American Board of Internal Medicine (ABIM) Certification Practice Exam

In initial evaluation of metastatic nonsquamous non-small cell lung cancer, which mutation should be tested for?

1. PIK3CA mutation

2. EGFR mutation

3. BRCA mutation

4. KRAS mutation

The correct answer is: EGFR mutation

In the initial evaluation of metastatic nonsquamous non-small cell lung cancer (NSCLC), testing for an EGFR mutation is crucial because the presence of this mutation significantly influences treatment decisions and patient outcomes. EGFR mutations are found in a substantial subset of patients with nonsquamous NSCLC and are particularly associated with a response to targeted therapies such as tyrosine kinase inhibitors (TKIs) like erlotinib, gefitinib, and afatinib. Identifying the presence of EGFR mutations allows clinicians to tailor treatment more effectively, potentially leading to improved survival rates and better quality of life for patients. The guidelines recommend routine testing for EGFR mutations at diagnosis in patients with advanced nonsquamous NSCLC, establishing this assessment as a standard practice in the management of the disease. In contrast, while other mutations such as KRAS and BRCA are relevant in specific contexts or other types of cancer, they do not have the same impact on first-line treatment decisions for metastatic nonsquamous NSCLC as EGFR mutations do. PIK3CA mutations, although important in some cancer types, lack the direct correlation with targeted therapy in NSCLC that EGFR mutations hold. Therefore, focusing on EGFR mutations in the initial evaluation is