TLS is characterized by several metabolic derangements that may be life-threatening.
It is caused by massive release of intracellular contents after tumor cell death. The nucleic acid products released result in hyperuricemia. The high concentration of uric acid can lead to crystallization within the renal tubules, resulting in obstruction of tubular flow and acute renal failure. The release of intracellular potassium, along with decreasing renal function, lead to hyperkalemia that may cause life-threatening arrhythmias. Increasing levels of phosphorus result in hypocalcemia and sometimes tetany, seizures, and arrhythmias.
It is most commonly seen after therapy for aggressive hematologic malignancies, such as high-grade lymphomas and acute leukemias. In addition, TLS may be seen after the treatment of kinetically active solid tumors and may occur spontaneously.
Every attempt should be made to anticipate and prevent TLS in patients at risk. The risk of TLS can be reduced by administering allopurinol
for 2 to 3 days before planned chemotherapy and by maintaining good hydration status. Patients at high risk, such as those with tumors of high proliferative rate, high baseline uric acid, large tumor burden, and chemosensitive disease, may benefit from intravenous recombinant urate oxidase (rasburicase
). Alkalinization of the urine has been recommended in the past, but usefulness remains controversial. Diuretics such as furosemide
can be used cautiously to increase urine output if the patient is not hypovolemic.
Patients with established TLS need hospital admission and may need cardiac monitoring. Aggressive treatment of hyperkalemia is indicated. Calcium gluconate and sodium bicarbonate should be used in addition to insulin, dextrose, and sodium polystyrene sulfonate (Kayexalate) in severe hyperkalemia associated with cardiac conduction disturbance. Dialysis is indicated in severe cases, including patients with oliguric renal failure, congestive heart failure, severe hyperkalemia, or patients who do not respond to medical therapy. Hypocalcemia should not be treated unless symptomatic.
Halfdanarson T, Hogan W, Moynihan T. Oncologic Emergencies: Diagnosis and treatment. Mayo Clin Proc 2006; 81(6): 835-848.