How to assess kidney function in oncology patients.

Assessment of kidney function in oncology patients is a fundamental factor in profiling the survival risk, determining the appropriate dose of chemotherapeutic drugs, and defining a patient eligibility for clinical trials with novel agents. Both overestimation and underestimation of kidney function may affect the treatment efficacy and outcomes. Overestimation may lead to overdosing or inappropriate agent selection and the corresponding toxicity, whereas underestimation may be responsible for underdosing or inappropriate agent exclusion and subsequent treatment failure. This is of utmost importance in patients with cancer. Evaluation of kidney function is not only limited to the estimation of glomerular filtration rate or creatinine clearance. An accurate assessment of kidney function is advisable to reduce variability in decision making and ultimately the therapeutic outcomes of toxicity and clinical benefit. Therefore, additional studies are needed to investigate the validity of currently used formulas estimating kidney function in this population as well as their applicability to traditional chemotherapy, novel targeted therapies, and immunotherapies. Because of rapid discovery and development of new cancer agents, a reliable and comprehensive manner to screen for potential nephrotoxicity is critically important. As kidney function not only is limited to glomerular filtration rate changes but also involves tubular and even vascular dysfunction, urinalysis and kidney imaging studies should also be considered before therapeutic decisions are taken. However, several questions remain regarding these new technologies such as kidney-on-a-chip systems for the assessment of kidney function and injury, particularly in oncology, and it has yet to be implemented in clinical practice.