Tumor Lysis Syndrome: A metabolic breakdown crisis in cancer post-treatment
Tumor lysis syndrome (TLS) occurs when there is rapid breakdown of a large mass of cancer cells releasing large amounts of potassium, phosphate, and nucleic acids into the systemic circulation into the bloodstream. TLS usually arises 48-72 hours after beginning chemotherapy with most types of cancers; it can also occur spontaneously in some high-grade blood cancers.
High risk for TLS is typically observed with large and bulky cancers that respond well to chemotherapy including acute leukemias, high-grade non-Hodgkin’s lymphomas such as Burkitt’s lymphoma, hepatoblastoma and stage IV neuroblastoma. TLS may also be associated with other cancer treatments: radiation therapy, corticosteroids, hormonal agents, biologic response modifiers, and monoclonal antibodies.
The abnormal chemical processes (metabolic disturbances) that occur in TLS lead to a rapid development of acute kidney injury and is considered a cancer-related emergency. It is, therefore of prime importance to identify TLS and begin appropriate treatment.
Increase in blood potassium levels (hyperkalemia) usually occurs first, along with or followed by an increase in blood phosphate levels (hyperphosphatemia), both as a result of cancer cell wall rupture. This leads to decreased calcium levels (hypocalcemia) and increased blood uric acid levels (hyperuricemia). The kidneys, unable to clear these large amounts of chemical byproducts cause acute kidney injury. Clinically, patients may complain of difficulty in passing urine and flank pain, weakness, and vomiting. Seizures, abnormal heart rhythms (arrhythmias) and sudden death can also occur.
Management of TLS includes preventive measures taken for high-risk cancer patients before commencing cancer treatment. This will include analysis of tumor mass, type of tumor (histopathology), and kidney function tests. Ideally, cancer treatment should be postponed until all parameters are normalized to reduce the occurrence of TLS.
All patients identified with TLS need cancer specialist care