Association of Treatment Intensity With Survival in Older Patients With Hodgkin Lymphoma.

Importance: Hodgkin lymphoma is an aggressive blood cancer that is highly curable in younger patients who receive multiagent chemotherapy. Worse survival in older patients may reflect less-aggressive treatment, competing risks of death, or different disease biological factors. Objective: To examine the association between treatment intensity and cause-specific mortality among older adults with Hodgkin lymphoma. Design, Setting, and Participants: This was a population-based cohort study of patients aged 65 years or older with Medicare Part A and B fee-for-service coverage who received a diagnosis of Hodgkin lymphoma from 2000 to 2013. The association between treatment intensity and cause-specific mortality was estimated separately for early-stage and advanced-stage disease with Cox proportional hazards models. Multivariable adjustment and propensity score weighting helped control for confounding. Data are from the 1999 to 2016 Surveillance, Epidemiology, and End Results Medicare database. Data analysis was performed from April 2020 to June 2021. Exposures: First-line treatment categorized as (1) full chemotherapy regimen, (2) partial chemotherapy regimen, (3) single chemotherapy agent or radiotherapy, or (4) no treatment. Main Outcomes and Measures: The main outcome was 3-year Hodgkin lymphoma-specific and other-cause mortality. Results: Among 2686 patients (mean [SD] age, 75.7 [6.9] years; 1333 men [50%]), 1307 had early-stage disease and 1379 had advanced-stage disease. For Hodgkin lymphoma-specific mortality in patients with early-stage disease, hazard ratios (HRs) were higher for partial regimens (HR, 1.77; 95% CI, 1.22-2.57) or no treatment (HR, 1.91; 95% CI, 1.31-2.79) than for full regimens; there was no difference between single-agent chemotherapy or radiotherapy and full regimens. For other-cause mortality in patients with early-stage disease, HRs were higher for partial regimens (HR, 1.69; 95% CI, 1.18-2.44), single-agent chemotherapy or radiotherapy (HR, 1.62; 95% CI, 1.13-2.33), or no treatment (HR, 2.71; 95% CI, 1.95-3.78) than for full regimens. For Hodgkin lymphoma-specific mortality in patients with advanced-stage disease, HRs were higher for partial regimens (HR, 3.26; 95% CI, 2.44-4.35), single-agent chemotherapy or radiotherapy (HR, 2.85; 95% CI, 1.98-4.11), or no treatment (HR, 4.06; 95% CI, 3.06-5.37) than for full regimens. For other-cause mortality in patients with advanced-stage disease, HRs were higher for partial regimens (HR, 1.76; 95% CI, 1.32-2.33), single-agent chemotherapy or radiotherapy (HR, 1.65; 95% CI, 1.15-2.37), or no treatment (HR, 2.24; 95% CI, 1.71-2.94) than for full regimens. Conclusions and Relevance: This cohort study found variability in the magnitude of the association between treatment intensity and mortality by stage and cause-specific mortality, possibly reflecting competing risks of death. However, full chemotherapy regimens were associated with lower mortality and could be considered for older adults who can tolerate them.