Hyponatremia is the most frequently observed electrolyte abnormality in clinical practice, and its frequency is almost double in hospitalized cancer patients. As a subset of cancer, hyponatremia is quite common in lung cancer patients, and it is often coupled with the diagnosis of syndrome of inappropriate antidiuretic hormone secretion. The presence of hyponatremia is consequential in that its presence adversely affects cancer patients' prognosis and outcomes. Limited data suggest that correcting hyponatremia in lung cancer patients can increase response to anticancer treatment, may help reduce length of hospital stay and cost, and reduce morbidity and mortality. The type of treatment for hyponatremia depends on several factors; the key factors are the duration and severity of neurological symptoms of hyponatremia and the status of extracellular volume. When hyponatremia is caused by syndrome of inappropriate antidiuretic hormone, hypertonic saline is indicated for acute symptomatic cases, whereas fluid restriction is recommended in chronic asymptomatic hyponatremia. The latter allows a slower rate of correction, thus avoiding the dreaded complication of osmotic demyelination syndrome. Fluid restriction is, however, insufficient or impractical, and often the use of pharmacological therapy such as antidiuretic hormone receptor antagonists becomes necessary. Availability of these antagonists as an effective treatment in the management of hyponatremia has been a major breakthrough, and furthermore, its clinical or investigational use in cancer-related hyponatremia may offer a potential opportunity to gain further insights into the prognostic impact of hyponatremia correction on cancer patients' outcomes. Tolvaptan is a prototype of ADH receptor antagonists that acts at renal tubular levels to increase free water excretion without inducing major systemic electrolyte abnormalities such as hypokalemia or alkalosis. The aim of this paper is to provide a brief review while focusing on cancer hyponatremia; (1) of the epidemiology of hyponatremia and its pathophysiology and diagnostic approaches and (2) of the pharmacokinetics of tolvaptan and its clinical efficacy, safety, and compliance.

Erythropoietin (EPO) is used at present in clinical practice to stimulate red cell production. However, a number of reports have emerged suggesting the presence of nonerythropoietic properties for EPO. Chief among them is its ability to confer protection against acute tissue injury. In this report, we briefly review the role of EPO in tissue protection and provide examples of tissue protection using cisplatin-induced kidney injury model. Also provided is a brief description of potential pathways through which EPO may be mediating this effect.

Background

Several biomarkers are becoming available for the early detection of acute kidney injury (AKI), but few have been directly compared.

Objective

To compare urinary kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and N-acetyl glucosaminidase (NAG) against serum creatinine and renal histological score in the initiation, maintenance, and recovery phases of cisplatin (CP)-induced AKI.

Methods

Sprague-Dawley rats (300-350 g) were injected once through their tail veins with CP (CP group) at 5.5 mg/kg or with same volume of normal saline vehicle (Control group). Rats were euthanized at 2, 4, 6, 12, and 24 hours, and on days 2, 3, 6, and 10 (n = 12 in the CP group and n = 6 in the Control group at each time point), and urine, blood, and kidney samples were analyzed.

Results

A significant increase in serum creatinine was noted by day 3 in the CP group versus Control group [1.46 (0.12) vs 0.28 (0.03) mg/dL; mean (SE); P < 0.05]. The renal histology scores for brush border loss and tubular necrosis were significantly higher at 12 and 24 hours, respectively, in the CP group. Urinary kidney injury molecule-1 levels were significantly higher at 24 hours in the CP group than in the Control group [48.26 (13.13) vs 8.21 (3.31) pg/mg creatinine; P < 0.05] and remained elevated through day 10. Both urine NAG and NGAL levels were significantly higher by day 2 in the CP than in the Control group [NAG, 8.19 (0.82) vs 3.48 (0.40) pg/mg creatinine, P G 0.05; NGAL, 2911.80 (368.10) vs 1412.60 (250.20) pg/mg creatinine, P < 0.05]. Urinary NAG remained elevated for 6 days and NGAL for 3 days.

Conclusions

Our study suggests a temporal hierarchy in the ability of certain urinary protein-based biomarkers to detect AKI after a well-defined tubular injury. Comparative analyses of urinary biomarkers are warranted in clinical settings such as patients receiving CP to discern the time course and pattern of expression.

Background

The use of rasburicase has been evaluated extensively in children, but not in adults. We review the current literature to evaluate its effect on adults.

Study design

Systematic review and meta-analysis.

