Tumor lysis syndrome

Tumor lysis syndrome (TLS) is an oncologic emergency caused by rapid breakdown of cancer cells and subsequent release of large amounts of intracellular content into the bloodstream.

The pathophysiologic manifestations of TLS can lead to acute kidney injury, cardiac arrhythmias, seizures, and neuromuscular dysfunction, which can cause considerable morbidity and in some cases death. TLS can compromise the clinical management of cancer patients.

Most commonly associated with highly proliferative, bulky, treatment-sensitive hematologic malignancies, particularly high-grade B-cell lymphoid malignancies (e.g., acute lymphoblastic leukemia and Burkitt lymphoma). Reports of TLS associated with other malignancies (including solid tumors) are increasing due to advances in cancer treatment.

Early identification of patients at risk of TLS and initiating appropriate preventive management is effective in most patients. Vigorous hydration and use of antihyperuricemic agents are the cornerstones of both prevention and treatment.

TLS is an oncologic emergency characterized by metabolic and electrolyte abnormalities that can occur after the initiation of any cancer treatment, but can also occur spontaneously.[1]Coiffier B, Altman A, Pui CH, et al. Guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review. J Clin Oncol. 2008 Jun 1;26(16):2767-78. http://www.ncbi.nlm.nih.gov/pubmed/18509186?tool=bestpractice.com It is caused by rapid breakdown of large numbers of cancer cells and subsequent release of large amounts of intracellular content (potassium, phosphate, nucleic acids) into the bloodstream, which overwhelms normal homeostatic mechanisms resulting in hyperuricemia, hyperphosphatemia, hyperkalemia, and/or hypocalcemia.

TLS can be classified as laboratory TLS (defined as the presence of two or more of the following metabolic abnormalities: hyperuricemia, hyperphosphatemia, hyperkalemia, or hypocalcemia) or clinical TLS (defined as laboratory TLS with one or more of the following clinical manifestations: acute kidney injury [i.e., increased serum creatinine], cardiac arrhythmia, seizure, or sudden death).