[1379] Utility of Flow Cytometric Immunophenotyping Analysis in Bone Marrow Staging of Patients with Mantle Cell Lymphoma after Therapy

W Liu, LJ Medeiros, JL Jorgensen. MD Anderson Cancer Center, Houston, TX

Background: Mantle cell lymphoma (MCL) is a B-cell neoplasm characteristically associated with CCND1 translocation. Most patients present with lymphadenopathy with frequent bone marrow (BM) involvement at time of diagnosis. Less is known about MCL in BM after therapy. Persistence or relapse of MCL in BM is traditionally defined by morphologic (M) detection of disease. However, in a subset of patients we have observed flow cytometric (FC) evidence of MCL in the BM in the absence of M evidence supporting involvement. The goal of this study was to evaluate the utility of FC immunophenotyping in the re-staging of patients with MCL after therapy.
Design: 100 patients with MCL who were treated with chemotherapy and had subsequent BM examination (median interval, 3 months; range 1 to 6) formed the study cohort. BM aspirate samples were assessed by FC using the following panel of antibodies: CD5, CD10, CD19, CD20, CD38, FMC7, and surface Igκ and Igλ.
Results: The median survival time (calculated in months starting from initial treatment date) was 90 months. 27 patients had M and/or FC evidence of persistent/relapsed MCL involving a total of 57 BM specimens. In 39/57 (68.4%) specimens from 19 patients, both M and FC evidence of MCL were identified. By contrast, BM involvement was detected only by FC analysis in 18/57 (31.6%) specimens from 8 patients. Clinical follow up on this group was as follows: 5 (62.5%) patients developed subsequent M relapse in the BM (median 3 months, range 2 to 24 months); 2 (25%) patients had concurrent lymph node relapse; 1 (12.5%) had no relapse clinically or in BM followup specimens. There were no patients who had M evidence of MCL without FC concordance. The percentage of monoclonal B cells identified by FC was higher in patients with M evidence of MCL compared with patients who only had FC evidence (mean, 8.67% versus 1.17%). In a subset of patient specimens in which disease was only detected by FC, a cyclin D1 immunostain was performed but the results did not contribute substantially to improving the sensitivity.
Conclusions: FC is clearly more sensitive in cases with a low percentage of monoclonal B-cells and is therefore the more powerful tool to assess the effectiveness of high-dose chemotherapy. Significantly, nearly all patients with MCL detected by FC eventually developed clinical relapse or morphologically evident BM relapse. In our experience, one cannot confidently establish the presence of MCL using M criteria when the percentage of monoclonal B-cell by FC is less than 5%.
Category: Hematopathology

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 200, Wednesday Afternoon


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