Although routine prophylactic administration of G-CSF is not usually recommended, clinical guidelines recommend that patients with risk factors for febrile neutropenia who are treated with chemotherapeutic regimens associated with a ≥ 20% risk of febrile neutropenia should be administered G-CSF as primary prophylaxis.28,29 Routine prophylactic administration of G-CSF during chemotherapy in CRT in older patients with LD-SCLC is not recommended. Here, CSF3 is linked to small cell lung carcinoma.