Acute renal failure in cancer patients*

Abstract

Acute renal failure (ARF) is an important complication in oncologic patients that will negatively affect their outcome. Although ARF is frequent in hospitalized patients, epidemiologic data on its impact on morbidity and mortality of the oncologic population is scarce. However, it is clear that ARF has the potential to alter the outcome of cancer patients and sometimes prevent them from receiving optimal treatment.ARF is defined as a sustained and abrupt decline, within hours to days, of the glomerular filtration rate (GFR). It usually alters extracellular volume status, electrolytes, and acid-base balance, and causes retention of nitrogen products released from protein catabolism. Until recently, there was no consensus on the definition of ARF. The Acute Dialysis Quality Initiative group (ADQI) and more recently the Acute Kidney Injury Network (AKIN) proposed the broader term AKI for acute kidney injury as well as the RIFLE (Risk-Injury-Failure-Loss-ESRD) criteria for acute renal dysfunction, defining injury as a doubling of baseline serum creatinine or a GFR decrease >50% and failure as a tripling of serum creatinine or GFR decrease >75%. Several studies have shown that the RIFLE system is directly related to outcomes in critically ill patients with acute kidney injury (AKI) (see Fig. 9.1 and Table 9.1).Renal failure in cancer patients is often multi-factorial; however, for diagnostic purposes and clinical management, the multiple causes of ARF are classified according to practical pathophysiology. Pre-renal causes represent the majority of cases of hospital-acquired ARF. The renal response to hypoperfusion is characterized by a fast and reversible rise in serum urea and creatinine. If the effective blood flow is rapidly restored, renal function returns to normal since the integrity of renal tissue is preserved. Intra-renal ARF occurs with pathologies affecting renal parenchyma. The spectrum of intrinsic renal diseases in the cancer population is broad and includes diseases of the renal vessels, glomeruli, and tubulo-intersitium. A frequent cause of intrinsic ARF is acute tubular necrosis secondary to renal hypoperfusion and/or toxins. Post-renal ARF is due to obstruction of the urinary tract usually distal to the bladder.While the general approach to ARF in cancer patients is not different from that used in relation to other patients, there are some particularities that will be specified in this chapter.