Management of nonbacterial thrombotic endocarditis (NBTE) in advanced non-small cell lung cancer (NSCLC) patients with driver mutation: two case reports

Nonbacterial thrombotic endocarditis (NBTE) is a rare disease that most often found post mortem. Malignant neoplasms, particularly adenocarcinomas, are the common underlying diseases associated with NBTE. In recent years, remarkable advances in targeted therapy have been made, but the effectiveness in treating NBTE in patients with severe lung cancer is poorly reported. Here we present two cases of severe NBTE in patients with stage IV lung adenocarcinoma harboring driver gene mutations, one with EGFR mutation, the other with positive ALK fusion oncogene. Both patients scored 4 according to the Cooperative Oncology Group performance status (ECOG PS) before the initiation of targeted therapies and anticoagulation therapies. Both patients showed significant improvement: the vegetations in their hearts vanished, their ECOG PS score changed from 4 to 3. We also discuss the current understanding of NBTE, including its epidemiology, pathogenesis, clinical presentation, evaluation, diagnosis, and treatment. Our report highlights the necessity of early and timely diagnosis of NBTE and gene classification for NSCLC patients (ECOG PS score ≥3), the importance of concurrent therapy for the cancer and its complications, and further stresses the effectiveness of targeted therapy for NBTE in patients with severe lung cancer harboring driver gene mutations.