Study: Low White Blood Cell Count Compromises Chemotherapy

Neutropenia (very low levels of white blood cells) delays chemotherapy in half of breast cancer patients and causes as many as one in four to receive lower than standard doses of chemotherapy, according to researchers at Albany Medical Center in New York.

There are also new ways to predict the risk of neutropenia that may help doctors identify patients at the greatest risk, according to the study presented at the annual meeting of the American Society of Clinical Oncology.

Neutropenia is considered to be the primary reason for limiting chemotherapy doses, and may necessitate the delay or reduction of chemotherapy treatment, possible compromising the effectiveness of treatment.

"The findings from our studies have important public health implications," said Dr. Gary Lyman, author of the study. "They suggest that the delivery of lower than standard chemotherapy is common in patients with early breast cancer being treated in community oncology settings. This potentially compromises treatment effectiveness and long-term outcomes."

Researchers studied the medical records of over 20,000 breast cancer patients and found that more than half of the patients experienced delays of adjuvant chemotherapy, and 20 to 25 percent received less than 85 percent of the targeted dose, the minimum percentage below which chemotherapy is thought to lose effectiveness.

Elderly patients were more than half as likely as younger patients to receive below standard doses of chemotherapy, according to the researchers.

Researchers have studied the effect of Granulocyte Colony Stimulating Factor (G-CSF) and have found that it stimulates production of infection-fighting white blood cells when used to reduce the risk of neutropenia in chemotherapy patients.

"G-CSF is very helpful to us in managing neutropenia, but it's cost-prohibitive to treat everyone preventively," said Dr. Gary Lyman, author of the study. "Current risk projection models appear to set the barrier too high. We need to develop improved models to predict which patients are most at risk for neutropenic complications, and administer growth factors prophylactically.

" The findings from our studies are a first step in developing such models," Lyman said. "These findings also lay important ground work for further research to improve models to predict which patients are most at risk for severe neutropenia, and who can benefit most from prophylactic treatment with G-CSF."

Other sources: Albany Medical Center