Tumor lysis syndrome (TLS) is a range of metabolic imbalances that occur after initiation of cancer treatment. It is a common side effect of treatment in patients suffering from bulky, rapidly proliferating and treatment-responsive tumors. Tumor lysis syndrome, therefore, frequently affects patients suffering from leukemia and lymphomas (e.g. Burkitt lymphoma). The syndrome may also affect individuals with solid tumors.
This syndrome develops due to death of numerous neoplastic cells, which release their previously intracellular ions and metabolic byproducts into the patient's blood. These substances and electrolytes are responsible for damage to many organs in the body. The most common issues include hyperkalemia, hyperphosphatemia, hypocalcemia and acute renal failure. Due to all the mentioned it is of great importance to identify patients at risk and provide them with preventive therapy or, in case this is not possible, to recognize the condition in early stage and treat it adequately.
What is the Damage?
Release of many different ions, electrolytes and byproducts is responsible for a variety of metabolic derangements. The first symptoms generally occur 48-72 hours after the treatment has started. One of the first metabolic imbalances is hyperkalemia. It, together with hyperphosphatemia, is directly connected with rapid tumor cell lysis. Hyperuricemia results from rapid release of nucleic acid purines and their metabolism into uric acid in the liver. Hypocalcemia is the complication that is closely connected to hyperhosphatemia.
Acute Renal Failure
Excess of uric acid may induce uric acid crystal formation in the kidneys. This is the leading cause of acute renal failure in patients suffering from tumor lysis syndrome. Renal failure can be additionally caused by acute nephrocalcinosis (precipitation of calcium phosphate crystals). Due to oliguria, patients further develop volume overload and subsequent hypertension and pulmonary edema. Pericarditis may result from high blood urea nitrogen. If renal failure is severe enough, patients must undergo dialysis.
This is another complication associated with tumor lysis syndrome. It develops as a consequence of rapid increase of the level of kalium in blood. There are specific EKG changes such as peaked T waves, flattened P waves and prolonged PR interval with widened QRS complexes, deep S wave and sine waves.
Acidemia is a complication closely related to acute renal failure. It results from a large amounts of endogenous intracellular acids released during tumor cell lysis. This complication can even get worse due to many electrolytes which have already been released during the process of lysis. Such patients require proper fluid management, alkalinization of the urine and prompt correction of acidosis.