A Case of Secondary Primary Malignancy after Lenalidomide Therapy for Multiple Myeloma

Lenalidomide, an orally administered immune-modulating drug, has several mechanisms of action against multiple myeloma (MM). However, the mechanisms of action of immune-modulating drugs are not understood completely. Lenalidomide maintenance therapy prolongs the time to progression and increases the overall survival in patients with MM. However, secondary primary malignancy (SPM) has been noted as a serious adverse event in patients with MM treated with lenalidomide. Lenalidomide treatment is not covered by insurance. Consequently, physicians have little experience with the adverse events of lenalidomide treatment in patients with MM. Here, we describe a case of breast cancer after lenalidomide treatment for MM. To our knowledge, this is the first report of a lenalidomide-associated SPM in Korea. The risk factors associated with lenalidomide-associated SPM should be considered carefully when implementing chemotherapy regimens in patients with MM. (Korean J Med 2014;86:353-356)