Setting & population

Adults receiving rasburicase for tumor lysis syndrome (TLS).

Selection criteria for studies

Electronic databases, regulatory documents, and websites were searched up to August 7, 2012. Reference lists of published articles were examined for additional relevant references. Any controlled trial or observational studies (controlled before and after) were included. Studies considering children only or mixing data for children and adults were excluded.

Intervention

Rasburicase for TLS.

Outcomes

The primary outcome was TLS development. Secondary outcomes included percentage of patients improving, total adverse events, acute kidney failure, deaths, and serum uric acid and creatinine levels.

Results

21 studies (24 publications) reported data for 1,261 adult patients, 768 receiving rasburicase for either the treatment or prophylaxis of TLS; these comprised 4 controlled trials and 17 observational studies. No statistically significant differences in clinical TLS development were observed in the controlled trials between the rasburicase and control groups. For the observational studies, 7.4% of patients developed clinical TLS after rasburicase (95% CI, 1.7%-16.7%), 93.4% of patients achieved normalized serum uric acid levels after rasburicase treatment (95% CI, 91.7%-94.6%), 4.4% developed acute kidney injury (95% CI, 3.0%-6.0%), and 2.6% died (95% CI, 0.95%-5.0%). The mean reduction in serum uric acid levels ranged from 5.3-12.8 mg/dL, and for serum creatinine levels, from 0.10-2.1 mg/dL.

Limitations

Controlled trials differed in outcomes reported; meta-analysis was not performed.

Conclusions

Rasburicase is effective in reducing serum uric acid levels in adults with TLS but at a significant cost, and evidence currently is lacking in adults to report whether rasburicase use improves clinical outcomes compared with other alternatives. Until new evidence is available, use of rasburicase may be limited to adult patients with a high risk of TLS.

Background and objectives

Incidence of AKI in hospitalized patients with cancer is increasing, but reports are scant. The objective of this study was to determine incidence rate, clinical correlates, and outcomes of AKI in patients admitted to a cancer center.

Design, setting, participants, & measurements

Cross-sectional analysis of prospectively collected data on 3558 patients admitted to the University of Texas M.D. Anderson Cancer Center over 3 months in 2006.

Results

Using modified RIFLE (Risk, Injury, Failure, Loss, ESRD) criteria, 12% of patients admitted to the hospital had AKI, with severity in the Risk, Injury, and Failure categories of 68%, 21%, and 11%, respectively. AKI occurred in 45% of patients during the first 2 days and in 55% thereafter. Dialysis was required in 4% of patients and nephrology consultation in 10%. In the multivariate model, the odds ratio (OR) for developing AKI was significantly higher for diabetes (OR, 1.89; 95% confidence interval [CI], 1.51-2.36), chemotherapy (OR, 1.61; 95% CI, 1.26-2.05), intravenous contrast (OR, 4.55; 95% CI, 3.51-5.89), hyponatremia (OR, 1.97; 95% CI, 1.57-2.47), and antibiotics (OR, 1.52; 95% CI, 1.15-2.02). In patients with AKI, length of stay (100%), cost (106%), and odds for mortality (4.7-fold) were significantly greater.

Conclusion

The rate of AKI in patients admitted to a comprehensive cancer center was higher than the rate in most noncancer settings; was correlated significantly with diabetes, hyponatremia, intravenous contrast, chemotherapy, and antibiotics; and was associated with poorer clinical outcomes. AKI developed in many patients after admission. Studies are warranted to determine whether proactive measures may limit AKI and improve outcomes.

Purpose

Declining kidney function has been associated with adverse hospital outcome in cancer patients. ICU literature suggests that small changes in serum creatinine are associated with poor outcome. We hypothesized that reductions in renal function previously considered trivial would predict a poor outcome in critically ill patients with malignant disease. We evaluated the effects on hospital mortality and ICU length of stay of small changes in creatinine following admission to the intensive care unit.

Methods

We conducted a retrospective cohort study utilizing clinical, laboratory and pharmacy data collected from 3,795 patients admitted to the University of Texas M.D. Anderson Cancer Center's Intensive Care Unit. We conducted univariate and multivariate regression analysis to determine those factors associated with adverse ICU and hospital outcome.

