Prognostic factors in Merkel cell carcinoma: analysis of 240 cases

Merkel cell carcinoma: A series of seven cases

Background

Merkel cell carcinoma (MCC) is a rare neuroendocrine malignancy affecting the skin, for which timely diagnosis and aggressive treatment are essential. MCC has most often been reported in Caucasians, and case reports in Asians are rare. This study presents our experiences with the surgical treatment and radiotherapy of MCC in Asian patients.

Methods

We retrospectively reviewed the records of seven MCC patients between 2000 and 2018 from a single institution, and analyzed patient characteristics, tumor characteristics, surgical treatment, sentinel lymph node evaluation, reconstruction, adjuvant radiation therapy, and prognosis.

Results

Eight MCC lesions occurred in seven patients, most commonly in the head and neck region. All patients underwent surgical excision with reconstruction. The final surgical margin was 1.0 cm in most cases, and reconstruction was most commonly performed with a split-thickness skin graft. Five patients received adjuvant radiotherapy, and two patients received sentinel lymph node biopsy. During the follow-up period, three patients remained well, two died from other causes, one experienced recurrence, and one was lost to follow-up.

Conclusions

We treated seven Asian MCC patients and our series confirmed that MCC is a very dangerous cancer in Asians as well. Based on our experiences, thorough surgical excision of MCC with histopathological clearance should be considered, with sentinel lymph node evaluation if necessary, followed by appropriate reconstruction and careful postoperative observation. Adjuvant radiation therapy is also recommended for all Asian MCC patients. The results of this case series may provide guidance for the treatment of Asian MCC patients in the future.

Prognostic Significance of "Nonsolid" Microscopic Metastasis in Merkel Cell Carcinoma Sentinel Lymph Nodes

Our recent work regarding Merkel cell carcinoma sentinel lymph node (SLN) metastasis found that "solid" pattern microscopic metastasis conferred worse prognosis than the "nonsolid" ones. The goals of the present study were to (1) compare the prognostic significance/outcomes of 2 diagnostic groups-patients with a nonsolid pattern of SLN metastasis and those with diagnostically negative SLN biopsies (SLNB), and (2) evaluate the durability of SLN metastasis after extensive sectioning. Five-level, step-wise sectioning at 250-μm intervals was performed in all SLN blocks with an immunohistochemical stain for CK20 on all levels. The presence and pattern of metastases were recorded and analyzed as were corresponding patient and tumor parameters. Median follow-up durations for all patients (n=38), positive SLNB (n=16) and negative SLNB (n=22) groups were 56.3, 50.4, and 66.8 months, respectively. Overall survival (OS) and disease-specific survival (DSS) did not differ between the 2 diagnostic groups (OS P=0.65, DSS P=0.37) but did differ by immune status (immunocompetent vs. immunosuppressed, OS P=0.03, DSS P=0.005) and primary tumor category (OS P<0.0001, DSS P=0.001). On deeper sectioning, all 16 diagnostically positive SLNB continued to show nonsolid microscopic metastasis, and 32% (7/22) diagnostically negative SLNB revealed nonsolid metastasis. DSS was worse for sinusoidal-pattern metastasis versus all others (P=0.02). Five of 38 patients (13%) died of disease; the only immunocompetent patient had sinusoidal-pattern metastasis discovered in a diagnostically negative SLNB. Our data suggest that outcome for nonsolid metastasis is similar to that of negative SLNB with the exception of the sinusoidal pattern, which was associated with worse outcome. Larger studies are warranted to quantify and compare microscopic metastatic tumor burden by pattern and confirm whether the sinusoidal pattern confers an intermediate prognostic risk between solid and other nonsolid microscopic metastases.

S2k guidelines for Merkel cell carcinoma (MCC, neuroendocrine carcinoma of the skin) - update 2018

Merkel cell carcinoma (MCC, ICD-O M8247 / 3) is a rare malignant primary skin tumor with epithelial and neuroendocrine differentiation. The neoplastic cells share many morphological, immunohistochemical and ultrastructural characteristics with Merkel cells of the skin. The diagnosis of MCC is rarely made on clinical grounds. Histological and immunohistochemical studies are usually required to confirm the clinical suspicion. Given the frequent occurrence of occult lymph node metastasis, sentinel lymph node biopsy should be performed once distant metastasis has been ruled out by cross-sectional imaging. Primary tumors without evidence of organ metastases are treated with complete surgical excision with appropriate surgical margins. Radiation therapy should be considered at all stages of the disease. For advanced MCC that is no longer amenable to curative treatment by surgery or radiation therapy, there is currently no established systemic therapy for which an improvement in recurrence-free survival or overall survival has been demonstrated in a prospective randomized trial. However, immunotherapy using PD-1/PD-L1 blockade seems to be superior to chemotherapy. Various factors warrant that further diagnostic and therapeutic interventions be determined by an interdisciplinary tumor board. These factors include the tumor's aggressiveness, the frequent indication for sentinel lymph node biopsy along with the frequent occurrence in the head and neck region, the potential indication for adjuvant radiation therapy as well as the complexity of the required diagnostic workup.

Sentinel lymph node biopsy in Merkel cell carcinoma: Predictors of sentinel lymph node positivity and association with overall survival

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive malignancy with high rates of recurrence and metastasis.

OBJECTIVE

To evaluate predictors of sentinel lymph node (SLN) positivity in MCC using the National Cancer Database.

METHODS

The National Cancer Database, from 2012 to 2014, was used to identify 3048 patients with MCC, of whom 1174 received an SLN biopsy. Predictors of SLN positivity were evaluated using logistic regression. Overall survival was evaluated using a Cox proportional hazards model.

