Potential impact of consolidation radiation therapy for advanced Hodgkin lymphoma: a secondary analysis of SWOG S0816

The role of radiotherapy (RT) in the management of advanced Hodgkin Lymphoma (HL) is inadequately defined in this era of functional imaging with PET scan. SWOG-S0816 treated advanced stage Hodgkin lymphoma patients with ABVD+/- escBEACOPP and no RT. We queried whether RT might have benefited patients in S0816 who would have met the GHSG-HD15 criteria for RT by simulating RT use as per HD15 criteria of PET + residual disease >= 2.5 cm. Receiver-operating-characteristics analyses were performed by varying disease-control rates within radiation fields and size cutoffs for residual disease. Among the 49 PET3+ S0816 patients, RT would have raised the 2-year PFS from 30.6% to 50.2-58.1% using three residual disease cutoffs (1.5, 2.0 and 2.5 cm) and assuming 80 and 90% in-field control rates . Although there may be improvement in PFS as size cutoff point is lowered, consequential toxicities from RT require further definition to assess relative benefits.