this review, we discuss the genetic biomarkers of the subtypes of ocular melanoma and their impacts on the clinical care of these patients.

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

Background: Melanoma of unknown primary (MUP) is an uncommon clinical subtype of melanoma of known primary (MKP). Objectives: We aimed to compare treatment outcomes of MUP and MKP patients who had undergone therapy with immune checkpoint inhibitors (ICPI). Methods: We studied 41 metastatic melanoma patients (32 with MKP and 9 with MUP) with an indication for ICPI. Results: Clinical characteristics such as age, gender, stage of disease, etc., did not significantly differ (P < .05) between MUP and MKP patients. 20/32 (62.5%) melanoma-specific deaths (MSD) were observed in the MKP group, whereas 2/9 (22.2%) were detected in the MUP group (P = .035). On logistic regression, the MUP status proved to be an independent predictor for a more favorable outcome under immunotherapy when compared to MKP (P = .030). Conclusion: Our preliminary results indicate that MUP patients show better clinical outcome under ICPI when compared to MKP.

Intracardiac melanoma metastases on 18F-FDG PET-CT-a case report and review of literature with imaging features

Cutaneous malignant melanoma is one of the few malignancies that can metastasize to the heart. It is important not to miss cardiac metastases on imaging as they are often clinically asymptomatic, but if present and undiagnosed could lead to significant cardiac compromise, arrhythmias, congestive heart failure, cardiac tamponade or transient ischaemic attacks.

Identifying intracardiac metastases on imaging often requires a multimodality approach as they can evade detection due to cardiac motion artefact; be confused with intracardiac thrombus, or be misinterpreted as a normal/anatomical finding.

We present an interesting case report of asymptomatic intracardiac melanoma metastases, initially identified on staging 18-fludeoxyglucose positron emission tomography-CT and eventually confirmed on cardiac MRI. The latter was able to differentiate myocardial metastases from tumour thrombus. We also review the relevant literature.

Approach to Patients with Malignant Melanoma of Unknown Primary Origin

Objectives:

Although malignant melanoma accounts for 3% of skin cancers, it is responsible for 75% of deaths associated with skin cancer. In our study, all melanoma cases diagnosed and treated at our clinic were retrospectively reviewed, and the cases of unknown primary origin among them were examined in detail in terms of diagnosis and treatment.

Methods:

The patients with malignant melanoma treated at the inpatient services of our clinic between January 1991 and April 2017 were retrospectively screened in the records. These patients were evaluated for age, sex, tumor type, Breslow depth, metastasis, and treatment. Among these patients, four cases of unknown primary origin were examined in detail.

Results:

During January 1991 and April 2017, 173 patients received inpatient care for malignant melanoma at our clinic. As regards to the melanoma subtypes, nodular type in 45 patients, acral lentiginous type in 43 patients, superficial spreading type in 63 patients, lentigo maligna melanoma in 15 patients, subungual type in 7 patients, and either unidentified melanoma or other subtypes in 10 patients were identified.

Conclusion:

The ideal treatment of a patient with melanoma is multidisciplinary, with plastic surgery having a central role.

Treatment of melanoma of unknown primary in the era of immunotherapy and targeted therapy: A Dutch population-based study

Melanoma of unknown primary (MUP) may have a different biology to melanoma of known primary, but clinical trials of novel therapies (e.g., immune checkpoint or BRAF/MEK inhibitors) have not reported the outcomes in this population. We therefore evaluated the overall survival (OS) among patients with MUP in the era of novel therapy. Data for stage III or IV MUP were extracted from a nationwide database for the period 2003–2016, with classification based on the eighth edition of the American Joint Committee on Cancer criteria. The population was divided into pre‐ (2003–2010) and post‐ (2011–2016) novel therapy eras. Also, OS in the post‐novel era was compared between patients with stage IV MUP by whether they received novel therapy. In total, 2028 of 65,110 patients (3.1%) were diagnosed with MUP. Metastatic sites were known in 1919 of 2028 patients, and most had stage IV disease (53.8%). For patients with stage III MUP, the 5‐year OS rates were 48.5% and 50.2% in the pre‐ and post‐novel eras, respectively (p = 0.948). For those with stage IV MUP, the median OS durations were unchanged in the pre‐novel era and post‐novel era when novel therapy was not used (both 4 months); however, OS improved to 11 months when novel therapy was used in the post‐novel era (p < 0.001). In conclusion, more than half of the patients with MUP are diagnosed with stage IV and the introduction of novel therapy appears to have significantly improved the OS of these patients.

