Tumor Lysis Syndrome
A dangerous surge of chemicals released when many cancer cells die at once
Quick Facts
- Type: Oncologic emergency
- When it occurs: Often soon after starting cancer treatment
- Key disturbances: High potassium, phosphate, uric acid; low calcium
- Seek urgent care: It can be life-threatening and needs hospital care
Overview
Tumor lysis syndrome (TLS) is a medical emergency that happens when a large number of cancer cells die and break apart rapidly, spilling their internal contents into the bloodstream faster than the kidneys can clear them. This flood of substances disturbs the body's chemistry and can damage the kidneys, heart, and other organs.
TLS most often develops within hours to a few days after starting cancer treatment such as chemotherapy, but it can occasionally occur on its own in fast-growing cancers. It is most associated with blood cancers that have a high cell turnover, such as certain leukemias and lymphomas. Because it can be life-threatening, prevention and prompt recognition are critical, and high-risk patients are monitored closely.
Symptoms
Symptoms result from the chemical imbalances and can come on quickly. They include:
- Nausea, vomiting, and loss of appetite
- Weakness, fatigue, and muscle cramps
- Tingling or numbness
- Irregular or rapid heartbeat and palpitations
- Reduced urination or signs of kidney trouble
- Confusion, seizures, or fainting in severe cases
Some abnormalities, especially dangerous changes in potassium and calcium, can affect the heart rhythm without obvious warning, which is why blood tests and monitoring are essential. TLS is treated as an emergency.
Causes
TLS occurs when dying cancer cells release large amounts of substances normally found inside cells:
- Potassium: Released in high amounts, it can cause dangerous heart rhythm problems.
- Phosphate: Excess phosphate binds calcium, lowering blood calcium and forming deposits that can harm the kidneys.
- Uric acid: Produced as cell genetic material breaks down, it can crystallize in the kidneys and impair their function.
The most common trigger is the start of effective cancer treatment, such as chemotherapy, which kills many cells at once. Large, fast-growing, or treatment-sensitive cancers are most likely to cause it.
Risk Factors
- Blood cancers with high cell turnover, such as acute leukemias and aggressive lymphomas
- A large tumor burden or widespread disease
- Cancers very sensitive to chemotherapy
- Pre-existing kidney problems or dehydration
- High uric acid levels before treatment
- Starting or intensifying cancer therapy
Diagnosis
TLS is diagnosed mainly through blood tests, often performed routinely in at-risk patients around the time of treatment:
- Blood chemistry panel: Measures potassium, phosphate, calcium, and uric acid; characteristic patterns confirm the syndrome.
- Kidney function tests: Such as creatinine, to detect kidney injury.
- Electrocardiogram (ECG): To check for heart rhythm changes from abnormal potassium and calcium.
- Urine output monitoring: To track kidney function.
Established criteria help doctors classify TLS based on these laboratory and clinical findings.
Treatment
TLS is managed in the hospital, often with close monitoring. Treatment focuses on protecting the kidneys and heart and correcting the chemical imbalances:
- Intravenous fluids: Aggressive hydration helps the kidneys flush out uric acid and other substances.
- Uric acid-lowering medicines: Drugs that reduce or break down uric acid lower the risk of kidney damage.
- Correcting electrolytes: Treatments to lower dangerous potassium and phosphate and to manage low calcium.
- Cardiac monitoring: To catch and treat rhythm disturbances.
- Dialysis: Used when the kidneys cannot keep up or imbalances become severe.
For high-risk patients, doctors take preventive steps before treatment, including hydration and uric acid-lowering medicine, to reduce the chance of TLS developing.
Prevention
- Identifying high-risk patients before cancer treatment begins
- Giving intravenous fluids to keep the kidneys flushing well
- Starting uric acid-lowering medication before or with treatment
- Frequent blood tests and heart monitoring during the highest-risk period
- Adjusting the pace of treatment in very high-risk situations
When to See a Doctor
If you are receiving cancer treatment, tell your care team right away about new nausea, muscle cramps, weakness, reduced urination, palpitations, or numbness. Seek emergency care immediately for an irregular or racing heartbeat, fainting, seizures, confusion, or severe weakness, because TLS can rapidly become life-threatening and needs urgent hospital treatment.
Frequently Asked Questions
What causes tumor lysis syndrome?
It is caused by the rapid breakdown of a large number of cancer cells, which release potassium, phosphate, and uric acid into the blood faster than the kidneys can remove them. It most often follows the start of cancer treatment such as chemotherapy.
Is tumor lysis syndrome dangerous?
Yes. It is a medical emergency that can cause kidney failure, dangerous heart rhythms, seizures, and death if not treated promptly. This is why high-risk patients are monitored closely and treated preventively.
Can tumor lysis syndrome be prevented?
Often, yes. In high-risk patients, doctors give intravenous fluids, start uric acid-lowering medication before treatment, and monitor blood tests frequently to prevent or catch TLS early.
Which cancers are most likely to cause it?
Fast-growing blood cancers with a high tumor burden, such as acute leukemias and aggressive lymphomas, carry the greatest risk, especially when they respond strongly to chemotherapy.
How is tumor lysis syndrome treated?
Treatment is given in the hospital and includes intravenous fluids, medicines to lower uric acid and correct electrolyte imbalances, heart monitoring, and dialysis if the kidneys cannot cope or imbalances are severe.
References
- National Cancer Institute (NCI). Tumor lysis syndrome.
- MedlinePlus, U.S. National Library of Medicine. Tumor lysis syndrome.
- Cleveland Clinic. Tumor lysis syndrome.
- American Society of Clinical Oncology (ASCO). Side effects of cancer treatment.