Survival Benefit of Post Induction Consolidation Therapy in MCL (Mantle Cell Lymphoma): a Polish Lymphoma Research Group (PLRG) Retrospective Multicenter Analysis

Background: In MCL, early intensification and consolidation of the first line therapy by ASCT is the treatment of choice. Elderly age and co-existing co-morbidities makes it however feasible for less than a third of patients.

Methods: All MCL cases consulted in 8 PLRG centers within the last 5 years (n=140) were included in a retrospective analysis. Only 23% (n=32) were consolidated with ASCT, further 28% (n=40) by radioimmunotherapy (Ibritumomab), while in 49% (n=68) neither consolidation was performed. Rituximab was used in 36/72 patients subjected to consolidation and 25/68 treated without consolidation. There were no statistically significant differences in IPI, CS (clinical stage), frequency of extranodal manifestations and B symptoms between analyzed subgroups (Table 1) although patients subjected to ASCT were younger (median age 54 vs 62) and tend to have higher LDH (556 IU vs 473), while those who were not consolidated more frequently had a large tumor burden (defined as a mass > 7 cm, 24 vs 15%).

Results: There was a clear impact of consolidation on Overall and Progression Free Survival (OS,PFS): at 5 years OS 65 vs 20 % (p= 0.0003 in Gehan Wilcoxon test); and PFS 40 vs 0 % (p= 0.0003 in Gehan Wilcoxon test). Rituximab used in the first line therapy further increased it’s efficiency in terms of PFS, prolonging median time to progression from 15 to 26 months, however the OS benefit was seen only in consolidated patients (at 5 years 75% OS in those with Rituximab including induction followed by consolidation).

Conclusion: With all limitations of retrospective analysis, it strongly supports the necessity of post induction therapy in MCL patients. The role of ASCT is established in younger patients, radioimmunotherapy may prove to be a feasible approach for the elderly and unfit ones.