RESULTS

Of patients who underwent SLN biopsy, those with primary lesions on the trunk (odds ratio, 1.98; 95% confidence interval [CI], 1.23-3.17; P = .004), tumor-infiltrating lymphocytes (odds ratio, 1.58; 95% CI, 1.01-2.46; P = .04), or lymphovascular invasion (odds ratio, 3.45; 95% CI, 2.51-4.76; P < .001) were more likely to have positive SLNs on multivariate analysis. Overall survival was negatively affected by age ≥75 years (hazard ratio [HR], 2.55; 95% CI, 1.36-4.77; P = .003), male sex (HR, 1.78; 95% CI, 1.09-2.91, P = .022), immunosuppression (HR, 3.51; 95% CI, 1.72-7.13; P = .001), and SLN positivity (HR, 3.15; 95% CI, 1.98-5.04; P < .001).

LIMITATIONS

Lack of disease-specific survival and potential selection bias from a retrospective data set.

CONCLUSIONS

Truncal MCC, tumor-infiltrating lymphocytes, and presence of lymphovascular invasion were independent predictors of positive SLNs. Overall survival was negatively affected by advancing age, male sex, immunosuppression, and SLN positivity.

Adjuvant radiotherapy for Merkel cell carcinoma: A systematic review and meta-analysis

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous malignancy with a high propensity for local recurrence and regional and distant metastases. The main treatment is surgery with narrow excision margins and draining nodes, plus or minus adjuvant radiotherapy (RT) on the surgical bed and/or lymph nodes. We performed a systematic review and meta-analysis of the benefits of adjuvant RT in MCC treatment. PubMed, EMBASE, and the Cochrane Library were systematically searched to identify relevant studies published before September 2018. Prospective trials and retrospective series comparing adjuvant RT vs. no RT in resected primary MCCs were included. Primary endpoint was to evaluate the outcomes of MCC patients who received adjuvant RT in term of overall survival (OS) and disease-free survival (DFS). Hazard ratios (HRs) for OS and DFS were aggregated according to a fixed or random effect model. Secondary endpoints were local, locoregional, and distant DFS. A total of 17,179 MCCs across 29 studies were analysed. There was a significant difference in OS between the RT and no RT arms (HR = 0.81, 95%CI 0.75-0.86, P < 0.001). There was also a significant difference in DFS in favour of adjuvant RT (HR = 0.45, 95%CI 0.32-0.62, P < 0.001). Adjuvant RT improved locoregional DFS and local DFS but not distant DFS (HR = 0.3, 95%CI 0.22-0.42; HR = 0.21, 95%CI 0.14-0.33, and HR = 0.79, 95%CI 0.49-1.14, respectively). Meta-regression analysis showed that high Newcastle-Ottawa scale scores, stage I-II MCCs, shorter follow-up durations, size >2 cm, and being of a younger age were associated with increased OS. This systematic review and meta-analysis suggests a survival and DFS benefit for postoperative radiation of MCCs. Intermediate stage MCCs derive the maximum benefit with local and regional relapses reduced by 80% and 70%, respectively. Conversely, distant metastases were not significantly prevented.

Differential Outcomes Among Immunosuppressed Patients With Merkel Cell Carcinoma: Impact of Immunosuppression Type on Cancer-specific and Overall Survival

OBJECTIVES

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer with higher incidence among whites, elderly, and immunosuppressed patients. Although immunosuppressed MCC patients are at higher risk of recurrence and MCC-related death, it is unknown whether immunosuppression type is associated with differential outcomes.

MATERIALS AND METHODS

We retrospectively evaluated 89 nonmetastatic MCC patients with a diagnosis of chronic immunosuppression. Immunosuppression was categorized as chronic lymphocytic leukemia (31% of cohort), other hematologic malignancies (18%), solid organ transplant (21%), autoimmune disease (21%), and human immunodeficiency virus acquired deficiency syndrome (8%). Progression-free survival (PFS) and MCC-specific survival (MSS) were estimated with the cumulative incidence function. Overall survival (OS) was estimated by the Kaplan-Meier method.

RESULTS

With a median follow-up of 52 months, 53 deaths occurred (42 from MCC, 7 unknown, and 4 non-MCC). Two-year PFS, MSS, and OS were 30%, 55%, and 52%, respectively. Human immunodeficiency virus/acquired deficiency syndrome and solid organ transplant patients were diagnosed with MCC at a younger age (median 55 and 59 y, respectively) and with more advanced stage disease compared with other immunosuppressed subgroups. PFS did not significantly differ among the 5 immunosuppression subgroups (P=0.30), but significant differences were observed in MSS and OS (both P=0.01). Controlling for potential confounders for OS, including age and stage, immunosuppression type was still significantly associated with risk of death (P=0.01).

CONCLUSIONS

Among immunosuppressed MCC patients, recurrent MCC is the major cause of mortality. The risk of death from MCC differs among immunosuppression types, suggesting important biological differences in host-tumor immune interactions.

A novel report of a primary Merkel cell carcinoma lesion in the nasal vestibule

Merkel cell carcinoma (MCC) accounts for less than 1% of cutaneous malignancies. As the lesion may mimic benign entities, clinicians' differential should include rare entities to improve outcomes by early intervention. We present a case of primary MCC in the nasal vestibule requiring partial rhinectomy, suprahyoid lymphadenectomy, and radiation therapy.

