Use of pegfilgrastim primary prophylaxis and risk of infection, by chemotherapy cycle and regimen, among patients with breast cancer or non-Hodgkin's lymphoma

This study aims to examine granulocyte colony-stimulating factor (G-CSF) prophylaxis by cancer type, chemotherapy regimen, and cycle in a real-world setting to assess if practice conforms to clinical guidelines, which recommend G-CSF prophylaxis every cycle when a patient's risk of febrile neutropenia (FN) is 20 % or greater, and to describe the incidence of FN among patients who discontinue pegfilgrastim (peg) prophylaxis. The cohort was selected from administrative claims data and includes adults diagnosed with non-Hodgkin's lymphoma (NHL) or breast cancer (BC) who began chemotherapy 2005-2010. About 83.2 % of the 4,470 patients with BC treated with dose-dense doxorubicin, cyclophosphamide (ddAC), 83.6 % of 2,197 patients with BC treated with docetaxel, doxorubicin, cyclophosphamide (TAC), and about 55.6 % of the 2,722 patients with NHL treated with cyclophosphamide, doxorubicin, vincristine, with or without prednisone for 3-week cycles (CHOP-R Q3W) received peg prophylaxis in cycle 1. Among patients on these regimens who received peg prophylaxis in cycle 1 and were still on the regimen in cycle 4, about 90 % received peg prophylaxis in that cycle. Among patients with BC or NHL who discontinued G-CSF, the incidence proportion of infection or FN varied by regimen and cycle, with a range from 0 to 14 %. Despite clinical guidelines recommending G-CSF prophylaxis with chemotherapy regimens with a high risk of FN, many NHL and BC patients do not receive FN prophylaxis in cycle 1. However, among patients who receive G-CSF in cycle 1 and remain on the regimen, the majority appear to continue prophylaxis as indicated.