Interim PET-CT-guided therapy in elderly patients with Hodgkin lymphoma-a retrospective national multi-center study.

Hodgkin lymphoma (HL), a disease of mostly young patients, also peaks in the elderly. Despite the profound improvement in the outcome of young patients, in the elderly, 5-year progression-free survival (PFS) rates are under 70%. Interim PET-CT (iPET) is known to be highly predictive for PFS in young HL patients, but it has not been sufficiently validated in the elderly patient population. In this multi-center collaboration, all consecutive elderly patients (age ≥ 60) diagnosed with HL between 1998 and 2016 were retrospectively reviewed. Baseline characteristics, outcome measures, and iPET results, classified according to the Deauville score, were recorded and analyzed. We identified 78 elderly HL patients (median age 69) who underwent iPET. ABVD was the treatment regimen in 52 (67%) patients. Eighty-three percent of patients had iPET scores of 1-3 while 17% had scores of 4-5. Patients with iPET scores of 1-3 had 5-year PFS and OS rates of 72% and 82% compared with 25% and 45%, respectively, in patients with scores of 4-5 (p < 0.001). Our findings show that iPET is highly predictive of outcome in elderly HL patients and provide evidence that iPET-guided therapy in this patient population may be key to achieving superior treatment outcome.