What tests and assessments are recommended for a pre-cyclophosphamide workup?

Pre-Cyclophosphamide Workup

Before initiating cyclophosphamide therapy, obtain a complete blood count with differential, comprehensive metabolic panel including liver and renal function tests, urinalysis, cardiac assessment (echocardiogram or MUGA scan), and pulmonary function tests if high-dose therapy or concurrent pulmonary toxins are planned. 1, 2

Essential Laboratory Testing

Hematologic Assessment

• Complete blood count (CBC) with differential to establish baseline white blood cell count, platelet count, and hemoglobin levels 1, 3
• Baseline values are critical since cyclophosphamide dose adjustments are required if WBC falls below 4,000/mm³ or platelets drop below 100,000/mm³ 1

Metabolic and Organ Function Panel

• Comprehensive metabolic panel including 1, 2:
  • Serum creatinine and blood urea nitrogen (BUN) to assess renal function
  • Liver function tests (AST, ALT, alkaline phosphatase, bilirubin)
  • Electrolytes (sodium, potassium, chloride, bicarbonate)
  • Serum calcium
  • Glucose

Critical caveat: Renal function assessment is particularly important because cyclophosphamide metabolites accumulate in renal failure, potentially causing severe toxicity including myopericarditis and prolonged myelosuppression 4. However, standard dose adjustments are not typically required for renal insufficiency alone 5.

Hepatic Monitoring

• Baseline liver function tests are essential since cyclophosphamide can cause hepatotoxicity, though this is rare 6
• Monthly monitoring of hepatocellular injury is recommended during treatment, with dose reduction or discontinuation if transaminases exceed three times normal 1

Cardiac Evaluation

Obtain baseline cardiac function assessment with either echocardiogram or multigated acquisition (MUGA) scan 1. This is particularly critical because:

• High-dose cyclophosphamide (especially in bone marrow transplant conditioning) can cause cardiac toxicity 5
• Baseline cardiac function guides monitoring during therapy and helps identify patients at higher risk for cardiotoxicity

Urinary System Assessment

Baseline Urinalysis

• Perform urinalysis to establish baseline and screen for pre-existing hematuria 1
• This is essential because cyclophosphamide causes hemorrhagic cystitis, particularly at cumulative doses >3 g/m² or when combined with pelvic radiation >30 Gy 1

Preventive Measures Discussion

• Counsel patients on forced diuresis (>8 glasses of water daily) to prevent hemorrhagic cystitis 1
• Plan for monthly urine monitoring for red blood cells during treatment 1

Pulmonary Function Testing

Obtain baseline pulmonary function tests (PFTs) including spirometry and DLCO if 1:

• High-dose cyclophosphamide is planned (>7.5 g/m² cumulative or conditioning for transplant)
• Patient will receive concurrent pulmonary toxic agents (bleomycin, busulfan, carmustine)
• Chest radiation is planned or previously administered

This establishes a baseline for monitoring progressive pulmonary dysfunction, as cyclophosphamide is a selected alkylating agent associated with pulmonary toxicity 1.

Infectious Disease Screening

Tuberculosis Assessment

• Tuberculin skin testing before initiating therapy when possible, as corticosteroids (often given with cyclophosphamide) suppress immune response to skin tests 1
• Consider prophylaxis with isoniazid for positive tuberculin tests or high-risk patients receiving >15 mg prednisone daily for >3 weeks 1

Pneumocystis Prophylaxis Consideration

• Consider trimethoprim/sulfamethoxazole (one single-strength tablet three times weekly) as prophylaxis against Pneumocystis carinii in patients receiving immunosuppressive therapy 1

Fertility and Reproductive Counseling

For Males

• Discuss risk of infertility, particularly with cumulative cyclophosphamide doses >7.5 g/m² 1
• Offer sperm banking before therapy initiation

For Females

• Counsel regarding risk of acute ovarian failure or premature menopause with cumulative doses >7.5 g/m² 1
• Discuss fertility preservation options before treatment

Additional Considerations

Blood Type and Antibody Screen

• Obtain blood type and screen, particularly if surgery or transfusion support may be needed 1

Coagulation Studies

• Baseline coagulation testing (PT/INR, PTT) may be warranted depending on clinical context 1

Important timing note: If cyclophosphamide is being used as lymphodepleting chemotherapy before CAR T-cell therapy, it must be stopped ≥2 weeks before CAR T-cell infusion 1.