Is a high Lactate Dehydrogenase (LDH) level required for tumor lysis syndrome (TLS) to occur after a biopsy?

From the Guidelines

No, a high Lactate Dehydrogenase (LDH) level is not required for tumor lysis syndrome (TLS) to occur after a biopsy. TLS is diagnosed based on laboratory criteria that include hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia. While elevated LDH is often present in patients at risk for TLS and can be a marker of high tumor burden or cell turnover, it is not one of the defining laboratory parameters for diagnosing TLS 1. TLS occurs when large numbers of tumor cells are rapidly destroyed, releasing their intracellular contents into the bloodstream and overwhelming the body's excretory mechanisms. This can happen after a biopsy if the procedure disrupts a significant number of tumor cells, particularly in highly proliferative or bulky malignancies. Some key points to consider in the management and prevention of TLS include:

• Patients at high risk of developing TLS carry specific host-related, disease-related, and therapy-related factors, including dehydration, hyponatremia, pre-existing renal impairment, and elevated serum LDH (>2 upper normal limit) 1
• Preventive measures may include hydration, allopurinol or rasburicase, and careful electrolyte monitoring depending on the patient's risk factors 1
• Rasburicase has been shown to be effective in reducing uric acid levels and preventing TLS in patients at high risk, with some studies suggesting it may be more effective than allopurinol 1 Patients undergoing biopsies of large tumors, especially those with hematologic malignancies like high-grade lymphomas or leukemias, should be monitored for TLS regardless of their baseline LDH levels. It is essential to be aware of the causes, physiologic consequences, and predisposing risk factors of TLS, and to implement appropriate prophylactic measures and monitoring to prevent and manage this potentially life-threatening condition 1.

From the Research

Tumor Lysis Syndrome and LDH Levels

• Tumor lysis syndrome (TLS) is a potentially life-threatening complication of cancer therapy, characterized by hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia following massive lysis of malignant cells 2, 3.
• A high Lactate Dehydrogenase (LDH) level is not always required for TLS to occur, but it is a common risk factor associated with the development of TLS 2, 4, 5.
• Other risk factors for TLS include pretreatment renal insufficiency, hyperuricemia, and bulky or metastatic disease 2, 4, 5.

Biochemical Parameters and TLS

• The cardinal signs of TLS are hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia 6.
• Elevated LDH levels are often seen in patients with TLS, but the absence of elevated LDH does not rule out the diagnosis of TLS 2, 5.
• Biochemical monitoring and early recognition of TLS are crucial for prompt initiation of therapeutic measures to prevent or mitigate the complications of TLS 3, 4, 6.

Management and Prevention of TLS

• Management of TLS requires hydration, fluid balance, electrolytes and hyperuricemia correction, and ultimately dialysis when acute kidney injury is worsening 3.
• Prophylactic treatment to avoid TLS includes allopurinol, hydration prior to treatment, and alkalization of the urine, as well as the use of urate oxidase (rasburicase) in high-risk patients 2, 4.