Cairo-Bishop Criteria for Tumor Lysis Syndrome
The Cairo-Bishop criteria are the standardized diagnostic system used to identify and grade tumor lysis syndrome (TLS) in patients with cancer, distinguishing between laboratory TLS (based on metabolic abnormalities) and clinical TLS (when laboratory abnormalities are accompanied by organ dysfunction). 1
Laboratory TLS Definition
Laboratory TLS is diagnosed when two or more of the following serum abnormalities occur within the timeframe of three days before to seven days after initiating anticancer treatment 1, 2:
- Uric acid: Increase >25% from baseline OR absolute value ≥476 μmol/L (8 mg/dL) 1, 2
- Potassium: Increase >25% from baseline OR absolute value ≥6.0 mmol/L (6 mEq/L) 1, 2
- Phosphorus: Increase >25% from baseline OR absolute value ≥1.45 mmol/L (4.5 mg/dL) in adults or ≥2.1 mmol/L (6.5 mg/dL) in children 1, 2
- Calcium: Decrease >25% from baseline OR absolute value ≤1.75 mmol/L (7 mg/dL) 1, 2
Clinical TLS Definition
Clinical TLS requires the presence of laboratory TLS plus at least one of the following clinical complications 1, 2:
- Renal failure: Estimated glomerular filtration rate (eGFR) ≤60 mL/min 1, 2
- Cardiac arrhythmias or sudden death 1
- Seizures 1, 2
Important Refinement on Renal Assessment
The Cairo-Bishop criteria specifically recommend using eGFR rather than serum creatinine alone to assess renal dysfunction, as creatinine levels are influenced by age, hydration status, and muscle mass 1. Calculate eGFR using either the MDRD formula or Cockroft-Gault equation 1, 2.
Key Advantages Over Previous Systems
The Cairo-Bishop system addressed critical shortcomings in the earlier Hande-Garrow classification 1:
- Accounts for pre-existing abnormal values (not just 25% increases from baseline) 1
- Extended timeframe from 4 days to 7 days post-treatment initiation 1
- Includes spontaneous TLS occurring before treatment starts 1, 3
Clinical Application and Mortality Impact
TLS occurs most commonly in hematologic malignancies, particularly Burkitt's lymphoma, acute lymphoblastic leukemia, and acute myeloid leukemia 1. However, it can occur in solid tumors, where it carries particularly high mortality 3. Clinical TLS is associated with 83% mortality versus 24% in patients without clinical TLS 4, with hyperkalemia being directly responsible for deaths in multiple case series 4.
Common Pitfall
The Cairo-Bishop criteria eliminated "grade 0 TLS" from the original classification, as this designation simply meant no TLS was present 1. Do not use this outdated grading when applying the current criteria 1.