What is tumor lysis syndrome and what prophylaxis is commonly used?

• A. TLS is the rapid release of intracellular contents from tumor cells causing hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia; prophylaxis includes aggressive hydration and urate-lowering therapy (allopurinol or rasburicase) and monitoring.
• B. TLS is a mild electrolyte fluctuation with no special prophylaxis.
• C. TLS occurs only after surgery and does not require hydration.
• D. TLS is associated with infections and is prevented with antibiotics.

Answer: (A)

Tumor lysis syndrome happens when a large number of tumor cells break open at once, releasing their contents into the bloodstream. This dumps potassium, phosphate, and nucleic acids into circulation, which the body converts to uric acid. The result is high potassium, high phosphate, high uric acid, and low calcium, which can lead to kidney injury and heart or nerve problems if not prevented. The best way to prevent TLS is to start protective measures before chemotherapy or other cytotoxic therapy. Aggressive IV hydration keeps the kidneys flushing out uric acid and minerals. Urate-lowering therapy—either allopurinol to reduce new uric acid formation or rasburicase to rapidly break down uric acid—helps prevent uric acid–related kidney damage. Ongoing monitoring of electrolytes, kidney function, and uric acid is essential, and urine alkalinization is not routinely recommended due to risk of calcium phosphate precipitation. This combination—hydration, urate-lowering therapy, and close monitoring—addresses the key risks of TLS and explains why the listed approach is the correct prophylaxis.