Trends in the use of primary prophylactic colony-stimulating factors and neutropenia-related hospitalization in elderly cancer patients receiving myelosuppressive chemotherapy in the USA: 1995-2015

Purpose To assess changes in neutropenia-related hospitalization, myelosuppressive chemotherapy, and primary prophylactic colony-stimulating factor (PP-CSF) use in elderly cancer patients receiving myelosuppressive chemotherapy. Methods We identified annual cohorts of patients aged >= 66 years with breast cancer, lung cancer, or non-Hodgkin lymphoma (NHL) initiating myelosuppressive chemotherapy during 1995-2015 using Medicare 5% (1994-2008) and 20% (2007-2015) data. We described myelosuppressive chemotherapy changes by febrile neutropenia (FN) risk category (high, intermediate, unclassified), PP-CSF use, and, in the first cycle of myelosuppressive chemotherapy, neutropenia-related hospitalization (ICD-9-CM: 288.0X, first 5 positions). We evaluated hospitalization trends using a logistic regression model with spline curve of calendar year adjusting for baseline characteristics. Results Annual cohorts included 1451-2114 eligible patients for 1995-2007 and 5272-7603 for 2008-2015. Myelosuppressive chemotherapy use with high/intermediate FN risk increased from 31% in 1995 to 56% in 1999, stabilized through 2008 (range 56-61%), then decreased to 52% in 2015. PP-CSF use increased from 5.5% in 1995 to 52.7% in 2015, mainly due to pegfilgrastim introduction in 2002. Crude neutropenia-related hospitalization incidence decreased from 5.2% in 1995 to 2.7% in 2015; adjusted incidence decreased, on average, by 4.7% yearly before 2010 (p < 0.0001) and was flat from 2010 onward (p = 0.53). Conclusions Among elderly patients with breast cancer, lung cancer, or NHL receiving myelosuppressive chemotherapy, PP-CSF use increased substantially after 2002. Neutropenia-related hospitalization incidence in the first cycle decreased yearly before 2010 and was flat afterward. Further studies are needed to understand overall decreasing neutropenia-related hospitalization trends and effects of changes in myelosuppressive chemotherapy and FN management.