Approach to diagnostic evaluation of patients with suspected lung cancer

CT: computed tomography; MRI: magnetic resonance imaging; FDG: F18-fluoro-deoxyglucose; PET: positron emission tomography; EBUS-TBNA: endobronchial ultrasound-transbronchial needle aspiration; EUS-FNA: esophageal ultrasound-fine needle aspiration.

* Choosing among the approaches is influenced by clinician preference, institution and regional practices, and patient presentation. Both approaches are targeted at noninvasively assessing the highest radiologic stage and identifying the optimal biopsy site. The major difference is imaging in patients with small, localized lung cancers for which metastatic likelihood is low; some argue whole-body imaging is not needed in the absence of symptoms and risk factors, whereas others have a low threshold to obtain whole-body FDG PET/CT in this setting. In such patients with early stage disease, the approach is controversial and dependent upon several factors including radiographic stage, lesion size, and amenability of resection. Many experts obtain FDG PET/CT in this group of patients with the expectation that PET/CT will further reduce the risk of unnecessary surgery and guide the optimal biopsy site while others perform FDG PET/CT first in some patients (eg, patients with evidence of hilar node enlargement) or perform tissue biopsy first without FDG PET/CT (eg, patients with small lesions that are amenable to curative resection). By contrast, when extensive disease is likely, most experts typically obtain whole-body imaging with FDG PET/CT and brain imaging in those with a high likelihood of brain metastases. Both options carry risk, specifically the risk of false positives and a small risk from the ionizing radiation exposure when PET/CT is performed and the risk of missing occult disease when PET/CT is not performed. Patient values and preferences may play a key role when making this decision.

¶ The site chosen depends on the result of metastatic imaging (eg, bone, bronchus, lymph nodes). The optimal biopsy sample is typically one that yields enough tissue for microscopic, immunohistologic, and genetic analyses. For example, for patients with suspected stage I/II disease and small FDG PET-negative lymph nodes, surgery for the primary tumor may be pursued, but mediastinal lymph node dissection at the time of resection is still required for accurate staging. For patients with suspected stage I/II disease but with large or FDG PET-positive lymph nodes, EBUS-TBNA (or EUS-FNA or, less commonly, mediastinoscopy) may be obtained. In general, tissue confirmation of metastasis is required, unless there is overwhelming evidence of metastatic disease (eg, multiple bony metastases) or brain metastases are suspected based upon imaging findings.