Multiple myeloma after kidney transplantation

Background: Data regarding multiple myeloma (MM) that develops after kidney transplantation (KTx) are scarce. The outcomes of these patients were evaluated in a retrospective study. Methods: Patients with newly diagnosed MM after KTx were selected. Patients with a diagnosis of MM or those who received treatment for monoclonal gammopathy of renal significance (MGRS) prior to KTx were excluded. Results: Between 2001 and 2012, seven patients developed MM after KTx. Reasons for ESRD included ADPKD (1), C1q nephropathy (1), MPGN (2), hypertensive nephrosclerosis (2), and chronic interstitial nephritis (1). Before KTx, only four patients had monoclonal protein studies, four had monoclonal gammopathy of undermined significance (MGUS), and two of them had clonal plasma cells in bone marrow. Median follow-up after MM was 70 months (range 19-100). Median survival was 80 months. Median time from KTx to MM was 72 months (range 3-204 months). The Kidney allograft failed in four patients due to monoclonal protein-related renal disease. Five patients received chemotherapy: bortezomib (n = 3), lenalidomide (n = 2), melphalan (n = 1), thalidomide (n = 1), pomalidomide (n = 1), and high-dose dexamethasone (n = 1). Three patients received ASCT. Conclusion: Multiple myeloma after KTx is rare. Most patients who develop MM had MGUS prior to KTx. There is significant renal involvement in these patients. Survival is not worse when compared to MM without KTx. Further work is needed to identify the best treatment options for these patients.