Two prospectively randomized intergroup trials of the European MCL Network investigating the impact of different combined immuno-chemotherapy protocols for patients with stage II–IV mantle cell lymphoma (MCL) >< 65 yrs followed by autologous stem cell transplantation (PBSCT) for patients <65 yrs and a rituximab or interferone maintenance treatment for patients >65 yrs are currently performed.
Patients and methods: 180 German patients with diagnostic peripheral blood (PB) involvement detectable by consensus IGH PCR were analysed for t(11;14) translocation by FISH and 4-colour Flow Cytometry (FC) at diagnosis as well as molecular response (MR) by quantitative IGH-RQ-PCR after induction. The results were compared to clinical parameters at diagnosis and PFS.
Results: Patients had a median age of 61 years, an elevated LDH in 37%, B-symptoms in 41% and extranodal involvement in 37%. According to the MIPI risk factor score 26% had an adverse, 34% an intermediate and 40% a good prognosis. PB involvement by MCL was demonstrated in 67% (74/111) by t(11;14) FISH and in 97% (152/156) by FC. Detection of MCL cells by FC in PB did not correlate with clinical parameters as stage, LDH, extranodal involvement or bone marrow infiltration. However, median % of MCL cells measured by FC differed significantly with clinical stage (p<0.0001), LDH (p=0.0096) bone marrow infiltration (<0.0001) and MIPI prognostic index (0.0002). MR after induction treatment was achieved in 60% (60/100) of patients and correlated with BM infiltration at diagnosis (p=0.0117). There was a trend for improved PFS in patients achieving MR (PFS 90% vs. 75% at 15 months after induction) however, the observation time is still too short for definitive evaluation.
Conclusion: FC is highly sensitive for detection of PB involvement in MCL and improves staging accuracy. Achievement of MR might be an early indicator for treatment outcome after immuno-chemotherapy in MCL with the potential of defining prognostic subgroups.
Disclosure: No relevant conflicts of interest to declare