Merkel cell carcinoma and cellular cytotoxicity: sensitivity to cellular lysis and screening for potential target antigens suitable for antibody-dependent cellular cytotoxicity

The recent success of checkpoint inhibitors in the treatment of Merkel cell carcinoma (MCC) confirms that MCC tumors can be immunogenic. However, no treatment directly targeting the tumor is available for use in combination with these checkpoint inhibitors to enhance their efficacity. This study was carried out to characterize MCC line sensitivity to cellular lysis and to identify cell surface antigens that could be used for direct targeting of this tumor. For five representative MCC lines, the absence or low expression of MICA, MICB, HLA-I, and ICAM-1 was associated with low level of recognition by NK cells and T lymphocytes. However, expression of HLA-I and ICAM-1 and sensitivity to cellular lysis could be restored or increased after exposure to INFγ. We tested 41 antibodies specific for 41 different antigens using a novel antibody-dependent cellular cytotoxicity (ADCC) screening system for target antigens. Anti-CD326 (EpCAM) was the only antibody capable of inducing ADCC on the five MCC lines tested. Because MCC tumors are often directly accessible, local pharmacologic manipulation to restore HLA class-I and ICAM-1 cell surface expression (and thus sensitivity to cell lysis) can potentially benefit immune therapeutic intervention. In line with this, our observation that ADCC against EpCAM can induce lysis of MCC lines and suggests that therapeutic targeting of this antigen deserves to be explored further.

Effect of Patient Immune Status on the Efficacy of Radiation Therapy and Recurrence-Free Survival Among 805 Patients With Merkel Cell Carcinoma

PURPOSE

Patients with Merkel cell carcinoma (MCC) with chronic immunosuppression (IS) have worse outcomes, but the mechanisms are not well understood. We hypothesized that these differences may be mediated in part by differential response to treatment, and we evaluated whether radiation therapy (RT) efficacy is altered among IS compared with immune-competent (IC) patients with MCC.

METHODS AND MATERIALS

Among 805 patients with MCC, recurrence-free survival (RFS) and patterns of first recurrence were compared between 89 IS and 716 IC patients with stage I to III MCC treated with curative intent. We used a Fine and Gray's competing risk multivariable analysis to estimate associations with RFS.

RESULTS

IS and IC patients with MCC had similar demographic and disease characteristics. Most (77% IC, 86% IS) were irradiated (median, 50.4 Gy IC, 50.3 Gy IS), although more IS patients were irradiated to the primary site (97% vs 81%). With a median follow-up of 54.4 months, IS patients had inferior RFS (2-year: 30% vs 57%; P < .0001) and higher rates of local recurrence as the first site of relapse (25% vs 12%; P = .0002). The association between RT and RFS differed by immune status (interaction P = .01). Although RT was associated with significantly improved RFS among IC patients (hazard ratio 0.56, 95% confidence interval 0.44-0.72), no difference in RFS was observed with RT among IS patients (hazard ratio 1.49, 95% confidence interval 0.70-3.17).

CONCLUSIONS

Radiation therapy efficacy at current standard RT doses for MCC is impaired among immunosuppressed patients with MCC. Although a strong link between durability of RT response and immune function does not appear to be evident in most cancers, our results may reflect an especially dynamic interaction between immune status and RT efficacy in MCC.

Mohs Micrographic Surgery: Development, Technique, and Applications in Cutaneous Malignancies

Mohs micrographic surgery (MMS) is a specialized technique for treating skin malignancies that offers the highest cure rate by allowing histological evaluation of the entire peripheral and deep margins. MMS also maximally preserves as much uninvolved, normal adjacent tissue as possible, allowing for the best cosmetic and functional outcomes. When used for appropriate indications, this technique is also more cost-effective than other treatment modalities. In this article, the authors will discuss the development of MMS, the steps involved in this procedure, and the indications for this technique. They will also review the use of MMS for basal cell carcinoma, squamous cell carcinoma, melanoma in situ, and some less common skin malignancies.

Intratumoral and peritumoral lymphovascular invasion detected by D2-40 immunohistochemistry correlates with metastasis in primary cutaneous Merkel cell carcinoma

Primary cutaneous Merkel cell carcinoma (MCC) is an aggressive neuroendocrine malignancy in which lymphovascular invasion (LVI) correlates with more aggressive phenotype. The prognostic significance of LVI detected by D2-40 immunohistochemistry (IHC) in MCC remains controversial. We aimed to determine how LVI detected by D2-40 IHC compares with LVI detected by hematoxylin and eosin (H&E) staining in predicting MCC metastasis. Clinical and histopathologic features of MCCs diagnosed and treated in 2002 to 2015 were assembled and included 58 MCC tumors from 58 patients. H&E-stained tissue sections and D2-40 IHC studies were reviewed. When LVI was present, the location (peritumoral or intratumoral) and the size of the largest invaded vessel were recorded. LVI findings by H&E staining and D2-40 IHC were compared with each other and with histologic features and clinical outcomes. H&E staining showed LVI in 37 of 58 cases; D2-40 IHC confirmed LVI in 30 of these cases but failed to confirm LVI in 7. D2-40 IHC also detected 14 cases of LVI not identified on H&E staining. Histologically, D2-40-detected LVI was associated with infiltrative growth pattern and nonbrisk lymphoid infiltrate (P = .005 and P = .055, respectively). There was a statistically significant difference between the frequency of detection of peritumoral LVI by H&E in comparison to D2-40 IHC (P = .0009). MCCs in which D2-40 IHC-detected both intratumoral and peritumoral LVI were typically larger than MCCs without (mean, 24.5 mm versus 17.3 mm; P = .03) and more frequently metastasized (87% versus 51%; P = .03). D2-40 IHC detection of both intratumoral and peritumoral LVI is associated with metastasis.

Update on Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma. Incidence of MCC continues to rise, and risk factors include advanced age, pale skin, chronic sun exposure, and immune suppression. Diagnosing MCC utilizes a combination of morphology and immunohistochemistry. Merkel cell polyomavirus (MCPyV) is present in approximately 70-80% of MCCs and represents a key pathogenic driver in those MCCs. In contrast, MCPyV-negative MCCs arise through progressive accumulation of ultraviolet-light induced somatic mutations. Staging of MCC proceeds according to the American Joint Commission on Cancer (AJCC) 8th Edition, which utilizes features of the primary tumor together with regional lymph node(s) (clinically and/or pathologically detected) and/or distant metastases. Many potentially useful biomarkers have been studied to refine risk stratification in MCC. In recent years, the host immune infiltrate has been leveraged as immune checkpoint blockade has emerged as an efficacious mode of treatment for patients with advanced MCC.

