This multicenter, prospective study aims to investigate the efficacy and safety of low-dose radiotherapy (15Gy/1.5 Gy bid × 10 fractions) combined with 4-6 cycles of systemic chemotherapy plus anti-PD-L1 antibody, followed by anti-PD-L1 antibody maintenance for up to two years, in participants with extensive-stage small cell lung cancer (ES-SCLC).
Additionally, dynamic monitoring using next-generation sequencing (NGS) technology will be performed to assess ctDNA levels, genetic information, and mutation abundance at the following time points: before and after low-dose radiotherapy, after 4-6 cycles of chemotherapy plus anti-PD-L1 antibody (chemotherapy-immunotherapy), and before the initiation of anti-PD-L1 maintenance therapy. This approach aims to guide efficacy and prognosis prediction, as well as to identify potential biomarkers associated with treatment response.
Age ≥18 years and ≤75 years.
Histologically or cytologically confirmed extensive-stage small cell lung cancer (SCLC).
No prior systemic anti-tumor therapy.
ECOG performance status 0-2 and life expectancy ≥12 weeks.
Presence of interstitial pneumonia or infectious fever prior to treatment.
Comorbid autoimmune diseases or long-term oral corticosteroid use (including those who received oral corticosteroids within 14 days prior to treatment).
Prior history of thoracic radiotherapy or thoracic surgery.
Presence of Grade ≥3 hematologic toxicity or hepatic/renal impairment.