Management and Outcomes of Hodgkin Lymphoma Patients Who Achieve Partial Metabolic Response on PET Scans Post-Chemotherapy

Abstract

Optimal management of patients with Hodgkin Lymphoma (HL) who do not achieve PET (positron emission tomography) complete metabolic response after primary systemic therapy is unclear. Options vary significantly and include radiation therapy (RT) to localized sites of PET avid disease, salvage chemotherapy followed by autologous stem-cell transplantation (ASCT), or observation with serial imaging. This multi-center study sought to investigate the management approaches and outcomes for HL patients who achieved partial metabolic response after primary systemic therapy. In this retrospective study, patients diagnosed with HL were identified from the electronic medical records database of two large academic centers between January 2009 and September 2021. PET scan results following initial chemotherapy were reviewed and responses were categorized using International Working Group (IWG) criteria, with the initial staging imaging being used as the reference against which response was evaluated. We performed descriptive analysis of demographic and clinical characteristics of the population and Kaplan-Meier estimates were used to determine progression-free survival (PFS). The charts of 1,093 HL patients were reviewed. A total of 765 patients had a post chemotherapy PET scan with 57 of those showing partial metabolic response. Among these 57 patients, 31 (54%) were male, the median age at diagnosis was 31 (range:18-74), and the median length of follow up was 1.6 years (average 2.9 years). Five percent stage I, 32% stage II, 23% stage III, and 40% stage IV. Typical initial chemotherapy included ABVD, ABVD switched to BEACOPP due to abnormal interim PET, and AVD with Brentuximab. Among all patients with metabolic partial response to chemotherapy, the 2-year PFS was 72.8% (95% CI = 60.9-87%). Thirty-three of these patients (58%) were treated with planned radiation therapy alone, and 2-year PFS was 80.7% (95% CI = 66.6-97.9%). For those who did not receive radiation as part of their treatment, progression rate was 38% at 2 years. To our knowledge, this is the largest series of HL patients with partial metabolic response following primary chemotherapy. Our preliminary analysis showed that treatment with radiation was associated with good PFS at 2 years and many of those treated with radiation alone were cured.