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Breath Test for Cancer Drugs
Doctors who fight cancer may soon have a new tool to
help them determine if their patients will react badly to chemotherapy, according to a
report in the April issue of Clinical Cancer Research.
Chemotherapy - a course of powerful drugs used to
destroy tumors - is well known to have toxic side effects. In some cases, those side
effects can be lethal, because a patient's liver can't clear the drug at a normal rate.
Until recently, doctors had no way to know which patient wouldn't be able to handle
chemotherapy. However, Paul B. Watkins, M.D., and his colleagues at the University of
North Carolina at Chapel Hill have pioneered a simple breath test to help.
In the development process, they gave patients trace
doses of the common antibiotic erythromycin and then measured the amount of carbon dioxide
they exhaled. Higher concentrations of carbon dioxide mean that patients are metabolizing
the antibiotic more quickly. The liver uses the same enzyme system to clear erythromycin
as it does to process docetaxel, a common chemotherapy drug. A quick test with the
antibiotic can therefore predict problems with chemotherapy.
"It is rapid, relatively noninvasive; requires
only a single time point, and can be used prospectively before dosing," said Dr.
Watkins. "Because of the narrow therapeutic range of anticancer drugs, lowering the
likelihood of toxicity in the patient at the greatest risk is a useful
contribution." |