What's new?

Melanoma of unknown primary (MUP) site may have a different biology to melanoma of known primary, but clinical trials of novel therapies (e.g., immune checkpoint or BRAF/MEK inhibitors) have not reported the outcomes in this population. Knowledge about outcomes could however aid clinical management of patients with MUP. In this nationwide study from 2003 to 2016, the authors show that the introduction of novel therapy has significantly improved the overall survival for patients with stage IV melanoma of unknown primary, who represented more than half of the patients diagnosed with MUP in the Netherlands.

Melanom

Das Melanom ist der gefährlichste Hautkrebs mit der höchsten Sterblichkeitsrate, der schon bei jungen Menschen auftreten kann und seit Jahrzehnten steigende Inzidenz verzeichnet (Jemal et al. 2007; Little et al. 2012). Jährlich erkranken weltweit etwa 137.000 Menschen am Melanom und 37.000 versterben an der Erkrankung (Boyle et al. 2004). Die Inzidenz liegt weltweit jährlich bei 2,3–2,6/100.000 Einwohner (Pisani et al. 2002). In Deutschland beträgt die Inzidenz 19,2/100.000 Einwohner und es verstarben 2711 Betroffene im Jahre 2010 (Statistisches Bundesamt).

Melanoma of unknown primary

Formally described in the 1960s, melanoma of unknown primary (MUP) is characterized by the finding of metastatic melanoma within the lymph nodes, subcutaneous tissues, and other distant sites without an evident primary lesion. The most likely hypothesis of its etiology is an immune-mediated regression of the primary after metastasis has occurred. In addition, patients with MUP appear to have equivalent or better outcomes compared with patients with known primaries of a similar stage.

Metastatic Melanoma of Uncertain Primary with 5-Year Durable Response after Conventional Therapy: A Case Report with Literature Review

A 51-year-old Thai woman presented with bilateral leg edema and painful left inguinal mass for 6 months. Physical examination revealed matted bilateral inguinal lymph nodes up to 9 cm in size. Otherwise, physical examinations including skin were unremarkable. The result of the lymph node incisional biopsy is consistent with that of metastatic melanoma. The extensive investigation demonstrated multiple intra-abdominal and inguinal lymph nodes without detectable primary tumor. Palliative radiation and conventional chemotherapy were prescribed. The CT scan between treatments showed that the response was stable disease, but the following CT scan demonstrated a gradual decrease in size from August 2012 to November 2017 including the lesions outside radiation fields. Moreover, she developed vitiligo during a follow-up visit. The previous data reported the median overall survival among the patients who were treated with conventional chemotherapy ranging from 9.1 to 9.3 months and whose 5-year survival was less than 10%. This case represented a metastatic melanoma of unknown primary who achieved a durable response by conventional treatment. The clinical features including nodal-only disease, vitiligo, and abscopal effect of radiation were considered to be the favorable factors.

