[Renal failure in multiple myeloma: Specific management issues]

Renal impairment is common during multiple myeloma and persistent reduction in kidney function strongly affects prognosis. Cast nephropathy, by monoclonal free light chains precipitation with uromodulin in renal tubules, is the main cause of acute kidney injury in multiple myeloma. Kidney biopsy, although not necessary for diagnosis, allows assessment of renal prognosis according to the extent of cast formation, tubular atrophy and interstitial fibrosis. Prevention and early diagnosis of acute kidney injury are essential to optimize management and avoid progression to chronic kidney disease. Rehydration, interruption of nephrotoxic treatments, correction of precipitating factors, anti-plasma cell chemotherapy can rapidly reduce the free light chains nephrotoxicity. The association of the proteasome inhibitor Bortezomib and high dose Dexamethasone is the reference treatment in newly diagnosed patients with renal impairment. Adding Cyclophosphamide or the immunomodulator Lenalidomide may improve the hematological response, but with a poorer tolerance. Use of anti-CD38 monoclonal antibodies is being evaluated in this population. Hemodialysis with high-flux or high-cut-off membranes, combined to chemotherapy, may improve renal function recovery. Management of multiple myeloma have to be adapted in patients with chronic kidney disease, dialysis or kidney transplantation. Because of improvement in global survival, kidney transplantation remains an option to consider in selected patients. Collaboration between hematologists and nephrologists is essential throughout the course of the disease.