A Retrospective Real-World Study on the Efficacy and Safety of Anlotinib Hydrochloride Combined With Immunotherapy Maintenance Therapy Following Standard Chemoimmunotherapy for ES-SCLC (ALTER-L059)

Inclusion Criteria: 1. Male or female patients aged 18 years or older; 2. Histologically or cytologically confirmed extensive-stage small cell lung cancer (ES-SCLC) (per the Veterans Administration Lung Study Group \[VALG\] staging criteria); 3. Patients who previously received chemotherapy for limited-stage SCLC must have undergone curative-intent therapy (e.g., chemotherapy, radiotherapy, or chemoradiotherapy) and have a treatment-free interval of at least 6 months from the end of prior therapy (last chemotherapy cycle or radiotherapy) to the diagnosis of ES-SCLC; 4. At least one measurable target lesion (per RECIST version 1.1 criteria); 5. No disease progression after receiving 4-6 cycles of first-line chemoimmunotherapy induction therapy for ES-SCLC; 6. ECOG performance status: 0-2; 7. Life expectancy ≥3 months. Exclusion Criteria: 1. Patients with limited-stage SCLC who previously received chemotherapy and underwent curative-intent therapy (e.g., chemotherapy, radiotherapy, or chemoradiotherapy) but experienced disease recurrence within 6 months after completion of prior therapy; 2. Patients with limited-stage SCLC who previously received immunotherapy agents (e.g., PD-1/PD-L1 inhibitors) or anti-angiogenic agents (e.g., Anlotinib, Apatinib, Bevacizumab); 3. Patients with extensive-stage small cell lung cancer (ES-SCLC) who developed disease progression during induction therapy with a standard chemoimmunotherapy regimen; 4. Active autoimmune diseases requiring systemic therapy (e.g., disease-modifying agents, corticosteroids, or immunosuppressants) within 2 years prior to the first dose; 5. Patients with coagulation dysfunction, defined as an International Normalized Ratio (INR) \>1.5 or activated partial thromboplastin time (APTT) \>1.5 × upper limit of normal (ULN), and/or those with a bleeding tendency; 6. Patients deemed by the inves.