Disparities in Mantle Cell Lymphoma Outcomes in Hispanics: A Population Based Analysis in Texas and Florida

Introduction:

Mantle cell lymphoma (MCL) is a rare, aggressive type of B-cell non-Hodgkin lymphoma (NHL) that accounts for approximately 7% of adult NHL's in the United States. (JCO PMID: 9704731)Although recent advancements in treatment have improved survival, prognosis remains poor. (Blood PMID: 30154113) There have been several recent studies demonstrating ethnic disparities in MCL, however, there is a paucity of survival outcome data in Hispanic (H) patients with MCL. (CLMLPMID: 31029647) The purpose of this study was to compare the demographics, treatment patterns, and survival outcomes of H and Non-Hispanic (NH) patients diagnosed with MCL, and to contrast Hispanic cohorts between Texas (TX) and Florida (FL).

Methods:

This is a retrospective cohort study of patients diagnosed with lymphoma (Hodgkin and Non-Hodgkin) from the Texas Cancer Registry (TCR) and the Florida Cancer Data System (FCDS) from 2006-2017. This particular analysis focuses on patients with diagnosis of MCL. Key variables included gender, race, ethnicity, birthplace, dates of diagnosis and death, primary payer at diagnosis, poverty index, stage at diagnosis, and type of treatment. The significance of variation in distribution of categorical outcomes with ethnicity [H, NH] was assessed with Fisher's Exact tests or Pearson's Chi-square as appropriate; age was assessed with T-test or Wilcoxon. Survival time was measured in years from date of primary diagnosis to date of death. Survival distributions were described with Kaplan-Meier curves and significance of variation in median survival with ethnicity was assessed with log rank testing. All statistical testing was two-sided with a significance level of 0.05.

Results:

We identified a total 4619 (2078 TX, 2541 FL) patients with MCL. 669 (15%) were H and 3950 (85%) were NH. In TX, the median age of diagnosis was 65.6 years (y) in H and 68.3 y in NH (p < 0.001). In FL, the median age of diagnosis was 67.56 in H and 70.06 in NH (p < 0.001). There was a statistically significant difference in poverty index between the cohorts in both TX and FL. The majority of H (50%) in TX were in the 20-100% bracket while the majority of NH (36%) in TX were in the 10-19.9% bracket (p < 0.001). The majority of H (39%) in FL were in the 10-19.9% bracket, and the majority of NH (35%) were also in the 10-19.9% bracket (p < 0.001). Interestingly, there were only 30% of H in FL in the 20-100% bracket. There was a statistically significant difference in insurance status with the most frequent insurance being government-sponsored insurance for H in TX (48%), NH in TX (58%), H in FL (48%), and NH in FL (62%). Patients were without insurance at time of diagnosis in 14% of H in TX and 9% of H in FL, in contrast to 4% of NH in TX and 2% NH in FL. The most common stage at diagnosis in both cohorts in TX and FL was Stage III/IV with 68% H in TX vs 65% NH in TX (p = 0.746) and 69% H in FL vs 67% NH in FL (p = 0.316). The most frequent chemotherapy regimen included multiple agents for all cohorts, 43% H in TX vs 37% NH in TX (p = 0.063), and 48% H in FL vs 42% NH in FL (p = 0.695). Median survival time was 3.4 y H in TX, 3.5 y NH in TX, 4.1 y H in FL, and 4.3 y NH in FL. The survival probability at 2 years was 0.636, 0.640, 0.707, 0.675 for H in TX, NH in TX, H in FL, and NH in FL, respectively. The survival probability at 5 years was 0.371, 0.379, 0.445, 0.459 for H in TX, NH in TX, H in FL, and NH in FL, respectively. The survival probability at 10 years was 0.147, 0.118, 0.276, 0.245 for H in TX, NH in TX, H in FL, and NH in FL, respectively. There was no statistically significant difference in survival probability at 2, 5, or 10 years between H and NH in TX (p = 0.68) and FL (p = 0.72).

Conclusions:

Our study of patients diagnosed with MCL demonstrated statistically significant differences between H and NH patients in median age of diagnosis, poverty index, and insurance status at diagnosis. These disparities were observed in patients between the cancer registries in both states. Although there were no statistically significant differences in median survival time or survival probability at 2, 5, and 10 years among the H cohorts within each state, we observed intriguing data when the two states were compared. Strikingly, H in TX had much lower survival probability at 2, 5, and 10 years compared to H in FL. In addition, H in TX were noted to have a shorter median survival time compared to H in FL. These disparities may be a direct reflection of the significantly higher rates of poverty and lack of insurance among H in TX compared to H in FL.

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