Immunochemotherapy for small cell lung cancer with paraneoplastic Cushing syndrome: A case report and literature review

Rationale: Paraneoplastic Cushing syndrome (PCS) is an adverse prognostic factor for small cell lung cancer (SCLC) patients. Retrospective studies have shown that the median survival of SCLC complicated with PCS was <7 months. No immunochemotherapy has been recorded in the treatment of SCLC with PCS. Previous preclinical and clinical studies have suggested glucocorticoid exposure may affect the efficacy of immunotherapy. Patient concerns and diagnosis: A 60-year-old man was admitted for his irritability and palpitation. During hospitalization, a chest computed tomography scan revealed a lobar soft tissue shadow in his left lower lung. He was diagnosed as limited-stage SCLC (T2bN1M0 IIB) with PCS, ultimately. Interventions and outcome: The patient received 4 courses of immunochemotherapy of etoposide plus platinum with durvalumab and 1 adjuvant radiotherapy alone in 2022 for his limited-stage SCLC, and underwent 5 courses of immunochemotherapy of irinotecan plus platinum with serplulimab in 2023 for his extensive-stage SCLC. The patient achieved a long survival of 20 months. Lessons: The case preliminarily demonstrated the efficacy of immunochemotherapy in the management of SCLC complicated with PCS. The regime of serplulimab with irinotecan-based chemotherapy also indicated its satisfactory efficacy as a second-line treatment for extensive-stage SCLC. Furthermore, the case has highlighted that the management of hypercortisolism, the improvement of myelosuppression, and the prophylaxis against infection were 3 hinges for the continuation of immunochemotherapy and the holistic management of SCLC with PCS.