Merkel cell carcinoma: Epidemiology, pathogenesis, diagnosis and therapy

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer with a neuroendocrine phenotype. Incidence varies according to the geographic regions but is overall increasing. Different risk factors have been identified namely advanced age, immunosuppression, and ultraviolet light exposure. An association between MCC and polyomavirus infection is known. However, the exact mechanism that leads to carcinogenesis is yet to be fully understood. Surgery when feasible is the recommended treatment for localized disease, followed by adjuvant radiation or chemoradiation. In the metastatic setting, chemotherapy has been the standard treatment. However, two recently published trials with immune checkpoint inhibitors in first and second line showed promising results with a tolerable safety profile and these might become the standard therapy shortly. Somatostatin receptors are expressed in many MCC but such expression is not associated with disease severity. Presently there are no biomarkers predictive of response that could help to better select patients to these new therapies, and additional research is essential.

Sentinel lymph node biopsy in Merkel cell carcinoma: The Mayo Clinic experience of 150 patients

BACKGROUND

Merkel cell carcinoma (MCC) is a rare cutaneous malignancy of neuroendocrine origin with a high propensity for lymph node metastasis. Sentinel lymph node (SLN) status is important for accurate staging; however, the optimal treatment following SLN biopsy, regardless of nodal status, remains unclear.

METHODS

150 patients with MCC who underwent SLN biopsy from 1995 to 2011 at 3 Mayo Clinic sites were reviewed.

RESULTS

Of 150 patients with MCC who underwent SLN biopsy, 39 (26%) were positive and 111 (74%) were negative. There was no significant difference between the sex, age, tumor location, or size of primary in the positive and negative SLN groups. While there was no difference in the cumulative incidence of any regional recurrence between SLN groups, the rate of in-transit recurrences was significantly higher in patients with a positive SLN (p = 0.022). The disease-specific survival for MCC was 97.0%, 82.4%, and 82.4% at 1, 3, and 5 years with a positive SLN and 99.0%, 94.9%, and 86.8% with a negative SLN (p = 0.31). Among those alive at last follow up, the median follow up was 3.8 years (IQR, 2.1-8.4) and 2.9 years (IQR, 1.8-6.1) for positive and negative SLN cohorts respectively.

CONCLUSIONS

Occult nodal metastasis is common in MCC(26%). No tumor or patient characteristics were identified to predict SLN positivity. Patients with a positive SLN have a higher risk of in-transit recurrence and may benefit from adjuvant radiation with inclusion of the in-transit field in amenable cases. When patients with a positive SLN receive additional treatment to the at-risk nodal basin, both OS and DSS are similar to patients with a negative SLN.

Merkel Cell Carcinoma of the Head and Neck: Recommendations for Diagnostics and Treatment

Background

Merkel cell carcinoma (MCC) is a rare, aggressive tumor that often occurs in the head and neck region. Because of these features, the classifications and diagnostic and treatment regimens are frequently modified. Especially in the anatomically complex head and neck region, it is crucial to be aware of the current recommendations for diagnostics and treatment of MCC to ensure appropriate treatment. This overview aims to summarize the currently available literature.

Methods

The authors reviewed the relevant literature and international guidelines for MCC from 2012 to 2017 with respect to epidemiology and prognosis, diagnostic procedures and imaging, surgery, radiation, systemic treatment, and aftercare. These results were compared with existing guidelines, some of them current, and recommendations were derived.

Results

Marked developments in imaging have resulted in an increased use of functional imaging. The surgical concepts have changed regarding safety margins and the use of sentinel node biopsies. In systemic treatment, a move from conventional agents toward immuno-oncology can be observed.

Conclusions

For staging, it is important to be as exact as possible using functional imaging (e.g., positron emission tomography/computed tomography scan), especially in the head and neck area with its complex lymph drainage. This often plays an especially important role in early stages of the tumor, when the resection margin can be reduced to preserve the organ. Aftercare also should include functional imaging. In an advanced, metastatic stage, immuno-oncology (PD-1, PD-L1, CTLA-4) is superior to the previous methods of systemic treatment.

Increased expression of EZH2 in Merkel cell carcinoma is associated with disease progression and poorer prognosis

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that affects tumorigenesis by epigenetic gene silencing. Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine carcinoma that has a high risk of disease progression with nodal and distant metastases. Here, we evaluated EZH2 expression by immunohistochemistry in a cohort of 85 MCC tumors (29 primary tumors, 41 lymph node metastases, 13 in-transit metastases, and 2 distant metastases) with clinical follow-up. We show strong/moderate EZH2 expression in 54% of tumors. Importantly, weak expression of EZH2 in the primary tumor, but not nodal metastases, correlated with improved prognosis compared to moderate/strong EZH2 expression (5-year MCC-specific survival of 68% versus 22%, respectively, P=.024). In addition, EZH2 was expressed at higher levels in nodal metastases compared to primary tumors (P=.005). Our data demonstrate that EZH2 has prognostic value and may play an oncogenic role in MCC.

Tumor vascularization and clinicopathologic parameters as prognostic factors in merkel cell carcinoma

PURPOSE

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine tumor of the skin with an increasing incidence. The clinical course is variable and reliable prognostic factors are scarce. Tumor angiogenesis has been shown to have prognostic impact in different types of cancer. The aim of our study was to determine potential prognostic factors, including tumor vascularization, for clinical outcome of MCC.

