Consolidation Radiation Therapy for Patients With Advanced Hodgkin Lymphoma in Complete Metabolic Response According to PET-CT or Gallium Imaging

The role of consolidation radiation therapy (RT) in advanced Hodgkin lymphoma is controversial, especially if a complete response (CR) is achieved according to positron emission tomography-computed tomography imaging after chemotherapy. In this series, low-dose (approximately 20 Gy) RT to all sites of original disease improved progression-free survival, even in the setting of a CR after ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine). Long-term toxicity was similar between chemotherapy and combined modality therapy. Introduction: The purpose of this study was to evaluate the role of consolidation radiation therapy (RT) in advanced Hodgkin lymphoma (HL) in the setting of a complete metabolic response (CR) to chemotherapy (ChT). Patients and Methods: Patients with stage III/IV HL treated with ChT alone or combined modality therapy (CMT) between 1992 and 2012 were reviewed. Only patients in a CR according to positron emission tomography-computed tomography (PET-CT) or gallium imaging were included. Clinical end points were estimated using the Kaplan-Meier method and a multivariate analysis using the Cox proportional hazards model was performed. Results: Ninety patients were identified (46 CMT; 44 ChT alone). Median follow-up was 50 months. ChT (median 6 cycles) consisted primarily of ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine; 74%) or an ABVD hybrid (10%). Post-ChT imaging consisted of PET-CT (71%) or gallium (29%). RT plans primarily included all initially involved sites of disease with a median dose of 21 Gy (range, 13-31 Gy). CMT was associated with improved 5-year progression-free survival (PFS; 88% vs. 65%, respectively; P < .001) and overall survival (97% vs. 78%, respectively; P = .002) compared with ChT alone. In multivariate analysis, age younger than 45 years (hazard ratio [HR], 0.23; 95% confidence interval [CI], 0.07-0.74; P = .013) and CMT (HR, 0.32; 95% CI, 0.11-0.96; P = .04) were independently associated with improved PFS. Secondary malignancies were comparable in both cohorts (5 with CMT, 4 with ChT), whereas cardiac events were slightly more frequent with CMT (5 vs. 2). Conclusion: Low-dose RT, administered to all sites of original involvement, was associated with improved PFS, even in the setting of a metabolic CR after ABVD.