Avelumab treatment for patients with metastatic Merkel cell carcinoma can be safely stopped after 1 year and a PET/CT-confirmed complete response

BACKGROUND

Immune checkpoint inhibitor treatment of patients with metastatic Merkel cell carcinoma (mMCC) has shown high response rates, ranging from 33% to 73%. The ideal duration of treatment, however, is currently unknown. The aim of this study was to evaluate if avelumab treatment for mMCC can be safely stopped after 1 year of treatment and a complete response (CR) confirmed by fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) imaging.

METHODS

Patients who received more than one dose of avelumab treatment for mMCC between November 2017 and February 2022 were included in this study. Treatment was discontinued in case of a FDG-PET/CT confirmed CR after 1 year (26 cycles) of avelumab or a CR and unacceptable toxicity earlier. The primary end point was recurrence-free survival (RFS).

RESULTS

Sixty-five patients were included: 25 (38%) had a FDG-PET/CT-confirmed CR at discontinuation of avelumab. In those 25 patients, reasons for discontinuation of treatment were completion of 1 year of treatment in 13 (52%), toxicity in five (20%), and patient preference in seven (28%). Median duration of treatment in this group was 11 months (interquartile range, 6.1-11.7). Median follow-up was 27 months (interquartile range, 15.8-33.8). The 12-month RFS was 88% (95% CI, 0.74-1) and median RFS was not reached. Two patients (8%) had a recurrence at 4 and 7 months after discontinuation of treatment.

CONCLUSIONS

Patients with mMCC who acquire a CR on PET/CT imaging appear to have durable responses after discontinuation of treatment after 1 year.

Lymph Node Metastases from Non-Melanoma Skin Cancer of the Head and Neck

Non-melanoma skin cancer (NMSC) represents the most common malignancy in the world, comprising exceedingly common lesions such as basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) and rare lesions such as Merkel cell carcinoma. Risk factors are widely recognized and include ultraviolet (UV) light exposure, radiation exposure, immunosuppression, and many others. As a whole, survival and functional outcomes are favorable, but each histopathological subtype of NMSC behaves differently. Treatment regimens for the primary site usually include wide surgical excision and neck dissection in cases of clinically involved metastatic lymph nodes. The elective management of draining nodal basins, however, is a contested topic. Nearly all subtypes, excluding BCC, have a significant risk of lymphatic metastases, and have been studied with regard to sentinel lymph node biopsy (SLNB) and elective neck dissection. To date, no studies have definitively established a true single standard of care, as exists for melanoma, for any of the NMSCs. As a result, the authors have sought to summarize the current literature and identify indications and management options for the management of the cervical lymphatics for each major subtype of NMSC. Further research remains critically necessary in order to develop complete treatment algorithms.

Case report: Metastatic Merkel cell carcinoma presenting seven years after loco-regional disease resection of primary tumor with interval in-transit and nodal metastases

Merkel cell carcinoma (MCC) is a rare tumor with a high risk of recurrence after definitive therapy; however, the optimal duration of surveillance is unclear. First recurrences typically occur within 3 years. National guidelines recommend that patients undergo physical examination and imaging for surveillance during this time period. However, the duration of surveillance beyond this is not defined. Here, we describe a case of a patient developing a recurrence of MCC 7 years after the primary diagnosis with interval in-transit and regional lymph node metastases 15 months following the treatment of the primary MCC. Such late recurrences are rare, largely not reported, and the risk factors contributing to late recurrences are not well described. This case highlights the possibility of late recurrences of MCC after an initial in-transit and nodal recurrence and underscores the importance of identifying predictors of recurrence that may better guide the duration of surveillance.

Baseline ultrasound and FDG-PET/CT imaging in Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a cutaneous tumor with a high tendency to metastasize, and a significant proportion of patients have metastases at first presentation. This study aims to determine the value of baseline ultrasound (US) and ¹⁸ fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸ FDG-PET/CT) imaging in both patients with clinically localized MCC (Stage I/II) and patients who present with palpable lymph nodes (Stage III).

METHODS

This retrospective cohort included 135 MCC patients who underwent baseline US (with fine needle aspiration cytology (FNAC)) and/or FDG-PET/CT imaging between 2015 and 2021.

RESULTS

Of the 104 patients with clinically localized disease, 48% were upstaged to Stage III and 3% to Stage IV by imaging or sentinel lymph node biopsy (SLNB). FDG-PET/CT imaging identified regional metastases in 23%, while US with FNAC identified regional metastases in 19%. SLNB was performed in 56 patients, of whom 57% were upstaged to Stage III. Of the 31 patients who presented with palpable lymph nodes, 16% were upstaged to Stage IV by FDG-PET/CT imaging.

CONCLUSION

Baseline imaging frequently upstages Stage I/II MCC patients to Stage III, both by US and FDG-PET/CT, Stage IV disease is rarely identified. Patients who present with palpable nodes are frequently upstaged to Stage IV by FDG-PET/CT imaging.

