Tumor Lysis Syndrome

Author: Marisa Healy, BSN, RN
Content Contributor: Katherine Okonak, MSW, LSW
Last Reviewed: January 25, 2024

What is tumor lysis syndrome (TLS)?

Tumor lysis syndrome (TLS) is when cells in your body break down too quickly causing chemicals and electrolytes in your body to get out of balance. TLS can be caused by cancer or its treatments. TLS is an emergency and needs to be treated right away. 

Chemotherapy and radiation therapy break down and kill cancer cells, as well as some healthy cells. Your kidneys are not always able to process the quick breakdown of these cells and the release of the cell’s contents into your bloodstream. The result is an imbalance of electrolytes, which could cause:

  • Hyperuricemia – High levels of uric acid in your blood. Uric acid is a chemical created when the body breaks down purine. Purine is found in foods and drinks like liver, anchovies, dried beans, and beer. Uric acid is dissolved in the blood, travels to the kidneys, and then leaves the body through urine. You may have no symptoms, but possible symptoms are gout (inflammation of a joint) and kidney stones.
  • Hyperkalemia – High levels of potassium in your blood. Potassium is needed for cells to work normally, which helps nerves and muscles communicate. Most people get all the potassium their body needs by eating foods like bananas, oranges, and green leafy vegetables. Potassium leaves the body through urine. You may have no symptoms, but possible symptoms are muscle weakness, chest pain, and heart palpitations.
  • Hyperphosphatemia – High levels of phosphate in your blood. Phosphate makes energy in the body. It also helps muscles and nerves work, supports bone growth, and keeps the acid-base level in your body balanced. It enters your body through food. It leaves the body through urine. There are no symptoms of hyperphosphatemia.
  • Hypocalcemia – Low levels of calcium in your blood. Calcium is a mineral used for cell signaling (how cells communicate and respond), and helps your muscles, nerves, and heart work. It is also needed for blood clotting and bone maintenance and formation. Calcium leaves the body through urine. Signs and symptoms of hypocalcemia are muscle twitching, numbness and tingling of fingers and toes, and confusion.

When these minerals and electrolytes leave the dying cells too quickly, your body cannot keep up. TLS can cause kidney failure, seizures, problems with your heart rhythm (cardiac dysrhythmias), and if not quickly treated, death.

Other symptoms you could have are:

  • Nausea and vomiting.
  • Diarrhea.
  • Feeling more tired than usual.
  • Changes in how much you urinate (pee) or blood in your urine (hematuria).
  • Low blood pressure.

Talk with your provider right away if you have any of these symptoms.

How is TLS treated?

If you are at high risk for TLS, you will receive treatment to try to prevent it. You will be watched closely during treatment, with frequent blood tests and your urine will be measured. You are at high risk for TLS if you have a large tumor volume (many cancer cells in your body). Large tumor volume happens mostly with lymphomas or leukemias when white blood cell counts are high. If you are at high risk, your chemotherapy will be given in the hospital so that you can be closely watched. To prevent TLS, you may receive:

  • Intravenous (IV) Hydration – Fluid is given through an IV. The goal of IV hydration is to improve renal perfusion (the movement of fluid through the kidneys). The more you urinate, the less uric acid and calcium phosphate can build up in your kidneys. Your provider will make sure you aren’t given too much fluid.
  • Hypouricemic Medication – These medications cause your body to make less uric acid, which prevents hyperuricemia. Allopurinol and rasburicase are the two most common medications used.

Even with these steps to prevent it, some patients still develop TLS. Treatment of TLS includes:

  • Heart and lab value monitoring.
  • Treating electrolyte changes with medications.
  • The use of medications like allopurinol or rasburicase.
  • Kidney dialysis if needed. Dialysis is a treatment where your blood is filtered through a machine and returned to the body, carrying out the filtering action of the kidneys.

When should I call my care team?

If you are having signs and symptoms of hyperuricemia, hyperkalemia, hyperphosphatemia, or hypocalcemia as listed above, you should call your care provider right away.

Calvo Villas JM. Tumour lysis syndrome. Med Clin (Barc). 2019 May 17;152(10):397-404. English, Spanish. doi: 10.1016/j.medcli.2018.10.029. Epub 2019 Jan 3. PMID: 30612747. https://pubmed.ncbi.nlm.nih.gov/30612747/  

Howard, S. C., Jones, D. P., & Pui, C. H. (2011). The tumor lysis syndrome. The New England journal of medicine364(19), 1844–1854. https://doi.org/10.1056/NEJMra0904569

Cleveland Clinic. Tumor Lysis Syndrome. 2022,

Canadian Cancer Society. Tumor lysis syndrome. Retrieved 2024.

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