Merkel cell carcinoma in kidney transplant recipients in Ireland 1964–2018

Merkel Cell Carcinoma: Integrating Epidemiology, Immunology, and Therapeutic Updates

Merkel cell carcinoma (MCC) is a rare skin cancer characterized by neuroendocrine differentiation. Its carcinogenesis is based either on the integration of the Merkel cell polyomavirus or on ultraviolet (UV) mutagenesis, both of which lead to high immunogenicity either through the expression of viral proteins or neoantigens. Despite this immunogenicity resulting from viral or UV-associated carcinogenesis, it exhibits highly aggressive behavior. However, owing to the rarity of MCC and the lack of epidemiologic registries with detailed clinical data, there is some uncertainty regarding the spontaneous course of the disease. Historically, advanced MCC patients were treated with conventional cytotoxic chemotherapy yielding a median response duration of only 3 months. Starting in 2017, four programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) immune checkpoint inhibitors-avelumab, pembrolizumab, nivolumab (utilized in both neoadjuvant and adjuvant settings), and retifanlimab-have demonstrated efficacy in treating patients with disseminated MCC on the basis of prospective clinical trials. However, generating clinical evidence for rare cancers, such as MCC, is challenging owing to difficulties in conducting large-scale trials, resulting in small sample sizes and therefore lacking statistical power. Thus, to comprehensively understand the available clinical evidence on various immunotherapy approaches for MCC, we also delve into the epidemiology and immune biology of this cancer. Nevertheless, while randomized studies directly comparing immune checkpoint inhibitors and chemotherapy in MCC are lacking, immunotherapy shows response rates comparable to those previously reported with chemotherapy but with more enduring responses. Notably, adjuvant nivolumab has proven superiority to the standard-of-care therapy (observation) in the adjuvant setting.

Clinicopathological features, MCPyV status and outcomes of Merkel cell carcinoma in solid-organ transplant recipients: a retrospective, multicentre cohort study

BACKGROUND

The proportion of Merkel cell carcinomas (MCCs) in solid-organ transplant recipients (SOTR) harbouring Merkel cell polyomavirus (MCPyV) is unknown, as are factors affecting their outcomes.

OBJECTIVE

To describe clinicopathological features of MCC in SOTR, investigate the tumoral MCPyV-status and identify factors associated with tumour outcomes.

METHODS

Retrospective, international, cohort-study. MCPyV-status was investigated by immunohistochemistry and polymerase chain reaction.

RESULTS

A total of 30 SOTR and 44 consecutive immunocompetent patients with MCC were enrolled. SOTR were younger at diagnosis (69 vs. 78 years, P < 0.001). Thirty-three percent of SOTR MCCs were MCPyV-positive vs. 91% of immunocompetent MCCs (P = 0.001). Solid-organ transplantation was associated with an increased cumulative incidence of progression (SHR: 3.35 [1.57-7.14], P = 0.002), MCC-specific mortality (SHR: 2.55 [1.07-6.06], P = 0.034) and overall mortality (HR: 3.26 [1.54-6.9], P = 0.002). MCPyV-positivity and switching to an mTOR inhibitor (mTORi) after MCC diagnosis were associated with an increased incidence of progression (SHR: 4.3 [1.5-13], P = 0.008 and SHR: 3.6 [1.1-12], P = 0.032 respectively) in SOTR.

LIMITATIONS

Retrospective design and heterogeneity of SOTR cohort.

CONCLUSIONS

MCPyV appears to play a less prominent role in the aetiopathogenesis of MCC in SOTR. SOTR have a worse prognosis than their immunocompetent counterparts and switching to an mTORi after the diagnosis of MCC does not improve progression.

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.

Gender and immunosuppression impact on Merkel cell carcinoma diagnosis and prognosis. A population based cohort study

Background

Merkel cell carcinoma (MCC), a rare cutaneous neuroendocrine endocrine tumour is increasing in incidence, and continues to carry a poor prognosis.

