Reduced Mortality Risk in the Recent Era in Early-Stage Hodgkin Lymphoma Patients Treated With Radiation Therapy With or Without Chemotherapy

Abstract

To determine the effect of treatment changes over time on all-cause mortality risk in patients with early-stage Hodgkin lymphoma (HL) after radiation therapy. The long-term survivorship of those with HL necessitates quantification of the late risk of mortality from HL and other causes. An institutional review board-approved retrospective study was conducted using a multi-institutional database of 1541 stage I and II HL patients treated from 1968 to 2007 with radiation therapy alone or combined-modality treatment. The analytic methods included cumulative incidence function, Kaplan-Meier estimates and log-rank tests for overall survival (OS) differences, and Cox proportional hazards modeling. The median age at diagnosis was 27 years. At a median follow-up of 15.2 years (35% of patients with >20 years of follow-up), 395 patients had died of all causes, including 85 HL, 168 second malignancy (25 hematologic and 143 nonhematologic), 70 cardiovascular, and 21 pulmonary deaths. The cumulative incidence of non-HL mortality had surpassed HL mortality at 8.3 years. For patients treated from 1968 to 1982, 1983 to 1992, and 1993 to 2007, the 15-year OS rates were 78%, 85%, and 88%, respectively (P=.0016). On Cox proportional hazards analysis, age, B symptoms, and number of disease sites were significantly associated with all-cause mortality in the first decade of follow-up, with a trend toward significance for radiation field extent. The all-cause mortality risk was significantly lower for patients treated in the most recent era during the first decade of follow-up, likely due to improved HL therapy resulting in a higher cure rate and lower treatment-related toxicity from smaller radiation fields. Current efforts toward radiation treatment reduction might further reduce the long-term mortality risk for these patients.