Tumor Lysis Syndrome
Summary of Key Points
• Tumor lysis syndrome can occur in any patient with newly diagnosed or relapsed cancer, and thus all patients should undergo risk stratification and management according to their risk for clinical tumor lysis syndrome.
• Laboratory tumor lysis syndrome is defined as the presence of two or more of the following abnormalities present on the same day: hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia as a result of hyperphosphatemia.
• Clinical tumor lysis syndrome is defined as laboratory tumor lysis syndrome plus acute kidney injury, symptomatic hyperkalemia, or symptomatic hypocalcemia, and it should be prevented whenever possible.
• The incidence of clinical tumor lysis syndrome depends on the number of risk factors present at presentation and on the management of patients potentially at risk.
• Risk factors for clinical tumor lysis syndrome include a large cancer mass, high cell lysis potential (chemosensitivity), and patient factors (e.g., preexisting nephropathy, dehydration, acidosis, hypotension, and nephrotoxin exposure).
• Management depends on the risk of the development of clinical tumor lysis syndrome:
1. Which of the following is the most important treatment for patients with laboratory tumor lysis syndrome?
2. Why do clinicians sometimes alkalinize the urine in patients with newly diagnosed leukemia or lymphoma?
3. Which of the following is not a risk factor for clinical tumor lysis syndrome?
4. The severity of clinical tumor lysis syndrome is graded on the basis of which of the following?
1. Answer: A. Although all of these treatments are potentially useful for patients who have tumor lysis syndrome or are at risk of its development, hyperhydration is the most important because it improves renal blood flow and urine output. Increased urine output decreases the urinary concentrations of uric acid, phosphorus, and calcium and thus reduces the risk of crystal formation and acute kidney injury.
2. Answer: B. Although bicarbonate does indeed stabilize the myocardium and move potassium to the intracellular compartment, the primary reason for alkalinization at diagnosis is to make uric acid more soluble, which is particularly important in countries in which rasburicase is not available to remove uric acid enzymatically.
3. Answer: C. Risk factors for clinical tumor lysis syndrome include hyperuricemia, oliguria, bulky cancers, and chemosensitive cancers, but not male sex.
4. Answer: E. According to the Cairo-Bishop grading system, the grade of clinical tumor lysis syndrome is determined by the maximum grade of associated clinical symptoms. For example, if a patient with tumor lysis syndrome has grade 3 acute kidney injury and grade 4 hypocalcemic seizures, the tumor lysis syndrome would be considered a grade 4 toxicity.
