Late Relapse of Classical Hodgkin Lymphoma: An Analysis of the German Hodgkin Study Group HD7 to HD12 Trials

Abstract

Purpose Clinical characteristics, therapeutic approaches, and prognosis of late relapse (LR) in patients with classic Hodgkin lymphoma (cHL) are poorly understood. We performed a comprehensive analysis of LR of Hodgkin lymphoma (LR-HL). Methods To estimate the incidence of LR-HL, we retrospectively analyzed 6,840 patients with cHL included in the German Hodgkin Study Group trials HD7 to HD12. Patients who experienced a relapse > 5 years into remission were compared with patients in continued remission for > 5 years and with those who experienced a relapse ≤ 5 years after first diagnosis. Results With a median observation time of 10.3 years, 141 incidences of LR-HL were observed. Cumulative incidences at 10, 15, and 20 years rose linearly and were 2.5%, 4.3%, and 6.9%, respectively. The standardized incidence ratio for HL with respect to age- and sex-matched German reference data was 84.5 (95% CI, 71.2 to 99.7). LR-HL was more frequently observed in patients with early-stage favorable than unfavorable or advanced stage at first diagnosis (15-year cumulative incidence, 5.3% v 3.9% and 3.9%, respectively; P = .01). Overall survival from first diagnosis was worse after LR compared with nonrelapse survivors (10-year estimate, 95.8% v 86.1%; hazard ratio, 2.5; 95% CI, 1.7 to 3.5; P < .001). In patients with LR-HL, survival was better compared with 466 patients with earlier relapse (hazard ratio, 0.6; 95% CI, 0.4 to 0.9, P = .01). Forty-four percent and 49% of patients with LR-HL and earlier relapse, respectively, received stem cell transplantations. Conclusion Apart from treatment-associated adverse effects, survivors after initially successful therapy for cHL are at an 85-fold risk for recurrence of disease compared with the general German population. After risk-adapted treatment strategies, especially in early-stage favorable HL, regular clinical follow-up is recommended for timely detection of LR-HL. With adequate treatment, prognosis of LR-HL is better compared with early relapses.