Tumor lysis syndrome
Tumor lysis syndrome (TLS) is a common disease mostly experienced by children and adults suffering from hematologic cancers (blood cancer). TLS occurs when tumors break down following cancer treatment and release various substances into the bloodstream. Fortunately, when detected early, it is possible to treat TLS.
Definition & Facts
Tumor lysis syndrome (TLS) is a combination of metabolic disturbances that result from the treatment of cancer. When cancer cells break down and die rapidly, they can prevent the kidneys from filtering the substances from the blood, and TLS may occur. It is a potentially life-threatening oncologic emergency that has to be monitored before, during, and after chemotherapy sessions.
When not controlled, abnormal blood levels may lead to multiple problems. First, when uric acid builds up in the kidney, the kidneys may become damaged and kidney stones may begin to form. Also, high levels of phosphate can cause acute kidney failure and/or permanently damage the kidney. Abnormal calcium and potassium levels may affect the rhythm of the heart, causing cardiac arrhythmia and they may also cause neurological changes such as confusion and weakness.
Symptoms & Complaints
- Shortness of breath
- Muscle cramps
- Irregular heart beat/Cardiac arrhythmias
- Loss of muscle control
- Decreased urination
Tumor lysis syndrome's symptoms may occur after a few hours of chemotherapy and are often noticed within 48-72 hours after treatment. If any of these symptoms are experienced, it is necessary to visit a healthcare facility immediately.
TLS is caused by the sudden death of cells, especially cancer cells in people with
- Aggressive non-Hodgkin's lymphoma
- Acute leukemia
- Solid tumors like a neuroblastoma that has metastasized
- Myeloproliferative disorders
- Cancers that lead to poor kidney function prior to treatment
Cell death occurs in response to therapies. When the cells are killed by therapy, they may excrete their intracellular components making them accumulate rapidly in the body. Electrolyte imbalances result.
Usually, TLS occurs at the start of cancer treatment when large numbers of tumor cells are destroyed. Various chemotherapy agents including cisplatin, cytarabine, paclitaxel, and etoposide are linked to TLS.
The disorder is not only caused by systemic chemotherapy. It can also occur as a result of intrathecal chemotherapy, usually given directly into the brain and spinal cord’s fluid-filled spaces. Tumor lysis syndrome has also been linked to other treatments such as hormone replacement therapy, radiation therapy, and biological therapy.
Some of the patients at the highest risk of developing this syndrome are those with a pre-existing kidney disease or impaired renal function. Those with high levels of lactate dehydrogenase are also at a high risk.
Diagnosis & Tests
Laboratory results from blood tests will indicate the syndrome's progression. The results should show high potassium, advanced phosphorus levels, uric acid, and low calcium in the blood. Depending on the presence of certain risk factors, TLS patients can be categorized into high-risk, low-risk, or intermediate risk categories.
- High-risk are patients with lymphoblastic lymphoma
- Intermediate risk applies to patients with large-cell lymphoma as well as other types of rapidly growing cancers.
- Low-risk patients tend to have slow-growing lymphoma
This syndrome is diagnosed by clinical symptoms or lab tests. It should be suspected in patients suffering from acute kidney failure, large tumor burden as well as hyperuricemia. In tests, uric acid crystals may be seen. At this point, drugs that help in stopping uric acid from forming crystals may be recommended in order to expel uric acid from the body.
Treatment & Therapy
Once electrolyte abnormalities develop, the patient should be monitored closely and efforts should be taken to restore a proper balance of electrolytes. Hyperkalemia is managed with sodium polystyrene sulfonate. Insulin and dextrose may also be administered to reduce potassium levels. Calcium gluconate may be administered for patients with hypocalcaemia.
Calcium channel blockers and other antiarrhythmic agents may be administered to control cardiac arrhythmia. Phosphate binders such as aluminum hydroxide manage hyperphosphatemia when taken in limited dosages.
Prevention & Prophylaxis
Preventative care involves administering recombinant urate oxidase which helps rid the body of uric acid. Hydration is also crucial. IV hydration can begin two days prior to chemotherapy. It is further continued during chemotherapy, and up to three days after chemotherapy.
IV fluids help in the production of high urine output which enables the excretion of excess phosphate, uric acid, and potassium with the aim of reducing the risk of these substances accumulating in the blood to unhealthy degrees.
It is vital to monitor signs of hypervolemia in which there is too much fluid in the blood. Signs of this condition include weight gain and pulmonary crackles. Conversely, hypovolemia in which there is insufficient fluid in the blood causes symptoms including unexplained weight loss, poor skin turgor, dry mucous membranes and thirst which should also be monitored.
By identifying tumor lysis syndrome signs and intervening appropriately, it is possible to prevent life-threatening complications of cancer treatment.