Background: Febrile Neutropenia (FN) is a common and serious condition related to cancer chemotherapy. Human recombinant Granulocyte-Colony Stimulating Factor (G-CSF) prevents and attenuates the severity and duration of FN. We evaluated the use and predictors of G-CSF adherence among women with breast cancer with a high risk of FN in Puerto Rico.

Methods: This retrospective cohort study used the Puerto Rico Central Cancer Registry-Health Insurance Linkage Database. Women with invasive breast cancer diagnosed during 2009-2015 who received selected chemotherapy regimens (n = 816) were included. The risk of FN was categorized as high and low risk based on the chemotherapy regimens according to the National Comprehensive Cancer Network guidelines and literature. Adherence was defined as the use or no use of G-CSF at the start of the first chemotherapy cycle among women with breast cancer based on the risk of developing FN. We used a multivariate logistic model to identify factors associated with G-CSF use in women classified at high risk for FN.

Results: Adherence to G-CSF clinical practice guidelines was low (38.2%) among women with a high risk of FN. Women at high risk of FN with Medicaid (aOR: 0.14; CI 95%: 0.08, 0.24) and Medicare/Medicaid (aOR: 0.33; CI 95%: 0.15, 0.73) were less likely to receive G-CSF than women with private health insurance. Women with regional stage (aOR: 1.82; CI 95%: 1.15, 2.88) were more likely to receive G-CSF than women with localized cancers.

Conclusions: Adherence to clinical practice guidelines was poor among women with a high risk of FN. Furthermore, disparities in the adherence to G-CSF use in terms of health insurance, health region, and cancer stage granted the opportunity to implement strategies to follow the recommended guidelines for using G-CSF as part of cancer treatment.