METHODS

The medical records of 46 patients with MCC diagnosed between 1997 and 2010 were analyzed retrospectively. Tissue samples were immune-stained for the lymphatic endothelial vessel marker podoplanin/D2-40 and the panvascular marker CD31. These immunostained sections were analyzed using computer-assisted morphometric image analyses. Aside from the parameters of tumor vascularization, clinicopathologic features were investigated, and progression-free survival (PFS) and tumor-specific survival (TSS) were assessed. Univariate and multivariate analyses were performed to determine prognostic factors.

RESULTS

Male sex of the MCC patients and a high cross-sectional whole vessel area (WVA) in relation to the entire tumor area as determined on CD31-stained tumor sections were found to be negative prognostic factors for PFS in a univariate and multivariate regression analysis. Ulceration of the primary tumor was significantly associated with both impaired PFS and TSS.

CONCLUSIONS

Our results indicate a high prognostic impact of tumor vascularization on the clinical outcome of MCC patients. Male sex and ulceration of the primary MCC were identified as independent unfavorable prognostic markers for the clinical outcome. As an outlook, MCC patients with increased angiogenesis might be identified and subjected to a targeted anti-angiogenic treatment.

Prognostic factors in Merkel cell carcinoma patients undergoing sentinel node biopsy

INTRODUCTION

Debate remains about prognostic factors in primary Merkel cell carcinoma (MCC). We investigated clinicopathological factors as determinants of survival in patients with MCC submitted to sentinel node biopsy.

METHODS

Sixty-four consecutive patients treated for a primary MCC were identified from a prospectively maintained database at Fondazione IRCCS Istituto Nazionale dei Tumori, Milan. Time to events outcome were described by product limit estimators and proportional hazards model was used to investigate the association between outcome and potential predictors.

RESULTS

The most common site of primary tumor was lower limbs (56.3%). The size of primary lesion was ≤2 cm in 67.2% of cases. Presence of residual disease after the diagnostic surgical excision was observed in 28% of cases. All patients received sentinel node biopsy (SNB) and a SN positivity was detected in 26.6%. The median follow up was 78 months. Disease recurrence occurred in 17 patients (26.6%). In the SN negative group 10 recurrences occurred (21.3%), whereas 7 (41.2%) were found in SN positive one. Nine patients SN negative (19.1%) died of disease and 3 (17.6%) among SN positive. SN status was not associated with survival (p = 0.78). Neither age, gender, size and site of primary tumor resulted predictors of patients' outcome. The presence of residual tumor in the specimen of the wide local excision, after the diagnostic surgical excision, was the only variable associated with survival (p = 0.03).

CONCLUSIONS

Presence of residual tumor in the specimen of the wide local excision is the main prognostic factor in MCC patients.

Mohs Micrographic Surgery for the Treatment of Merkel Cell Carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive malignant neoplasm. Traditionally, wide local excision has been used for local control. However, the tissue-sparing capability of Mohs micrographic surgery (MMS) and the greater certainty of complete tumor removal offer a potential advantage over wide local excision if MMS offers acceptable cure rates.

OBJECTIVE

This study aims to help elucidate management of MCC and includes one of the largest groups of patients from a single institution.

MATERIALS AND METHODS

This study is a retrospective chart review of 22 patients with cutaneous MCC treated with MMS at our practice over 20 years. Clinical characteristics and outcomes were examined. The study protocol conformed to the ethical guidelines of the 1975 Declaration of Helsinki as reflected in the approval by our institution's human research review committee.

RESULTS

The overall local recurrence rate was 5% (1/22). The overall rate of biopsy-proven metastasis to regional lymph nodes was 14% (3/22). No cases of distant metastases were documented.

CONCLUSION

To our knowledge, this is the largest group of patients with MCC treated with MMS from a single institution and indicates that MMS may be a useful treatment modality for this rare aggressive disease.

Frequency and locations of systemic metastases in Merkel cell carcinoma by imaging

Background

The primary neuroendocrine skin cancer, Merkel cell carcinoma (MCC), has a well-known predilection to metastasize systemically. However, the experience of systemic metastases in MCC is mainly disseminated through case reports due to the rarity of MCC.

Purpose

To elucidate the frequency and locations of systemic metastasis in MCC by reviewing the imaging of patients with metastatic MCC in a national cohort.

Material and Methods

Patients with diagnosed metastatic MCC by imaging studies in Finland during 1999–2012 were included in this study. We reviewed their imaging studies to evaluate the most frequent sites for systemic metastasis and determined the latency between the primary tumor diagnosis and systemic metastasis. The material includes 30 MCC patients with complete imaging series and 187 examinations, of which 102 (54%) were CT images.

Results

The mean latency from the primary tumor diagnosis to systemic metastasis was 2.1 years and the mean latency between the radiologic diagnosis of the metastases and death was 299 days. Metastases were recorded in several organ systems in most of the cases, and at least two separate metastatic sites in 63% of the cases. Metastatic spread was noted in 60% of the cases in distant lymph nodes. Liver and lungs were the most affected solid organs.

Conclusion

Systemic metastasis in MCC has no predilection site, basically every organ system can be involved. Most of the systemic metastases were recorded during the first two years after the MCC diagnosis.

Planning study for Merkel cell carcinoma based on the relapse pattern

PURPOSE

To develop a technique for radiation (RT) of in-transit path ways (IT) in Merkel cell carcinoma.

METHOD

In the planning study, IT were ink-marked on the skin during sentinel lymphscintigraphy and wire-marked in planning-CT. Pre- and post-operative planning-CTs were acquired. The clinical target volume (CTV) included tumor bed plus safety margin, IT and draining nodes, the planning volume (PTV) the CTV plus 0.5-1cm margin. VMAT plans with 2-3 arcs were analyzed.

