Onco-Nephrology: An Invitation to a New Field

TO THE EDITOR: Kidney disease is common in patients with cancer and includes disorders that occur in people without cancer as well as entities that are unique to people with cancer, such as tumor lysis syndrome. However, as the field of oncology hasdevelopedareasofincreasingsubspecializationandthearrayof treatment options with novel agents has expanded, the need has been created for a new field: onco-nephrology. Such a necessity resultsfromseveralfactors.First,certainrenaldisordersareunique to patients with cancer, related either to therapy or the malignancy itself. Paraneoplastic glomerulonephritis, posthematopoietic stem-cell transplantation microangiopathy and sinusoidal obstruction syndrome, and kidney injury from graft-versus-host disease are prime examples. Therefore, it is a requirement that nephrologistsbeknowledgeableabouttheseuniquedisorders.Second, many patients with cancer are now cared for at comprehensive cancer centers where nephrologists have become integral members of treatment teams. Nephrologists must provide expertiseintheevaluationandmanagementofacuteandchronickidney disease, fluid and electrolyte disorders, and the use of various extracorporeal therapies in patients with cancer. Third, the presence of acute and chronic kidney disease in patients with cancer can adversely affect treatment and outcome. Patients with cancer are at increased risk of developing acute kidney injury (AKI) 1 ; survival rates are significantly lower in patients with cancer and AKI compared with patients with similar disease severity who do not have cancer. 2 In patients with chronic kidney disease (CKD), therapeutic doses may need to be reduced (thus decreasing the so-called killing effect), or some promising agents may need to be omitted altogether. Fourth, given that the prevalence of both cancer and CKD are high, a growing number of patients require the expertise of onco-nephrologists, who must be knowledgeable about the array of new chemotherapeutic agents and their potential effects on kidney function. The hypertension, CKD, and proteinuria that are associated with the use of antivascular endothelial growth factor (anti-VEGF) agents are examples. 3 Onconephrology in general, and the effects of anti-VEGF agents in particular, provide fertile ground for both clinical and basic research. Understanding the effects of anti-VEGF therapy has led to more insight into the function of the glomerular filter and the pathogenesis of preeclampsia. Onco-nephrologists must also be awareoftheeffectsofvariousdialyticmodalitiesondrugclearance.