To explore the efficacy and safety of consolidation radiotherapy after Durvalumab immunotherapy combined with chemotherapy in patients with oligometastatic small cell lung cancer (1-5 lesions), so as to provide scientific basis for making the best comprehensive treatment plan in the future.All subjects will receive the following treatments:~Induction period (3 weeks as a cycle, 4 cycles of administration): Durvalumab + carboplatin/cisplatin + etoposide, intravenous drip~Consolidation radiotherapy period: radiotherapy for primary chest lesions + oligometastatic lesions.~Maintenance phase (administered every 4 weeks): Durvalumab intravenous infusion.
In patients with oligometastatic (1-5 lesions) extensive-stage small cell lung cancer, to explore the efficacy and safety of Durvalumab immunotherapy combined with chemotherapy followed by consolidation radiotherapy, to provide scientific basis for the formulation of the best comprehensive treatment plan in the future.