RESULTS

A planning study was performed for five pts. including two pts. with primary tumor (PT) in head and neck, 1 pt. each with PT of elbow, forearm and upper leg respectively. Plans showed satisfactory PTV coverage: D_mean 100%±0%, D_98% 92.4%±2.24%, homogeneity index (HI) 0.095±0.01, conformation number (CN) 0.84±0.01 and conformality index (CI) 0.95±0.01.

CONCLUSION

The planning study confirms feasibility of highly conformal irradiation of IT pathways based on individualized target delineation. Currently, patients referred for non-metastatic MCC are encouraged to enroll in a prospective clinical study that evaluates the feasibility of radiation of IT pathways.

Tumor-Infiltrating Merkel Cell Polyomavirus-Specific T Cells Are Diverse and Associated with Improved Patient Survival

Tumor-infiltrating CD8+ T cells are associated with improved survival of patients with Merkel cell carcinoma (MCC), an aggressive skin cancer causally linked to Merkel cell polyomavirus (MCPyV). However, CD8+ T-cell infiltration is robust in only 4% to 18% of MCC tumors. We characterized the T-cell receptor (TCR) repertoire restricted to one prominent epitope of MCPyV (KLLEIAPNC, "KLL") and assessed whether TCR diversity, tumor infiltration, or T-cell avidity correlated with clinical outcome. HLA-A*02:01/KLL tetramer+ CD8+ T cells from MCC patient peripheral blood mononuclear cells (PBMC) and tumor-infiltrating lymphocytes (TIL) were isolated via flow cytometry. TCRβ (TRB) sequencing was performed on tetramer+ cells from PBMCs or TILs (n = 14) and matched tumors (n = 12). Functional avidity of T-cell clones was determined by IFNγ production. We identified KLL tetramer+ T cells in 14% of PBMC and 21% of TIL from MCC patients. TRB repertoires were strikingly diverse (397 unique TRBs were identified from 12 patients) and mostly private (only one TCRb clonotype shared between two patients). An increased fraction of KLL-specific TIL (>1.9%) was associated with significantly increased MCC-specific survival P = 0.0009). T-cell cloning from four patients identified 42 distinct KLL-specific TCRa/b pairs. T-cell clones from patients with improved MCC-specific outcomes were more avid (P < 0.05) and recognized an HLA-appropriate MCC cell line. T cells specific for a single MCPyV epitope display marked TCR diversity within and between patients. Intratumoral infiltration by MCPyV-specific T cells was associated with significantly improved MCC-specific survival, suggesting that augmenting the number or avidity of virus-specific T cells may have therapeutic benefit. Cancer Immunol Res; 5(2); 137-47. ©2017 AACR.

Clinical features and treatment of vulvar Merkel cell carcinoma: a systematic review

Background

Merkel cell carcinoma is a rare and aggressive neoplasm originating from mechanoreceptor Merkel cells of the stratum basale of the epidermis. Cases affecting the vulva are exceedingly rare, with the currently available literature primarily in case report form.

Body

Systematic review of the PubMed database returned 17 cases of Merkel cell carcinoma affecting the vulva. Patients presented at a mean age of 59.6 years with a firm, mobile vulvar mass. Symptoms of pain, erythema, pruritus, edema, and ulceration have been reported. Tumor histology is consistent with that of neuroendocrine tumors and typical Merkel cell carcinomas. Neuroendocrine and cytokeratin immunostains are frequently utilized in histopathological workup. Surgical management was the unanimous first-line therapy with adjuvant radiation in most cases. Recurrence occurred in 70.6% of patients at a mean follow-up of 6.3 months. Mortality was at 47.0% at a mean of 7.8 months after initial operation.

Conclusion

Merkel cell carcinoma affecting the vulva is an extremely rare and highly aggressive neoplasm. The present review of published cases serves to comprehensively describe the clinical course and treatment approaches for vulvar Merkel cell carcinoma.

Postoperative radiation therapy is associated with a reduced risk of local recurrence among low risk Merkel cell carcinomas of the head and neck

PURPOSE

Merkel cell carcinoma (MCC) is a rare and often aggressive skin cancer. Typically, surgery is the primary treatment. Postoperative radiation therapy (PORT) is often recommended to improve local control. It is unclear whether PORT is indicated in patients with favorable Stage IA head and neck (HN) MCC.

METHODS AND MATERIALS

We conducted a retrospective analysis of 46 low-risk HN MCC cases treated between 2006 and 2015. Inclusion criteria were defined as a primary tumor size of ≤ 2 cm, negative pathological margins, negative sentinel lymph node biopsy, and no immunosuppression. Local recurrence (LR) was defined as tumor recurrence within 2 cm of the primary surgical bed and estimated with the Kaplan-Meier method.

RESULTS

Omission of PORT was offered to all 46 patients, of which 23 patients received PORT and 23 did not. No patient received adjuvant chemotherapy. There were no significant differences in surgical margins, tumor size, depth, lympho-vascular invasion status, or demographics between the two patient groups. Median follow-up for all patients was 3.7 years. Six of the 23 patients who did not receive PORT developed an LR. Compared to the group that received PORT, there was a significantly higher risk of LR in the group treated without PORT (26% vs. 0%, P = .02). Median time to LR was 11 months. All local failures were effectively salvaged. There was no difference in MCC-specific and overall survival between the 2 groups.

CONCLUSIONS

For patients with HN MCC, omission of PORT was associated with a significantly higher risk of local recurrence even among those patients with the lowest-risk tumors (i.e., Stage IA without immune suppression). Thus, it is important to weigh the benefits of PORT against the side effect profile on a case-specific basis for each patient.

A high neutrophil-to-lymphocyte ratio as a potential marker of mortality in patients with Merkel cell carcinoma: A retrospective study

BACKGROUND

The prognostic relevance of a high blood neutrophil-to-lymphocyte ratio (NLR) has been reported in many cancers, although, to our knowledge, not investigated in patients with Merkel cell carcinoma (MCC) to date.

