Risk of Nonkeratinocyte Skin Cancers in People Living with HIV during the Era of Antiretroviral Therapy

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.

Clinical Features and Outcomes of Black Patients With Melanoma

Importance

Melanoma in Black individuals has an annual incidence of approximately 1 in 100 000 people. Most studies of melanoma in Black patients have used population databases, which lack important, precise clinical details.

Objective

To identify patient-level and tumor-level characteristics of melanoma in Black patients.

Design, Setting, and Participants

This case series included Black patients with melanoma at 2 tertiary care centers (University of Texas Southwestern [UTSW] Medical Center and Parkland Health), affiliated with a single institution, UTSW in Dallas, Texas. Self-reported Black patients with a histopathologic diagnosis of melanoma were identified between January 2006 and October 2022.

Main Outcomes and Measures

The main variables were demographics, clinical characteristics, personal and family medical history, immunosuppression history, comorbidities, histopathology reports, molecular/genetic studies, imaging reports, melanoma treatments and responses, time to progression, metastatic sites, and survival rates.

Results

A total of 48 Black patients with melanoma (median [range] age at diagnosis, 62 [23-86] years; 30 [63%] female) were included in the study. Of 40 primary cutaneous melanomas, 30 (75%) were located on acral skin, despite only 10 of 30 (33%) being histologically classified as acral lentiginous melanomas. Compared with those with acral disease, patients with nonacral cutaneous melanomas were more likely to be immunocompromised (4 of 10 [40%] vs 2 of 30 [7%]) or have a personal history of cancer (6 of 10 [60%] vs 5 of 30 [17%]), with all 3 patients with superficial spreading melanoma having a history of both. No patients had more than 1 confirmed primary melanoma. Overall, 13 Black patients (27%) with melanoma developed stage IV disease, of whom 12 died because of disease progression. Those diagnosed with advanced acral melanoma, mucosal/ocular melanoma, or melanoma of unknown primary lacked actionable sequence variations, were nonresponsive to immunotherapy, and had the poorest outcomes. No patients with nonacral cutaneous melanomas developed distant metastases or died of melanoma.

Conclusions and Relevance

This single-institution case series highlights several features of melanoma in Black patients that have not been captured in existing population-level registries, including precise anatomic sites, immune status, family and personal cancer history, and genetics. Multi-institutional registries would improve understanding of melanoma in Black patients.

Malignant Melanoma in a Retrospective Cohort of Immunocompromised Patients: A Statistical and Pathologic Analysis

BACKGROUND

Malignant melanoma is the leading cause of death due to cutaneous malignancy. Immunocompromised individuals have an elevated risk of developing melanoma. We aimed to provide histopathologic and statistical characterization of melanoma development in immunocompromised patients.

METHODS

We reviewed our institution's databases to identify all patients with a confirmed history of immunosuppression who subsequently developed melanoma, focusing on diagnoses during the follow-up period of 2011-2019. A total of 93 patients with a combined 111 melanoma lesions were identified.

RESULTS

Common causes of immunosuppression included transplantation and lymphoproliferative disorders. Superficial spreading and lentigo malignant melanoma were the most common malignant melanoma subtypes. Median Breslow depth was 0.7 mm, and the most common primary tumor stage was T1a. Our transplant sub-cohort had an overall melanoma incidence of 0.9 per 1000 person-years (95% CI 0.66 to 1.20) and a standardized incidence ratio (SIR) of 1.53 (95% CI 1.12 to 2.04) relative to a general population cohort from the Surveillance, Epidemiology, and End Results Program (SEER).

CONCLUSIONS

We report histopathologic characteristics of immunocompromised patients developing melanoma at a large academic tertiary-care center. Differences in age, sex, time since transplantation, and transplant type may play a significant role in melanoma SIR in this patient demographic.

Epidemiology of Merkel Cell Polyomavirus Infection and Merkel Cell Carcinoma

Merkel cell polyomavirus (MCPyV) is a ubiquitous virus replicating in human dermal fibroblasts. MCPyV DNA can be detected on healthy skin in 67−90% of various body sites, and intact virions are regularly shed from the skin. Infection occurs early in life, and seropositivity increases from 37 to 42% in 1- to 6-year-olds to 92% in adults. Merkel cell carcinoma (MCC) is a rare but very aggressive neuroendocrine tumor of the skin. It develops mainly on sun-exposed areas as a fast-growing, reddish nodule. Two MCC entities exist: about 80% of MCC are MCPyV-associated. Tumorigenesis is driven by viral integration into the host genome and MCPyV oncogene expression. In MCPyV-negative MCC, UV radiation causes extensive DNA damage leading to the deregulation of the cell cycle. In recent decades, MCC incidence rates have increased worldwide, e.g., in the United States, from 0.15 in 1986 to 0.7/100,000 in 2016. Risk factors for the development of MCC include male sex, older age (>75 years), fair skin, intense UV exposure, and immunosuppression. Projections suggest that due to aging populations, an increase in immunosuppressed patients, and enhanced UV exposure, MCC incidence rates will continue to rise. Early diagnosis and prompt treatment are crucial to reducing high MCC morbidity and mortality.