Selective Inhibition of Histone Deacetylation in Melanoma Increases Targeted Gene Delivery by a Bacteriophage Viral Vector

The previously developed adeno-associated virus/phage (AAVP) vector, a hybrid between M13 bacteriophage (phage) viruses that infect bacteria only and human Adeno-Associated Virus (AAV), is a promising tool in targeted gene therapy against cancer. AAVP can be administered systemically and made tissue specific through the use of ligand-directed targeting. Cancer cells and tumor-associated blood vessels overexpress the αν integrin receptors, which are involved in tumor angiogenesis and tumor invasion. AAVP is targeted to these integrins via a double cyclic RGD4C ligand displayed on the phage capsid. Nevertheless, there remain significant host-defense hurdles to the use of AAVP in targeted gene delivery and subsequently in gene therapy. We previously reported that histone deacetylation in cancer constitutes a barrier to AAVP. Herein, to improve AAVP-mediated gene delivery to cancer cells, we combined the vector with selective adjuvant chemicals that inhibit specific histone deacetylases (HDAC). We examined the effects of the HDAC inhibitor C1A that mainly targets HDAC6 and compared this to sodium butyrate, a pan-HDAC inhibitor with broad spectrum HDAC inhibition. We tested the effects on melanoma, known for HDAC6 up-regulation, and compared this side by side with a normal human kidney HEK293 cell line. Varying concentrations were tested to determine cytotoxic levels as well as effects on AAVP gene delivery. We report that the HDAC inhibitor C1A increased AAVP-mediated transgene expression by up to ~9-fold. These findings indicate that selective HDAC inhibition is a promising adjuvant treatment for increasing the therapeutic value of AAVP.

Stage IV melanoma of unknown primary: A population-based study in the United States from 1973 to 2014

BACKGROUND

Melanoma of unknown primary (MUP) is incompletely described on a population level.

OBJECTIVE

We sought to characterize stage IV MUP in a population-based cancer registry.

METHODS

We developed a novel search algorithm to identify cases of stage IV MUP in the Surveillance, Epidemiology, and End Results 18 registries from 1973 to 2014. Cases of stage IV melanoma of known primary (MKP) served as a comparison group. Age-standardized incidence rates, demographic characteristics, adjusted disease-specific survival, and Cox proportional hazard models were calculated for MUP and MKP.

RESULTS

A total of 322 stage IV MUP cases and 12,796 stage IV MKP cases were identified in Surveillance, Epidemiology, and End Results 18 registries from 1973 to 2014. The incidence of stage IV MUP is increasing, particularly for patients younger than 30 years of age. In multivariate analyses, age older than 50 and a lack of surgical treatment were negative prognostic factors for stage IV MUP. Relative survival, but not 5-year adjusted disease-specific survival, was higher for stage IV MUP than for MKP.

LIMITATIONS

Limitations include the retrospective study design and possible misclassification of MUP.

CONCLUSIONS

The incidence of stage IV MUP is increasing, and stage IV MUP shares similar prognostic factors with stage IV MKP, including age and surgical treatment.

Melanoma Unknown Primary Brain Metastasis Treatment with ECHO-7 Oncolytic Virus Rigvir: A Case Report

Melanoma is considered an aggressive malignancy with a tendency of forming metastasis in the brain. Less than 10% of all melanoma cases present with unknown primary tumor location. This diagnose is yet to be fully understood, because there are only theoretical assumptions about the nature of the disease. Melanoma brain metastases have many severe side effects and, unfortunately, any disease related to the brain has limited therapeutic options due to the blood-brain barrier. The course of the disease after a treatment course is complicated to predict, and it is difficult to obtain long-lasting remission. In this report, we describe a female patient with unknown primary melanoma brain metastasis treated with the oncolytic ECHO-7 virus Rigvir^® after brain surgery. The patient has been stable, as monitored by magnetic resonance imaging, for more than 3.8 years with ongoing therapy. The median expected overall survival from the time of diagnosis is approximately 5 months. Additional positive effect could have been gained from use of the intranasal administration route, which is considered effective due to the direct anatomical connection between the nasal cavity and the central nervous system. However, further studies are required to fully understand this mode of drug administration.

