Treatment Side Effects - Tumor Lysis Syndrome (TLS)

Reviewed by: HU Medical Review Board | Last reviewed: February 2018

Tumor lysis syndrome is a potentially serious condition that can occur with treatment of fast-growing blood cancers, including certain leukemias and lymphomas. As the cancer cells die from exposure to chemotherapy, they release substances that can overwhelm the kidneys, whose function is to filter these substances from the blood and pass them into urine. Tumor lysis syndrome can cause high levels of uric acid (hyperuricemia), potassium (hyperkalemia), and phosphate (hyperphosphatemia), or cause low levels of calcium (hypocalcemia). If not treated, the change in these chemicals in the blood can cause damage to the kidneys or other organs.1,2

Tumor lysis syndrome most often occurs at the beginning of treatment with chemotherapy, usually 48-72 hours after treatment has been given. This is a time when large numbers of cancer cells are destroyed. Because tumor lysis syndrome can cause irreversible damage or even death if not treated, doctors focus on identifying those patients who may be at high-risk for developing the condition, attempting to prevent tumor lysis syndrome if possible, and early recognition of the symptoms to promptly provide treatment.2,3

Who's at risk for tumor lysis syndrome?

People with certain blood cancers have an increased risk of developing tumor lysis syndrome, including:

In addition, people with poor kidney function prior to chemotherapy are generally at an increased risk of developing tumor lysis syndrome.2,3

Preventing tumor lysis syndrome

Patients who are at high risk for tumor lysis syndrome should be monitored for signs and symptoms of the condition, and they may also have blood tests to monitor the level of the different chemicals in the blood. Hydration is one of the best ways to prevent tumor lysis syndrome, and patients who are at high risk may be given fluids through an intravenous (IV) line 24-48 hours before chemotherapy begins, as well as several days after chemotherapy. Urine output (the amount of urine that is passed from the body) will also be monitored.2,4


If tumor lysis syndrome does develop, prompt treatment is important to protect the organs like the heart and kidneys from permanent damage. Tumor lysis syndrome is serious and can cause death if not treated. Report any of these signs or symptoms to a healthcare professional:

  • Nausea
  • Vomiting
  • Diarrhea
  • Muscle cramps or twitches
  • Fatigue or weakness
  • Numbness or tingling
  • Less urination than usual
  • Irregular heartbeat
  • Confusion
  • Irritability
  • Restlessness
  • Hallucinations
  • Seizures2

Symptoms of tumor lysis syndrome may begin in a mild fashion and worsen quickly as the cancer cells die off due to the chemotherapy.2

Diagnosis of tumor lysis syndrome

A diagnosis of tumor lysis syndrome is made through an evaluation of symptoms, blood tests (complete blood count and blood chemistry labs), and a urinalysis. These tests may be repeated as treatment for tumor lysis syndrome is given to monitor the levels of chemicals in the blood, as well as monitoring function of organs like the liver and kidneys.2,4

Treating tumor lysis syndrome

Treatment for tumor lysis syndrome includes hydration, which will typically be given as IV fluids, and medications, such as allopurinol (brand names Zyloprim® or Aloprim®) that stops the body from making uric acid, or rasburicase (brand name Elitek™), which breaks down uric acid.2,4

If kidney function worsens or the kidneys fail, dialysis may be used. Dialysis is a process to filter the waste materials from the blood by machine if the kidneys are not functioning.2

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