Comparison of whole-body 18F-FDG-PET/CT with 18F-FDG-PET/CT limited to skull base to upper abdomen for primary staging of lung cancer - a retrospective explorative analysis.

The gold standard for ruling out distant metastases as part of primary staging in lung cancer is whole-body F-FDG-PET/CT, but this method is resource-intensive. Recent evidence suggests that examining only the thorax and upper abdomen may be sufficient 1 2 3. If a limited F-FDG-PET/CT approach proves effective for proper staging, it could lead to quicker examinations and reduced radiation exposure. This study aimed to determine whether limited F-FDG-PET/CT is adequate for the primary staging of lung cancer.In this study, a retrospective analysis of 161 patients (87 men, 74 women; age range 31-88 y) with recent or suspected lung cancer who had undergone a whole-body F-FDG-PET/CT examination for primary staging at our clinic between 2018 and 2022 was conducted. None of these patients showed evidence of extrathoracic metastases before the F-FDG-PET/CT examination. The images were divided into three regions: "head-neck" (HN), "thorax-upper abdomen" (TUA), and "lower abdomen-hip" (LAH). TNM staging based on the HN plus TUA region was compared with TNM staging based on the whole body.Among the 161 subjects, 7 (4%) showed malignancy-suspect lesions in HN, 110 (68%) in TUA and 7 (4%) had suspected distant metastases in LAH. The TNM staging based on HN plus TUA corresponded to TNM staging based on the whole body in 161 (100%) examinations. This finding aligns with similar results in previous literature. F-FDG-PET/CT limited to HN and TUA yielded accurate staging in all cases. Adopting this method could facilitate the examination and correct staging of more individuals, reducing exam waiting times and physician reporting time and minimising radiation exposure.