Treatment Outcomes for Metastatic Melanoma of Unknown Primary in the New Era: A Single-Institution Study and Review of the Literature

BACKGROUND

Metastatic melanoma of unknown primary (MUP) is uncommon, biologically ill defined, and clinically understudied. MUP outcomes are seldom reported in clinical trials. In this study, we analyze responses of MUP patients treated with systemic therapy in an attempt to inform treatment guidelines for this unique population.

METHODS

New York University (NYU)'s prospective melanoma database was searched for MUP patients treated with systemic therapy. PubMed and Google Scholar were searched for MUP patients treated with immunotherapy or targeted therapy reported in the literature, and their response and survival data were compared to the MUP patient data from NYU. Both groups' response data were compared to those reported for melanoma of known primary (MKP).

RESULTS

The MUP patients treated at NYU had better outcomes on immunotherapy but worse on targeted therapy than the MUP patients in the literature. The NYU MUP patients and those in the literature had worse outcomes than the majority-MKP populations in 10 clinical trial reports.

CONCLUSIONS

Our study suggests that MUP patients might have poorer outcomes on systemic therapy as compared to MKP patients. Our cohort was small and limited data were available, highlighting the need for increased reporting of MUP outcomes and multi-institutional efforts to understand the mechanism behind the observed differences.

Imaging characteristics of cardiac metastases in patients with malignant melanoma

BACKGROUND

Due to prolonged survival and technical advances in CT imaging, cardiac metastases in patients with malignant melanoma are observed more frequently nowadays. The aim of the present study was to assess the anatomic distribution as well as the morphologic and histologic appearance of cardiac metastases from malignant melanoma.

METHODS

Twenty five patients with known metastasized melanoma and with incidental finding of cardiac metastases during routine staging CT were retrospectively included in this study. CT images were assessed for the presence, localization and extent of cardiac metastases. Histological results, mutational analysis and tumor markers were reviewed.

RESULTS

Fourteen out of 25 patients presented with singular cardiac mass (56%), whereas ten patients (40%) presented with multifocal and one patient with disseminated cardiac metastases. Twelve patients presented with endocardial (48%), eight with myocardial and two with pericardial metastases. Most frequent site involved in endocardial metastases was the right atrium (67%) followed by the right ventricle (33%). There seems to be a correlation between histological subtype and location of cardiac metastasis. Median survival after diagnosis of cardiac metastases was 8 months, with no significant difference regarding the localization of metastases within the heart.

CONCLUSION

Cardiac metastases can involve every part of the heart possibly in dependence of histological subtype. The awareness of different types of cardiac metastases and their characteristic appearance on CT images is necessary for further investigations and might contribute to targeted therapy.

Intralesional treatment of metastatic melanoma: a review of therapeutic options

Intralesional therapy of melanoma patients with locally advanced metastatic disease is attracting increasing interest, not least due to its ability to lead to both direct tumor cell killing and the stimulation of both a local and a systemic immune response. An obvious pre-requisite for this type of approach is the presence of accessible metastases that are amenable to direct injection with the therapeutic agent of interest. Patients who present with these characteristics belong to stages IIIB/C or IV of the disease. Surgical resection with intention to cure is the standard of care for patients with limited tumor burden and confined spread of disease (resectable patients). However, this category of patients is at a high risk of further recurrences until the disease becomes inoperable (unresectable) or progresses to a more advanced stage with visceral organ involvement, after which the prognosis is particularly grim. Most of the intralesional treatments tested so far, including the recently approved oncolytic virus talimogene laherparepvec, target the subpopulation of patients with unresectable disease, but the possibility to use the intralesional treatment in a neoadjuvant setting for fully resectable patients is attracting considerable interest. The present article reviews approved products and advanced stage pharmaceutical agents in development for the intralesional treatment of melanoma patients.

