Consolidation Radiotherapy Could Be Omitted in Advanced Hodgkin Lymphoma With Large Nodal Mass in Complete Metabolic Response After Abvd. Final Analysis of the Randomized Hd0607 Trial

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Introduction: Consolidation Radiotherapy (cRT) was originally proposed for ABVD-treated advanced stage Hodgkin Lymphoma (aHL) presenting with bulky or a residual mass (RM) after ABVD. However, very few published data exist on the role of cRT on RM in patients (pts) with a negative end-of treatment PET (EoT-PET) after ABVD. Methods: In the HD0607 clinical trial (Gallamini JCO 2018) aHL pts (stage IIB-IVB) were treated with 2 ABVD courses, followed by an interim PET (PET-2). PET-2 positive pts were randomized to 4 BEACOPP escalated + 4 BEACOPP baseline cycles ± rituximab before each cycle. PET-2 negative pts were treated with 4 more ABVD and a EoT-PET was performed afterwards. PET-2 and EoT-PET negative pts were randomized to either cRT on the sites where a large nodal mass (LNM) was detected at baseline, or no further therapy (NFT). LNM was defined as single or a conglomerated nodal mass with the largest diameter ≥ 5 cm in baseline CT. Results: After ABVD, 47/630 (7%) PET2 negative pts with a positive EoT-PET, 27/630 off study pts for disease progression or consent withdrawal and 260 pts without LNM were not suitable for the random, while 296 were randomized to cRT (148) or NFT (148). In this pts cohort the largest diameter of LNM was 5-7 cm in101 (34%) 8-10 cm in 96 (32%), while a classical bulky (diameter >10 cm) was detected in 99 (33%) pts. Prognostic factors, age, sex, stage, IPS, Performance status, extra-nodal sites, bulky disease were well balanced between the two cohorts. In pts presenting with one (265) or more (31) LNM, the most common nodal region was mediastinum (82%), followed by cervical (14%), abdominal (6%) or axillary (3%) regions. A post-ABVD RM was detected in 260 (88%) of 296 pts presenting with a LNM and in 92/99 pts with classical bulky. The median dose of RT was 30.6 (24.0-113.6) Gy, by involved field (88%) involved node (1%) or involved site (11%) technique. After a median follow-up of 5.9 (0.5-10) years the 6-year PFS for RT versus NFT in an intention to treat analysis was 92% (95% CI, 88-97%) versus 90% (95% CI, 85-95%) p = .48 (Figure) and a 6-year OS 99% (95% CI, 97-100%) versus 98% (95% CI, 96-100%), respectively. When the analysis was limited to patients with a classical bulky lesion, the 6-year PFS was 89% (95% CI, 81-99%) for consolidation RT and 86% (95% CI, 77-96%) for NFT (p = .53). The 6-year PFS of the 260 non-randomized pts without LNM at baseline, was 92% (95% CI, 88-95%). When the analysis was limited to those with RM, the relapse rate of patients treated or not with cRT was 7% versus 9%, with a 6-year PFS of 93% (95% CI, 88% to 97%) versus 89% (95% CI, 84% to 95%) (P = .41).