Bronchial Fistula: Rare Complication of Treatment with Anlotinib

Background and objective Anlotinib is a newly developed small molecule multiple receptor tyrosine kinase (RTK) inhibitor that was approved for the treatment of patients with lung cancer in China. We aim to report 3 cases of rare complication of anlotinib-bronchial fistula (BF) during the treatment of lung cancer patients and summarize the possible causes. Methods We collected three patients who developed BF due to anlotinib treatment, and conducted a search of Medline and PubMed for medical literature published between 2018 and 2020 using the following search terms: "anlotinib, " "lung cancer, " and "fistula." Results Our literature search produced two case reports (three patients) which, in addition to our three patients. We collated the patients' clinical characteristics including demographic information, cancer type, imaging features, treatment received, risk factors for anlotinib related BF, and treatment-related outcomes. The six patients shared some common characteristics: advanced age, male, concurrent infection symptoms, diabetes mellitus (DM), advanced squamous cell and small cell lung cancers, centrally located tumors, tumor measuring ≥5 cm in longest diameter, and newly formed tumor cavitation after multi-line treatment especially after receiving radiotherapy. Fistula types included broncho-pericardial fistula, broncho-pleural fistula, and esophago-tracheobronchial fistula. Six patients all died within 6 months. Conclusion Although anlotinib is relatively safe, it is still necessary to pay attention to the occurrence of BF, a rare treatment side effect that threatens the quality of life and overall survival of patients. Anlotinib, therefore, requires selective use and close observation of high-risk patients.