Current Status of Demographics and Survival Outcomes of Cutaneous T-Cell Lymphoma - Not Otherwise Specified in United States: A Contemporary Population Based Study with Focus on Hispanics

BACKGROUND: Cutaneous T-cell lymphoma, not otherwise specified (CTCL-NOS), is a rare malignancy with limited understanding, as it is a heterogenous disease with a variable clinical course.(Hematol OncolPMID 34105822) The prognosis of this disease has been described to be independent of age at diagnosis or clinical presentation. (J Eur Acad Dermatol VenereolPMID 32997839) Due to its low incidence; there is a need for information regarding its behavior in Hispanics (HI) and Non-Hispanics (NH) in the United States (US).(Blood PMID 30635287, LeukemiaPMID 35732829) This first nationwide study aims to provide information on how demographic, clinical, and survival outcomes differ in HI versus NH patients with CTCL-NOS.

METHODS: Data were analyzed on CTCL-NOS patients in the US reported to the Surveillance, Epidemiology, and End Results (SEER) 18 database between 2000-2018. SEER 18 contains the most comprehensive population-based cancer information in the US, covering approximately 27% of the total US population, and up to 36% of HI alone. Racial groups analyzed included NH whites, HI whites, blacks, and Asians or Pacific Islanders. Patient characteristics, age-adjusted incidence rate, and survival rate were compared across ethnic groups, HI vs NH. Stratification by age, gender, and stage at diagnosis was considered. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS) between HI and NH. Multivariate analysis and propensity score matching were performed with adjustment for age, stage and B-symptoms.

RESULTS: From 2000-2018, 3783 CTCL-NOS patients were diagnosed, 317 HI and 3466 NH (Table 1). Male gender predominated for both ethnicities, 52% for HI and 58% NH. HI were diagnosed at a younger median age of 54 years, in contrast to NH who were 63 years [p<0.001]. The majority of HI (34%) were diagnosed in the age bracket of 40-60 years, while the majority of NH (43%) belonged to the age bracket of 60-80 years [p=<0.001]. Patients in both cohorts were principally diagnosed from 2010-2014. Most of HI and NH were whites, but more racial diversity was noted among NH [p=<0.001].

Stage I at diagnosis predominated for HI and NH [p=0.127]. Most of the patients in both cohorts didn't receive radiation.

On survival analysis; the survival probability at 2, 5 and 10 years for HI was 0.845, 0.752, and 0.637; vs for NH was 0.825, 0.706, and 0.589, respectively (Table 1). The median survival time was 14.8 years for HI, vs 15.2 years for NH. There was not a statistically difference in OS [p=0.26] (Figure 1).

On multivariate analysis, when adjusted for age, patients who were older than 80 years and between 60-80 years, had worse OS compared to those younger than 60 years, with hazard ratio (HR) 8.2 [95% CI: 6 - 11] and 3.3 [95% CI: 2.6 - 4.2], respectively. Regarding stage, patients at stage III and IV, had inferior OS than those at early stages, I and II, with HR 3.3 [95% CI: 2.3 - 4.9] and HR 3.1 [95% CI: 2.4 - 4.2], respectively.

CONCLUSION In this population-based analysis, no difference in OS was noted among ethnicities with CTCL-NOS. On multivariate analysis, patients diagnosed at an earlier age and stage had better OS. Notably, although HI presented at a younger age, OS was not significantly affected, which suggests that other intrinsic disease characteristics or biological factors may be driving this outcome. Better understanding of transcriptional factors, and tumor markers can help in characterizing this malignancy to create targeted algorithms for treatment. Despite the limited information available; in this SEER analysis, older age and advanced stage had an unfavorable prognosis in both HI and NH diagnosed with CTCL-NOS .

Diaz Duque:Epizyme: Consultancy; Incyte: Consultancy; Astra Zeneca: Consultancy; ADCT: Consultancy; Morphosys: Consultancy.