R-CHOP + R-HAD vs R-CHOP Followed by Maintenance Lenalidomide + Rituximab vs Rituximab for Older Patients With MCL

This study aims to evaluate whether the addition of lenalidomide to rituximab-maintenance improves progression free survival (PFS) compared to standard rituximab maintenance after induction treatment consisting of R-CHOP + R-HAD versus R-CHOP alone in older patients (≥ 60 year old) with mantle cell lymphoma. 643 patients will be randomized in induction phase and 433 in maintenance phase. The treatments consist of two phases: * induction treatment will be 3 cycles of R-CHOP21 + 3 cycles of R-HAD28(alternating) versus 8 cycles of R-CHOP21 alone * maintenance treatment will be 13 cycles of rituximab every 8 weeks + 26 cycles of lenalidomide every 4 weeks vs 13 cycles of rituximab every 8 weeks. Patients will be followed 2.5 years after the last patient randomized for maintenance for final analysis. All subjects who complete or discontinue the maintenance treatment for any reason will be followed for at least 3 years after his/her last study treatment administration in maintenance period for Second Primary Malignancies (SPM). A long term follow-up for progression/death will be done up to the end of period of SPM data collection.