Assessing Rates of Positive Surgical Margins After Standard Excision of Vulvar Melanomas

BACKGROUND

Vulvar melanoma is a rare malignancy with frequent recurrence and poor prognosis. National guidelines recommend wide local excision of these tumors with allowances for narrower margins for anatomic and functional limitations, which are common on specialty sites. There is presently a lack of data of margin positivity after standard excision of vulvar melanomas.

OBJECTIVE

We aim to evaluate the rate of positive margins after standard excision of vulvar melanomas.

MATERIALS AND METHODS

Retrospective cohort study of surgically excised vulvar melanomas from the NCDB diagnosed from 2004 to 2019.

RESULTS

We identified a total of 2,226 cases. Across surgical approaches and tumor stages, 17.2% (Standard Error [SE]: 0.8%) of cases had positive surgical margins. Among tumor stages, T4 tumors were most commonly excised with positive margins (22.9%, SE: 1.5%). On multivariable survival analysis, excision with positive margins was associated with significantly poorer survival (Hazard Ratio 1.299, p = .015).

CONCLUSION

We find that positive margin rates after standard excision of vulvar malignancies are higher than for other specialty site melanomas. Our data suggest that use of surgical approaches with complete margin assessment may improve local control and functional outcomes for patients with vulvar melanoma as they have for patients with other specialty site melanomas.

Demographic and Clinicopathological Factors as Predictors of Lymph Node Metastasis in Merkel Cell Carcinoma: A Population-Based Analysis

Merkel cell carcinoma is an aggressive malignant skin tumor with high recurrence and low survival. Lymph nodal metastases are associated with a worse overall prognosis. Our aim was to assess how lymph node procedures and positivity are influenced by demographic, tumor, and treatment characteristics. The Surveillance, Epidemiology and End Results database was searched for all cases of Merkel cell carcinoma of the skin between 2000 and 2019. Univariable analysis was conducted using the chi-squared test with the aim of identifying differences in lymph node procedures and lymph node positivity for each variable. We identified 9182 patients, of which 3139 had sentinel lymph node biopsy/sampling, and 1072 had therapeutic lymph node dissection. Increasing age, increasing tumor size, and truncal location were associated with higher positive lymph node rates.

Patterns of Care and Data Quality in a National Registry of Black and White Patients with Merkel Cell Carcinoma

Merkel Cell Carcinoma (MCC) is a rare cancer most commonly affecting White patients; less is known for Black patients. We aim to report presentation, treatment, and quality of registry data by race with a secondary endpoint of overall survival. We conducted a retrospective cohort analysis between 2006−2017 via the National Cancer Database of Black and White MCC patients with and without known staging information. Multivariable logistic, proportional odds logistic, and baseline category logistic regression models were used for our primary endpoint. Multivariable Cox regression was used to interrogate overall survival. Multiple imputation was used to mitigate missing data bias. 34,503 patients with MCC were included (2566 Black patients). Black patients were younger (median age 52 vs. 72, p < 0.0001), had higher rates of immunosuppression (28% vs. 14%, p = 0.0062), and were more likely to be diagnosed at a higher stage (proportional OR = 1.41, 95% CI 1.25−1.59). No differences were noted by race across receipt of definitive resection (DR), though Black patients did have longer time from diagnosis to DR. Black patients were less likely to receive adjuvant radiation. Black patients were more likely to have missing cancer stage (OR = 1.69, CI 1.52−1.88). Black patients had decreased adjusted risk of mortality (HR 0.73, 0.65−0.81). Given the importance of registry analyses for rare cancers, efforts are needed to ensure complete data coding. Paramount to ensuring equitable access to optimal care for all is the recognition that MCC can occur in Black patients.

Diagnosis and treatment of Merkel cell carcinoma: European consensus-based interdisciplinary guideline - Update 2022

Merkel cell carcinoma (MCC) is a rare skin cancer, accounting for less than 1% of all cutaneous malignancies. It is found predominantly in white populations and risk factors include advanced age, ultraviolet exposure, male sex, immunosuppression, such as AIDS/HIV infection, haematological malignancies or solid organ transplantation, and Merkel cell polyomavirus infection. MCC is an aggressive tumour with 26% of cases presenting lymph node involvement at diagnosis and 8% with distant metastases. Five-year overall survival rates range between 48% and 63%. Two subsets of MCC have been characterised with distinct molecular pathogenetic pathways: ultraviolet-induced MCC versus virus-positive MCC, which carries a better prognosis. In both subtypes, there are alterations in the retinoblastoma protein and p53 gene structure and function. MCC typically manifests as a red nodule or plaque with fast growth, most commonly on sun exposed areas. Histopathology (small-cell neuroendocrine appearance) and immunohistochemistry (CK20 positivity and TTF-1 negativity) confirm the diagnosis. The current staging systems are the American Joint Committee on Cancer/Union for international Cancer control 8th edition. Baseline whole body imaging is encouraged to rule out regional and distant metastasis. For localised MCC, first-line treatment is surgical excision with postoperative margin assessment followed by adjuvant radiation therapy (RT). Sentinel lymph node biopsy is recommended in all patients with MCC without clinically detectable lymph nodes or distant metastasis. Adjuvant RT alone, eventually combined with complete lymph nodes dissection is proposed in case of micrometastatic nodal involvement. In case of macroscopic nodal involvement, the standard of care is complete lymph nodes dissection potentially followed by post-operative RT. Immunotherapy with anti-PD-(L)1 antibodies should be offered as first-line systemic treatment in advanced MCC. Chemotherapy can be used when patients fail to respond or are intolerant for anti-PD-(L)1 immunotherapy or clinical trials.

