Disparities in Cutaneous T-Cell Lymphoma Incidence by Race/Ethnicity and Area-Based Socioeconomic Status

Geospatial analyses demonstrate variation of cutaneous T-cell lymphomas across Australia, providing insights into possible causes

BACKGROUND

Cutaneous T-cell lymphomas (CTCLs) are rare with distinct diagnostic challenges. Equitable access to cancer care is a recognized priority, internationally. To date, the geospatial distribution of CTCL has not been definitively studied. Understanding the incidence and geographical distribution of patients with CTCL are critical first steps towards the ultimate goal of equity of care. Geospatial analyses also allow the opportunity to explore environmental causative factors: for CTCL, the contribution of solar ultraviolet (UV) radiation on causation remains unclear.

OBJECTIVES

We investigate geospatial patterns of CTCL incidence across Australia, compare with all rare cancers, and consider solar UV exposure on causality and diagnosis rates.

METHODS

All CTCL diagnoses (1 January 2000 to 31 December 2019) were obtained from the nationwide dataset. Areas of residence were collected according to nationally approved definitions. Bayesian spatial incidence models were applied. Geospatial distributions were visually analysed.

RESULTS

The CTCL age-standardised incidence rate was 7.7 (95% confidence interval 7.4-7.9) per million people per year in Australia. Diagnostic disparity was seen between Australian states/territories, with lower diagnosis rates in rural/remote and socioeconomically disadvantaged areas. Incidence exceeded the national average within more densely populated capital cities. Visual comparisons of the geospatial distribution of CTCL revealed marked discordances with the geospatial patterns of all rare cancers and solar UV in Australia.

CONCLUSIONS

Geographical heterogeneity in CTCL exists across Australia. Incidence reflects population density. Geospatial patterns of CTCL differ substantially from all rare cancers, with implications for the unique diagnostic challenges and unmet needs of this patient population. The distribution of CTCL across Australia does not support a causative link with UV exposure. Further global evaluation of geospatial patterns is warranted.

Cutaneous T-cell lymphoma in skin of colour: a review

Skin cancer generally causes disproportionate morbidity and mortality in people of colour. Although skin cancers occur most frequently in White individuals overall, cutaneous T-cell lymphoma (CTCL) is an exception. CTCL is a rare skin cancer comprising several subtypes of non-Hodgkin lymphoma; each contains a unique clinical profile that varies with race. Our aim is to review and compile the differences in epidemiology, clinical presentation, treatments and outcomes of the CTCL subtypes in Black, Asian or Pacific Islander (API) and Hispanic patients. The current literature supports that there are nuances in the course of CTCL that differ with race. Across multiple studies, racial differences in incidence patterns have been reported, with the highest rates among Black patients. Cutaneous manifestations of CTCL are highly variable in people of colour, and the predilection for clinical CTCL variants often differs with race, as well as severity of cutaneous involvement (body surface area). Response to and type of treatment also differs among people of colour and may be partially attributable to the varying CTCL subtypes experienced by certain races. Prognostic factors tend to vary with race, although Black patients consistently experience poor outcomes, while API patients may have a more favourable prognosis. Currently, there is no definitive conclusion to account for differences observed in patients with skin of colour with CTCL; however, biological and socioeconomic factors have been proposed as potential drivers. As the proportion of people of colour in our population continues to grow, adequate physician awareness and knowledge of racial nuances in CTCL are necessary to begin addressing these disparities.

Final clinical diagnosis in cases of histopathologic psoriasiform dermatitis: retrospective cross-sectional analysis of a Southeastern United States population, 2004-2017

BACKGROUND

Psoriasiform dermatitis can be defined both clinically and histologically, but is not a traditionally recognized clinical or histologic diagnosis.

OBJECTIVE

Analyze the final clinical diagnosis, demographics and clinical characteristics in patients with histologic psoriasiform dermatitis.

METHODS

Retrospective cross-sectional analysis of patients with histologic psoriasiform dermatitis 2004-2017.

RESULTS

Patients (N = 586) were most often female (53.4%) and race/ethnicity included White (61.3%), Black (29.5%), Asian (4.8%), Hispanic (0.7%); mean (SD) age was 52.0 (17.9) years. Median time from histologic psoriasiform dermatitis to final clinical diagnosis was 0.5 months and median duration of follow-up was 6.0 years. The most frequently involved body sites were legs (37.2%), trunk (35.8%) and arms (25.3%). Final clinical diagnoses most associated with histologic psoriasiform dermatitis were psoriasis (N = 191, 32.6%), dermatitis (N = 173, 29.5%), "no clinical diagnosis" (N = 59, 10.1%) and cutaneous T-cell lymphoma (CTCL) or parapsoriasis (N = 48, 8.2%).

LIMITATIONS

Retrospective study at one academic center.

CONCLUSION

The most frequent clinical diagnoses associated with histologic psoriasiform dermatitis were psoriasis in about one third of patients, dermatitis in just under one third of patients, "no clinical diagnosis" in approximately 10% and CTCL/parapsoriasis in just under 10%.

