When is dialysis indicated in tumor lysis syndrome?

Indications for Dialysis in Tumor Lysis Syndrome

Dialysis is indicated in tumor lysis syndrome when there is persistent hyperkalemia, severe metabolic acidosis, volume overload unresponsive to diuretic therapy, or overt uremic symptoms including pericarditis and severe encephalopathy. 1

Primary Indications for Renal Replacement Therapy

Absolute indications for initiating dialysis in TLS include:

• Persistent hyperkalemia unresponsive to medical management
• Severe metabolic acidosis unresponsive to treatment
• Volume overload unresponsive to diuretic therapy
• Overt uremic symptoms:
  • Pericarditis
  • Severe encephalopathy
  • Progressive peripheral neuropathy 1, 2

Prophylactic Indications

Dialysis may also be initiated "prophylactically" before the development of overt uremic symptoms in the following situations:

• Severe, progressive hyperphosphatemia (>6 mg/dL)
• Severe symptomatic hypocalcemia 1, 2

The appropriate timing for prophylactic dialysis remains unresolved, but early intervention is generally preferred to prevent complications.

Dialysis Modality Selection

Intermittent Hemodialysis (IHD)

• First-line treatment for most patients with TLS
• Efficiently removes uric acid (clearance approximately 70-100 mL/min)
• Reduces plasma uric acid levels by about 50% with each 6-hour treatment
• Oliguria due to acute uric acid nephropathy often responds rapidly as plasma uric acid falls to 10 mg/dL 1, 2

Continuous Renal Replacement Therapy (CRRT)

CRRT is preferred for:

• Hemodynamically unstable patients (less likely to exacerbate hypotension)
• Patients with pulmonary edema
• Cases requiring strict fluid balance management
• Patients needing nutritional support
• Patients with ARDS requiring improved gas exchange 1

Alternative Options

• Long-duration daily dialysis may be a good alternative in patients with cardiovascular instability when CRRT is unavailable
• Peritoneal dialysis should be reserved for situations where other therapy modalities are unavailable due to lower efficiency in removing solutes and fluid 1

Dialysis Frequency and Dosing

• Frequent (daily) dialyses are recommended due to the continuous release of purine products, potassium, and other metabolites from lysed tumor cells
• The timing of dialysis and dialysis dose should be linked to the purine generation rate 1

Special Considerations

Risk Factors for Requiring Dialysis

• Decreased renal function at baseline
• Advanced age
• Associated comorbidities (diabetes, cardiovascular disease)
• High tumor burden
• Aggressive cytotoxic therapy 1, 3

Monitoring During Treatment

• Vigilant laboratory monitoring of electrolytes, especially potassium, phosphorus, and calcium
• Close monitoring of fluid status and acid-base balance
• Early involvement of nephrology team in high-risk cases 2, 3

Important Caveats

• The threshold for RRT initiation may be lower in TLS than in other clinical situations since the process of cell breakdown is ongoing and rapid increases in serum electrolytes cannot be predicted 3
• In patients with high risk of TLS, cytotoxic chemotherapy should be given in facilities with ready access to dialysis, with a treatment plan discussed with the nephrology team beforehand 3
• There are no studies directly comparing outcomes with IHD and CRRT in TLS, so modality choice should be based on patient characteristics and facility capabilities 1