What is the role of positron emission tomography (PET) scanning in the workup of non–small cell lung cancer (NSCLC)?

Updated: Jul 15, 2021
  • Author: Winston W Tan, MD, FACP; Chief Editor: Nagla Abdel Karim, MD, PhD  more...
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Answer

PET scanning (see the image below) using fluoro-18–2-deoxyglucose (FDG) has proven to be an excellent modality for evaluating solitary pulmonary nodules and has been approved by the US Food and Drug Administration (FDA) for this indication. The average sensitivity and specificity of FDG-PET scanning for detecting a malignancy was reported to be 0.97 and 0.78, respectively. [49] However, a meta-analysis by Deppen and colleagues found that FDG-PET had lower specificity for diagnosing malignancies in areas with endemic infectious lung disease compared with areas with nonendemic disease. [50]

Lung cancer, small cell. Coronal positron emission Lung cancer, small cell. Coronal positron emission tomogram shows abnormal areas of increased metabolic activity in the left hilar and left adrenal regions consistent with a hilar tumor with left adrenal metastasis.

Studies also suggest that PET scanning is useful for searching for systemic spread if other diagnostic modalities cannot clarify an abnormality that may change the treatment of the patient’s condition. However, false-positive and false-negative results occur.

Additional data have emerged that underscore the importance of PET scanning in patients with NSCLC. PET scans appear to be more sensitive, specific, and accurate than CT scans for staging mediastinal disease. Whereas radiographs and CT scans show images of structures, PET scans reveal the nature of the area under study. PET scans often detect abnormalities not demonstrated on CT scans.

Published reports suggest that staging of NSCLC may be influenced by PET scan results in up to 60% of the cases and that as many as 25% of cases may be upstaged after PET scanning.

Caution is required when interpreting the results of PET scans in patients who may be denied potentially curative surgical resection based on PET results.

Go to Imaging in Non-Small Cell Lung Cancer for complete information on this topic.


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