OBJECTIVE

We assessed whether the NLR at baseline was associated with specific survival and recurrence-free survival in MCC.

METHODS

We retrospectively included MCC cases between 1999 and 2015 and collected clinical data, blood cell count at baseline, and outcome. A Cox model was used to identify factors associated with recurrence and death from MCC.

RESULTS

Among the 75 patients included in the study, a high NLR at baseline (NLR ≥4) was associated with death from MCC in univariate (hazard ratio 2.76, 95% confidence interval 1.15-6.62, P = .023) and multivariate (hazard ratio 3.30, 95% confidence interval 1.21-9.01, P = .020) analysis, but not with recurrence.

LIMITATIONS

Because of the retrospective design, we excluded patients with missing data and not all confounding factors that may influence the NLR were available.

CONCLUSION

A high NLR at baseline was independently associated with specific mortality in patients with MCC. The NLR seems to constitute an easily available and inexpensive prognostic biomarker at baseline.

Analysis of Prognostic Factors from 9387 Merkel Cell Carcinoma Cases Forms the Basis for the New 8th Edition AJCC Staging System

BACKGROUND

The first consensus Merkel cell carcinoma (MCC) staging system was published in 2010. New information on the clinical course prompts review of MCC staging.

METHODS

A total of 9387 MCC cases from the National Cancer Data Base Participant User File with follow-up and staging data (1998-2012) were analyzed. Prognostic differences based on clinical and pathological staging were evaluated. Survival estimates were compared by disease extent.

RESULTS

Sixty-five percent of cases presented with local disease, whereas 26 and 8 % presented with nodal and distant disease. Disease extent at presentation was predictive of 5-year overall survival (OS) with estimates of 51, 35, and 14 % for local, nodal, and distant disease. Tumor burden at the regional nodal basin was predictive of 5-year OS with estimates of 40 and 27 % for clinically occult and clinically detected nodal disease. For local disease, we confirm improved prognosis when the regional nodal basin was negative by pathological compared with clinical staging. We identified 336 cases with clinically detected nodal disease and unknown primary tumor and showed improved prognosis over cases presenting with concurrent primary tumor (OS estimates of 42 vs. 27 %).

CONCLUSIONS

Analysis of a national dataset of MCC cases validates the predictive value of disease extent at presentation. Separation of clinical and pathological stage groups and regrouping of unknown primary tumors are supported by the analysis. The revised staging system provides more accurate prognostication and has been formally accepted by the AJCC staging committee for inclusion in the 8th edition.

Isolated limb perfusion in Merkel cell carcinoma offers high rate of complete response and durable local-regional control: Systematic review and institutional experience

INTRODUCTION

Hyperthermic isolated limb perfusion (HILP) has an established role in the management of melanoma, but its role for Merkel cell carcinoma (MCC) is less well defined.

METHODS

Retrospective review of our institutional experience with HILP for MCC was conducted (2009-2015). Literature search was performed through 04/2015 and 10 studies met inclusion criteria.

RESULTS

Four patients underwent HILP for MCC at our institution. There were no major complications and complete response was achieved in all patients. Early metastatic recurrence developed in two patients. The remaining two had no evidence of disease at last follow-up (36 months) or death (39 months). Systematic review identified an additional 12 pts that underwent HILP for MCC, for a total of 16 cases. Median age was 73 [IQR 69-78] years and 56% were men. Of the patients with reported follow-up, 12 (86%) had complete response, 1 had stable disease, and 1 partial response. Four patients developed local-regional recurrence and six distant metastases, all within 6 months. Overall median follow-up time was 15 [7-36] months.

CONCLUSION

Among a highly selective group of patients, regional perfusion for MCC is safe and has a high complete response rate. HILP is an acceptable therapeutic modality for obtaining durable loco-regional control but early distant metastatic disease remains a significant cause of mortality. J. Surg. Oncol. 2016;114:187-192. © 2016 Wiley Periodicals, Inc.

Density, Distribution, and Composition of Immune Infiltrates Correlate with Survival in Merkel Cell Carcinoma

PURPOSE

Merkel cell carcinoma (MCC) is an aggressive cancer with frequent metastasis and death with few effective therapies. Because programmed death ligand-1 (PD-L1) is frequently expressed in MCC, immune checkpoint blockade has been leveraged as treatment for metastatic disease. There is therefore a critical need to understand the relationships between MCPyV status, immune profiles, and patient outcomes.

EXPERIMENTAL DESIGN

IHC for CD3, CD8, PD-1, PD-L1, and MCPyV T-antigen (to determine MCPyV status) was performed on 62 primary MCCs with annotated clinical outcomes. Automated image analysis quantified immune cell density (positive cells/mm²) at discrete geographic locations (tumor periphery, center, and hotspot). T-cell receptor sequencing (TCRseq) was performed in a subset of MCCs.

RESULTS

No histopathologic variable associated with overall survival (OS) or disease-specific survival (DSS), whereas higher CD3⁺ (P = 0.004) and CD8⁺ (P = 0.037) T-cell density at the tumor periphery associated with improved OS. Higher CD8⁺ T-cell density at the tumor periphery associated with improved DSS (P = 0.049). Stratifying MCCs according to MCPyV status, higher CD3⁺ (P = 0.026) and CD8⁺ (P = 0.015) T-cell density at the tumor periphery associated with improved OS for MCPyV⁺ but not MCPyV^- MCC. TCRseq revealed clonal overlap among MCPyV⁺ samples, suggesting an antigen-specific response against a unifying antigen.

