Abstract P084

Role of consolidative radiotherapy in preventing relapses and subsequently salvage ASCT in early-stage classic Hodgkin lymphoma

Introduction: The role of consolidative radiotherapy (RT) in upfront management of patients with early-stage classic Hodgkin lymphoma (cHL) is subject of debates. Particularly, its impact on preventing relapses and subsequent necessity of salvage autologous stem cell transplantation (ASCT).

Patients and methods: We analyzed in this multicenter retrospective study data of patients with early stage cHL. The study evaluates whether the omission of RT increases risk of relapse and consequently need of ASCT. Relapse rates and frequency of ASCT were compared between patients who got combined modality treatment (CMT) versus chemotherapy alone.

Total of 490 patients (median age 27, mean follow-up 57 months) were included with 57.8% patients receiving CMT. After end of treatment, complete metabolic remission (CMR) was documented in 90.4% in CMT versus 90.8% in chemotherapy alone arm. 33.3% of patients with positive EOT-PET gained CMR after RT. Relapse rates in chemotherapy alone and CMT cohort were 10.6% and 8.5% (p=0.92), respectively. Of the 42 patients who had r/r disease during observation time 45.2% and 54.7% were in chemotherapy alone and CMT group, respectively. Among these patients, ASCT was carried out in 42.1% in chemotherapy alone and 65.2% in CMT (HR 0.65, 95% CI 0.35–1.18; p = 0.14). Considering both cohorts, overall 8/207 (3.9%) versus 15/283 (5.3%) had ASCT, respectively (p=0.19). Post-ASCT complete metabolic remission rate was similar (80% in CMT vs 75% in chemotherapy alone; p=0.78). Five-years overall survival rate was not different ((HR: 1.03; p=0.95). During the observational period, one patient in the chemotherapy alone group failed ASCT in comparison with three patients in the CMT group corresponding to ASCT failure rate of 12.5% and 20%, respectively. One patient in CMT cohort had allogeneic stem cel transplantation due to relapse post ASCT.

Conclusions: Our real-world data suggests that routine consolidative RT can be omitted in patients with early-stage cHL who achieve a negative EOT-PET, without increasing of the likelihood of requiring ASCT. Conversely, RT demonstrates meaningful efficacy in significant proportion of patients with positive EOT-PET. Therefore, we suggest to reserve consolidative RT for responding patients with early-stage cHL with positive EOT-PET, where it confers clear therapeutic benefit.