Metastatic Melanoma of a MetatarsalA Case Report

A 53-year-old woman presented with painful swelling of the right forefoot presenting clinically as a metatarsal stress fracture. Radiographs showed destructive changes, and diagnostic imaging revealed an aggressive neoplasm. The lesion was biopsied, and the pathologic diagnosis was metastatic melanoma. A thorough physical examination and advanced imaging did not reveal a primary tumor. Ray resection was performed with en bloc resection of the neoplasm. The patient continues to receive long-term immune stimulation chemotherapy 34 months after the ray resection.

Combinatorial immunotherapy for melanoma

Melanoma has been a long-standing focal point for immunotherapy development. In this review, we explore the evolution of melanoma treatments with particular attention to the history and recent advances in melanoma immunotherapy. We also discuss novel combinations of these modalities and their potential to offer novel therapeutic options for patients with advanced melanoma.

Competing risks survival of older patients with metastatic cutaneous melanoma: a SEER population-based study

Mortality from metastatic cutaneous melanoma is substantially heterogeneous as reflected in three distant metastatic (M1) subtypes with metastasis to skin, subcutaneous tissue, or distant lymph nodes (M1a), conferring nearly half the risk of death compared with distant visceral metastasis (M1c). It remains unknown whether older patients experience the survival benefit from the M1a subtype given a higher overall mortality risk. Surveillance, Epidemiology, and End Result data were retrieved from 1878 metastatic melanoma patients, from 2005 to 2009, with follow-up through 2011. Hazard ratios (HRs) for 2-year overall survival were estimated for M1 subtypes among older (≥65) and younger (<65) patients. Proportional subdistribution hazard ratios (SHRs) were calculated for melanoma-specific and competing risk mortality. For both older and younger patients, worse overall survival was observed for the M1c compared to the M1a subtype [HR: 2.65, 95% confidence interval (CI): 2.02-3.49; and, SHR: 3.36, 95% CI: 2.56-4.41; respectively]. For competing mortality, older compared to younger patients had increased risk in the M1a and M1b subtypes (SHR: 6.07, 95% CI: 1.94-19.0, and SHR: 2.34, 95% CI: 1.08-5.05, respectively). Conversely, when examining melanoma-specific mortality, older patients had decreased risk in M1a and M1b subtypes (SHR: 0.28, 95% CI: 0.14-0.53, and SHR: 0.60, 95% CI: 0.38-0.94, respectively) compared to those under 65 years. The persistent prognostic advantage of M1a among older patients should be considered when calculating the risk-benefit ratio for treatment. Prior reports of a protective effect of older age on melanoma-specific mortality, when based on traditional competing risks analyses, might be explained as an artifact of increased competing mortality risk.

Prognosis of Mucosal, Uveal, Acral, Nonacral Cutaneous, and Unknown Primary Melanoma From the Time of First Metastasis

BACKGROUND

Subtypes of melanoma, such as mucosal, uveal, and acral, are believed to result in worse prognoses than nonacral cutaneous melanoma. After a diagnosis of distant metastatic disease, however, the overall survival of patients with mucosal, uveal, acral, nonacral cutaneous, and unknown primary melanoma has not been directly compared.

MATERIALS AND METHODS

We conducted a single-center, retrospective analysis of 3,454 patients with melanoma diagnosed with distant metastases from 2000 to 2013, identified from a prospectively maintained database. We examined melanoma subtype, date of diagnosis of distant metastases, age at diagnosis of metastasis, gender, and site of melanoma metastases.

RESULTS

Of the 3,454 patients (237 with mucosal, 286 with uveal, 2,292 with nonacral cutaneous, 105 with acral cutaneous, and 534 with unknown primary melanoma), 2,594 died. The median follow-up was 46.1 months. The median overall survival for those with mucosal, uveal, acral, nonacral cutaneous, and unknown primary melanoma was 9.1, 13.4, 11.4, 11.7, and 10.4 months, respectively. Patients with uveal melanoma, cutaneous melanoma (acral and nonacral), and unknown primary melanoma had similar survival, but patients with mucosal melanoma had worse survival. Patients diagnosed with metastatic melanoma in 2006-2010 and 2011-2013 had better overall survival than patients diagnosed in 2000-2005. In a multivariate model, patients with mucosal melanoma had inferior overall survival compared with patients with the other four subtypes.