CONCLUSIONS

These findings establish the tumor-associated immune infiltrate at the tumor periphery as a robust prognostic indicator in MCC and provide a mechanistic rationale to further examine whether the immune infiltrate at the tumor periphery is relevant as a biomarker for response in ongoing and future checkpoint inhibitor trials in MCC. Clin Cancer Res; 22(22); 5553-63. ©2016 AACR.

Merkel cell carcinoma: Do you know your guidelines?

BACKGROUND

Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy that exhibits clinically aggressive features and is associated with a poor prognosis. The incidence of MCC seems to be increasing for reasons unknown, and is estimated to be 0.32/100,000 in the United States.

METHODS

This article will review the current literature and National Comprehensive Cancer Network practice guidelines in the treatment of MCC.

RESULTS

Resection of MCC with negative margins remains the mainstay of therapy. Positive nodal disease should be treated with neck dissection and adjuvant radiotherapy. High-risk patients should undergo adjuvant radiotherapy, which improves oncologic outcomes. The role of chemotherapy is less clear and is currently reserved for advanced-stage MCC and palliative therapy.

CONCLUSION

The pathogenesis of MCC has recently been impacted with the discovery of the Merkel cell polyomavirus (MCPyV). Research to establish targeted and immunologic therapeutic options are ongoing.

Sentinel lymph node biopsy in Merkel cell carcinoma: a 15-year institutional experience and statistical analysis of 721 reported cases

Merkel cell carcinoma (MCC) is a rare aggressive cutaneous neuroendocrine malignancy that frequently metastasizes to the regional lymphatic basin. Pathological assessment of regional lymph nodes with sentinel lymph node biopsy (SLNB) in patients without clinical involvement has permitted more accurate staging and more appropriate management. Nonetheless, concerns have been raised regarding the accuracy of this technique and its prognostic implications. We conducted a review of previously published data analysing the positive and false negative rates of SLNB in MCC. A search of the Medline and Embase databases to April 2015 identified 36 published studies between 1997 and 2015 comprising 692 patients. With the addition of 29 patients treated at our own institution, we conducted an analysis of 721 patients. Among this cumulative cohort, SLNBs were performed from 736 regional sites with 29·6% recorded as positive. Regional metastasis occurred in 45 cases following a negative SLNB, for a false negative rate of 17·1%. Adjuvant regional radiotherapy in the setting of a negative SLNB did not affect regional recurrence (P = 0·31), providing credence to emerging evidence that regional therapy can be safely omitted in the setting of a negative SLNB. Distant relapse was noted far more frequently following a positive rather than negative SLNB (17·6% vs. 7·3%, P < 0·001).

Update on the biology and clinical management of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine cutaneous malignancy, with a predilection for sun-exposed sites in elderly patients. Despite an incidence 30 times less than that of melanoma, its disease-specific mortality is three times higher. Management of MCC remains challenging because of a limited understanding of its molecular biology, lack of prospective clinical trials, and limitations associated with retrospective reviews of therapeutic options. With the recent discovery of an associated human polyomavirus, significant progress has been made in the understanding of the pathogenesis of this malignancy. With this progress, there has been increasing optimism regarding new tools in the therapeutic armamentarium to fight this deadly disease. Here we present an overview on MCC with an emphasis on the most recent biologic discoveries and the rationale for novel targeted and immunotherapies.

Merkel cell carcinoma of unknown primary site; case presentation and review of the literature

Merkel cell carcinoma (MCC) is a rare skin malignancy associated with sun exposure and considered as a Neuroendocrine Tumor due to its characteristic histologic features. However there is increasing number of reports of Unknown Primary MCC's (UPMCC). Although initially UPMCC was considered a variant of known primary MCC, there is growing evidence that it could represent a different clinical entity.

We present the case of a 60 year-old male patient who was referred to our department for surgical management of lymph node disease for UPMCC. The patient had undergone excisional biopsy of an inguinal lump, which was found to be an infiltrated lymph node by MCC. The patient underwent full imaging staging including a PET/CT, which failed to identify a primary site, and revealed only intra-abdominal lymph node disease. The patient underwent extended retroperitoneal and inguinal lymph node dissection and remains free of recurrence 16 months postoperatively.

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Unknown Primary Merkel cell carcinoma is a rare NET, which usually presents with extensive lymph node involvement.

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This tumor follows a more indolent natural course than a Merkel cell carcinoma of known primary and of similar staging.

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Surgical excision with R0 resection remains a common practice in the management of unknown primary Merkel cell carcinoma.

•

Adjuvant chemotherapy after R0 resection is the usual practice, despite the lack of good quality literature evidence.

Dramatic Increase in the Incidence and Mortality from Merkel Cell Carcinoma in the United States

Merkel cell carcinoma is a cutaneous neuroendocrine neoplasm that has been poorly studied in contemporary cohorts. Patients with Merkel cell carcinoma from 1986 to 2011 were identified in the Surveillance Epidemiology and End Results registry. A total of 5211 patients met the inclusion criteria. The mean age was 74.9 years; majority were male (61.4%) and white (94.9%). Patients were divided into two cohorts: Group 1 (1986 and 1999) and Group 2 (1999-2010). Group 2 was more likely to have Stage III disease (14.6 vs 23.3%, P < 0.001) and less likely to have Stage I/II disease (71.8 vs 65.1%, P < 0.0001). The increase in Stage III was likely secondary to increased use of sentinel lymph node biopsy. Disease-specific five-year survival for Stages I/II was 78.1 per cent and Stage III was 54 per cent. Disease-specific five-year survival was unchanged between Groups 1 and 2, 69.9 versus 66.6 per cent, respectively (P = 0.44). Both incidence and mortality significantly increased over the study period with P value for both trends <0.0001. In 1986, incidence and mortality rates per 100,000 were 0.22 and 0.03, respectively, and increased to 0.79 and 0.43 in 2011, respectively. There has been a greater than 333 per cent increase in mortality from Merkel cell carcinoma.