Impact of Racial Disparities and Demographic Factors on Presentation, Treatment, and Survival Amongst Patients with Hodgkin Lymphoma

Introduction: Hodgkin lymphoma (HL) is a rare lymphoid neoplasm that has a bimodal distribution, affecting both young and elderly populations. HL survival is historically favorable, with stage I and II patients demonstrating approximately 90% 5-year overall survival and stage III and IV patients demonstrating approximately 60% 5-year overall survival. Chemotherapy and radiation are the cornerstones of HL treatment. The advent of modern treatments, such as the ABVD regimen, have improved 5-year survival rates and rendered HL a curable disease. Racial disparities in survival in the pediatric HL population are well-documented, however, little is known about these discrepancies in adults. We sought to investigate if there are treatment and survival differences in HL patients of difference races.

Methods: This retrospective observational study used the US population-based Surveillance, Epidemiology, and End Results (SEER)-18 Database. Patients were included if they were diagnosed with HL between the years 2000 - 2017 and were at least 18 years old at the time of diagnosis. Patients were grouped based on demographic information. Baseline characteristics included demographics, treatment information, staging, and presence of B symptoms. Survival data were collected for each group. Chi-Squareand t-test were used to compare differences in characteristics between groups. Cox proportional hazards regression models were used to calculate hazard ratios (HR) for survival.

Results: We analyzed a total of 30,014 patients who met inclusion criteria. 9,606 (32%) patients were treated with radiation and 26,670 (88.9%) received chemotherapy. 20,607 (68.7%) were White, 4,543 (15.1%) were Hispanic, 3,298 (11.0%) were Black, 1,441 (4.8%) were Asian, and 124 (0.4%) were Native American. Black and Hispanic patients were less likely to have income >$75,000 as compared to White patients (24.0% vs 34.0% p<0.001, and 29.2% vs 34.0%, p<0.001). Black and Hispanic patients were more likely than White patients to present with Stage IV disease (21.1% vs 15.3%, p<0.001 and 20.2% vs 15.3%, p<0.001) and with B symptoms (22.7% vs 17.0%, p<0.001 and 21.5% vs 17.0%, p<0.001). Black patients were less likely to receive chemotherapy (87.5% vs 88.8%, p=0.03) despite presenting at a younger age (49.6% vs 44.4% < 40 years old, p<0.001).

Black and Hispanic patients had a shorter median survival time from diagnosis than White patients (86 months vs 96 months, p<0.001 and 74 months vs 96 months, p<0.001). Further, Black and Hispanic patients had a longer interval from diagnosis to treatment initiation than White patients (28 vs 23 days, p<0.001 and 25 vs 23 days, p=0.008).

Multivariable Cox proportional hazards ratio demonstrated that Ann Arbor stage was the most important prognostic factor (HR for Stage IV 3.22, 95% CI 3.07 - 3.38). Age > 40 years (HR 1.31, 95% CI 1.28 - 1.34), Black race (HR 1.17, 95% CI 1.10 - 1.24), Hispanic race (HR 1.26, 95% CI 1.21 - 1.30), divorced status (HR 1.54, 95% CI 1.42 - 1.66), low-income status (HR 1.35, 95% CI 1.35 - 1.74), male sex (HR 1.03, 95% CI 1.01 - 1.06), refusal of radiation (HR 1.51, 95% CI 1.23 - 1.86) and receipt of chemotherapy (HR 1.10, 95% CI 1.05 - 1.14) were significant predictors of survival status.

Conclusions: We demonstrate that age, gender, race, marital status, income status, disease stage, and treatment characteristics were all significant predictors of survival according to multivariable Cox regression. Expectedly, the strongest predictive variable for death was stage at diagnosis. Black and Hispanic patients were more likely to present with late-stage disease and experience delays in treatment initiation, while being less likely to receive chemotherapy, which may lead to inferior outcomes observed in these groups. Such discrepancies may be due to a number of factors, including implicit biases, barriers to accessing patient navigators, or financial toxicity. Our findings demonstrate that despite an overall decrease in mortality, disparities in outcomes associated with demographic factors are still present in patients with HL. These results highlight subgroups that may benefit from targeted interventions, such as improved education regarding implicit biases, increased access to care, and development of management approaches specific to these populations.

Hamouda:Ludwig Institute for Cancer Research: Research Funding; Bayer: Research Funding; Immunovaccine: Research Funding.