Tumour lysis syndrome can be life-threatening but is largely preventable when high-risk patients are identified before chemotherapy. This tool applies a Cairo-Bishop-based risk stratification from the tumour type, white cell count, LDH, and baseline patient factors, and suggests the matching prophylaxis tier.
How it works
The tool scores three groups of factors and assigns the highest applicable tier:
Tumour type:
high-risk lymphoma/leukaemia (Burkitt, lymphoblastic, ALL/AML) -> high
intermediate lymphomas / other leukaemias -> intermediate
most solid tumours -> low
Tumour burden escalators (move risk up a tier):
WBC > 100 ×10^9/L, or markedly raised LDH (≥ 2× upper limit)
Patient escalators (move risk up a tier):
baseline renal impairment, pre-existing high urate/electrolytes,
or volume depletion
Prophylaxis:
low -> monitor + oral hydration
intermediate -> IV hydration + allopurinol
high -> IV hydration + rasburicase (screen G6PD first)The final tier is the most severe one triggered by any factor, because a single high-risk feature is enough to warrant escalated prophylaxis.
Risk factors at a glance
| Factor | Escalates risk if… |
|---|---|
| Tumour type | Burkitt, lymphoblastic, ALL, high-count AML |
| WBC | Greater than 100 × 10⁹/L |
| LDH | Two or more times the upper limit of normal |
| Renal function | Pre-existing impairment or oliguria |
| Urate / electrolytes | Elevated uric acid, phosphate, or potassium at baseline |
| Volume status | Dehydration or reduced urine output |
Any single escalating factor moves the patient to a higher tier; the worst tier triggered determines the prophylaxis recommendation.
What TLS looks like and why prevention matters
TLS occurs when a large number of tumour cells die rapidly — from chemotherapy, targeted therapy, or occasionally spontaneously in very aggressive tumours — and release their intracellular contents into the bloodstream. The result is a characteristic cluster of metabolic derangements:
- Hyperuricaemia — uric acid from nucleic acid breakdown; can precipitate in renal tubules
- Hyperkalaemia — the most immediately dangerous abnormality; can cause fatal arrhythmia
- Hyperphosphataemia — phosphate released from cells; binds calcium
- Hypocalcaemia — secondary to phosphate rise; causes neuromuscular irritability and tetany
- Acute kidney injury — from urate and calcium phosphate deposition, and reduced perfusion
The Cairo-Bishop definition requires at least two of these abnormalities (or one plus a clinical complication such as renal failure, arrhythmia, or seizure) to formally diagnose TLS. The goal of prophylaxis is to prevent reaching that threshold.
Prophylaxis by tier
Low risk — Monitor electrolytes, urate, creatinine, and phosphate before and during treatment. Ensure adequate oral hydration. Allopurinol is not routinely indicated but is sometimes added if any borderline features are present.
Intermediate risk — Aggressive intravenous hydration (commonly 2–3 L/m² per day) to maintain urine output above 2 mL/kg/hour. Allopurinol reduces new uric acid production but does not lower existing urate levels, so start before chemotherapy begins. Monitor laboratories at least twice daily during the high-risk period.
High risk — All the above, plus rasburicase, a recombinant urate oxidase that rapidly converts existing uric acid to the more soluble allantoin. Far more effective than allopurinol at bringing down an already elevated urate. Screen for G6PD deficiency before use — rasburicase causes severe haemolysis and methaemoglobinaemia in G6PD-deficient patients. ICU monitoring is often appropriate in the highest-risk cases.
Worked examples
For example, a patient with Burkitt lymphoma, a WBC of 80 × 10⁹/L, and normal renal function at baseline: high risk on tumour type alone, so IV hydration plus rasburicase after G6PD screening is indicated.
A patient with a newly diagnosed intermediate-grade diffuse large B-cell lymphoma, a normal WBC of 12 × 10⁹/L, LDH 1.5× upper limit, and normal kidney function: intermediate risk — IV hydration and allopurinol, with close monitoring around the first cycle.
A patient with stage I colon cancer on standard chemotherapy, no elevated LDH, normal WBC: low risk — monitoring and oral hydration.
Always recheck potassium, phosphate, calcium, urate, and renal function before, during, and after the first treatment cycle, and follow local protocols. This tool guides the tier; it does not replace clinical judgement or prescribe treatment.