We conducted this multi-centered retrospective real-world study on efficacy and safety of the mainstream maintenance regimens, thalidomide (T-MT)...Patients with 1q21+ on T-MT had shorter median PFS compared to those without (16.1m vs 22.5m, p=0.14), so did impaired median OS (52.3m vs 96.5m, p= 0.003)....Only a few patients with 17p- in T-MT and B-MT, yet presented remarkably inferior PFS (6.7m vs 22.5m, p=0.007) and OS (39.6m vs 79.5m, p=0.02) with T-MT.