CONCLUSION

Additional research and advocacy are needed for patients with mucosal melanoma because of their shorter overall survival in the metastatic setting. Despite distinct tumor biology, the survival was similar for those with metastatic uveal melanoma, acral, nonacral cutaneous, and unknown primary melanoma.

IMPLICATIONS FOR PRACTICE

Uveal, acral, and mucosal melanoma are assumed to result in a worse prognosis than nonacral cutaneous melanoma or unknown primary melanoma. No studies, however, have been conducted assessing the overall survival of patients with these melanoma subtypes starting at the time of distant metastatic disease. The present study found that patients with uveal, acral, nonacral cutaneous, and unknown primary melanoma have similar overall survival after distant metastases have been diagnosed. These findings provide information for oncologists to reconsider previously held assumptions and appropriately counsel patients. Patients with mucosal melanoma have worse overall survival and are thus a group in need of specific research and advocacy.

Primary Melanoma of Infra Temporal Fossa: A Case Report

This is the second case report in English literature of a primary non-cutaneous non mucosal melanoma (NCNM) originating from Infratemporal fossa (ITF). A 21 year woman who was previously treated for craniopharyngioma 14 years back with surgery and radiation, presented with left ITF swelling which after excision was histologically confirmed to be NCNM. She has been disease free till date. Therapeutic difficulties and diagnostic dilemmas in such a case are discussed. We propose the term of non cutaneous non mucosal melanoma (NCNM) for this rare entity.

Treatment patterns of advanced malignant melanoma (stage III-IV) - A review of current standards in Europe

AIMS AND BACKGROUND

With the recent emergence of immunotherapies and novel targeted treatments for advanced and metastatic melanoma such as selective B-Raf inhibitors and checkpoint inhibitors, the treatment landscape in Europe has changed considerably. The aim of this review was to provide an overview of current treatment pathways in Europe for the treatment of advanced melanoma, unresectable stage III-IV.

METHODS

A literature search of four databases was conducted to identify publications reporting on the treatment patterns of advanced and metastatic melanoma (stage III-IV) in European populations.

RESULTS

Seven full-text publications and two conference abstracts reported on observational studies of melanoma treatment practices in France, Italy and the United Kingdom. Treatment patterns were identified for two time periods: 2005-2009 and 2011-2012. Common treatments reported for both periods included chemotherapy with dacarbazine, fotemustine or temozolomide. The main differences between the two periods were the introduction and prescription of immunotherapy ipilimumab and targeted therapy vemurafenib between 2011 and 2012. Across the three countries studied, the types of treatments prescribed between 2005 and 2009 were relatively similar, however, with noticeable differences in the frequency and priority of administration.

CONCLUSION

Treatment practices for advanced melanoma vary markedly across different European countries and continue to evolve with the introduction of new therapies. The results of this review highlight a considerable evidence gap with regards to recent treatment patterns for advanced melanoma in Europe, especially post-2011 after the introduction of novel therapeutic agents, and more recently with the introduction of programmed cell death 1 inhibitors.

Melanoma: Clinical Presentations

The malignant cell in melanoma is the melanocyte. Because melanocytes are located in the basal layer of the epidermis, melanoma is most commonly seen on the skin. However, melanoma can also arise on mucosal surfaces such as the oral cavity, the upper gastrointestinal mucosa, the genital mucosa, as well as the uveal tract of the eye and leptomeninges. Melanomas tend to be pigmented but can also present as pink or red lesions. They can mimic benign or other malignant skin lesions. This chapter presents the spectrum of typical and less typical presentations of melanoma, as well as patterns of spread. It is divided into (1) cutaneous lesions; (2) patterns of regional spread, (3) non-cutaneous lesions; and (4) distant metastases.

