Prognostic significance of PCR-based molecular staging in patients with diffuse large B-cell lymphoma treated with R-CHOP immunochemotherapy.

The prognostic role of detecting clonal immunoglobulin gene rearrangement (IgR) from bone marrow (BM) aspirates was evaluated by BIOMED-2 PCR in 97 patients with diffuse large B-cell lymphoma (DLBCL) treated with rituximab-CHOP immunochemotherapy. Sixteen (16.5%) patients had BM involvement (BMI) defined by BM biopsy (MOR+) and 39 (40.2%) had positive IgR (PCR+). Patients with MOR + BMI showed inferior event-free survival (EFS) compared to those with MOR-/PCR- (p < 0.001) or those with MOR-/PCR + BMI (p = 0.002), while no significant difference in EFS was observed between patients with MOR-/PCR + and those with MOR-/PCR - BMI (p = 0.497). Use of the BIOMED-2 for PCR resulted in significant increase in detection of BMI. However, the increased sensitivity by PCR did not translate into improved prediction of prognosis, emphasizing the essential role of histopathological review of trephine biopsy for the detection of BMI.