Merkel Cell Carcinoma, the Impact of Clinical Excision Margins and Mohs Micrographic Surgery on Recurrence and Survival: A Systematic Review

BACKGROUND

When treating Merkel cell carcinoma (MCC), the relation between wide local excision (WLE) margin and recurrence or survival is unclear. Mohs micrographic surgery (MMS) is an alternative surgical option for MCC, but it is unknown whether the local recurrence rate differs between MMS and WLE.

OBJECTIVE

To systematically assess the available literature to determine the recurrence and survival rates when treating MCC with MMS and different clinical excision margins.

MATERIALS AND METHODS

The MEDLINE, EMBASE, and CENTRAL databases were searched. Two independent reviewers selected studies that defined clear excision margins and either recurrence or survival. When possible, individual cases were extracted from case series and included in the analyses. Other studies were reviewed narratively.

RESULTS

Overall, 1108 studies were identified; of which, 19 case series (168 cases) and 12 cohort studies were eligible. None of the cohort studies showed significant differences in recurrence or survival for either excision margins or MMS. Equally, logistic and Cox regression analyses of the case series revealed no significant differences in recurrence or survival between different excision margins and MMS.

CONCLUSION

Synthesis of the available data does not indicate differences in recurrence and/or survival rates for MCC between different clinical excision margins and MMS.

Treatment of Locally Advanced Merkel Cell Carcinoma-A Multi-Center Study

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer with a high risk of recurrence and poor prognosis. The treatment of locally advanced disease involves surgery and radiotherapy. To analyze real-life treatment patterns and clinical outcomes, we conducted a retrospective analysis of data from 161 MCC patients treated with curative intent in four oncological centers in Poland. The median age at diagnosis was 72 years (30-94); 49.7% were male. Lymph node (LN) involvement at diagnosis was found in 26.9% of patients. Sentinel lymph node biopsy (SLNB) was performed in 36.5% of patients (positive in 10.5%), and 51.9% of patients received perioperative treatment. The relapse rate was 38.3%. With the median follow-up of 2.3 years, the median disease-free survival (DFS) was not reached, and the 1-year rate was 65%. The negative independent risk factors for DFS were male gender, metastases in LN at diagnosis, no SLNB in patients without clinical nodal metastases, and no perioperative radiotherapy. The estimated median overall survival (OS) was 6.9 years (95% CI 4.64-9.15). The negative independent risk factors for OS were male gender, age above 70, metastases in LN at diagnosis, and no SLNB in patients without clinical nodal metastases. Our results confirm that the MCC treatment should be conducted in an experienced multidisciplinary team; however, the outcomes are still unsatisfactory.

Sentinel Lymph Node Biopsy Positivity in Patients With Acral Lentiginous and Other Subtypes of Cutaneous Melanoma

IMPORTANCE

Acral lentiginous melanoma (ALM) is a rare subtype of malignant melanoma typically occurring on the palmar and plantar surfaces. Although it has distinctive genetic, prognostic, and behavioral characteristics relative to cutaneous melanomas overall, owing to its rarity, treatment is largely guided by data extrapolated from more common subtypes. Although sentinel lymph node (SLN) status has been shown to be a significant prognostic factor for ALM, the independent effect of ALM-subtype disease on the likelihood of SLN positivity and the stage-specific positivity rates for ALM are not well characterized.

OBJECTIVE

To evaluate the association of ALM with SLN status as well as to characterize the clinical stage-specific rates of SLN positivity for ALM based on the AJCC Cancer Staging Manual, 8th edition (AJCC-8).

DESIGN, SETTING, AND PARTICIPANTS

The National Cancer Database (NCDB) includes all reportable cases from Commission on Cancer accredited facilities and represents approximately 50% of all newly diagnosed melanoma cases in the US. This retrospective cohort study included cases of AJCC-8 clinical stage I to II melanomas from the NCDB diagnosed from 2012 to 2015. The analysis took place between April 2021 and September 2021.

EXPOSURES

Melanoma histopathologic subtype.

MAIN OUTCOMES AND MEASURES

Sentinel lymph node status.

RESULTS

We identified 60 148 patients with malignant melanomas, 959 of whom had ALM-subtype disease. Among patients in the cohort, 25 550 (42.5%) were women and the mean (SD) age was 64 (16) years. Multivariable logistic regression controlling for demographic and histopathologic characteristics revealed that ALM was independently associated with the highest risk for SLN positivity among included subtypes (vs superficial spreading melanoma: odds ratio, 1.91; 95% CI, 1.59-2.28). Subgroup analysis by AJCC clinical stage demonstrated that ALM was independently associated with the highest risk for SLN positivity for both stage IB and II disease. The rate of SLN positivity for patients with stage IB and II ALM was 18.39% (95% CI, 13.82%-24.03%) and 39.53% (34.98%-44.26%), respectively.

