CSF3 and neutropenia: While G-CSF prophylaxis is not routinely used in multiple myeloma, it is advised for patients undergoing regimens with a high (≥ 20%) risk of febrile neutropenia, those with intermediate risk (10–20%) who have additional factors (e.g., age > 65 years, frailty), or those on treatments with a neutropenia rate over 50% (e.g., lenalidomide-based combinations).42