Impact of double/triple hit pathology on rates and durability of RT response among patients with relapsed/refractory large B-cell lymphoma
Menée à partir de données portant sur 41 patients atteints d'un lymphome à grandes cellules B récidivant ou réfractaire aux traitements et présentant un réarrangement du gène c-MYC (durée médiane de suivi : 2 ans), cette étude évalue l'effet de la présence d'un réarrangement du gène BCL2 et/ou du gène BCL4 sur l'efficacité d'une radiothérapie du point de vue du taux de réponse, de la progression de la maladie et de la survie
Purpose : Double/triple-hit lymphomas (DHL/THL), also known as high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements, are associated with chemoresistance and inferior survival. However, whether RT efficacy is altered in DHL/THL is less well characterized. Among patients with relapsed/refractory (R/R) large B-cell lymphoma (LCBL), we compared rates and durability of response between patients with and without DHL/THL. Methods and Materials : We retrospectively reviewed consecutive R/R LBCL patients that were irradiated at a single institution from 1/2008-6/2017. Patients in whom c-MYC rearranged status was known were evaluated for response to RT, in-field control, progression-free (PFS) and overall survival (OS). Results : Among 245 irradiated patients with LBCL, 41 patients with confirmed c-MYC status were treated for R/R disease (14 DHL/THL, 27 non-DHL/THL) and formed our cohort. Compared to non-DHL/THL, more DHL/THL patients had progressive disease at RT (71% vs 48%), had larger gross tumor volumes (GTV; median 696 mL vs 117 mL), and were treated with palliative intent (71% vs 41%). Despite similar RT doses (median 35 Gy), radiographic complete response rate was lower among DHL/THL patients: 14.3% vs 64.7% (p=0.01). With a median 2 years of follow-up, one in-field failure was observed in each group. DHL/THL patients had inferior PFS (7% vs 46%; p=0.02) and OS (14% vs 68%; p=0.03) at 6 months. Conclusions : R/R LBCL is responsive to RT, although RR are lower among DHL/THL patients. Given poor survival after RT, in-field control was hard to evaluate in this cohort. Larger cohorts are required to better elucidate whether differences in response rates are driven by larger disease burden at RT versus tumor biology. These findings are of increasing pertinence in light of use of RT as bridging therapy to cellular immunotherapies.