Effect of Radiation Therapy on Survival in Hodgkin's Lymphoma: A SEER Data Analysis

Hodgkin's Lymphoma (HL) is curable in up to 80% of patients due, in part, to simultaneous advances in chemotherapy regimens as well as radiation therapy planning and delivery. Concerns regarding the historical use of large-field radiotherapy on overall survival have been published. In this study, we performed a Surveillance, epidemiology, and end results (SEER) data analysis to evaluate the impact of patients and treatments related factors on survival in HL.

Data from 39,700 adult patients registered in the SEER data with diagnosis of HL, between 1983-2011 and follow-up through 2012 were analyzed. Impact of patient demographics (sex, age, race, ethnicity, year of diagnosis, family income, education, unemployment, poverty level and stage of disease) and treatment characteristics (delivery of radiotherapy) on survival were evaluated via multivariate analysis.

Median age was 36 years. Most patients were Ann Arbor Stage II (39%) at diagnosis with the remainder distributed evenly between the remaining stages (I, III, IV: 19-21%). In multivariate analysis, after adjusting for secondary predictor variables including stage of disease, Radiation therapy (RT) was a statistically significant predictor of overall survival from HL (HR=0.72, (95% CI=0.68-0.75). At follow up of more than 25 years, Kaplan-Meier analysis showed that RT improved survival for all patients, irrespective of stage. Factors associated with worse survival included older age, male sex, extra nodal disease, advanced stage, African-American race, and non-Hispanic ethnicity.

Radiation therapy improved survival in patients with all stages of HL. Demographic and disease factors associated with worse survival in this study may be related to particular patterns of care and warrant additional study.