CONCLUSIONS AND RELEVANCE

In this cohort study ALM was independently associated with SLN positivity and had relatively high positivity rates at clinical stage IB and II. This suggests that SLNB should be encouraged for all patients with clinical stage IB and II ALM, and such patients should receive appropriate counseling about the higher regional metastatic risk of their cancers. Future work with a larger cohort is required to elucidate the risk of SLN positivity for stage IA ALM.

Merkel Cell Polyomavirus Antibody Titer Predicts Recurrence-Free Survival

BACKGROUND

Merkel cell polyomavirus (MCPyV) is associated with the development of Merkel cell carcinoma (MCC). Antibody (MCPyV-Ab) titers may have prognostic implications. This study evaluated the impact of the presence or absence of MCPyV-Ab on the 2-year overall survival (OS) and disease-free survival (DFS) of MCC patients.

METHODS

This single-center, IRB-approved, retrospective cohort study evaluated 51 adult patients with MCC from 2014 to 2021 using a prospectively maintained database. Patients were compared by MCPyV-Ab status, and Kaplan-Meier analysis was used to evaluate 2-year OS and DFS.

RESULTS

Of the 51 patients, 13 (25.4%) were seropositive, 41 (80.4%) underwent wide excision, 40 (80.0%) received radiotherapy, and 43 (84.3%) received multimodal therapy. The median follow-up period was 15.5 months (range 1-69.5 months). The median 2-year OS of the entire cohort was not reached. The median 2-year OS was not reached for either the seronegative or the seropositive patients. The difference in 2-year OS between the groups was not statistically significant (p = 0.37). Eight patients, all seronegative, were never rendered disease-free and were removed from recurrence analysis. The seropositive patients experienced no recurrences. Of the 30 seronegative patients, 9 (30.0%) experienced recurrence. The median 2-year DFS of the entire cohort was not reached. The median 2-year DFS of the seronegative group was 22.2 months. The 2-year DFS was not reached for the seropositive cohort. Seropositivity conferred a significantly better 2-year DFS than seronegativity (p = 0.04).

CONCLUSION

The MCPyV-Ab seropositive patients demonstrated improved 2-year DFS. The seropositive patients showed a strong trend toward improved 2-year OS, although the difference not statistically significant. This study substantiated the value of MCPyV-Ab assessment for MCC.

Effects of surgery on survival of patients aged 75 years or older with Merkel cell carcinoma

Objective

To investigate whether surgery improves prognosis in elderly patients with Merkel cell carcinoma (MCC).

Materials/Methods

Data of all patients with MCC diagnosed between 2004 and 2015 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Differences in baseline characteristics were analyzed among the age groups (75–80, 80–85, and ≥85 years). Multivariate Cox proportional hazards analysis was used to assess the effects of each variable on patient outcomes. The Kaplan–Meier curves were employed to evaluate MCC overall survival (OS) and MCC‐specific survival (MSS).

Results

A total of 1156 of patients with MCC met the inclusion and exclusion criteria. The surgery rate decreased with age (75–80, 80–85, and ≥85 years were 93.3%, 91.1%, and 88.7%, respectively; p = 0.082). Multivariate Cox proportional hazards analysis showed that the OS of patients in the 80–85 years group (hazard ratio [HR] = 1.39; 95% confidence interval [CI] = 1.14–1.70; p = 0.001) and the ≥85 years group (HR = 2.18; 95% CI = 1.80–2.63; p < 0.0001) was worse than that in the 75–80 years group. Compared with the non‐surgery groups, the HR for the surgery group was 0.75 for OS (95% CI = 0.56–1.00; p = 0.048) and 0.73 for MSS (95% CI = 0.48–1.10; p = 0.130). Subgroup analyses showed that patients aged ≥85 years undergoing surgery had better OS (HR = 0.65; 95% CI = 0.45–0.95; p = 0.024).

Conclusions

MCC patients aged 75 years and older would benefit from surgical resection. However, surgical resection should be performed cautiously, and larger prospective clinical trials are needed to further verify these findings.

Postoperative Radiotherapy in Stage I-III Merkel Cell Carcinoma

BACKGROUND

Postoperative radiotherapy (PORT) is currently recommended for the treatment of Merkel cell carcinoma. Nevertheless, deviations occur frequently due to the generally elderly and frail patient population. We aimed to evaluate the influence of PORT on survival in stage I-III MCC patients treated in the Netherlands.

METHODS

Patients were included retrospectively between 2013 and 2018. Fine-Gray method was used for cumulative incidence of recurrence and MCC-related survival, cox regression was performed for overall survival (OS). Analyses were performed in patients with clinical (sentinel node biopsy [SN] not performed) stage I/II (c-I/II-MCC), pathologic (SN negative) stage I/II (p-I/II-MCC) and stage III MCC (III-MCC), separately. Propensity score matching (PSM) was performed to assess confounding by indication.

