Long Term Follow up of Elderly Patients with Classical Hodgkin's Lymphoma: An Analysis of the Texas Cancer Registry

Introduction Advances in the management of classical Hodgkin's Lymphoma (cHL) have improved patient outcomes, particularly in younger, fit patients. However, there is little data on whether the evolution of multiagent systemic therapies has impacted outcomes in the growing elderly population. This is the first study investigating the epidemiological factors, clinical characteristics, and treatment patterns using the Texas Cancer Registry (TCR). The TCR is a statewide, population-based registry that serves as the foundation for measuring the cancer burden in Texas and is one of the largest cancer registries in the United States1.

Methods/Materials

The TCR database was used to retrospectively identify patients ≥65 years diagnosed with cHL between 1995-2018 and followed through 2020. Data was stratified based on age (65-74, ≥75), race, histologic subtype (lymphocyte rich, lymphocyte depleted, mixed cellularity, nodular sclerosis), poverty index, stage, and treatment (none, chemotherapy, radiation therapy, or both). Outcomes (alive/dead), and causes of death were evaluated. Patients with unknown cHL subtype or missing treatment data were excluded. Patients were seperated into three groups according to year of diagnosis, including 1995-2003, 2004-2012, and 2013-2018, and covariates were compared using Pearson chi-squared test and cox-proportional hazard models along with hazard ratios (HR) and 95% confidence intervals (95% CI). Median overall survival (OS) and disease-specific survival (DSS) were analyzed via Kaplan-Meier methodology, with the log-rank test used to compare survival distributions. P < 0.05 was considered statistically significant for all comparisons.

Results

There were 1,033 patients with cHL identified between 1995 and 2018, with a median age of 74 (65-97) years. Of these, 537 (51.9%) were males, 671 (64.9%) were white, and 302 (29.2%) were Hispanic. Histologic subtypes comprised nodular sclerosis in 589 (57.1%), mixed cellularity in 335 (32.4%), lymphocyte rich in 59 (5.7%), and lymphocyte depleted in 50 (4.8%). There were 422 (40.8%), 387 (37.5%), and 224 (21.7%) diagnosed in 1995-2003, 2004-2012, and 2013-2018, respectively. There was a trend toward increasing utilization of multiagent chemotherapy over time, with 46.7%, 51.4%, and 56.7% in 1995-2003, 2004-2012, and 2013-2018 receiving therapy. DSS in each era was 79 (95% CI: 59.62, 98.38) months, 99 (95% CI: 83.84, 114.16) months, and not reached, respectively (p=0.027) (Figure 1). Median OS was 29 (95% CI: 20.68, 37.31), 44 (95% CI: 29.06, 58.94), and 35 (95% CI: 21.49, 48.51) (p=0.248) (Figure 2) months, respectively. Utilization of multiagent chemotherapy as opposed to no therapy (HR: 0.44 [95% CI: 0.217, 0.908], p=0.026) was associated with improved outcomes. Patient age, sex, lymphoma subtype, stage, and poverty index did not significantly impact survival outcomes. At the last follow up, 835 (80.8%) patients died, of which 398 (47.7%%) were attributed to a non-cHL death. The most common causes of non-cHL deaths included cardiovascular in 115 (28.9%), neurologic events in 48 (12.1%), and second primary cancers in 46 (11.6%).

Conclusion

Evolving treatment strategies and an increasing provision of multiagent therapies in elderly patients ≥65 years have improved DSS trends over the past 25 years in Texas, yet OS remains stagnant and cHL mortality remains high at 52.3%. Strategies to optimize treatment efficacy, minimize toxicities, and improve elderly patient outcomes are needed. Moreover, close clinical monitoring following successful treatment of cHL is needed to mitigate deaths arising from cardiovascular, neurologic, and second primary cancers.

1. Cancer incidence data have been provided by the Texas Cancer Registry, Cancer Epidemiology and Surveillance Branch, Texas Department of State Health Services, 1100 West 49th Street, Austin, TX 78756, https://www.dshs.texas.gov/tcr/.

No relevant conflicts of interest to declare.