Results

Increases in creatinine as small as 10% (0.2 mg/dl) were associated with prolonged ICU stay (5 days vs 6.6 days, p < 0.001) and increased mortality (14.6% vs 25.5%, p < 0.0001). Patients with a 25% rise in creatinine during the first 72 h of ICU admission were twice as likely to die in the hospital (14.3% vs 30.1%, p < 0.001). RIFLE criteria were accurate predictors of outcome, though they missed much of the risk of even smaller increases in creatinine.

Conclusions

Even small rises in serum creatinine following admission to the ICU are associated with increased morbidity and mortality in oncologic patients. The poor outcome in those with rising creatinine could not be explained by severity of illness or other risk factors. These small changes in creatinine may not be trivial, and should be regarded as evidence of a decline in an individual patient's condition.

Background

The rate of hyponatremia is higher in hospitalized cancer patients than in hospitalized patients without cancer and is associated with poor clinical outcomes. The availability of V2 receptor antagonists has been a major breakthrough in the management of hyponatremia, but its efficacy and safety in treating hyponatremia in patients with cancer is not known.

Methods

Adult patients with cancer who were admitted to The University of Texas MD Anderson Cancer Center with nonhypovolemic hyponatremia (125-130 mmol/L) were randomized to receive either tolvaptan or placebo in a double-blind, placebo-controlled, adaptive, randomized trial. Both groups received the standard of care for hyponatremia, except that patients were allowed to drink to thirst.

Results

A preplanned Data Safety Monitoring Board analysis of 30 of 48 randomized patients who completed the study revealed that the primary endpoint of hyponatremia correction was met by 16 of 17 patients who received tolvaptan and by 1 of 13 patients who received placebo (94% vs 8%; P < .001), which met the study stopping rule for superiority. The secondary endpoints between the tolvaptan and placebo groups (mean ± standard deviation) for length of stay (21 ± 15 days vs 26 ± 15 days, respectively) and change in the Mini-Mental State Examination score (-0.35 ± 1.66 vs 0.31 ± 2.42, respectively) were not significantly different. No overcorrection of serum sodium (>12 mmol/L per day) was noted in the tolvaptan group, and the main adverse events noted were dry mouth, polydipsia, and polyuria, leading to 13% study withdrawal.

Conclusions

Although tolvaptan was effective for correcting hyponatremia in patients with cancer, studies with a larger sample size will be required to confirm the current findings, including the outcomes of secondary endpoints.

Background

Hyponatremia is the most common electrolyte abnormality in clinical practice, yet little is known about its frequency in patients with cancer or its impact on their clinical outcomes.

Study design

Retrospective analysis of prospectively collected data.

Setting & participants

Patients with cancer admitted to the University of Texas M.D. Anderson Cancer Center in 2006 for 3 months.

Predictor

Serum sodium levels categorized as eunatremia (serum sodium, 135-147 mEq/L) and mild (134-130 mEq/L), moderate (129-120 mEq/L), and severe (<120 mEq/L) hyponatremia.

Outcomes

(1) Length of hospital stay and (2) 90-day mortality.

Results

In 4,702 admissions in 3,357 patients with cancer, hyponatremia (serum sodium <135 mEq/L) was noted in 47% of admissions. It was mild in 36%, moderate in 10%, and severe in 1%. Hyponatremia was acquired during the hospital stay in 24%. Using the first admission data, mean length of stay was 5.6 ± 5.0 days for patients with eunatremia and 9.9 ± 9.2, 13.0 ± 14.1, and 11.5 ± 12.6 days for those with mild, moderate, and severe hyponatremia, respectively. The respective HRs in the multivariate Cox model for longer hospital stay, using patients with eunatremia as reference, were 1.92 (95% CI, 1.75-2.13; P < 0.01), 2.94 (95% CI, 2.56-3.45; P < 0.01), and 2.32 (95% CI, 1.32-4.00; P = 0.01). 283 (8.4%) deaths occurred during 90 days, and in the multivariate model, the respective HRs for 90-day mortality for mild, moderate, and severe hyponatremia were 2.04 (95% CI, 1.42-2.91; P < 0.01); 4.74 (95% CI, 3.21-7.01; P < 0.01), and 3.46 (95% CI, 1.05-11.44; P = 0.04). These findings were consistent when analyses were repeated with sodium levels in tertiles.

Limitations

Observational study, retrospective, inability to adjust for all comorbid conditions.

Conclusion

Hyponatremia in patients with cancer is associated with longer hospital stay and higher mortality. Whether long-term correction of hyponatremia would improve these outcomes remains to be determined.