Overall survival and causes of death in elderly patients with Hodgkin lymphoma—a Norwegian population‐based case‐control study

Abstract

Background: Elderly Hodgkin Lymphoma (HL) patients (pts) are poorly characterized and underrepresented in high-quality studies. Populations-based studies with individual disease- and treatment-factors together with causes of death are lacking. Methods: Pts ≥60 years diagnosed with HL between 2000 and 2015 were identified by Cancer Registry of Norway. Hospital and other health-care records were reviewed and pts grouped according to treatment into ineligible (no HL directed treatment), palliative (intended dose intensity <50%) or curative (>50% intended dose intensity of HL regimens or curative radiotherapy only). Pts’ causes of death were obtained from records and compared to The Norwegian Cause of Death Registry providing date and cause of death for pts and cancer-free controls matched 1:10 based on age, sex and place of residency. Overall survival was analyzed by Kaplan-Meier statistics. Cumulative incidence functions were calculated using the Aalen-Johansen estimator and compared using Gray’s test. Risk differences between pts and controls were calculated for each competing event at 2, 5 and 10 years. Results: Of 492 pts, 81 (16.5%) were ineligible for the analysis of treatment outcomes, due to composite lymphoma (n = 51), diagnosis after death (n = 13), severe comorbidity (n = 16) or incomplete patient data (n = 7). 74 (15%) and 337 (68.5%) pts were treated with palliative or curative intent, respectively, most commonly with CHOP. Median overall survival in the ineligible, palliative and curative groups were 0.5 (95% Confidence interval [CI] 0.4–0.6), 0.8 (0.4–1.2) and 9.1 (7.5–10.7) years, respectively. With 359 deaths, the most common cause was HL in all groups, with 30% dying from HL, 8% from treatment-related mortality and 62% from other causes. The risk difference of dying from HL compared to controls increased from 16% (95% CI: 12%–20%) at 2 years to 28% (23%–33%) after 10 years for the curative group, compared to 59% (48%–71%) and 42% (31%–53%) after 10 years in the palliative and ineligible groups, respectively. There was an increased risk of dying from other hematological malignancies, including Non-Hodgkin lymphoma in all groups, but not from other causes of death (Figure 1). Keyword: Hodgkin lymphoma No conflicts of interests pertinent to the abstract.