Effect of Epidermal Growth Factor Receptor Inhibitors on Magnesium Homeostasis in Patients With Cancer

Pilot Study of the Effects of Epidermal Growth Factor Receptor (EGFR) Inhibitors on Magnesium Homeostasis

RATIONALE: Studying samples of blood and urine in the laboratory from patients with cancer receiving epidermal growth factor receptor inhibitors may help doctors understand the effect of epidermal growth factor receptor inhibitors on magnesium levels in the body.

PURPOSE: This laboratory study is looking at the effect of epidermal growth factor receptor inhibitors on magnesium homeostasis in patients with cancer.

OBJECTIVES:

• Determine the effects of EGFR inhibitors on magnesium homeostasis in patients with cancer.

OUTLINE: This is a pilot study.

Patients undergo blood and urine sample collection at baseline and at 2, 4, and 8 weeks during treatment.

After finishing treatment, patients are followed periodically for up to 10 weeks.

Inclusion Criteria:

• Diagnosis of malignancy

  • Planning to receive therapy with an inhibitor of the EGFR pathway (either on or off a clinical trial and may be monotherapy or combined with other therapies)

• Normal serum magnesium level

Exclusion Criteria:

• Glomerular filtration rate ≥ 60 mL/min
• No severe underlying renal dysfunction
• Normal serum potassium and calcium level
• No history of primary or secondary hyperparathyroidism

PRIOR CONCURRENT THERAPY:

• No prior EGFR pathway inhibitor