Objective To investigate the clinical efficacy and safety of anlotinib monotherapy in second-line treatment of extensive stage small cell lung cancer （ES-SCLC） with poor performance status （PS） score after treatment failure with first-line standard regimen. Methods Thirty-three patients with ES-SCLC who failed to receive first-line standard treatment and had poor PS score were selected from Fuyang People's Hospital of Anhui Province from January 2021 to December 2022. All patients were given anrotinib 10 mg orally for second-line treatment， which was taken for 2 weeks and stopped for 1 week， with every 21 days being a cycle period， until the disease progressed or the patient became intolerable. Objective response rate （ORR）， disease control rate （DCR） and adverse reactions were observed. Progression-free survival （PFS） was estimated by Kaplan-Meier method， and the influencing factors of PFS were analyzed by Cox regression model. Results After at least 2 cycles of anlotinib monotherapy， there were no complete remission， 5 cases of partial remission， 17 cases of stable disease， 11 cases of progressive disease. ORR was 15.2% （5/33）， DCR was 66.7% （22/33）. The median PFS was 3.7 months （95%CI： 2.9-4.5 months）. Univariate analysis showed that first-line recurrence time （χ2=4.90， P=0.027）， brain metastases （χ2=12.42， P<0.001）， liver metastases （χ2=11.05， P=0.001） and controlling nutritional status （CONUT） score （χ2=12.43， P<0.001） were the influential factors of PFS in ES-SCLC patients with poor PS score and first-line treatment failure of anlotinib monotherapy. Multivariate analysis showed that brain metastases （HR=3.21， 95%CI： 1.24-8.29， P=0.016）， liver metastases （HR=2.80， 95%CI： 1.03-7.61， P=0.044） and CONUT score （HR=2.72， 95%CI： 1.16-6.38， P=0.021） were independent influencing factors of PFS in ES-SCLC patients with first-line treatment failure of anlotinib monotherapy and poor PS score. Common adverse reactions were fatigue， hypertension， anorexia， etc. Most of the adverse reactions were grade 1-2， with the incidence of grade 3 adverse reactions being 9.1% （3/33）， and no grade 4-5 adverse reactions occurred. Conclusion The clinical efficacy of anlotinib monotherapy in second-line treatment of ES-SCLC with poor PS score and failure of first-line standard regimen is good， and the adverse reactions are controllable.