Breaking Down the Barriers for Patients With Cutaneous T-Cell Lymphoma: Current Controversies and Challenges for Radiation Oncologists in 2024

Cutaneous T-cell lymphomas (CTCL) are a rare collection of diseases, frequently associated with diagnostic challenges and complex management dilemmas. The multidisciplinary team is vital for accurate clinico-pathological diagnoses and for collaborative therapeutic decisions throughout the management journey, which frequently involves multiple lines of therapy. Radiotherapy (RT) is a highly effective skin-directed therapy for CTCL, commonly delivered as localised fields or as total skin electron beam therapy (TSEBT). Mycosis fungoides (MF) is the most common of the CTCL, and patients typically experience high rates of morbidity and long natural histories of relapse and progression. Patients with MF typically present with incurable disease; in these patients, RT has an established role in symptom- and disease-control, achieving excellent response rates and proven therapeutic benefits. The role of RT continues to evolve, with modern practices favouring lower doses to reduce toxicity risks and allow for re-irradiation. Less commonly, there are situations where RT has an integral role in the potential cure of patients with MF: firstly, in the setting of unilesional MF where localised RT alone may be curative, and secondly, in the setting of preconditioning prior to curative-intent allogeneic hematopoietic stem cell transplant for patients with advanced MF/Sezary syndrome, where conventional-dose TSEBT is indicated as the most effective single agent for maximal debulking of skin disease. Radiotherapy also has an important role in the management of the less common CTCL, including the curative treatment of localised primary cutaneous anaplastic large cell lymphoma. Despite proven efficacy and quality of life benefits, disparity exists in access to RT and TSEBT. World-wide, stronger multidisciplinary collaborations and greater patient advocacy are required to increase access to RT and improve equity of care for our patients with CTCL.

Leveraging nuclear receptor mediated transcriptional signaling for drug discovery: Historical insights and current advances

Nuclear receptors (NRs) are ligand-activated transcription factors that regulate gene expression in response to physiological signals, such as hormones and other chemical messengers. These receptors either activate or repress the transcription of target genes, which in turn promotes or suppresses physiological processes governing growth, differentiation, and homeostasis. NRs bind to specific DNA sequences and, in response to ligand binding, either promote or hinder the assembly of the transcriptional machinery, thereby influencing gene expression at the transcriptional level. These receptors are involved in a wide range of pathological conditions, including cancer, metabolic disorders, chronic inflammatory diseases, and immune system-related disorders. Modulation of NR function through targeted drugs has shown therapeutic benefits in treating such conditions. NR-targeted drugs, which either completely or selectively activate or block receptor function, represent a significant class of clinically valuable therapeutics. However, the pathways of NR-mediated gene expression and the resulting physiological effects are complex, involving crosstalk between various biomolecular components. As a result, NR-targeted drug discovery is challenging. With improved understanding of how NRs regulate physiological functions and deeper insights into their molecular structure, the process of NR-targeted drug discovery has evolved. While many traditional NR-targeting drugs are associated with side effects of varying severity, new drug candidates are being designed to minimize these adverse effects. Given that NR activity varies according to the tissue in which they are expressed and the specific isoform that is activated or repressed, achieving selectivity in targeting specific tissues and isoform classes may help reduce systemic side effects. In a recent breakthrough, the isoform-selective, hepato-targeted thyroid hormone-β agonist, Resmetirom (marketed as Rezdiffra), was approved for the treatment of non-alcoholic steatohepatitis. This chapter explores the structural and mechanistic principles guiding NR-targeted drug discovery and provides insights into recent developments in this field.

From Molecules to Microbes: Tracing Cutaneous T-Cell Lymphoma Pathogenesis through Malignant Inflammation

The etiology of CTCL is a subject of extensive investigation. Researchers have explored links between CTCL and environmental chemical exposures, such as aromatic hydrocarbons (eg, pesticides and benzene), as well as infectious factors, including various viruses (eg, human T-lymphotropic virus [HTLV]-I and HTLV-II) and bacteria (eg, Staphylococcus aureus). There has been growing emphasis on the role of malignant inflammation in CTCL development. In this review, we synthesize studies of environmental and infectious exposures, along with research on the aryl hydrocarbon receptor and the involvement of pathogens in disease etiology, providing insight into the pathogenesis of CTCL.

Role of Antigenic Stimulation in Cutaneous T-Cell Lymphomas

Cutaneous T-cell lymphoma (CTCL) involves a clonal expansion of malignant cells accumulating in the skin, a primary barrier site. CTCL has long been hypothesized to be caused or perpetuated by chronic antigen stimulation due to unknown exposures. These antigenic triggers, defined as any element that may cause activation of malignant T cells through TCR signaling, have been hypothesized to range from chemicals to microbes. This review covers current evidence supporting chemical and microbial stimuli that may act as antigenic triggers of CTCL and summarizes novel areas of investigation, in which the potential antigenicity of the exposure is still unknown.