Risk of subsequent primary malignancies (SPMs) associated with lenalidomide therapy in multiple myeloma (MM) patients, outside the context of melphalan-based therapy is not established. We assessed the risk of SPMs in lenalidomide treated MM patients (n = 1653) at Moffitt Cancer Center (2004-2012) outside the context of melphalan-based induction therapy and post-melphalan maintenance therapy, via (1) cohort analysis and (2) nested case-control study. Incident SPMs (n = 51) were matched to controls (n = 102) on age at MM diagnosis, gender, follow-up time, and date of diagnosis. Incidence of SPM differed significantly (p = 0.0038) between MM patients treated with and without lenalidomide (5-year incidence estimates of 3.2 and 6.2%, respectively), although not significant after adjustment for age and year of diagnosis (HR = 0.82, 95%CI = 0.43-1.57). Lenalidomide treatment was inversely associated with SPM in the nested case-control analysis (OR = 0.03, 95%CI = 0.002-0.34). In this large cohort of MM patients, lenalidomide treatment was not associated with an increased risk of SPM.
Keywords: Multiple myeloma; lenalidomide; subsequent malignancy.