RESULTS

In total 182 patients were included, 35 had p-I/II-MCC, 69 had c-I/II-MCC and 78 had III-MCC. Median follow up time was 53.5 (IQR 33.4-67.4), 30.5 (13.0-43.6) and 29.3 (19.3-51.0) months, respectively. Multivariable analysis showed PORT to be associated with less recurrences and improved OS, but not with MCC-related survival. In stage III-MCC, extracapsular extension (sub-distribution hazard [SDH] 4.09, p=0.012) and PORT (SDH 0.45, p=0.044) were associated with recurrence, and ≥4 positive lymph nodes (SDH 3.24, p=0.024) were associated with MCC-related survival.

CONCLUSIONS

PORT was associated with less recurrences and improved OS in patients with stage I-III MCC, but not with improved MCC-related survival. Trends in OS benefit are likely to be caused by selection bias suggesting further refinement of criteria for PORT is warranted, for instance by taking life expectancy into account.

The texture of collagen in the microenvironments of Merkel cell carcinoma

ABSTRACT

Solid tumors typically contain high levels of fibrillar collagen. The increased stromal collagen deposition usually promotes cancer progression since biochemical and biophysical cues from tumor-associated collagen fibers stimulate neoplastic cells. Few studies have investigated the relationship between Merkel cell carcinoma (MCC) and the extracellular matrix (ECM), but there are no works evaluating collagen.This is an observational, analytical, retrospective study including 11 patients with MCC. Primary tumor-stained sections were evaluated by second harmonic generation microscopy and texture analysis.Peritumoral texture features (area fraction, mean gray value, entropy, and contrast) showed much lower values than normal skin (P < .0001) revealing extensively altered structure of peritumoral collagen fibers. These differences were not significant between tumors with unfavorable and favorable known prognostic factors.Profound changes in collagen fibers present in the stroma accompanying primary MCC may contribute to the aggressive behavior of this tumor. Our results indicate that whatever MCC histological subtype, size or anatomical location, MCC promotes the same type of ECM for its development. As an outlook, therapies using ECM macromolecules or fibroblasts (the architects of ECM remodeling) as target could be useful in the treatment of MCC.

Beyond Nicotinamide Metabolism: Potential Role of Nicotinamide N-Methyltransferase as a Biomarker in Skin Cancers

Skin cancers (SC) collectively represent the most common type of malignancy in white populations. SC includes two main forms: malignant melanoma and non-melanoma skin cancer (NMSC). NMSC includes different subtypes, namely, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Merkel cell carcinoma (MCC), and keratoacanthoma (KA), together with the two pre-neoplastic conditions Bowen disease (BD) and actinic keratosis (AK). Both malignant melanoma and NMSC are showing an increasing incidence rate worldwide, thus representing an important challenge for health care systems, also because, with some exceptions, SC are generally characterized by an aggressive behavior and are often diagnosed late. Thus, identifying new biomarkers suitable for diagnosis, as well as for prognosis and targeted therapy is mandatory. Nicotinamide N-methyltransferase (NNMT) is an enzyme that is emerging as a crucial player in the progression of several malignancies, while its substrate, nicotinamide, is known to exert chemopreventive effects. Since there is increasing evidence regarding the involvement of this enzyme in the malignant behavior of SC, the current review aims to summarize the state of the art as concerns NNMT role in SC and to support future studies focused on exploring the diagnostic and prognostic potential of NNMT in skin malignancies and its suitability for targeted therapy.

Primary Merkel Cell Carcinoma: The Clinical Experience of Taipei Veterans General Hospital Revisited

BACKGROUND

Merkel cell carcinoma (MCC) is rare among Asians. To evaluate the presence and characteristics of MCC in Taiwan, we described the characteristics, treatment, and prognostic findings of MCC in our institution.

METHODS

We revisited and carried out a retrospective chart review of 16 consecutive patients with MCC treated from 1995 to 2018. Patient demographic data, tumor size, location, previous treatment, and follow-up data about presence of locoregional recurrence and metastasis were evaluated.

RESULTS

There were 14 male and 2 female patients (mean age = 75.1 years; range = 26-91 years). Clinical follow-up revealed local recurrences in 5 patients 1 to 4 months after surgical excision. Lymph node metastasis was observed in 3 patients. We reviewed previously published articles and analyzed the clinical findings, pathologic examinations, and treatments.

CONCLUSIONS

Surgical wide excision of the primary tumor remains the mainstay of treatment for patients with local/regional MCC. Additional management strategies, such as lymphadenectomy, radiotherapy, chemotherapy, and targeted therapy, depend on the presence or absence of clinically detectable lymph node disease. The prognosis for MCC is variable. Our findings highlight the importance of maintaining a high clinical suspicion for this malignancy in the appropriate clinical context to avoid delays in diagnosis and management.

Merkel Cell Carcinoma: New Trends

Simple Summary

In this review, we discuss a rare skin cancer that occurs mostly in elderly people called “Merkel cell carcinoma” (MCC). The incidence is increasing due to ageing of the population, increased sun exposure, and the use of medication that inhibits the immune system. Unlike most other skin cancers, MCC grows rapidly and forms metastases easily. We discuss the biology and treatment of MCC. Management should be by an experienced and multidisciplinary team, and treatment must start quickly. The standard practice of MCC treatment is surgery followed by radiotherapy. However, because it concerns an elderly and often frail population, (extensive) surgery may not always be feasible due to the associated morbidity. In those situations, radiotherapy alone is a good alternative. An important new development is immunotherapy that can cause long-lasting responses in a significant proportion of the patients with recurrent or metastatic MCC.

