A true therapeutic emergency, tumor lysis syndrome can occur in cases of acute leukemia, for example, during the first hours of cancer treatment with chemotherapy.
What is the definition of tumor lysis syndrome?
Tumor lysis syndrome (TLS) is a complication which occurs either spontaneously in cases of acute leukemia for example, or during the early stages (generally first hours) of treatment of cancer by chemotherapy. Cancer cells break down too quickly, releasing intracellular compounds into the blood circulation (hyperphosphatemia, hyperkalemia, hyperuricemia). Result, the kidneys are no longer able to carry out their filtration role. In the absence of support, the patient’s vital prognosis is compromised.
What are the symptoms ?
The symptoms of tumor lysis syndrome are linked to abnormally high substances in the blood (blood calcium, uric acid, serum potassium) and a rapidly progressive disease:
- Severe fatigue
- Very rapid swelling of a lymph node within a few days
- Nausea
- Vomiting
- Diarrhea
- Weakness
- Muscle cramps
- Heart rhythm disorders
- Irritability, delirium, hallucination, epilepsy.
What is the cause ?
“Tumor lysis syndrome generally occurs either spontaneously in cases of very rapidly progressive disease (such as acute leukemia, or Burkitt lymphoma, as well as certain solid cancers such as neuroblastoma), or at the start of their treatment with chemotherapy or other anti-cancer drugs. Cancer cells will break and release toxic substances into the blood system (uric acid, potassium and phosphate), which can cause kidney and heart complications. TLS can also follow a drop in calcium levels (hypocalcemia) in the blood because the phosphate will attach to the calcium and form small stones which will damage the kidneys.indicates Dr Clémentine Sarkozy.
The diagnosis of SLT is established using‘a blood test (biological SLT). It is confirmed by hypocalcemia (low calcium levels), hyperuricemia (high uric acid level), and hyperphosphatemia (high phosphate level), hyperkalemia (high potassium level in the blood). Severity is assessed based on the impact on the patient (clinical SLT), with the presence of an impact on renal function, heart rate, or even the appearance of neurological disorders. After the diagnosis, the severity will be graded to be able to adapt the treatment, according to a classification (from Cairo-Bishop).
What are the potential complications ?
“SLT exposes to several risks vital: cardiac arrhythmia, seizures, tetany, paresthesias and acute renal failure”explains the hematologist.
Above all, SLT can be prevented with hydration, stopping certain risky medications (such as potassium, or certain diuretics),administration of recombinant urate oxidase (Rasburicase) in prevention, and monitoring the lysis assessment after the start of treatment for high-risk cancer. “The prevention strategy will adapt to the risk of SLT occurrence. This is measured for each patient according to the disease, the tumor mass and elements of the blood test. If it occurs, tumor lysis syndrome requires curative treatment and hospitalization in intensive care.“, specifies Dr Clémentine Sarkozy. Various medications are administered, in addition to hydration which is fundamental: such as Allopurinol to interrupt the production of uric acid and Fasturtec®, diuretics or phosphate binders, or even insulin to lower serum potassium; Above all, certain medications will be stopped to avoid complications, particularly renal ones. Treatment can go as far as dialysis depending on the severity criteria.
Thanks to Dr Clémentine Sarkozy, hematologist at the Institut Curie