Abstract 813: Primary cutaneous gamma-delta T-Cell lymphoma in the United States: A nationwide analysis of demographics and survival outcomes among the Hispanic population
Authors: Thiel Katherine , White Rosa , Liu Qianqian , Michalek Joel , Diaz Duque Adolfo Enrique 
Published: March 2024

BACKGROUND: Primary Cutaneous Gamma-Delta T-Cell Lymphoma (PCGDTCL) is a rare subtype of cutaneous T-cell lymphoma (CTCL) that, despite comprising &lt;1% of cutaneous lymphomas, has gained recognition in recent years as an entity separate from other rare CTCLs. (LeukemiaPMID 35732829) A 5 year survival of 11% demonstrates a low response to current available therapies. (BloodPMID 30635287, Clin Hematol Int.PMID 35950208) Due to lack of consistency in behavior between CTCLs, there exists a need for studies of demographic, clinical, and survival disparities, including between Hispanics (HI) vs. non-Hispanics (NH).

METHODS: Data were analyzed on PCGDTCL patients in the United States reported to the National Cancer Database (NCDB) between 2004-2019. Demographic and treatment characteristics were compared between ethnic groups. Kaplan-Meier and Cox regression analyses were used to compare OS between populations. Multivariate analysis and propensity score matching was performed with adjustment for age, stage, co-morbidity score, and insurance status, type of facility and great circle distance.

RESULTS: Among 132 PCGDTCL patients studied (5% HI, 92% NH), the HI group was younger at diagnosis than NH (49.5y vs. 60y) (p=0.384); The majority of HI (50%) was diagnosed between 2010-2012 vs 2017-2019 for NH (45%) (p=0.673). Most of HI and NH were white (67% vs 79%).

Private insurance was the most prevalent type in HI (67%) vs government sponsored for NH (49%). The most non-Insured group was NH (3%) vs HI (0%).

The most prevalent bracket for Census Median Income (2008-2012) was $63,000+ for both HI (50%) and NH (31%). 17% HI vs 13%. NH had median income &lt;$38,000.

For Charlson-Deyo Score (comorbidities score), HI had 0% =/&gt; 2 score, vs NH 6%. NCI-designated comprehensive cancer centers were the most prevalent type of facility providing care for HI (100%) and NH (56%)

Survival probability (OS) at 2, 5 and 10y (HI vs NH) were (80% vs 48%), (80% vs 44%), and (80% vs 26%), respectively. Median survival time (MS) was not reached for HI vs 1.9 years for NH. Overall survival (OS) difference favored HI (p=0.13)

On multivariate analysis, there was no independent variable associated with better or worse OS. Interestingly, the propensity matched analysis demonstrated significant MS difference between HI vs NH (median not reached vs. 1.35 years).

CONCLUSION: There was no significant difference in OS between groups; however, the weighed MS favored the HI cohort, likely in part due to the difference in numbers between cohorts. The drastically low survival in all demographics is consistent with prior studies. These results demonstrate an unmet need for more comprehensive studies with the potential inclusion of correlatives looking at intrinsic biologic characteristics that may offer insight into druggable targets, aiming for improvement in survival outcomes for this rare lymphoma.

Citation Format: Katherine Thiel, Rosa White, Qianqian Liu, Joel Michalek, Adolfo Enrique Diaz Duque. Primary cutaneous gamma-delta T-Cell lymphoma in the United States: A nationwide analysis of demographics and survival outcomes among the Hispanic population [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 813.