Durvalumab as Consolidation for Patients LS-SCLC

"Drug: Durvalumab~Induction Phase: Durvalumab (1500mg D1 IV Q3W) combined with EP \[cisplatin or alternatively Carboplatin (AUC 5-6 D1) and Etoposide (100 mg/m² (BSA) D1-3) once every 3 weeks\] for minimum two cycles prior to thoracic radiotherapy Consolidation Phase: Durvalumab (1500 mg once every 4 weeks) until PD or unacceptable toxicities or for a maximum of 24 months, whichever occurs first.~Drug: Chemotherapy Concomitant chemoradiotherapy consists of further four cycles Etoposide (100 mg/m² D1-3), cisplatin (75 mg/m² D1) /carboplatin (AUC 5-6 D1) q3w~Radiation: Thoracic Radiotherapy Radiotherapy to the primary tumor is recommended to start with the 3rd cycle of EP, which can be delayed appropriately per investigator's decision. 60±6 Gy, 1.8-2 Gy/d or 45±1.5 Gy (1.5 Gy per fraction twice daily, with 4 hours or more between fractions) or other biologically equivalent regimens will be delivered."