Impact of peri-transplant consolidative radiotherapy in patients with relapsed or refractory classical Hodgkin lymphoma

Following salvage chemotherapy (SC) and autologous stem-cell transplantation (ASCT), 30-60% of patients with relapsed/refractory Hodgkin lymphoma (r/rHL) experience disease relapse. Appropriate patient selection for consolidation radiotherapy (cRT) may improve outcomes. Positron-emission tomography (PET) is a powerful prognostic tool, with potential utility in PET-directed therapy. Predictive roles of post-SC metabolic and structural response assessments, and prognostic impact of peri-transplant cRT, were retrospectively evaluated in r/rHL patients from two tertiary hospitals, median follow-up >5 years. Five-year progression-free survival (PFS) was 65% (95%CI 55-74%). Metabolic response post-SC significantly predicted PFS. For patients with complete metabolic response (CMR) post-SC, structural residuum ≥2 cm suggested inferior PFS. Potential PFS advantages from cRT were observed in all subgroups with limited-stage r/rHL, regardless of response post-SC. Peri-transplant cRT may abrogate the negative predictive value of non-CMR or residual masses ≥2 cm in CMR post-SC. In advanced-stage r/rHL, post-SC non-CMR predicted for poor outcomes, warranting prioritization of alternative salvage strategies.