Abstract

Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin mainly seen in the elderly. Its incidence is rising due to ageing of the population, increased sun exposure, and the use of immunosuppressive medication. Additionally, with the availability of specific immunohistochemical markers, MCC is easier to recognize. Typically, these tumors are rapidly progressive and behave aggressively, emphasizing the need for early detection and prompt diagnostic work-up and start of treatment. In this review, the tumor biology and immunology, current diagnostic and treatment modalities, as well as new and combined therapies for MCC, are discussed. MCC is a very immunogenic tumor which offers good prospects for immunotherapy. Given its rarity, the aggressiveness, and the frail patient population it concerns, MCC should be managed in close collaboration with an experienced multidisciplinary team.

Distinct Signatures of Genomic Copy Number Variants Define Subgroups of Merkel Cell Carcinoma Tumors

Simple Summary

Cancer results from genetic changes in cells. These changes are often mutations that alter the DNA sequence of critical genes. However, duplications and deletions in cancer-related genes can also contribute to malignant transformation. In this study we use Nanostring technology to assess DNA copy number changes in samples of Merkel cell carcinoma (MCC), a rare and aggressive neuroendocrine skin tumor. We were able to identify recurrent amplifications and deletions in cancer-related genes. We also found that MCC tumors grouped into three distinct copy number variant profiles. The first group consisted of tumors with multiple deletions. The second group contained tumors with low levels of genomic structural alterations. The last group comprised tumors containing multiple amplifications. Our study suggests that most MCC tumors are associated with deletions in cancer-related genes or are lacking in copy number changes, whereas a small percentage of tumors are associated with genomic amplifications.

Abstract

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer. Most MCC tumors contain integrated Merkel cell polyomavirus DNA (virus-positive MCC, VP-MCC) and carry a low somatic mutation burden whereas virus-negative MCC (VN-MCC) possess numerous ultraviolet-signature mutations. In contrast to viral oncogenes and sequence mutations, little is known about genomic structural variants in MCC. To identify copy number variants in commonly altered genes, we analyzed genomic DNA from 31 tumor samples using the Nanostring nCounter copy number cancer panel. Unsupervised clustering revealed three tumor groups with distinct genomic structural variant signatures. The first cluster was characterized by multiple recurrent deletions in genes such as RB1 and WT1. The second cluster contained eight VP-MCC and displayed very few structural variations. The final cluster contained one VP-MCC and four VN-MCC with predominantly genomic amplifications in genes like MDM4, SKP2, and KIT and deletions in TP53. Overall, VN-MCC contained more structure variation than VP-MCC but did not cluster separately from VP-MCC. The observation that most MCC tumors demonstrate a deletion-dominated structural group signature, independent of virus status, suggests a shared pathophysiology among most VP-MCC and VN-MCC tumors.

Immunotherapy for Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive form of skin cancer which, while chemosensitive, has high rates of relapse and chemoresistance, limiting the impact of chemotherapy. An immunogenic tumor, the management of advanced MCC has changed dramatically with the introduction of checkpoint inhibitors. This review will focus on the impact of immunotherapy in unresectable and metastatic MCC, ongoing research in the adjuvant and neoadjuvant settings, and future directions of immune-based strategies for this challenging cancer.

Improved survival in women versus men with merkel cell carcinoma

BACKGROUND

Studies have observed that women have better outcomes than men in melanoma, but less is known about the influence of sex differences on outcomes for other aggressive cutaneous malignancies.

OBJECTIVE

To investigate whether women and men have disparate outcomes in Merkel cell carcinoma (MCC).

METHODS

Patients with nonmetastatic MCC undergoing surgery and lymph node evaluation were identified from the National Cancer Database (NCDB) and the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier analysis and Cox proportional hazards regression models were used for overall survival, and competing-risks analysis and Fine-Gray models were used for cause-specific and other-cause mortality.

RESULTS

The NCDB cohort (n = 4178) included 1516 (36%) women. Women had a consistent survival advantage compared with men in propensity score-matched analysis (66.0% vs 56.8% at 5 years, P < .001) and multivariable Cox regression (hazard ratio, 0.68; 95% confidence interval, 0.61-0.75; P < .001). Similarly, women had a survival advantage in the SEER validation cohort (n = 1202) with 457 (38.0%) women, which was entirely due to differences in MCC-specific mortality (5-year cumulative incidence: 16.4% vs 26.7%, P = .002), with no difference in other-cause mortality (16.8% vs 17.8%, P = .43) observed in propensity score-matched patients.

LIMITATIONS

Potential selection bias from a retrospective data set.

CONCLUSION

In MCC, women have improved survival compared with men, driven by MCC-related mortality.

