Myeloma kidney: improving clinical outcomes?

Renal impairment is a common complication of multiple myeloma, affecting 20% to 40% of new cases (depending on the definition). Most cases are mild and easily reversible, but it may manifest as severe acute renal injury requiring dialysis. Renal impairment is associated with a large tumor mass and consequently confers a poor prognosis. The prognosis of myeloma has improved with the introduction of novel agents and autologous stem cell transplantation. These improvements appear to apply equally to patients with renal impairment, although the risk of complication is usually higher in this group of patients. In addition to improved overall survival, there is some evidence that novel therapies have improved the renal prognosis. Treatment with high-dose dexamethasone and bortezomib can rapidly reduce light chain production and provide an opportunity for renal recovery. Although trials of plasma exchange (to remove the nephrotoxic light chain) have shown a disappointing lack of benefit, high cutoff dialysis removes larger quantities of light chain; therefore, trials are underway to investigate whether this can improve the renal prognosis independently of chemotherapy. Outcomes in patients with myeloma kidney do appear to be improving, but more trials are needed (some of which are in progress). There is cause for optimism for physicians and for patients suffering from this condition.