Mapping cutaneous T-cell lymphoma in the state of Florida: A retrospective exploratory spatial analysis of incidence patterns

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.

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

Cutaneous T-cell lymphoma (CTCL) is a rare type of extranodal non-Hodgkin lymphoma (NHL). This study uses population-based data from the New Jersey (NJ) State Cancer Registry to examine geographic variation in CTCL incidence and evaluates whether CTCL risk varies by race/ethnicity and census tract socioeconomic status (SES). The study included 1163 cases diagnosed in NJ between 2006 and 2014. Geographic variation and possible clustering of high CTCL rates were assessed using Bayesian geo-additive models. The associations between CTCL risk and race/ethnicity and census tract SES, measured as median household income, were examined using Poisson regression. CTCL incidence varied across NJ, but there were no statistically significant geographic clusters. After adjustment for age, sex, and race/ethnicity, the relative risk (RR) of CTCL was significantly higher (RR = 1.47, 95% confidence interval: 1.22-1.78) in the highest income quartile than in the lowest. The interactions between race/ethnicity and SES indicated that the income gradients by RR were evident in all groups. Compared to non-Hispanic White individuals in low-income tracts, CTCL risk was higher among non-Hispanic White individuals in high-income tracts and among non-Hispanic Black individuals in tracts of all income levels. Our findings suggest racial disparities and a strong socioeconomic gradient with higher CTCL risk among cases living in census tracts with higher income compared to those living in lower-income tracts.

Characteristics and Outcomes for Hospitalized Patients With Cutaneous T-Cell Lymphoma

Importance

Cutaneous T-cell lymphoma (CTCL) is a group of rare, complex cutaneous malignant neoplasms associated with significant disease burden on patients and the health care system. Currently, the population of patients with CTCL admitted to the hospital remains largely uncharacterized and poorly understood.

Objective

To characterize the clinical characteristics, course of hospitalization, and mortality outcomes of an inpatient CTCL cohort.

Design, Setting, and Participants

This multicenter retrospective cohort study reviewed medical records for adult patients (age ≥18 years) with a CTCL diagnosis per National Comprehensive Cancer Network guidelines admitted for inpatient hospitalization at 5 US academic medical centers with inpatient dermatology consult services and CTCL clinics between August 2016 and August 2020.

Main Outcomes and Measures

Patient demographics, clinical history and findings, hospitalization courses, and mortality outcomes.

Results

A total of 79 hospitalized patients with CTCL were identified, including 52 (70.3%) men and 22 (29.7%) women, with a median (IQR) age at hospitalization of 62.9 (27-92) years. The majority of admitted patients with CTCL were White (65 patients [82.3%]), had disease classified as mycosis fungoides (48 patients [61.5%]), and had advanced-stage disease (≥IIB, 70 patients [89.7%]). Most hospitalizations were complicated by infection (45 patients [57.0%]) and required intravenous antibiotic therapy (45 patients [57.0%]). In-hospital mortality occurred in 6 patients (7.6%) and was associated with higher body mass index (36.5 vs 25.3), history of thromboembolic disease (50.0% vs 12.3%), and diagnosis of sepsis on admission (66.7% vs 20.5%). At 1-year postdischarge, 36 patients (49.3%) patients had died, and mortality was associated with history of solid organ cancers (27.8% vs 10.8%), wound care as the reason for dermatology consultation (58.3% vs 24.3%), and presence of large cell transformation (58.3% vs 22.9%).

Conclusions and Relevance

The findings of this cohort study improve the understanding of hospitalized patients with CTCL and lend valuable insight into identifying factors associated with both in-hospital and long-term mortality outcomes. This refined understanding of the inpatient CTCL population provides a foundation for larger, more robust studies to identify causal risk factors associated with mortality, development of prognostic scoring systems to estimate the probability of hospital mortality. Overall, the findings may prompt physicians caring for patients with CTCL to implement preventive strategies to diminish hospitalization and improve clinical management across this unique disease spectrum.

Geographic clustering of cutaneous T-cell lymphoma in New Jersey: an exploratory analysis using residential histories

PURPOSE

Cutaneous T-cell lymphoma (CTCL) is a rare type of non-Hodgkin lymphoma. Previous studies have reported geographic clustering of CTCL based on the residence at the time of diagnosis. We explore geographic clustering of CTCL using both the residence at the time of diagnosis and past residences using data from the New Jersey State Cancer Registry.

METHODS

CTCL cases (n = 1,163) diagnosed between 2006-2014 were matched to colon cancer controls (n = 17,049) on sex, age, race/ethnicity, and birth year. Jacquez's Q-Statistic was used to identify temporal clustering of cases compared to controls. Geographic clustering was assessed using the Bernoulli-based scan-statistic to compare cases to controls, and the Poisson-based scan-statisic to compare the observed number of cases to the number expected based on the general population. Significant clusters (p < 0.05) were mapped, and standard incidence ratios (SIR) reported. We adjusted for diagnosis year, sex, and age.

RESULTS

The Q-statistic identified significant temporal clustering of cases based on past residences in the study area from 1992 to 2002. A cluster was detected in 1992 in Bergen County in northern New Jersey based on the Bernoulli (1992 SIR 1.84) and Poisson (1992 SIR 1.86) scan-statistics. Using the Poisson scan-statistic with the diagnosis location, we found evidence of an elevated risk in this same area, but the results were not statistically significant.

CONCLUSION

There is evidence of geographic clustering of CTCL cases in New Jersey based on past residences. Additional studies are necessary to understand the possible reasons for the excess of CTCL cases living in this specific area some 8-14 years prior to diagnosis.