Exploring the Prognostic Role of Ki67 Proliferative Index in Merkel Cell Carcinoma of the Skin: Clinico-Pathologic Analysis of 84 Cases and Review of the Literature

The exact prediction of outcome of patients with Merkel cell carcinoma (MCC) of the skin is difficult to determine, although several attempts have been made to identify clinico-pathologic prognostic factors. The Ki67 proliferative index is a well-known marker routinely used to define the prognosis of patients with neuroendocrine neoplasms. However, its prognostic value has been poorly investigated in MCC, and available published results are often contradictory mainly because restricted to small series in the absence of standardized methods for Ki67 evaluation. For this reason, we explored the potential prognostic role of Ki67 proliferative index in a large series of MCCs using the WHO standardized method of counting positive cells in at least 500 tumor cells in hot spot areas on camera-captured printed images. In addition, since MCC may be considered as the cutaneous counterpart of digestive neuroendocrine carcinomas (NECs), we decided to stratify MCCs using the available and efficient Ki67 threshold of 55%, which was found prognostic in digestive NECs. This choice was also supported by the Youden index analysis. In addition, we analyzed the prognostic value of other clinico-pathologic parameters using both univariate and multivariate analysis. Ki67 index appeared significantly associated with prognosis at univariate analysis together with stage IV, lack of MCPyV, and p63 expression, but not at the multivariate analysis, where survival resulted independently influenced by p63 expression and tumor stage, only.

Merkel Cell Carcinoma: A Description of 11 Cases

Merkel cell carcinoma (MCC) is a malignant neuroendocrine tumor. Metastasis or lymph node spread is often detected at diagnosis. We performed a descriptive, retrospective study of patients diagnosed with MMC at Hospital Universitario Fundación Alcorcón in the Community of Madrid, Spain between January 1998 and December 2018. Eleven patients (7 men [63%] and 4 women [36%]; mean age, 77.6 years) were diagnosed with MCC during this 21-year period; 45% of patients had stage IIIB disease (pTNM) at diagnosis. All patients but one underwent local surgery, and lymphovascular invasion was detected in 7 cases. Eight patients received adjuvant therapy after surgery (radiation therapy in 5 cases and chemotherapy in 3). Six patients (54%) died of MCC (mean survival, 14.5 months). MCC is an uncommon malignant tumor with an annual incidence of around 0.18 to 0.41 cases per 100 000 inhabitants; this is similar to the rate of 0.29 to 0.32 cases per 100 000 inhabitants a year detected in our series. Results with avelumab, a drug recently approved for the treatment of metastatic MCC; have been promising.

Avelumab for advanced Merkel cell carcinoma in the Netherlands: a real-world cohort

BACKGROUND

Merkel cell carcinoma (MCC) is associated with high recurrence rates and poor survival when metastatic disease is present. The immune checkpoint inhibitor avelumab has shown high response rates (RRs) and durable responses in patients with advanced MCC (aMCC) in clinical trials. To date, only results from clinical trials, patients treated in an expanded access program and very small numbers of patients have been reported. In this study, detailed real-world efficacy and toxicity data of avelumab in patients with aMCC are reported.

METHODS

Patients with aMCC treated in four dedicated referral centers in the Netherlands were analyzed from February 2017 until December 2019. Patients were included if they had received at least one administration of avelumab, regardless of previous lines of therapy. Patient data were collected retrospectively from patient records. Primary endpoints were response rate (RR) and duration of response (DOR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and toxicity.

RESULTS

Fifty-four patients received avelumab. Eight (15%) patients had locally advanced disease (laMCC). In 40 (74%) patients, avelumab was first-line treatment, these included all patients with laMCC. The median follow-up was 8.9 (range 0.5-35.9) months. RR was 57% (n=31) with 24% (n=13) of patients achieving a complete response. The median DOR was 8.4 (range 1.3-22.1) months and 23 (43%) patients had an ongoing response at the end of the study. The median PFS was 8.6 (95% CI 1.6-15.5) months, and the median OS was 25.8 (95% CI 9.1-42.4) months. Six (11%) patients experienced grade 3 toxicity. No grade 4-5 toxicity was seen.

CONCLUSIONS

In this real-world cohort, clinical efficacy and toxicity outcomes in clinical practice were in line with results from clinical trials and showed relatively high RRs and durable responses in patients with aMCC.

Palliative care in dermatology: A clinical primer, review of the literature, and needs assessment

Palliative care has been shown to improve quality of life, symptoms, and caregiver burden for a range of life-limiting diseases. Palliative care use among patients with severe dermatologic disease remains relatively unexplored, but the limited available data suggest significant unmet care needs and low rates of palliative care use. This review summarizes current palliative care patterns in dermatology, identifying areas for improvement and future investigation.

The Clinical Utility of Neuron-Specific Enolase (NSE) Serum Levels as a Biomarker for Merkel Cell Carcinoma (MCC)

BACKGROUND

No adequate biomarker for Merkel cell carcinoma (MCC) has been identified. Serum neuron-specific enolase (NSE) has been tested and is commonly used as a biomarker for several other small cell malignancies. However, the role of NSE in MCC is still unclear. The purpose of this study was to investigate the role of NSE as a biomarker in MCC.

METHODS

A prospective cohort of MCC patients was analyzed using Kaplan-Meier curves with log-rank test, ROC curves, Cox regression, and mixed models. A separate evaluation was performed for patients treated with immunotherapy.

