The use of white blood cell growth stimulating factor drugs to reduce risk of infection in women with breast cancer receiving common first-cycle chemotherapies only reduced hospitalisation by 6 percent or less, according to a study published in the Journal of Clinical Oncology.

The study also confirmed that fever and infections among these women were very low even without the use of growth factor.

The study of medications that help white blood cell growth, also known as granulocyte colony-stimulating factor or G-CSF, was authored by representatives from HealthCore, Inc., Anthem, Inc. and the American Society of Clinical Oncology.  

The authors of study are Abiy Agiro, Qinli Ma, Anupama Kurup Acheson, Sze-jung Wu, Debra A. Patt, John J. Barron, Jennifer L. Malin, Alan Rosenberg, Richard L. Schilsky, and Gary H. Lyman.

Through the Choosing Wisely® campaign, ASCO issued guidance advising oncologists not to use white cell stimulating factor for prevention of neutropenia for patients with less than a 20 percent risk of getting an infection.

The three regimens studied have been considered low-to-moderate risk for inducing neutropenia-related complications as less than 20 percent of patients being treated with these chemotherapies experience febrile neutropenia.

“In women with breast cancer treated with a conventional dose of doxorubicin and cyclophosphamide, a chemotherapy regimen that has low risk of infection, more than half of them were also treated with G-CSF, with no benefit,” said Abiy Agiro, lead author and research manager for HealthCore. “This is unfortunate, especially given that patients can experience uncomfortable side effects from G-CSF, such as bone pain, headache and nausea. When the chemotherapy risk for neutropenia is low, these high-cost agents place an unnecessary burden on the healthcare system without providing a discernable benefit to the patient.”

The retrospective analysis included patients with breast cancer who began first-cycle chemotherapy from 2008 to 2013 using docetaxel and cyclophosphamide, also known as TC or carboplatin, docetaxel and trastuzumab, also known as TCH or doxorubicin, and cyclophosphamide, also known as conventional dose AC.

“This study confirms previous trials that have shown that G-CSF is effective at decreasing fever and infections with higher-risk chemotherapy treatments but failed to show any benefit with lower-risk regimens,” said Dr. Gary Lyman, co-director of the Hutchinson Institute of Cancer Outcomes Research for the Fred Hutchinson Cancer Research Center. “The study also showed that older age was associated with increased risk of neutropenia-related hospitalisation, however the health care community needs to study G-CSF further to better understand which patients on which chemotherapies can benefit most.”

The group of patients treated with doxorubicin and cyclophosphamide and G-CSF actually showed more patients experiencing neutropenia than those not taking any G-CSF, however the difference was not significant, according to the study.

However, hospitalisations occurred in 2 percent of patients with TC docetaxel and cyclophosphamide and G-CSF, and 7.1 percent with no G-CSF.

For TCH carboplatin, docetaxel and trastuzumab regimens, neutropenia occurred in 1.3 percent of the patients with G-CSF and 7.1 percent with no G-CSF.

Although G-CSF was associated with a lower rate of hospitalisation in low to modest benefit in TC and TCH regimen, the value of G-CSF treatment in such regimens is less clear.

For all regimens excluding high risk chemotherapy, about 48 patients would need to be treated at a total cost of more than $200,000 to prevent one more neutropenia related hospitalisation compared to patients who did not receive G-CSF.

“In spite of current guidelines and public campaign efforts about appropriate use of G-CSF prophylaxis, it is commonly used in chemotherapy regimens that do not have high risk for inducing neutropenia-related complications,” said Dr. Debra Patt, vice president of Texas Oncology. “Our study found no benefit in one regimen, and even when low to modest benefit is observed, the value proposition for such wide spread use of G-CSF is limited. Future research that integrates HIT platforms, such as ASCO’s CancerLinQ™, could refine the methods to identify patients for a targeted use of G-CSF.”

Source: JCO