How a Population-based Analysis Compares to Clinical Trials in Early Stage Classical Hodgkin Lymphoma

Abstract Objective/Background Early stage classical Hodgkin lymphoma (cHL) has an excellent outcome. Recent studies focus on decreasing toxicity related to the addition of radiation along with chemotherapy. Real-life reporting of the addition of radiation to chemotherapy is lacking. This study investigates the outcomes obtained from a statewide cancer registry for early stage cHL patients treated with chemotherapy alone (CT) versus patients treated with the combined modality of chemotherapy and radiation (CMT). Methods A retrospective study of cHL patients diagnosed and treated was identified using a statewide cancer registry from 2005 to 2014. Patients with early stage disease (I, II) were then grouped on the basis of the presence of B symptoms into favorable and unfavorable groups. Baseline characteristics (age, gender, extranodal involvement, and histology) as well as overall survival were compared for both groups depending on whether they received CT or CMT as first line therapy for their cHL. Results A total of 961 patients were identified; of those, 127 were excluded as they received only radiation or another form of treatment. Of the remaining patients, 293 were categorized as early stage favorable cHL (Group 1) and 130 adults were in the unfavorable cHL (Group 2). There were 335 patients with advanced stage cHL (Group 3) and 76 patients in an unknown stage. The 10-year overall survival for Group 1 was 81.3% versus 76.3% for Group 2 and 52.7% for Group 3. For Group 1, 10-year overall survival was 86.7% with CMT versus 75.1% for those receiving CT only (p = .004). For Group 2, there was no difference in 10-year overall survival between the CMT group (80.0%) and CT (72.5%) (p = .73). Conclusion While radiation therapy might increase long-term toxicity in cHL, in our large data cohort, radiotherapy consolidation as part of the initial therapy for early stage disease provides superior survival at 10 years, especially in favorable risk cHL.