RESULTS

Eighty-four patients were included [47 males, median age 71 years, stages I & II, III, and IV MCC in respectively 39 (46%), 42 (50%), and 4 (3%) patients at time of diagnosis] with 565 NSE samples (median 15; interquartile range 12.6-22 ng/ml). Baseline NSE had no association with prognosis. NSE correlated with extent of disease (P = 0.01) and increased with 15 ng/ml per class (no tumor load, localized MCC, regional or distant metastases, respectively). NSE was able to detect progression (AUC 0.89). A NSE of 18.2 ng/ml was considered the most optimal level for clinical use (sensitivity 91%, specificity 78%, PPV 48%, NPV 98%). During immunotherapy (N = 23; 248 NSE values), all complete responders (N = 10) had a normalized NSE (< 18.2 ng/ml), all partial responders (N = 5) had a decreasing NSE. In nonresponders (N = 8), all NSE levels remained elevated.

CONCLUSIONS

NSE could be a valuable biomarker in MCC. NSE correlates with extent of disease; it is able to rule out progression and distinguishes responders from nonresponders during immunotherapy.

New perspectives in Merkel cell carcinoma

PURPOSE OF REVIEW

Merkel cell carcinoma (MCC), a rapidly progressing skin cancer, has poor prognosis. We reviewed the epidemiology, pathogenesis, diagnosis and treatment of MCC, with a focus on recent therapeutic advancements.

RECENT FINDINGS

Risk factors for MCC, such as old age, immunosuppression, polyomavirus infection and exposure to UV radiation have already been identified, but the underlying mechanisms leading to carcinogenesis still need clarification. On the basis of recent advances, immunotherapy - in particular, inhibition targeting the programmed cell death protein 1/programmed death-ligand 1 (PD1)/PDL1) immune checkpoint blockade - is currently being investigated in the treatment of metastatic MCC. Avelumab, an anti-PDL1 antibody, was the first drug to be approved internationally as second-line monotherapy for patients with advanced MCC, based on results from the JAVELIN Merkel 200 clinical trial. Avelumab has also recently been approved as first-line treatment for advanced MCC in Europe. Pembrolizumab (anti-PD1) in first-line and nivolumab (anti-PD1) in first-line and second-line treatments are two other checkpoint inhibitors that are under investigation, and showing promising results. New innovative therapies are also in development.

SUMMARY

New insights concerning advances in MCC diagnosis and treatment have been highlighted. Immunotherapy for metastatic MCC constitutes a recent breakthrough in an unmet medical need, but alternative therapies should continue to be investigated.

Driving innovation for rare skin cancers: utilizing common tumours and machine learning to predict immune checkpoint inhibitor response

Metastatic Merkel cell carcinoma (MCC) and cutaneous squamous cell carcinoma (cSCC) are rare and both show impressive responses to immune checkpoint inhibitor treatment. However, at least 40% of patients do not respond to these expensive and potentially toxic drugs. Development of predictive biomarkers of response and rational, effective combination treatment strategies in these rare, often frail patient populations is challenging. This review discusses the pathophysiology and treatment of MCC and cSCC, with a particular focus on potential biomarkers of response to immunotherapy, and discusses how transfer learning using big data collected from patients with common tumours can be used in combination with deep phenotyping of rare tumours to develop predictive biomarkers and elucidate novel treatment targets.

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Metastatic Merkel cell carcinoma and cutaneous squamous cell carcinoma are rare tumours.

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Immunotherapy gives impressive responses but most patients do not survive long term.

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Small patient numbers prevent extensive biomarker research in clinical trials.

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Pooled data from common and rare tumours can be used to train neural networks.

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In rare cancers, neural networks can help identify biomarkers and novel treatment targets.

Immune Checkpoint Inhibitors and Beyond: An Overview of Immune-Based Therapies in Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is an aggressive skin cancer. Until 2017, patients with advanced disease were typically treated with conventional chemotherapies, with a median response duration of 3 months. Increased evidence of the role of the immune system in controlling this cancer has paved the way for immune-based therapies, with programmed cell death protein 1 (PD-1)/programmed cell death protein ligand 1 (PD-L1) inhibitors at the frontline. Avelumab, an anti-PD-L1 antibody, was the first-ever drug approved in advanced MCC after showing meaningful efficacy in a second-line setting. Objective responses were observed in one-third of patients and, most importantly, were durable with half of patients and one-third of patients still alive at 1 and 2 years, respectively. When used in a first-line setting, PD-1/PD-L1 inhibitors (avelumab, pembrolizumab, nivolumab) are even more promising as objective responses are observed in approximately 50-70% of patients within the first 4-8 weeks of treatment. Safety profiles are acceptable with 10-20% of patients experiencing adverse events grade ≥ 3. PD-1/PD-L1 inhibitors are considered the standard of care in advanced MCC and are currently being investigated in the adjuvant and neoadjuvant settings. However, innovative treatments are still needed in the metastatic setting, as approximately 50% of these patients will not persistently respond to currently available immunotherapies, and no predictors of response are available yet. Therefore, other immunotherapeutic strategies are now being investigated-ideally in combinations-to enhance the various aspects of the immune response against tumoral cells.