The prognostic value of bone marrow involvement at the molecular level in aggressive lymphoma

We retrospectively studied the prognostic role of molecular (gene rearrangement, GRR) bone marrow (BM) involvement in diffuse large B-cell lymphoma (DLBCL, 424 patients) and in peripheral T-cell lymphoma (PTCL, 67 patients). When correlating BM GRR to histological findings at diagnosis, the GRR test was more sensitive (p = 0.036) but less specific (p<0.0001) in PTCL than in DLBCL. For DLBCL (but not PTCL), a positive BM GRR correlated with advanced stage (p = 0.0001) and high IPI (p = 0.002), and worsened the progression free survival (PFS) (p = 0.05) and overall survival (OS) (p = 0.01), irrespective of rituximab treatment. Histologic negative/GRR positive cases had worse PFS/OS (p<0.0001) than histologic/GRR double negative cases, however BM GRR was not an independent prognostic survival factor. End-of-treatment BM GRR did not predict survival. We conclude that BM GRR is unjustified as a prognostic tool for PTCL and should be reserved for a subset of DLBCL patients with negative histology of the BM.