What is tumor lysis syndrome?
The goal of cancer treatment is to destroy tumors. When cancerous tumors break down very quickly, your kidneys have to work extra hard to remove all the substances that were in those tumors. If they can’t keep up, you can develop something called tumor lysis syndrome (TLS).
This syndrome is most common in people with blood-related cancers, including some leukemias and lymphomas. It generally happens within a few hours to several days after a first chemotherapy treatment.
TLS is uncommon, but it can quickly become life threatening. It’s important to know how to recognize it so you can seek immediate treatment.
What are the symptoms?
TLS increases the amounts of several substances in your blood, which can cause a range of symptoms.
These substances include:
- Potassium. High levels of potassium can lead to neurological changes and heart problems.
- Uric acid. Excess uric acid (hyperuricemia) can cause kidney stones and kidney damage. You can also develop uric acid deposits in your joints, which causes a painful condition similar to gout.
- Phosphate. A buildup of phosphate can lead to kidney failure.
- Calcium. Too much phosphate can also cause calcium levels to drop, possibly leading to acute kidney failure.
While the symptoms of TLS are usually mild in the beginning, as the substances build up in your blood, you might experience:
- restlessness, irritability
- weakness, fatigue
- numbness, tingling
- nausea, vomiting
- muscle cramping
- joint pain
- decreased urination, cloudy urine
If left untreated, TLS can eventually lead to more severe symptoms, including:
Why does it happen?
While TLS sometimes happens on its own before cancer treatment., this is very rare. In most cases, it happens shortly after chemotherapy begins.
Chemotherapy involves medications that are designed to attack tumors. As tumors break down, they release their contents into the blood stream. Most of the time, your kidneys can filter out these substances without any problems.
However, sometimes tumors break down faster than your kidneys can handle. This makes it harder for your kidneys to filter out the contents of the tumor from your blood.
Most of the time, this happens soon after your first chemotherapy treatment, when a large number of cancer cells are destroyed in a relatively short amount of time. It can also happen later in treatment.
In addition to chemotherapy, TLS is also linked to:
Are there any risk factors?
There are several things that can increase your risk of developing TLS, including the type of cancer you have. Cancers commonly associated with TLS include:
- non-Hodgkin's lymphoma
- myeloproliferative neoplasms, such as myelofibrosis
- blastomas in the liver or brain
- cancers that affect kidney function before treatment
Other potential risk factors include:
- large tumor size
- poor kidney function
- fast-growing tumors
- certain chemotherapy medications, including cisplatin, cytarabine, etoposide, and paclitaxel
How is it diagnosed?
If you are undergoing chemotherapy and have any risk factors for TLS, your doctor will perform regular blood and urine tests in the 24 hours immediately after your first treatment. This allows them to check for any signs that your kidneys aren’t filtering everything out.
The types of tests they use include:
- blood urea nitrogen
- complete blood cell count
- lactate dehydrogenase
- serum electrolytes
- uric acid
There are two sets of criteria doctors can use to diagnose TLS:
- Cairo-Bishop criteria. Blood tests must show at least a 25 percent increase in the levels of certain substances.
- Howard criteria. Laboratory results must show two or more unusual measurements within a 24-hour period.
How is it treated?
To treat TLS, your doctor will likely start by giving you some intravenous (IV) fluids while monitoring how often you urinate. If you’re not producing enough urine, you doctor might also give you diuretics.
Other medications you might need include:
- allopurinol (Aloprim, Lopurin, Zyloprim) to stop your body from making uric acid
- rasburicase (Elitek, Fasturtec) to break down uric acid
- sodium bicarbonate or acetazolamide (Diamox Sequels) to prevent uric acid from forming crystals
There are also two newer types of medications that may help as well:
- oral kinase inhibitors, such as ibrutinib (Imbruvica) and idelalisib (Zydelig)
- B-cell lymphoma-2 protein inhibitors, such as venetoclax (Venclexta)
If fluids and medications don’t help or your kidney function continues to decline, you may need kidney dialysis. This is a type of treatment that helps to remove waste, including that from destroyed tumors, from your blood.
Is it preventable?
Not everyone undergoing chemotherapy develops TLS. In addition, doctors have clearly identified important risk factors and usually know who has a higher risk.
If you have any of the risk factors, your doctor may decide to start giving you extra IV fluids two days before your first chemotherapy treatment. They’ll monitor your urine output over the next two days and give you a diuretic if you’re not producing enough.
You can also start taking allopurinol at the same time to prevent your body from making uric acid.
These measures can continue for two or three days after the chemotherapy session, but your doctor might continue to monitor your blood and urine throughout the rest of your treatment.
What’s the outlook?
The overall risk of developing TLS is low. However, when people do develop it, it can cause serious complications, including death. If you’re due to start cancer treatment, ask about your TLS risk factors and whether your doctor recommends any preventive treatment.
You should also make sure you’re aware of all the symptoms so that you can start to get treatment as soon as you start noticing them.