Open-label, multicenter, single-arm phase II DeCOG-study of ipilimumab in pretreated patients with different subtypes of metastatic melanoma

BACKGROUND

Ipilimumab is an approved immunotherapy that has shown an overall survival benefit in patients with cutaneous metastatic melanoma in two phase III trials. As results of registrational trials might not answer all questions regarding safety and efficacy of ipilimumab in patients with advanced melanoma seen in daily clinical practice, the Dermatologic Cooperative Oncology Group conducted a phase II study to assess the efficacy and safety of ipilimumab in patients with different subtypes of metastatic melanoma.

PATIENTS AND METHODS

We undertook a multicenter phase II study in melanoma patients irrespective of location of the primary melanoma. Here we present data on patients with pretreated metastatic cutaneous, mucosal and occult melanoma who received up to four cycles of ipilimumab administered at a dose of 3 mg/kg in 3 week intervals. Tumor assessments were conducted at baseline, weeks 12, 24, 36 and 48 according to RECIST 1.1 criteria. Adverse events (AEs), including immune-related AEs were graded according to National Cancer Institute Common Toxicity Criteria (CTC) v.4.0. Primary endpoint was the OS rate at 12 months.

RESULTS

103 pretreated patients received at least one dose of ipilimumab, including 83 cutaneous, seven mucosal and 13 occult melanomas. 1-year OS rates for cutaneous, mucosal and occult melanoma were 38 %, 14 % and 27 %, respectively. Median OS was 6.8 months (95 % CI 5.3-9.9) for cutaneous, 9.6 months (95 % CI 1.6-11.1) for mucosal, and 9.9 months (lower 95 % CI 2.3, upper 95 % CI non-existent) for occult melanoma. Overall response rates for cutaneous, mucosal and occult melanoma were 16 %, 17 % and 11 %, respectively. Eleven patients had partial response (16 %) and ten patients experienced stable disease (14 %), none achieved a complete response. Treatment-related AEs were observed in 71 patients (69 %), including 20 grade 3-4 events (19 %). No new and unexpected safety findings were noted.

CONCLUSIONS

Ipilimumab is a treatment option for pretreated patients with advanced cutaneous melanoma seen in daily routine. Toxicity was manageable when treated as per protocol-specific guidelines.

TRIAL REGISTRATION

Clinical Trials.gov NCT01355120.

Adrenalectomy for Metastatic Melanoma: Current Role in the Age of Nonsurgical Treatments

Surgical resection of metastases to the adrenal gland can improve overall survival of patients with stage IV melanoma, but its relative value with respect to current nonsurgical therapies is unknown. We hypothesized that surgery remains an optimal first-line treatment approach for resectable adrenal metastases. A search of our institution's prospectively collected melanoma database identified stage IV patients treated for adrenal metastases between January 1, 2000, and August 11, 2014. The 91 study patients had a mean age of 60.3 years at diagnosis of adrenal metastasis and 24 had undergone adrenalectomy. Improved survival was associated with an unknown primary lesion, surgical resection, and nonsurgical therapies. Median overall survival from diagnosis of adrenal metastases was 29.2 months with adrenalectomy versus 9.4 months with nonoperative treatment. Adrenalectomy, either as complete metastasectomy or targeted to lesions resistant to systemic therapy, is associated with improved long-term survival in metastatic melanoma.

Adrenalectomy for Metastatic Melanoma: Current Role in the Age of Nonsurgical Treatments

Surgical resection of metastases to the adrenal gland can improve overall survival of patients with stage IV melanoma, but its relative value with respect to current nonsurgical therapies is unknown. We hypothesized that surgery remains an optimal first-line treatment approach for resectable adrenal metastases. A search of our institution's prospectively collected melanoma database identified stage IV patients treated for adrenal metastases between January 1, 2000, and August 11, 2014. The 91 study patients had a mean age of 60.3 years at diagnosis of adrenal metastasis and 24 had undergone adrenalectomy. Improved survival was associated with an unknown primary lesion, surgical resection, and nonsurgical therapies. Median overall survival from diagnosis of adrenal metastases was 29.2 months with adrenalectomy versus 9.4 months with nonoperative treatment. Adrenalectomy, either as complete metastasectomy or targeted to lesions resistant to systemic therapy, is associated with improved long-term survival in metastatic melanoma.

