Tumour lysis syndrome (TLS) is a problem that can occur because of a rapid breakdown of cancer cells when chemotherapy is given. It may occur at the start of treatment when a large number of tumour cells are destroyed. It can occur within 6–72 hours after chemotherapy is started and last for 5–7 days.
When cancer cells are destroyed, they break down and release substances into the blood. This can lead to:
- high levels of uric acid (hyperuricemia), potassium (hyperkalemia) and phosphate (hyperphosphatemia)
- low levels of calcium (hypocalcemia)
Organs affected
If TLS is not controlled, it can cause problems in the:
- kidneys
- uric acid build-up can cause kidney stones and damage the kidneys
- increased phosphate levels can lead to kidney damage and failure
- joints
- uric acid can become deposited in the joints causing a painful, gout-like condition
- heart
- abnormal levels of potassium and calcium can affect heart rhythm
- brain (nervous system)
- abnormal levels of potassium and calcium can lead to neurological and mental status changes
Causes
Tumour lysis syndrome does not occur with all chemotherapy treatments. It is most likely to occur in:
- acute leukemia – more so than chronic leukemia
- aggressive (high grade) lymphomas
TLS can also occur with any cancer treatment that causes cancer cells to be destroyed rapidly, but this is rare.
Symptoms
Symptoms of TLS may be mild at first, but become more severe as abnormal levels of substances in the blood increase. Symptoms can include:
- fatigue
- nausea
- vomiting
- diarrhea
- muscle weakness and cramps
- cloudy urine
- decreased urination
- changes in heart rate
- restlessness
- irritability
- numbness or tingling and muscle irritability
Diagnosis
The doctor will monitor:
Prevention and treatment
Measures can be taken to prevent TLS,before cancer treatment is started and can include:
- extra fluids to keep the person well-hydrated and increase urine production
- intravenous fluids to get rid of uric acid from the body
- a drug called allopurinol (Zyloprim) toreduce the levels of uric acid in the body
- sodium bicarbonate (taken as pills or given through the intravenous) to keep uric acid from forming into crystals, so it can be easily removed by the kidneys
The doctor also monitors blood tests and checks for signs and symptoms of TLS throughout chemotherapy. If serious side effects do occur, chemotherapy may have to be temporarily reduced or stopped.