G-CSF-producing pulmonary sarcomatoid carcinoma treated with chemoradiotherapy followed by durvalumab: a case report.

Pulmonary sarcomatoid carcinoma (PSC) is a rare and aggressive subtype of non-small cell lung cancer, and granulocyte colony-stimulating factor (G-CSF)-producing PSC is associated with particularly poor prognosis and inconsistent responses to immune checkpoint inhibitors (ICIs). We report the case of a 67-year-old man presented with leukocytosis, systemic inflammation, and a right upper lobe mass diagnosed as PSC with positive G-CSF expression and a high programmed death-ligand 1 (PD-L1) tumor proportion score (95 %). Despite stage IIIB disease with mediastinal lymph node involvement and poor performance status, the patient was treated with chemoradiotherapy (CRT), in which radiotherapy was initiated first and subsequently combined with weekly carboplatin and paclitaxel. Durvalumab consolidation was initiated but discontinued because of radiation pneumonitis requiring corticosteroids. Nevertheless, he achieved durable disease control, exceeding 12 months, with normalization of inflammatory markers and improved performance status. This case suggests that multimodal therapy, including CRT and feasible use of consolidation durvalumab, may provide clinical benefit in G-CSF-producing PSC, for which optimal management remains undefined.