Treatment of Regional Metastatic Melanoma of Unknown Primary Origin

(1) Background: The purpose of this retrospective study was to evaluate the recurrence and survival rates of metastatic melanoma of unknown primary origin (MUP), in order to further refine current recommendations for the surgical treatment; (2) Methods: Medical data of all MUP patients registered between 2000 and 2011, were analyzed. Seventy-eight patients were categorized in either lymph node (axilla, groin, head-and neck) or subcutaneous MUP. Axillary node MUPs were generally treated with dissections of levels I-III, inguinal node MUPs with combined superficial and deep groin dissections, and head-and-neck node MUPs with neck dissections to various extents, based on lymph drainage patterns. Subcutaneous lesions were excised with 1–2 cm margins. The primary outcome was treatment outcomes in terms of (loco)regional recurrence and survival rates; (3) Results: Lymph node MUP recurred regionally in 11% of patients, with an overall recurrence rate of 45%. In contrast, subcutaneous MUP recurred locally in 65% of patients with an overall recurrence rate of 78%. This latter group had a significantly shorter disease-free interval than patients with lymph node MUP (p = 0.000). In the entire study population, 5-year and 10-year overall survival rates were 56% and 47% respectively, with no differences observed between the various subgroups; (4) Conclusion: The relatively low regional recurrence rate after regional lymph node dissection (11%) supports its current status as standard surgical treatment for lymph node MUP. Subcutaneous MUP, on the contrary, appears to recur both locally (65%) and overall (78%) at a significantly higher rate, suggesting a different biological behavior. However, wide local excision remains the best available option for this specific group.

Aggressive behaviour of metastatic melanoma in a patient with neurofibromatosis type 1

Malignant melanoma is a common skin neoplasm bearing poor prognosis when presenting with metastases. Rarely melanoma metastases present without an identifiable primary cutaneous lesion despite exhaustive workup. We describe the case of a solitary lung metastasis in a patient with neurofibromatosis type 1 without an identifiable primary tumour. The rapid progression of this malignant neoplasm that led to the patient's death within 1 year is described.

Metastatic melanomas of unknown primary show better prognosis than those of known primary: a systematic review and meta-analysis of observational studies

BACKGROUND

Melanoma of unknown primary (MUP) is a condition of metastatic melanoma without a primary lesion.

OBJECTIVE

We sought to identify the prognosis of MUP compared with melanoma of known primary (MKP).

METHODS

We searched for observational studies containing at least 10 patients with MUP from MEDLINE and EMBASE from inception to December 22, 2012. The outcomes of interest were overall and disease-free survival; meta-analyses of hazard ratio stratified by stage using a random effects model were performed. In addition, second systematic review identified risk factors influencing the survival of patients with MUP.

RESULTS

Eighteen studies including 2084 patients with MUP and 5894 with MKP were included. MUP had a better overall survival compared with MKP in stage III (15 studies; hazard ratio 0.83, 95% confidence interval 0.73-0.96, P = .010) and stage IV (6 studies; hazard ratio 0.85, 95% confidence interval 0.75-0.96, P = .008). Secondly, 22 studies including 3312 patients with MUP were reviewed, and increased stage and old age were the risk factors in patients with MUP.

LIMITATIONS

Diverse observational studies were reviewed, and selection and reporting biases are possible.

CONCLUSIONS

The current meta-analyses suggest better survival outcomes in patients with MUP than those in patients with MKP with the same corresponding tumor stage.