Objectives

The objectives of this study were to examine all Irish cases of MCC from 1 January 1994 over 2 decades, focusing on gender and organ transplantation recipients (OTRs). Cases were identified from the National Cancer Registry of Ireland. Covariates of interest included age, body site, period of diagnosis, deprivation‐status and history of non‐melanoma skin cancer (NMSC).

Results

In total 314 MCC cases were identified. A female predominance was noted (53.8%). Comparison between age‐standardised rates between the earliest period (1994–1996) with the latest period (2012–2014) showed an increase of 105% in total. The trend in age‐standardised incidence rates were noted to be increasing significantly (p = 0.0004). Average age at diagnosis was 77.6 years (male 75.1 years, female 79.7 years). Overall, the majority of MCC cases presented on the head and neck (n = 170, 54.1%). Differences in anatomical location of MCCs were noted between genders. Males were found to be more likely to have a history of previous NMSCs (males n = 73 [57.9%], females n = 53 [42.1%]). Thirty‐one percentage of patients died from MCC, average survival was 3.5 years in those who died of this malignancy. Ten organ transplant recipients developed MCC. OTR who developed MCC were diagnosed at a younger average age of 65.1 years. Standardized incidence ratio for MCC in OTR was 59.96. A higher proportion of OTR died from MCC (70%), with a shorter median survival of 0.14 years. In competing risks regression, gender was not significantly associated with risk of dying, females having a non‐significantly higher hazard of dying. Organ transplant recipients and patients from less deprived areas were at greater risk of dying from MCC.

Conclusions

This population based study provides epidemiological, clinical and outcome data for MCC over a 20‐year period.

JC and Human polyomavirus 9 after kidney transplantation: An exploratory serological cohort study

INTRODUCTION

Human polyomaviruses (HPyVs) cause disease in immunocompromised patients. BK polyomavirus (BKPyV) for instance persistently infects the kidneys. In kidney transplant recipients, (KTRs) BKPyV can cause allograft nephropathy. JCPyV, MCPyV, TSPyV and HPyV9 reside in the kidneys too, or have been detected in urine. In this study, we investigate exposure to JCPyV, MCPyV, TSPyV and HPyV9 after kidney transplantation by serological means.

MATERIALS AND METHODS

Serum samples from 310 KTR collected before and 6 months after transplantation (n = 620), from 279 corresponding kidney donors collected before transplantation, and from blood donor controls collected one year apart (n = 174) were assessed for HPyV species-specific IgG responses using a multiplex immunoassay. KTR HPyV IgG kinetics were compared to those of healthy blood donors by linear mixed modeling, and related to those of their donors by linear regression.

RESULTS

In the KTR, increased IgG levels during follow-up were observed for JCPyV (14.8%), MCPyV (7.1%), TSPyV (10.6%), and for HPyV9 (8.1%), while blood donor antibody levels remained stable. Seroconversion was observed for JCPyV (6.5%), MCPyV (2.3%), TSPyV (1.3%), and for HPyV9 (6.5%). The linear mixed model analysis showed that antibody increase was significant for JCPyV (p < 0.001) and HPyV9 (p < 0.001). Post-transplant JCPyV and HPyV9 antibody responses were associated with donor antibody levels against these HPyVs, respectively.

CONCLUSIONS

KTR are exposed to JCPyV and HPyV9 after transplantation. Whether the allograft serves as the source, as indicated by the donor serostatus association, deserves further study.

Cutaneous Head and Neck Cancers in the High-Risk Immunosuppressed Population

The immunosuppressed (IS) population encompasses a diverse cohort of patients to include iatrogenically immunocompromised organ transplant recipients as well as patients with chronic lymphoid malignancies, human immunodeficiency virus/acquired immunodeficiency syndrome, and autoimmune disorders. Cutaneous cancers in this high-risk patient group are clinically distinct from the general immunocompetent population, showing aggressive behavior with associated poor outcomes. This article reviews the pathogenesis, epidemiology, incidence, prognosis, and special considerations required in managing cutaneous cancers in the IS patient population.